O&M Best Practices for Small-Scale PV Systems Learner Guide

O&M Best Practices for Small-Scale PV Systems Learner Guide
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DOE FEMP First Thursday Seminar
Learner Guide
O&M Best Practices for Small-Scale PV Systems
Course Description
This course focuses on maintenance of existing PV systems and the ability to increase
predictability of operations, analyzing expected versus actual output, and reducing down time.
The topics covered will help energy managers plan for critical PV O&M activities; understand
the necessary qualifications for service personnel; ensure proper safety procedures during
diagnostics, isolation, and repair; and realize the economic benefits of a well-maintained
PV array.
Learning Objectives for O&M Best Practices for
Small-Scale PV Systems:
Assess critical items to manage assets and plan for a complete PV O&M program
Identify preventative maintenance practices necessary to perform on a regular basis
Identify and diagnose corrective maintenance and repair of failed PV components
Determine and follow proven safety procedures when repairing equipment
Understand the professional qualifications of personnel required to perform work on
PV equipment
Instructor Biographies
Brad Gustafson, Federal Energy M anagem ent Program
Brad Gustafson is supervisor for the U.S. Department of Energy (DOE) Federal Energy
Management Program (FEMP). In 1995, Gustafson began supporting federal energy initiatives
as an employee of Lawrence Berkeley National Laboratory. While at FEMP, he has acted
energy savings performance contract project facilitator, technology transfer program manager,
utility program manager, federal fleet management program manager. In 2002, he served as
Senate legislative advisor for Senator Lincoln Chafee. Before joining FEMP, Gustafson was
program manager for the Pacific Gas and Electric (PG&E) HVAC program at the PG&E Energy
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Andy W alker, Principal Engineer, National Renewable Energy Laboratory
Andy Walker, Ph.D., is principal engineer at the National Renewable Energy Laboratory. He
conducts engineering and economic analysis of energy efficiency and renewable energy
projects for the Federal Energy Management Program and other non-governmental clients and
specializes in assisting various organizations to plan renewable energy projects at multiple
sites. Walker also teaches energy classes. He is the author of more than 28 book chapters,
journal articles, and conference papers and has been recognized with 11 awards from
professional associations and government agencies. He holds Bachelor’s of Science, Master’s
of Science, and Doctorate degrees in mechanical engineering from Colorado State University
and is a registered professional engineer in Colorado.
Kris Sutton, Solar Energy International Instructor-Trainer,
Solar Energy International
Kris Sutton has worked full-time in the PV industry since 1999 and is a NABCEP Certified
Solar PV Installer. He regularly teaches technical trainings on the design and installation of
photovoltaic systems - both commercial and residential, with a heavy emphasis on safety.
He has been employed as an installer, project manager, and owned his own solar consulting
business working with utilities, architects, engineers, general contractors, building
departments, and homeowners through all phases of the PV design and installation process.
Sutton serves as Solar Energy International’s Instructor-Trainer and helps develop curriculum.
Joe Villacci, IREC Certified M aster Trainer/PV,
Solar Energy International
Joe Villacci specializes in system design, installation methods, and performance verification of
solar electric systems. He works as a technical trainer and curriculum developer for Solar
Energy International (SEI) and is responsible in part for development of SEI's PV training
facility. Joe also provides design review, commissioning, and troubleshooting services. Joe is
an IREC Certified Master Trainer/PV and NABCEP certified PV installation professional.
Karin Christensen, Chief, Facility Operations,
National Conservation Training Center, W V
John Seals, Facility Conditions Specialist, National Fish Hatchery
M ike M cM enam in, Facility M anager, John Heinz National W ildlife Refuge
FTS 27 Course Transcript
Course Introduction
Hello. I’m Brad Gustafson, FEMP’s program manager for Customer Services. I’m a professional
engineer, a certified energy manager, and a LEED accredited professional, and I’ll be your
instructor for this First Thursday Seminar: O&M Best Practices for Small-Scale Photovoltaic
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For many years, the federal government has led the way on installing PV systems. Now, with
many PV systems in place, it is increasingly important to focus attention on operating and
maintaining these systems for optimum power generation.
This training will focus on small-scale PV systems – 100 kW or less. But it covers many best
practices that apply to systems of all sizes.
Our subject matter experts for this seminar are Andy Walker from the National Renewable
Energy Laboratory, and Joe Villacci from Solar Energy International. Now, here’s a brief tour of
the site and how it works.
The left video box presents the main seminar content. The right video box presents supporting
information. From time to time, we’ll ask for your opinion and show the results here.
Use the zoom bar to change the video window size. Click on the lower right box for links to
additional resources and documents to download.
Click on the lower left box for links to training resources. Links will open a new browser window.
Click out of the window to return to the main screen.
Use the center box to submit questions or comments. FEMP will compile the questions and
make responses available after the broadcast.
And, at the end of this seminar, please click on the link to complete a short quiz and course
evaluation to receive continuing education credits. The seminar will also be archived for future
on-demand viewing.
Here are the learning objectives for today’s seminar:
Assess critical items to manage assets and plan for a complete PV O&M program
Identify preventative maintenance practices necessary to perform on a regular basis
Identify and diagnose corrective maintenance and repair of failed PV components
Determine and follow proven safety procedures when repairing equipment
Understand the professional qualifications of personnel required to perform work on PV
We hope this seminar will help you keep your PV system running at full capacity. Now let’s get
Module 1: O&M Benefits
PV systems are very reliable. With few moving parts, they can last 25 years or longer. But
over time, a burnt fuse here or a cracked module there can reduce energy delivery capacity to
80 or 90% of what the system is capable of. That’s why a sound PV O&M program is
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It can benefit your agency in three important ways:
First: it improves performance, to increase the amount of power delivered
at any given time;
Second: it reduces downtime, to maximize system availability and annual energy
delivery; and
Third: it increases system lifetime, to 25 years or longer.
However, some critical questions to ask right up front are:
“Who will maintain my PV system?”
“What level of O&M is needed to ensure performance without wasting money on unnecessary measures?”
“How much should I budget for O&M?”
“How can I find funding to make major repairs if necessary?”
The answers to these questions depend on your agency, your site, and your circumstances.
However, there are three good options:
One: use trained and qualified on-site maintenance staff;
Two: contract with the company that installed the system; or
Three: contract with a third-party maintenance provider.
The upside of a maintenance contract is that qualified experts come to the site, check the
system, and report findings on a regular basis. If problems are found, they are corrected
straight away, often under warranty. The downside is that a maintenance contract adds cost.
Ground M ounted at Fish and W ildlife Service National Conservation
Training Center
Now that we have a good understanding of the various options, let’s visit a ground-mounted
array at the U. S. Department of Interior’s U.S. Fish & Wildlife Service at the National
Conservation Training Center, in Shepherdstown, WV.
Benefits of Ground M ounted Array
Here we are at a 47kw photovoltaic array that is powering a wastewater treatment facility
for the U.S. Fish & Wildlife Service at the National Conservation Training Center, in
Shepherdstown, WV.
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This is a ground mounted photovoltaic system – specifically a fixed mounted rack. It does not
have a tracking system and is not tilt adjustable. It is designed to be fixed in place with an
average year-round tilt.
Ground mounts like this sets up a little high off the ground which is a good design for a site like
this. By examining the native vegetation and mounting the modules high enough, you may not
need to mow or deal with the vegetation growth under the array.
The other benefit of an elevated fixed mount is the space it creates for snow to fall mitigating
build up that could interfere with system production.
Ground mounted arrays also provide ease of access for cleaning and maintenance tasks and
do not require large roof mounts.
Audience Question:
Here’s question from our audience:
I understand the difference between O&M for small and large systems, but what about ground
mounted vs. roof mounted systems, or tracking vs. non-tracking systems?
Ground-m ounted vs. roof-m ounted; tracking vs. non -tracking
When it comes to operations and maintenance there are a few variables based on where is the
array. For starters let’s talk about roof mounted versus ground mounted.
Ground mounted has great benefits because it’s easy to access. You can drive a truck right up
to it, you can park up next to it for washing modules, maintenance – any of that sort of stuff
tends to be easier on a ground-mounted array.
When its roof mounted then you get into how high is the roof, what’s the pitch on the roof, and
can I get up there easily. You get into a much higher danger level once you’re on to roofmounted arrays. So repair work on roof arrays can be more dangerous and sometimes more
costly than a ground mounted array.
Now when we start to look at ground mounts we maybe put that into two categories – either a
fixed ground mount, something that’s fixed in position versus a tracking ground mount
something that’s going to move or track. There is a much higher probability that a tracking
ground mount is going to fail more often than a fixed ground mount because of the moving
mechanism and the control systems that are required to move and track that array. So there’s
definitely going to be some maintenance issues with tracking systems that are going to differ
significantly from a fixed ground mount.
Yes in addition to the roof mounted and ground mounted issues that Kris just described,
there’s a third type which is covered parking or shade structures. Those have their own
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operation and maintenance issues. They include things like ice and snow falling off the
structure and where that falls and maintenance of those systems up above the ground entails
their own challenges.
So each of these types has advantages and disadvantages – it’s not easy to say that one is
better than the other. And your selection might depend more on the needs and conditions at
your site rather than which one costs less to maintain.
In addition to the roof access and fall protection issues that Kris brought up on roof top
systems, you know just having people work on the roof can cause damage to the roof itself. So
that’s another issue to think about on rooftop systems.
In the early years we had a lot of trouble with tracking systems. A lot of times when we would
visit a system after it had been installed a lot of the trackers would be out of position. But
nowadays the reliability and the cost of the tracking systems has come down to the point
where a lot of times we do recommend them and if you put out an RFP for a system probably
all the proposals for a ground mounted system would come back proposing tracking. So the
maintenance of those hydraulic systems or electrical systems which cause those collectors to
track the sun from east to west across the sky would be another item on your maintenance todo list.
Safety Issues
Now, let’s look at one of the most important areas of your O&M program: safety! - including
personal protective equipment, arc flash protection, lock-out/tag-out procedures, and rooftop
Arc-Flash Protection and Personal Protective Equipm ent (PPE)
One of the most dangerous parts of a solar electric system is the electricity itself. There are a
lot of concerns when working around electricity. One concern is shock hazard and the other is
an arc flash or arc blast which is the result of an explosion of a fault in the system. This could
be caused by something I did as an electrician or it could be a piece of equipment that fails.
Either way, if an arc flash or arc blast happens when I’m standing in front of it I could be
injured, burned, or killed.
So we are going to take a look at a few of the things that a technician needs in order to go into
an electrical system and work safely. When talking about shock safety, the primary protection
from shock is an electrically insulated glove. The primary protection in the gloves is the
insulator. On the cuff of the insulator there is information about the gloves size and
classification. For example, a “Class 0” glove means it is 1,000 volt AC rated which also means
1,500 volt DC rated.
There is then a leather glove that is put over the top of the insulator. The leather is a physical
protection from nicks and punctures that could be caused by metal shavings, metal splinters anything that could puncture through the rubber part of the glove.
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The third part is a glove liner. You might think this third glove would be uncomfortably hot, but
in reality the liner keeps the rubber off of your hands keeping your hands a little cooer. It also
wicks some of the sweat off your hands. So your hands are usually better off with the liner
than without it.
Though it might look bulky, a lot of times you only need to use the gloves to make a few tests
so they don’t have to be worn very often or very long in a project. I have enough dexterity to
grab my leads, make my tests and get out of there safely.
It is important to make sure that the gloves are kept in good repair and nothing has damaged
the gloves. The things to be most concerned with are scrapes, cuts or punctures in the
insulation. It is easy for metal slivers or shavings to puncture through the insulation. That little
sliver of metal that you can’t see could be the difference between getting shocked and not
getting shocked.
When it comes to arc flashes and arc blasts, the explosive potential of a service, we need to
understand what to wear – does it have the ability to catch fire? So we wear flame-resistant
clothing. In selecting the things you wear consider the exposure category.
Exposure categories are determined by engineers who analyze the potential fault current for
the circuit. That is, how much current is available if I were to short across an electrical device –
what’s behind it? How big is the transformer? How big is the utility service supply? Is it a DC
side or an AC side?
On the DC side which tend to be more shock hazards and on the AC side there tend to be
flash or blast hazard potential because of the utility grid versus the solar array. So an engineer
needs to do a shock hazard or blast analysis to tell the technician the right suit and category
What I’m wearing right now is flame resistant clothing with a flame resistant or arc flash suit.
This will give a certain amount of resistance to fire if something were to come outside of the
The other parts to this system a hood which is worn to help protect against an explosion that
comes out and goes around my face shield. If I’m wearing this I’m also going to be wearing an
arc flash face shield that will help protect my face in case something comes after me. It’s a
multi-step system here.
This is not a normal face shield that you go by at a store. This is designed specifically for an
electrical arc. If you have an electrical arc, there is going to be a very intense UV exposure from
the arc, and the face shield will help prevent the UV from burning your eyes, burning your
retina, and burning your face. So this mask has a blast safety value and an energy impact
safety value as well as the UV protection. So this will go on top of your hood, your safety
glasses, and then your arc flash face shield above that.
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So there are a lot of things we need to understand about the safety side of working around
electrical components. The major part of that is training. Training is number one. If I don’t have
the proper training, I’m not authorized to go into electrical equipment to make tests and check
up on things. I’m not allowed to move the lid of an electrical device unless I have the proper
training and the proper personal protective equipment.
Lockout/tagout is a method to isolate sources of power to a piece of equipment that needs to
be serviced or maintained. It entails the ability to shut off and lock in the off position the source
of supply of energy, in this case electricity.
The basic components of lockout/tagout are the locking devices, a padlock, and an identifying
method to show that something is intentionally locked off for a reason.
First we will look at the AC/DC switch. Disconnect switches are very easy to lock off. When
you shut the switch off and the switch handle is in the off position, there is a hole in the switch
handle through which you can easily apply a lock. Then I have controlled the source of energy
into my inverter.
While disconnects are easy to lock off, other devices can be more challenging and we’ll look at
a few of those next. When we get into unique switches like this inverter that has an integrated
DC disconnect switch below it, how to lock it off is less intuitive. In this case, I’ll shut off the
switch and when it is in the off position there is a hole in the side where I can place my lock
and thus lock off the DC connect.
If we look at this combiner box which is called a disconnecting combiner – it has the
disconnect integrated with the combiner box. When I turn the disconnect into the off position I
can reach behind the disconnect handle and push out the little red tab. I then have ability to
lock the DC disconnect in the off position.
Now we are going to look at how to lock off solar modules. The module itself, or the string of
modules, is probably the most challenging to lock off because it was never meant to be locked
in the off position. It is more challenging to lock off my homerun wiring.
I cannot open the connectors unless I have verified that there is no current flowing in them.
That is step number one. I never will walk up to an array and unplug it. I need to go shut off the
load break rated disconnect switch that is mounted, in this case, near the inverter. I turned
that off and current should have stopped flowing through these circuits. We need to verify that
the current has stopped flowing.
So I’m going to grab my DC clamp-on amp meter. I’m going to turn it on to “Amps”, set if for
DC, zero out my meter, make sure everything is correct, and then I’m going to put my clampon meter around the wire and verify that there is no current in those conductors.
By shutting off the load break rated switch first, I protect myself and my conductors from
damage. The problem could be that if there was a fault in the array, some sort of failure, you
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could have a circulating current in the system in the case of a ground fault or some sort of a
miss-wiring. So even though I shut if off back there, I want to verify here that there is no current
flowing and everything is safe.
When it comes to locking off breakers, there are a couple of ways. If I want to lock off the AC
interconnection back to the converter I turn off the breaker. I shut the lid and use the lid
locking point for my lock. So one way is to shut and lock the lid but that limits access to the
whole panel.
The other method is to lock single breakers in the off position using clamping devices. One
device covers the breaker and is tightened and locked into place with a padlock. Another
device has a setscrew to tighten the clamp around the breaker and is then locked and tagged
in place.
One problem with the smaller devices, locks and tags, is that they create bulk and it is hard to
shut the cabinet lid. So for outdoor enclosures you may need to turn off the breaker and lock
the whole cabinet if it needs to be left in that position for a long time.
There is a lot of training required and a lot of systems that get put into place for managing
lockout/tagout procedures. The guideline is set through documentation and training in
conjunction with things like NFPA 70E as methods for proper lockout/tagout procedures.
What you need to look at is, does your company or your organization have a specific, written,
lockout/tagout procedure or policy?
Rooftop Safety
Here we are looking at an overview of safety procedures in rooftop access. We need to make
sure that we are keeping our contractors or our employees as safe as possible by preparing
them to deal with potential fall risks that are associated with rooftops.
There are two fundamental ways to manage fall safety. One is a guardrail or barrier or parapet
wall around a flat roof and the other is a personal fall arrest system which is a combination of
harnesses, lanyards, ropes, rope grab and anchorage to the roof.
One of the primary components of a fall arrest system is the harness. This harness has a waist
and leg attachments and over the shoulder attachments – it’s a full enclosure harness. When
we are dealing with a fall arrest situation, moving around freely on roofs, we need to be
attached to the backside of the harness. There is a d-ring attachment off the back of the
harness and in this case we are using a shock-absorbing lanyard. The lanyard gives an
attachment point to the rope, and a shock absorber in case someone were to fall on that
lanyard and have an impact.
O&M M anuals
Make sure your PV installer provides a full set of “as built” construction drawings from the
original build-out, and keep them on hand. These drawings will show what was really built,
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rather than what was planned. It’s easier to troubleshoot and diagnose problems from “as
built” drawings, especially if you were not involved with the system from the beginning.
When troubleshooting you will need to know the manufacturer’s startup and shutdown
procedures for the inverter.
Equipment manuals also list error codes that display when the system has a problem.
Maintenance staff must be able to easily find and interpret these error codes as a first step in
understanding a problem.
A good way to do this is to gather up all the supporting documentation for the installed
equipment and organize it into an O&M binder. Include standard calculations in the binder to
assist maintenance staff in predicting how the system should operate on a given day,
considering basic changes in sunlight intensity and temperature. This will provide a quick
check to monitor performance under changing conditions
You can also post simple flow charts and short lists of the main steps to maintain equipment -like the inverter. Post these right next to the equipment.
When installation is complete, the installer is often required to provide O&M training. A good
practice is to videotape this training as a refresher and to train new staff.
If you can’t diagnose the problem from the O&M manuals or as built drawings, call the
manufacturer. Manufacturers usually have good technicians to talk you through procedures
and assist you in diagnosing a problem.
M anufacturer W arranties, Guarantees, Perform ance M easures
When a PV system is constructed, the installer will provide the overall warranty on the system.
This warranty should cover parts and labor for the installation and should also carry the
manufacturers’ warranties through to the customer. For example, if the inverter fails, the
installer under warranty would replace that inverter under the manufacturer’s warranty.
Determine specifically what the installation warranty covers and for how long. It may be
possible to individualize or customize coverage when negotiating the installation. Always
check warranty “fine print” to see what is actually guaranteed.
The warranty might cover availability – that is, that the system components are operational. Or,
it might cover the efficiency performance of each component. Or, it might guarantee a specific
amount energy delivery.
System component extended warranties may be available but can be expensive, so you will
need to value those against the cost.
Also, make sure warranties for component parts are specified for the condition of operation.
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For example, many PV modules are not warrantied for marine conditions – located near a
The main components of a PV system – the modules and inverter – usually have separate
manufacturer warranties.
Module warranties are often based on array performance and have 20- or 25-year diminishing
power schedules that stipulate power loss over time.
Five-year inverter warranties were once common, but now average about 10 years, depending
on the manufacturer.
Even the best of companies will resist or challenge warranty claims, so expect staff time and
effort to enforce them should a problem arise.
Make sure the actions of the system installer and site technicians do not void the modules’
warranty. While the array is designed for a specific weight load, this weight is distributed for
environmental factors like snow. If a crew walks across the array to reach a spot, this could
cause damage and void the warranty. Vandalism will void the warranty. Physical damage can
occur, such as an object shattering the glass.
When it comes to inverters maintenance staff, must follow proper procedures. If there is a
wiring error, for example, this could cause damage from over voltage and void the warranty.
Holes drilled in the wrong locations can cause moisture damage.
Natural causes can include lightning, hail storms beyond the warranty specifications, and other
uncontrollable events. Biological infestation can include animal nests and other debris that
compromise performance.
When replacing a part under warranty, call the manufacturer first. Follow the proper
troubleshooting process and receive authorization to return the part. The contractor will usually
assist you, if the system warranty is still in effect. This will help cover the cost of both parts
and labor.
Audience Question:
Now it’s time to take another question from our audience:
Product and system warranties and guarantees are great, but what about the qualifications of
the service providers who operate and maintain the system?
Qualifications of Service Providers
So when we start thinking about working on or around a solar array we need to understand the
site personnel and what the risks and safety issues are when we start dealing with this sort of
electrical system.
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So what we need to think about is what is the task that is going to be done? And it can be
simple as far as someone who walks by the array or does maybe mowing or some sort of basic
activity around the array, pulling weeds, that sort of thing. That’s kind of one level. And then as
we go deeper into it we start going, “Well who’s qualified to actually do any troubleshooting,
any diagnostics, any testing?”- Those sorts of things.
There’s a lot of levels of kind of access control that then will have to be addressed by what the
training for that given personnel is and whether, you know, they are a technician or not,
whether they’ve been trained in solar or not. So those things have to be assessed by either the
site supervisor, or the company, or whoever is in charge of that array.
One of the things that we need to understand when dealing with solar arrays is that one, solar
is an electrical device and an electrical device can be very hazardous and potentially lethal
depending on contact and exposure. So, am I doing a task that is going to put me in direct
contact with anything electrical versus walking around and pulling weeds versus going into an
When we start looking at troubleshooting and doing that sort of testing and diagnostics work,
the exposure to electrical is pretty high. You’re going to have to be opening enclosures, going
in performing tests and when we go to perform those tests we need to know all the safety
precautions. A lot of this comes back to training.
It’s going to be the site supervisor’s job to determine who is allowed to and not allowed to
work on or around the solar arrays and determine that based on what your onsite training is
with your crews. At what point do I let maintenance staff work on the arrays versus go out and
hire a contractor to come in and deal with those sorts of things?
When we start looking at that we need to understand that solar is different than most other
electrical devices. And I’ve had many occurrences where you can have a great electrician, the
best electrician in the area, and if they don’t know the solar parts specifically, they’re not going
to be well suited to do proper troubleshooting and diagnostics because solar is kind of a niche
side of the electrical industry so training is going to be required whether it’s your site staff who
– maybe you have onsite electricians who do all the electrical work on site. In order for them to
work on the solar array they should have custom, special training about solar specifically on
how those things work so they can work safely.
If you are hiring in a contractor you really want to look at hiring in a local solar contractor or a
regional solar contractor who works on these systems all the time and not just any electrician
out there who doesn’t have specific training.
The same goes with engineers when we start dealing with designing systems. You can have a
great engineer who if they’ve never worked on designing solar specifically, it’s unique enough
system that it does require a very specific amount of training.
So the sorts of things we are trying to prevent is shocks, falls from roofs and things like arc
flash and arc blast and just all the dangers that are involved with working around any solar
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arrays. So be cautious about who you allow to do any sort of installation or troubleshooting
work out there in the field.
Yes, you know the PV panels are energized whenever the sun is shining so before you open a
cabinet or take the cover off of a piece of equipment you’d have to be a licensed electrician –
licensed within the jurisdiction that you’re performing the work.
And as Kris pointed out, an electrical license isn’t’ enough. You’re required to have some
special training in photovoltaic systems which are unique and different from the types of
electrical systems that you’d find in a building or facility.
One of the trainings and certifications that you might require, or have as an optional selection
criteria in selecting a service provider, would be a NABCEP certification which stands for North
American Board of Certified Energy Professionals. That will guarantee that the individual has
some specific training related to photovoltaic systems. So certainly when working on the
electrical parts of the system and especially the live circuits which can’t be turned off, you’d
need the specialized training, specialized certification, and personal protective equipment for
things such as arc flash protection that Kris mentioned.
But even for the non-electrical parts of the system there’s probably some qualification or some
training that’s required of almost everybody involved in this system. For example, the people
that are applying herbicides to control vegetation or pesticides to control insects, they might
also require some special training and certification in the handling of those hazardous
Poll #1
Now we would like to hear from you. Please take a moment to answer the questions on your
Thank you. Here are the results. Now, let’s move into the next part of our seminar, which
deals preventative maintenance.
MODULE 2: Routine Preventative Maintenance
In the next part of our seminar, we will cover some fundamental practices for routine scheduled
preventative maintenance. Topics will include how to factor in environmental conditions at
your site, cleaning modules, and inverter inspections. Environmental conditions that have been
found to affect O&M include: humidity, high temperatures, heavy snowfall, pollen in forested
areas, bird populations, marine environments, high wind areas, diesel soot, industrial
emissions, or dust caused by agriculture or a construction site nearby.
Vegetation Rem oval
When looking at arrays and solar equipment, one of the things that happens on ground mounts
is that the equipment gets growth underneath it whether it’s grasses or weeds. Plants and
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grasses growing underneath the array are not a problem. The problem starts when they start
growing up on to the modules through the array, making shadows on the modules, or if growth
starts to go into the equipment.
So in this case they are in the process of cleaning up and removing all of this vegetation. You
want to kill off the vegetation at the base and remove it so it does not grow through the
equipment. Certain plants and critters have a way of finding their way in to this type of
equipment and we need to protect it accordingly.
Environm ental Siting Conditions
So here we are with the Fish and Wildlife Service National Conservation Training Center and
here around and behind us is our photovoltaic arrays.
We are in the operations and maintenance part of it. It was important for us to consider the
natural resource, including the habitat and natural wildlife that is in this area. So we chose this
grassy field that was near our main distribution.
Its not because we are mandated, it’s because it’s the right thing to do, and we benefit from
the ease of maintenance. For example we accentuated the arrays so they are off the ground so
the base of the arrays come to about the natural height of the grasslands around it.
We only mow once a year, which minimizes the times we have to mow. We choose august for
the month to do that because at that point the ground nesting birds have left the area and also
other wild life like white tail deer and foxes, their young have matured and moved on as well.
The other thing is that August is still early enough in the season for the grasslands to grow a
small stand before the fall and winter set in, so other wildlife such as turtles can enjoy and
thrive in the environment.
The other thing I want to point out too is that we only spot spray for exotic invasive around the
area, instead of broadcasting for the whole area or mowing it all down to take care of thistles
or other exotic vines that may grow up the poles.
Routine Cleaning
When it comes to cleaning modules, the first question is, “Do I need to clean them at all?” A lot
of studies are showing that it’s often not worth the price and the time to clean the modules.
It comes down to, “How steep is the array?” The flatter the array is the dirtier it’s going to get
and the more it will hold dirt and the more often it will need cleaning. The steeper the array
gets, especially past 15 degrees or so the easier rain will wash the debris off and it will not
need additional cleaning.
The other question is, “How much rain do I get?” If there is a lot of rain in your area it is less
likely that the array will need cleaning. The things to look for are dirt, dust, pollen, bird
excrement, sap – regional issues.
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If I am going to clean the module, the first thing to look at is the presence of ground faults.
Check the inverter to make sure there are no faults or errors before approaching the array for
If it’s just dry dirt and dust I can use a dry brush the modules off. If I need more than that I can
use water. Use a hose with a sprayer, not a pressure washer. Use water only, no soap or
chemicals – in fact, using them could void the warranty.
Spray water on the modules either first thing in the morning or late in the day. Do not spray the
modules with cold water when the arrays or hot or in the heat of the day. Try to wash modules
either in the mornings or the evenings.
If there is dirt, grime or bird excrement that is baked on the module, a sponge or soft bristle
broom or brush can be used to agitate the dirt to get it moving. Usually I spray down the
module with water. Use a push broom to scrub the dirt, and then rinse if off. That’s about all
that is needed.
I don’t want to scrape the modules with a hard metal scraper, scratch the glass. I don’t need
to use a squeegee – a lot of times just water, use of a push broom, and a water rinse is
Be careful up there!
Inverter Power: Expected vs. Actual
We need to confirm that your system is producing the right amount of power. The nameplate
rating of our system is 8,400 watts at standard test conditions. In the real world you are not
always going to see standard test conditions. So we have three factors to consider. First is our
system derate factor, second our irradiance factor, and third our temperature factor.
To calculate our system derate factor for this array we are going to look at soiling and we’re
going to estimate a 1 percent loss for the dust on the array. We’re also going to consider a 1
percent voltage drop in our system up to our inverter. And we’ve looked up the CEC rated
efficiency of the unit and found it to be 96 percent efficient.
When you multiply these variables together we find that our system derate factor is .94.
Next we are going to look at our irradiance factor. To calculate or measure the irradiance you
need to use a pyranometer. Let’s walk around to the array and take a measurement.
To measure the irradiance, make sure that the calibrated cell of the irradiance meter is in the
same plane as the array. We are getting 800 watts per meter square. So let’s put that into our
Our measured irradiance was 800 watts per meter square and our standard test condition
irradiance is 1,000 watts per meter square. That gives us a .8 irradiance factor.
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We are going to use an infrared thermometer to test the cell temperature of our module.
The back sheet of the module is the most accurate place to do this. We are reading
55 degrees Celsius.
Now that we know the measured cell temperature of our module, the other thing we need to
account for is the temperature coefficient of power. We look on the spec sheet and find that
this module has a negative .4 percent temperature coefficient of power. That means if the
temperature is above standard test conditions we are going to lose power, and if we are below
the 25-degree standard test condition then we can gain a little power.
In this case we found that our cell temperature was 30 degrees above standard test condition
so we are going to lose a little power due to the high temperature that the array is operating at.
Once you run through your calculations you find that you have a .88 temperature factor. To
then figure out the total derate factor on the nameplate of the system, we multiply our system
derate factor of .94 times our irradiance factor of .8, times our temperature factor of .88. Let’s
see what we get.
Now we can calculate our total derate factor. We will take into account our system derate
factor of .94, multiply by our irradiance factor of .8, and multiply that by our temperature factor
of .88 and that gives us a .66 total derate factor.
Now we need to apply that derate factor to the STC nameplate rating of our system which is
8,400 watts. We multiply that times .66, which equals 5,544 watts. So this system should be
producing about 5,544 watts. Let’s go check and see what it is doing.
I’m reading 5,450 watts, which is within tolerance. So it seems that this system is performing
as expected.
Inverter Inspection
When it comes to maintaining inverters one of the few things that has to be done regularly and
checked is the ventilation fans for the inverter’s cooling system and whether the intake screens
are free of debris.
We’re going to take a minute and look at this inverter’s cooling system and see how the air
flows through the unit – where the intake and exhaust air move through and how to make sure
it’s a clean fan system.
In this case the inverter manual tells me to shut off the AC and DC disconnect switches and
then wait for five minutes for the internal capacitors to discharge before opening up the fan
housing. So we shut off the AC disconnect and the DC disconnect and then we’ll wait for five
minutes and then open the fan enclosure.
So now we’ll look at this inverter and how to remove the screen on the fan and check it for
debris. This unit has a fan on each side so you would repeat this process for each fan.
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In this case I’m taking a small flat-head screwdriver to leverage a little piece and remove the
screen for the intake air. The manufacturer recommends a few acceptable ways to clean the
screen. You can use compressed air and blow it out, you can use a little brush and scrub it
out, or you can use a shop-vac to remove any debris or buildup.
This inverter also allows us to remove and check the fan. Remove the fan from its housing,
disconnect the little wire harness and pull the fan out. Make sure there is nothing caught in the
fan – that there’s no debris – and that the fan blade is rotating, as it should. Then reinstall the
fan and get the system back on line.
Each inverter will have a slightly different procedure on this cleaning process so always check
the manual for the best process to follow for checking the fans.
We just looked at the intake ventilation on the inverter. The intake air comes from the bottom,
blows the air though the back of the inverter’s chassis and then the outtake air comes out
through the side fin. So in addition to the intake fan, be sure to remove the cover screen and
make sure that the outside exhaust is not clogged with and anything.
So we have a fresh air intake and an outtake and there is no debris built up inside.
Every inverter is different and the vents and fans will be checked differently. This inverter has a
removable screen. All you need to do is pop that out and make sure that it is clean and free of
debris. You can use a shop-vac or a little brush to make sure it is clean and then put it back in.
Some inverters may have multiple screens – so again, always consult the manual for the
appropriate process.
There are many inverters that do not have integrated fans and vents. This inverter has a heat
synch on the front of it that dissipates the electronics’ heat through air movement across the
fins. So for an inverter like this all you need to do is check the fins. Make sure there is no
debris, buildup, bird or wasps excrement, inside there – that the fins are clean and clear.
Every inverter on the market has slight differences when it comes to how to maintain and
check the fans and the ventilation system. So always check the manufacturer’s operating
manual for the proper procedure to work on that inverter.
Audience Question:
Now that we have covered routine maintenance, let’s take another question.
What does it mean when you hear inverters making a loud humming noise or if they get really
Inverter Noises and Hum m ing & Overheating
Another consideration is when the inverter’s making power that fan noise may change through
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the course of the day. In the morning when it’s cool out or on a cold winter day the inverter
may be making almost no noise and still making power. The fans often will ramp up and down
in an inverter based on the heat inside the unit.
So if it’s not very hot in there or there’s not very much power going through it, the fan may be
off. And the fan will go up and down based on the ambient air temperature and how many
watts the unit’s processing.
Now there’s going to be a spot where you’re taking internal air and external air, basically
throughput air, so there’s going to be a place on the unit where hot air is coming out – that’s
the exhaust air. So you are going to have spots on the inverter where it’s hotter than other
spots based on that exhaust air coming out.
The other thing to consider is some inverters don’t have fans – some inverters use a heat sync.
So there’s a metal thin set that dissipates heat through ambient air temperature with a heat
sync. If you touch that, especially on a hot day with full sun, that’s going to be very hot to the
touch and it’s supposed to be – that’s the purpose of it. It is dissipating heat through the heat
sync and that thing may be even hard to put your hand on because it’s hot to the touch.
So just be aware that the audible level will vary based on how many watts are going through it
so midday it could be louder and in the morning or end of day it could be quieter. And the fan
level will move with that as well or the physical temperature of the unit will change based on all
that power dissipation.
So that’s a normal condition. If you look at the inverter and it’s hot to the touch but the lights
are on and it’s green, and everything is happy, and there are no errors and it’s making
electricity, that’s what it’s meant to do.
If it overheats it is going to throttle back the array. It’s going to reduce the output of the array
in order to thermally manage the inverter. And so it will throttle down and it will back off on the
amount of solar it lets through if it has to. Or, if it was a problem, it would shut down all
together and just shut itself off and probably flag an error. So unless there’s an error on there
it’s probably fine to have varying levels of sound and heat coming off your inverter.
Poll #2
Now we would like to hear from you. Please take a moment to answer the questions on your
Thank you. Here are the results. Now, let’s move into the next part of our seminar, which
deals preventative maintenance.
Module 3: Corrective Maintenance
The corrective maintenance items we will review in this part of our seminar are among the most
typical you will find in small-scale applications. Many of these procedures can easily be
handled by qualified in-house personnel. They include diagnostics and testing, inverter
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trouble-shooting, and examples of emergency shutdown procedures at the module and
grid levels.
Fuse Checks
While performing operations and maintenance work, you may have to isolate an individual
source circuit of the system. So now we are going to go over how to safely perform that
operation. First off, you want to make sure you have your proper PPE on, based on the fault
hazard that is available. You also want consider that if the system is turn on its going to be
under load, so there will be current flowing in all of the circuits.
To safely lift a fuse holder, you are going to want to make sure there is no current flow, and to
do that were going to turn the whole system off
So now that we have our system turned off, we still want to confirm the there is no current
flow, because there may be a fault of some kind we don’t know about
The big difference you see here between this and a circuit breaker is that these are touch safe
fuse holders, there are not actually load break rated like a circuit breaker is. So if I go on and
open this thing up under load, it could have a really dangerous arc there that could set this box
on fire and hurt whoever is working on it. So I want to be sure to identify this as a touch safe
fuse holder, so I know that I have to confirm and double check to make sure that there is no
current flowing in the system.
I am going to use my clamp on meter to verify that there is no current flowing through the
system. Now, the typical meter you may find at your local hardware store may only be rated for
AC. This one is rated for both AC and DC, so you want to make sure you have the right Clamp
On Meter since we are testing DC.
I am going to set it to AMPs, and I will want to zero out the meter and make sure it’s on DC
So I’ve verified that there is no current flowing in the system, I can safely lift my fuse holders,
and now I have isolated each circuit in the system.
DC System Voltage and Polarity Checks
So we need to confirm we have the correct voltage and polarity in the system. So the polarity
test is pretty unique to the DC side of our system, On the AC side the polarity is changing 60
times per second, while on the DC side you have a fixed polarity. If you wire that wrong, you
can have a situation where you have increased voltage and that can damage the components
of the system and be a hazard.
We are going to go ahead and test for the correct voltage. We need to also understand that our
system is in an open circuit condition, so we can expect to see a VOC voltage from our array. If
we were in an operating condition we would see a volts maximum power or a VMP condition
from our array, which will result in a lower voltage. So it is important to know what you expect
to see before you run the test.
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We know that the array is warmer than usual; it is very hot right now so we are going to see
below an STC VOC. We want to make sure that our black lead plugged into our common goes
to the negative on our circuit, which we have here our black lead going into our negative bus
bar. Our positive lead, we do not want to run that to our positive bus bar, we want to run the
positive, the red wire, right to the individual circuit.
In circuit one we see 393, which is within tolerance of what we expected, circuit two also has
the correct polarity and it is at 392, and circuit three has the correct polarity and it is at 395.
Now, if we had the reverse polarity, you would see a little negative symbol show up before the
number. So it is really important to look at that while you are running these tests.
Checking Current on Source and Output Circuits
So now we are going to verify that our system is operating correctly on the DC side, we want
to confirm that the correct amount of current is running through the circuits. The inverter
should be maximum power point tracking, so we should see the IMP value from the circuit, so
that is what we are going to be looking for. Each circuit is mounted at the same tilt and
orientation so the current should be the same for each one of them.
Now the amount of current that is flowing is directly related to the amount of irradiance that’s
on the array right now. So we are going to have to use our pyranometer, or irradiance meter, to
measure the amount of irradiance that is on the array, and then we are going to use our DC
Clamp On Meter to measure the current in the wire.
Next we are going to use the irradiance meter to measure the amount of irradiance on the
array. Make sure to have the calibrated cell of the unit on the same plane as the module. I find
that this array is receiving 875 Watts per meter squared.
So before we even open up the combiner box we are going to want an expectation of the
current we will see on each circuit. So we looked at a spec sheet for our module and found
that the IMP value is 7.78 amps, but that’s at standard test conditions. When we measured
irradiance we found 875 Watts per meter square, which give us an irradiance factor of .875.
So I take me 7.78 amps as my IMP and multiply that by my irradiance factor of .875 and that
gives me an expected value of 6.8 amps for each source circuit that I am about to measure.
Now, the output circuit would be from the three source circuits that are in parallel in this box,
when they come together in parallel, they come to 23.34 amps at standard test conditions. But
we are not at standard test conditions, we measure 875 watts per meter squared, which is an
irradiance factor of .875. So you multiply 23.34 by .875 and that give you 20.4 amp as your
expected value on the PV output circuit. ‘
So lets open up this box and confirm the expected values.
This test needs to be done with the system in operation. So I can’t open up the DC circuit, I
need to leave the system operating, so I need to defeat the handle to open up the box while
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the system is still in operation. So again, you want to make sure you have the proper PPE on
before you run this test. We’re going t look at our source circuits. We’re going to make sure we
have our DC clamp meter, we set it to amps, we zero it out before our measurement.
So all of the strings are measuring about 7 amps, which is normal. What we are seeing is what
we expected from the system, so the system seems to be operating at maximum power.
Now we are going to look at the output of the system. Since we know that there are three
source circuits in parallel, and we are at 875 watts per meter squared, we should see about
20.4 amp for the output of this system. So again, we are going to get our meter set properly. I
like to test both the positive and the negative, because they are pretty easy to get to, and it’s a
good way to tell if you have a problem in your system. The current on the positive and negative
should be equal, and if not you might have a problem, you might have a fault of some kind.
Here everything was equal so it seems like the system is performing correctly.
Ground Fault Troubleshooting
One of the biggest hazards with the operation of a PV system is a Ground Fault. In normal
operation the current flows between the positive and negative, but in the case of a ground
fault, normally not energized components can become energized which then becomes a
hazard. So think of it like this, if you have a module with one of the wires coming off of it that’s
pinched between the metal racking and the module, that can make it that the current decides
to flow on the metal racking on the system, rather than the positive and the negative wire.
A ground fault also can be caused by expansion and contraction issues in the system, which
can be caused by wires expanding and contraction over a rough edge on the conduit fitting
before it comes into the box – lots of different issues that can cause a ground fault.
Per national electric code the inverter that we are using should be UL-listed, and it must be
able to provide ground fault protection. What that actually means is that the inverter must be
capable of detecting the ground fault, and in the event of a ground fault it will open up the
circuit. That won’t completely get rid of the hazard but it will mitigate the hazard. The other
thing the inverter needs to do is provide indication of the fault. So if you see here if you look a
little but closer, you can see that this inverter is showing a red light, which indicates that a
ground fault may be present on this system. So if I walk up to a system and I see a light like
this, I’m sure not to make any physical contact with any of the metal on the system before I put
on the appropriate PPE.
Now trouble shooting a ground fault like this and finding it to identify and isolate the circuits it’s
on. That will require certain training and experience. Typically the way that we do this is with a
digital multi-meter to find certain ground faults, or you might have to run an insolation
resistance test. But to do any of this safely you need to make sure you get the further training
and experience to safely take this on.
Page 22
Inverter Service Procedures
So we are standing behind the array here and we are looking at what we would call the balance
of systems, the rest of the equipment rather than the solar. So the solar array wiring is coming
down from the display into the DC disconnect wiring switch here. This DC disconnect switch is
the way we can isolate the solar array from the inverter on the DC side for service and
maintenance. So the wiring is going to come down from the array, into the switch, through the
disconnect, into the inverter itself
So now, this is the inverter, this is what is turning the DC electricity from the solar array into AC
electricity and synchronizing that power with the utility grid in order to export that power out
into the grid itself. So once we turn DC in to AC in the inverter, we leave through an AC
disconnect switch and that gives us the ability to isolate the AC or the grid side of the
connection to this inverter. If we leave that switch on we can go over to the main utility where it
connect to the grid itself.
If I need to do maintenance on this system from a technician stand point, I can walk up and
turn off the AC and DC switches and isolate this piece of electronics for service, maintenance,
check ups, anything I would need to do, for instance replace the inverter, I could turn off both
power sources and replace the inverter, then turn it back on and get it back online.
Em ergency Shutdown – M odule Level
If there is ever some kind of emergency, and you have to shut down the system as fast as you
can, what you are looking for is things like breakers and disconnect switches. Disconnect
switches with handles like these are called a low break rated switch, which means I can throw
that switch in the off position, and shut down the DC end of the converter. I can shut of the AC
switch as well and shut off the AC side of the converter. When this AC switch goes back to the
building it’s going to go to a breaker back in the building, and I could shut that breaker there
and shut down the current going to here.
So what you are looking for are things that you can safely isolate as quickly as possible, like
disconnect switches and breakers at the service panel.
So talking about emergency disconnects, while I said the things you can turn off are the
disconnects and breakers, what you CANNOT DO in an emergency is that you do not want to
come up to a plug connector and unplug that. These connectors, if there is power flowing
through those connectors you are not allowed to pull these apart. So what you do not want to
do is walk up and pull any connector apart and do not pull any fuses out of the circuit. Pulling
fuses out, or pulling connectors apart can create a greater hazard than throwing the disconnect
switches themselves.
Just to reiterate, breakers and disconnect switches are okay to throw if there is an emergency.
Fuses and plug connectors do not unplug in an emergency because that can create a greater
hazard potentially.
Page 23
Em ergency Shutdown – Grid Level
At this particular site we have multiple converters, each of the inverters has its own AC output
that need to be combined together so that they can feed into the utility itself. Behind me is an
AC breaker panel, that’s taking the output of each inverter and paralleling them into the AC
So when I look at these breakers behind me I see inverter 1, inverter 2, inverter 3, inverter 4,
and they are feeding into the AC bussing. We also have a main AC breaker here down at the
bottom, which connects this whole service back to the utility. Then there is a lightening or
surge protector off to the side in here as well.
It’s very common when we have a multi inverter site like this to have a panel that will be very
similar to this in some way, to take the multiple inverter outputs and connect them all together
and feed them all together back to the main point of connection with the utility grid itself.
Poll #3
Now we would like to hear from you. Please take a moment to answer the questions on your
Thank you. Here are the results. Now, let’s move into the next part of our seminar, which
deals preventative maintenance.
Module 4: Calculating Savings and Public Outreach
Finally, we will cover some important steps to ensure the accuracy of metering and reporting,
as well as outreach to staff, building occupants, and the public to showcase the energy,
environmental, and cost benefits of your PV system.
Before we discuss typical O&M maintenance costs and how to calculate savings resulting from
PV systems, here are a few main options to fund a small-scale solar energy project at your site.
They include Congressional Appropriations, Utility Energy Service Contracts (UESC), Energy
Savings Performance Contracts (ESPC), and ESPC Enable. ESPC Enable provides a
streamlined way to incorporate small-scale PV into your energy improvement projects.
After obtaining funding to install the system, the cost of maintaining it is very low compared to
O&M costs of traditional electricity technologies.
As you can see here, maintenance on the inverter, the PV arrays, and cleaning and removal of
vegetation make up the majority of O&M cost. Plan to budget an estimated $10 to $30 per
kilowatt per year, depending on the size of your system.
Em ergency Funding/ Contingency Funding for Repairs
Even with a sound O&M plan, unforeseen failures and equipment repairs may occur. Check
Page 24
with your site, your regional office, or your headquarters officials to determine the best options
to obtain contingency funds or emergency repair funding to keep your system operating.
A system that is down cannot save money for the agency, so calculate and emphasize the cost
of downtime when requesting contingency funds.
My name is Mike McMenanmin. I’m with the US Fish and Wildlife Service at the John Heinz
National Wildlife Refuge and I’m the Facility Manager here.
We have a 47-kilowatt system here at the John Heinz national wildlife refuge. Before the
system was installed, you can see that we were averaging approximately 600 dollars in utility
bills per month, and after the system was installed, we noticed that it dropped to about 50
dollars per month
With an understanding of renewable energy generation as part of a utility bill, let’s calculate the
amount of money your system is saving. We’ll show how to project what your bill would have
been without the system in place and, thereby, calculate the savings that result directly from
the PV panels. The best way to estimate savings is to calculate the utility bill both with and
without the PV. This can be a complicated calculation so fortunately most utilities will perform
this calculation for you.
To correctly calculate PV cost savings, it is important to know the building’s electric load
profile before the PV installation and how the PV system output affects the building load
Many utilities have charges that vary with time of day and seasonally, and utilities charge a
demand power factor in addition to charging for energy. The only way to calculate actual cost
savings due to the PV system is to analyze and compare the utility bill costs both with and
without solar power. The utility bill estimated without solar, minus the bill amount with solar,
will accurately show the savings, which is the difference between the two.
Agencies should report on the benefits of PV systems to site staff, building occupants, and the
general public. Many sites have developed public dashboards that can be located in public
areas or made available on computer networks. These public dashboards feature user-friendly
metrics and graphics for easy access.
This is our newly installed solar display, it’s really a to the visitor center and the wildlife refuge.
Last year our visitation was over 150,000 visitors to the refuge.
The information that the display is trying to get across to people is that not only showing the
location of the solar panels on the visitor panel, it also shows you what a solar panel looks like,
Page 25
it also talks about the amount of solar panels it has on the top, we have a 4,800 watt solar
system on the top of this building.
Our monitor here shows the amount of kilowatts, and you can see on a day like today we are
averaging about 32 kilowatts.
Thank you for joining us for this First Thursday Seminar. FEMP would like to thank the U. S.
Department of Interior’s Fish and Wildlife Service for its assistance in developing this First
Thursday Seminar.
Please click on the link on your screen and take a moment to complete the quiz and short
course evaluation. This will provide you with continuing education credits and provide FEMP
with valuable feedback to continue to improve its training offerings.
Check the FEMP website for updates on First Thursday Seminars and new training offerings.
Thank you for joining us.
Resources for Further Study
Ground Mount PV Racking Systems
PV Ground Mounting
Utility Scale PV Ground-Mounted Racking Solutions
Ground Mounted PV
Personal Protective Equipment: Insulating Gloves and Sleeves
Standard for Electrical Safety in the Workplace
Page 26
OSHA Lockout/Tagout Factsheet
Control of Hazardous Energy (Lockout/Tagout)
NFPA 70E: Lockout/Tagout Guide
Personal Fall Arrest Systems
Fall Protection Systems Criteria and Practices
Fall Protection Systems
Solar Farm Grounds Management Vegetation Control
Overview of Opportunities for Co-Location of Solar Energy Technologies and Vegetation
Unfortunate Solar Installation of the Month: Utility Scale Edition
Successful PV Site Evaluation
Pump Up the Power: Getting More from your Grid-Tied PV System
Page 27
Do You Wash Your Solar Modules Often Enough?
PV System Energy Performance Evaluations
Safety Considerations for Live Measurements: Keep your Eyes on the Job at Hand:
ABCs of DMMs
The New NEC 690.16(B) Fuse-Servicing Requirements and Combiner Boxes
The Circuit-Methods: Testing and Verifying Module Voltage and Current… Prior to Installation
Grid-Tied PV System Performance Factors
PV System Ground Faults
PV System Operations and Maintenance
Distributed Inverter Design
Salem Community College Energy Institute
Page 28
Glossary: Photovoltaic Operations and Maintenance Key Term Definitions
Asset M anagem ent: a systematic process of planning, operating, maintaining, upgrading
and replacing assets cost effectively with minimum risk and at the expected levels of service
over the assets’ lifecycle; it therefore contains all of O&M. Business services operations such
as billings and collections from PPA and leased based systems customers do fall within asset
management, but are not typically part of O&M.
Adm inistration of Operations: Ensures effective implementation and control of operation
and maintenance activities including archive as-built drawings, equipment inventories, owners
and operating manuals, and warranties. Includes keeping records of performance and O&M
measures provided, preparing scopes of work and selection criteria for service providers,
contracting with suppliers and service providers, preparing budget, and securing funding and
contingency plans for O&M activities.
Conduct of Operations: Ensures efficient, safe, and reliable process operations including
economic NPV/ROI cost benefit financial decision support. Includes serving as a point of
contact for personnel regarding operation of PV system, coordinating with others regarding
system operation and any required shutdown, and providing instructions regarding defined
work tasks scheduled in the morning or evening hours to avoid production losses, electrical
hazards, heat stress, and local access. In addition, includes providing instructions regarding
access routes, storage and lay-down areas, and hours when work can be conducted without
affecting the mission of the facility.
Provisions and Directions for the Perform ance of W ork: Ensures that maintenance is
performed safely and efficiently including the formalization and enforcement of safety policy
(including training for DC&AC safety, rooftop safety, minimum manning requirements, arc flash,
lock-out tag-out, etc.). Also includes compliance with any environmental or facility-level
policies regarding handling controlled materials such as solvents, weed-killer and insecticide.
Evaluation and Provision of Sufficient Equipm ent Status Control: Ensures effective
equipment monitoring and analytics to remain cognizant of status. Includes comparing results
of system monitoring to benchmark expectation and providing reports to facility stakeholders.
Design and M aintenance of Operator Knowledge, Protocols, and Docum entation:
Ensures that operator knowledge, training, and performance will support safe and reliable plant
operation. Includes confirming and enforcing qualifications of service providers.
Adm inistration of M aintenance: Ensures effective implementation, control and
documentation of maintenance activities and results. Administration includes establishing
budgets and securing funds for preventive maintenance, establishing reserves or lines of credit
for corrective maintenance, planning activities to avoid conflict with system operation or
operations at the customer site, correspondence with customers, selection and contracting
with service suppliers and equipment manufacturers, record keeping, enforcement of
warranties, providing feedback to designers of new systems, and reporting on system
performance and the efficacy of the O&M program.
Page 29
Preventative M aintenance: Scheduling and frequency of preventative maintenance is set
by the operations function and is influenced by a number of factors, such as: equipment type,
environmental conditions (marine, snow, pollen, humidity, dust, etc.) of the site, and warranty
terms. Scheduled maintenance is often carried out at intervals to conform to the manufacturer
recommendations as required by the equipment warranties.
Corrective M aintenance: Required to repair damage or replace failed components. It is
possible to perform some corrective maintenance such as inverter resets or communications
resets remotely; also, less urgent corrective maintenance tasks can be combined with
scheduled, preventative maintenance tasks.
FTS 27: O&M Best Practices for
Small-Scale Photovoltaic Systems
PV O&M Asset Management Service Descriptions
Asset Management
Daily Operations and Performance Monitoring
Admin Asst
Asset Management
Monitor alarms and site-specific alert
As needed
Asset Management
Manage inventory of spare parts
As needed
Document all O&M activities in a workbook
available to all service personnel.
Admin Asst
Confirm availability and take any measures to
secure operating instructions, warranties and
performance guarantees, and other project
Admin Asst
Review O&M agreements and ensure that
services are actually provided
As needed
Admin Asst
Update record with preventative maintenance
activities and track any problems or warranty
issues and secure the record on-site.
Admin Asst
Meet with key site staff to continue
awareness, question any issues, and report
on findings.
Maintain a log of cumulative power delivery
(kWh to date) and chart this value against
date. Chart the value even for uneven or
infrequent intervals. Explain variation by
season or weather.
Admin Asst
Compare actual output or savings
to output predicted under the
conditions. Solar Today magazine publishes
a map with the previous months output as
indicated by processed satellite data
regarding the solar resource across the
country, or an estimate may be derived from
local measurements.
Admin Asst
FTS 27: O&M Best Practices for
Small-Scale Photovoltaic Systems
PV Operations & Maintenance - Service Qualifications
Many PV O&M tasks require specialized knowledge. Typical building maintenance companies are not suitable for the requirements
of successful PV asset O&M because the average industrial technician is not familiar with DC wiring and components, power
conditioning equipment, and the uncontrollable and intermittent nature of the resource and resulting power generation.
Specialized training of third-party maintenance personnel is necessary, as is awareness on the part of the building owner and utility
staff, to provide effective O&M while ensuring safety. The qualifications of each job category depend on the requirements of the job
and are listed for labor; technician; electrician; designer; roofer.
NABCEP refers to North American Board of Certified Electricity Practitioners certification.
Service Categories and Associated Qualifications:
Service Category
Scope of Work
Administrative Assistant Record-keeping,
service confirmation,
Excellent interpersonal and communication skills (written and
verbal). Diligent record keeping. 2 to 5 years of experience.
Excellent MS Office and computer skills.
Specifications, drawings,
modeling and analysis,
codes and standards.
B.S. in EE (4-year engineering degree); registered PE licensed
to practice engineering in the jurisdiction; NABCEP PV Installer
Certification; CAD (AutoCAD) and graphics skills; knowledge of
IEEE, NEC, NESC, and other codes and standards for PV
systems; required level of errors and omissions insurance.
Module Cleaning
Cleaning PV Arrays
10 OSHA Card; Required level of bonding and insurance; drivers
license and reliable transportation; minimum 18 years old.
Tree Trimming
Removal of vegetation
50 OSHA Card; drivers license and reliable transportation;
required level of insurance; minimum 18 years old; any required
training or license for herbicide application.
Pest Control
Nesting vermin removal,
Nesting vermin prevention
10 OSHA Card; safety training in handling animals and detritus;
required level of bonding and insurance; drivers license and
reliable transportation; minimum 18 years old; most states
require license for pesticide
Roof leak repair, roof tile
repair, re-roof
Roofing contractor’s license for the jurisdiction; 10 OSHA Card;
safety training in fall protection equipment and use (or 50 OSHA
Card); required level of bonding and insurance. 2 to 5 years of
Structural Engineer
Foundations and rack
B.S. CE (4-year engineering degree); registered PE licensed to
practice engineering in the jurisdiction.
Maintenance and repair/
replace of tracking mount
50 OSHA Card; 2 to 5 years of experience; required level of
bonding and insurance.
Master Electrician
Module replacement,
inverter replacement,
fuse/breaker replacement,
conduit routing, wiring,
ground fault repair
Electrical Contractor’s license for the jurisdictions; 50 OSHA
Card; NABCEP PV Installer certification; experience in the
design of medium voltage electrical systems. 5+ years
experience with PV systems; color vision. Certification by
the North American Energy Reliability Corporation (NERC) is
necessary for positions that affect the power grid.
Service Category
Scope of Work
Journeyman Electrician
Module replacement,
Inverter replacement,
fuse/breaker replacement,
conduit routing, wiring,
ground fault repair
50 OSHA Card; training in arc-flash, lock-out/tag-out, and other
special protective equipment and procedures; NABCEP PV
Installer certification; experience in the design of medium
voltage electrical systems. 5+ years experience with
PV systems; color vision.
Internet/network repair,
monitoring equipment
Knowledge of specific monitoring devices (training by system
supplier) and how monitoring system is connected through
network connections or wireless or cellular modem; knowledge
of Modbus, DNP3 and other protocols, HMI operator interfaces;
2 to 5 years of experience. Locus, Enphase, Itron, etc.
monitoring device knowledge.
Diagnostic analysis; visual
inspection, specific testing,
Diagnostic analysis; NABCEP PV Installer Certification;
2 to 5 years of experience.
Inverter Specialist
Inverter repair, upgrades
Skills to perform maintenance, diagnostics and repair for
inverter: factory trained and certified; 5+ years experience.
PV module/
Array Specialist
Module repair
Skills to operate, troubleshoot, maintain, and repair photovoltaic
equipment: NABCEP PV Installer certification. 2 to 5 years of
Utilities locator
Locate underground
2 to 5 years of experience.
FTS 27: O&M Best Practices for
Small-Scale Photovoltaic Systems
PV Preventative Maintenance - Service Descriptions
Preventative maintenance is required to maximize system output and to take measures to prevent more expensive failures from
occurring. Conduct preventative maintenance work early in the morning or late in the evening to avoid heat stress, minimize electrical
hazards, and minimize production losses.
This is broken out into five activity areas: Inspection, Service, Testing, Cleaning and Emergency Response
PV Module
Clean PV modules with plain water or
mild dishwashing detergent. Do not use
brushes, any types of solvents,
abrasives, or harsh detergents.
Module Cleaning
Contractor available by email and phone
AC Wiring
Inspect electrical boxes for corrosion or
intrusion of water or insects. Seal boxes
if required.
AC Wiring
Check position of disconnect switches
and breakers.
AC Wiring
Exercise operation of all protection
DC Wiring
Test system grounding with “megger”
DC Wiring
Scan combiner boxes with Infrared
camera to identify loose or broken
DC Wiring
Inspect cabling for signs of cracks,
defects, pulling out of connections;
overheating, arcing, short or open
circuits, ground faults.
DC Wiring
Check proper position of DC disconnect
DC Wiring
Inspect and maintain the wiring and
condition of wire insulation and protective
DC Wiring
Open each combiner box and check
that no fuses have blown and that all
electrical connections are tight. Use an
infrared camera for identifying loose
connections because they are warmer
than good connections when passing
DC Wiring
Look for any signs of intrusion by pests
such as insects and rodents. Remove
any nests from electrical boxes (junction
boxes, pull boxes, combiner boxes) or
around the array. Use safe sanitation
practices because pests may carry
Vermin Removal
Observe instantaneous operational
indicators on the faceplate of the inverter
to ensure that the amount of power being
generated is typical of the conditions.
Compare current readings with
diagnostic benchmark.
Spot-check monitoring instruments
(pyranometer, etc) with hand-held
instruments to ensure that they are
operational and within specifications.
PV Module/Array
PV Array
Test open circuit voltage of series strings
of modules
PV Array
Check all hardware for signs of corrosion, Annual
and remove rust and re-paint if
PV Array
Check tightness of mounting clamps.
Re-install any modules that have become
PV Array
Walk through each row of the PV
array and check the PV modules for any
damage. Report any damage to rack
and damaged modules for warranty
replacement. Note location and serial
number of questionable modules.
PV Module/
Array Specialist
PV Array
Inspect ballasted, non-penetrating
mounting system for abnormal movement
PV Array
Determine if any new objects, such as
vegetation growth, are causing shading
of the array and move them if possible.
Remove any debris from behind
collectors and from gutters.
Tree Trimming
PV Module
Use infrared camera to inspect for hot
spots; bypass diode failure
PV Module/
Array Specialist
Inspect transformer meter, oil and
temperature gauges
AC Wiring
Re-torque all electrical connections on
AC side of system.
DC Wiring
Re-torque all electrical connections in
combiner box.
Exchange or re-calibrate instruments
As per manuf Journeyman
Replace transient voltage surge
suppression devices
As per manuf Journeyman
Install any recent software upgrades to
inverter programming or data acquisition
and monitoring systems
5 years
Inverter Specialist
Clean (vacuum) dust from heat rejection
Inverter Specialist
Replace any air filters on air-cooled
equipment such as inverter.
As needed
Inverter Specialist
Remove any pests such as insects and
nests from inverter enclosure; find and
repair cracks that pests use to enter
the enclosure.
Vermin Removal
PV Array
Remove bird nests from array and rack
Vermin Removal
PV Array
Nesting vermin removal, nesting vermin
Vermin Removal
Lubricate tracker mounting bearings/
Perform performance test: measure
incident sunlight and simultaneously
observe temperature and energy
output. Calculate PV module efficiency
as a function of temperature and
calculate the balance-of-system
efficiency. Compare readings with
diagnostic benchmark (original efficiency
of system).
PV Module/
Array Specialist
Test over-voltage surge suppressors in
5 Years
Inverter Specialist
PV Module
Test output of modules that exhibit
cracked glass, bubble formation
oxidation of busbars, discoloration of
busbars, or PV module hot spots
(bypass diode failure)
PV Module/
Array Specialist
PV Module
Test modules showing corrosion of
ribbons to junction box
PV Module/
Array Specialist
FTS 27: O&M Best Practices for
Small-Scale Photovoltaic Systems
PV Operations & Maintenance - Design Considerations
O&M considerations should be included among design criteria such as cost and efficiency. Some of these considerations include:
AC wiring
Peer review of designs and specifications to ensure constructability by experienced installer.
AC wiring
Perform “facility coordination studies” to avoid problems in AC components between inverter
output and point of common coupling (Voss et al, 2009)
Business practice
Provide for operator/technician training in installation of PV system.
DC wiring
Include both ground fault current interrupter and arc-fault detector in design.
DC wiring
A string inverter arrangement is reported to have 0.372% higher energy delivery due to reliability
issues than a central inverter arrangement (Wang et al, 2012). Micro-inverter arrangements are
reported to be more reliable than string or central inverters (Zhang et al, 2013).
DC wiring
Of five PV module configurations considered, total cross-tied (TCT) and bridge-linked (BL)
configurations increase the operational lifetime of the PV arrays by 30% according to Zhang
et al (2013).
Wang et al (2011) report that of six grounding configurations considered, attaching a tin-plated
lay-in lug to aluminum frame with a teeth washer laid between the lug and aluminum surface
(Teeth face towards the aluminum surface), had the best reliability under salt mist conditions.
Anti-oxidant compound applied between the grounding lug and the module frame increased the
mean time to failure of all types of grounding connections considered. (Wang et al, 2011).
Wang et al (2011) found that grounding connections that were installed without measuring the
applied torque failed 5 times faster than those that were properly installed with a torque wrench.
Include internet-connected communications that permit quick fault reporting and diagnostics;
remote debugging and re-boot capabilities.
Check for defects in high infant mortality items such as interconnects, wiring harnesses, and
moving parts.
Design redundant systems that have the ability to operate even when full capacity is hindered.
Select inverters that observe UL 1741; IPC-9592; EN 60730-1; GBIT 19064; IEC 62109 and 62093.
Avoid electrolytic capacitors in favor of solid-state ceramic low-ESR capacitors in order to avoid
overheating (Tulkof, 2013); Center for Advanced Life Cycle Engineering has found cracking in
ceramic capacitors to be a problem; film technology is ideal for solar inverters because it does not
have a short-circuit failure mode, provides for a calculable lifetime, is mechanically robust, and
offers appropriate characteristics to maximize inverter efficiency (Granata et al, 2011).
Specify AC voltage supervision, in order to limit the overvoltage from inverter that can damage
meter or other electronic components (Pazos et al, 2009)
Utilize SAC305 instead of SnPb solder (Tulkof, 2013)
Specify inverter with DC/DC converter to control and limit DC voltage, in order to limit the AC
overvoltage from inverter that can damage meter or other electronic components
(Pazos et al, 2009)
Of 8 different inverter anti-islanding topologies, Petrone et al (2008) identify General Electric
Frequency Shift (GEFS) as the most reliable.
Of 8 different maximum power point tracker (MPPT) topologies, Petrone et al (2008) identifies digital as more reliable than analog and of the digital types “Fuzzy-neuro” and search techniques to
be the most reliable.
Specify Application-specific Integrated Circuits (ASIC) to combine chips on a printed circuit board
thus reducing solder connections and potential for board warping (Tulkoff, 2013).
Design features that reduce insulated-gate bipolar transistor (IGBT) voltage failures due to overvoltage include: specify an extra switching voltage margin based on the application (high power?,
high temperature?), specify a low inductance bus, and/or snubbers to help reduce overvoltage and
resulting “avalanche” failure of IGBT. (Granata, 2011)
Take into account solar gains on the enclosure when specifying temperature requirements of
Include in inverter specifications the ability to re-boot inverter control software, clear fault codes,
and perhaps install upgrades over a remote monitoring and control system to avoid sending
service staff to perform these tasks.
Monitoring systems in initial design; instruments such as current transducers installed permanently
in circuit design.
Standardize monitoring communications and control protocols (i.e., EGD, EtherIP, Profinet, etc.)
Add more temperature sensors (ambient, enclosure, IGB T heat sink, etc) to provide intelligence to
fault report logs
PV Array
Provide laydown areas, pathways through the array, and places for holes to be opened for smoke
ventilation on roof layout.
PV Array
Install bird-spikes on edges to discourage roosting birds
PV Array
Shading analysis, installer evaluation
PV modules
Select and stress-test cells according to UL 1703, ASTM E2481-06 and/or qualification test for
crystalline modules IEC 61215; qualification tests for thin-film IEC 61646; and concentrator
modules IEC 62108
PV modules
Module construction does not include PV material all the way to edge of the laminate
(edge delete).
PV modules
Specify testing according to IEC 61853 Photovoltaic Module Performance Testing and Energy
Rating (2010)
PV modules
Carefully select and test bypass and blocking diodes, avoiding module hot spots.
PV modules
Include module manufacturers’ quality practices in selection criteria. Check for: Advanced
Product Quality Planning; Failure Modes Effects and Analysis; Fault Tree Analysis; Design for
Manufacturability, and Design Review Based on Failure Mode; or other structured approach to
quality improvement (Kurtz et al, 2009). ISO 9001 is also a good requirement although it requires
only that a process be in place not the details of the tests.
PV modules
Specify low-sodium glass to reduce a source of delamination.
PV modules
Modules incorporating silicone encapsulant showed lower degradation than EVA and polyvinyl
butyral encapsulants (Jordan and Kurtz, 2013).
PV modules
Glass–glass modules exhibited larger degradation rates than glass-polymer modules
(Jordan and Kurtz 2013)
Design to reduce stresses and component count.
Include that as-built drawings be delivered as part of design contract
Specify components that are “mature” (have passed the qualification test sequence, have been
tested in the field for at least 2-5 years, and have been manufactured under a Quality Assurance
Specify variable control of transformer taps to allow for voltage variations on collection systems,
especially in VAR control mode (Granate et al, 2011)
569 FW 1
Integrated Pest
Supersedes 30 AM 12 and 7 RM 14,
Date: August 3, 2010
Series: Environmental Quality
Part 569: Pest Management
Originating Office: Division of Environmental
PDF Version
1.1 What is the purpose of this chapter? This chapter:
A. Establishes policy, procedures, and responsibilities for pest management activities on and off
U.S. Fish and Wildlife Service (Service) lands. It is consistent with the Department of the Interior
(Department) Integrated Pest Management policy (517 DM 1) and other applicable authorities;
B. Adopts Integrated Pest Management (IPM) as our method for making pest management
decisions; and
C. Provides guidance to employees on how to implement IPM for all pest management activities.
1.2 What is Integrated Pest Management (IPM)? IPM is:
A. A sustainable approach to managing pests that uses the following kinds of tools in a way that
minimizes health, environmental, and economic risks:
(1) Biological (e.g., predators, parasites, and pathogens),
(2) Cultural (e.g., crop rotation, alterations in planting dates, and sanitation),
(3) Physical (e.g., barriers, traps, hand-pulling, hoeing, mowing, and tilling), and
(4) Chemical (e.g., pesticides, such as herbicides, insecticides, or fungicides).
B. A science-based, decisionmaking process that incorporates management goals, consensus
building, pest biology, monitoring, environmental factors, and selection of the best available
technology to achieve desired outcomes while minimizing effects to non-target species and the
environment and preventing unacceptable levels of pest damage.
1.3 What are pests? Pests are living organisms, including invasive plants and introduced or native
organisms, that may interfere with achieving our management goals and objectives on or off our
lands, or that jeopardize human health or safety.
1.4 What is the Service’s pest management policy? Our policy is to:
A. Promote and adopt pest prevention as the first line of defense by using a pathway management
strategy such as Hazard Analysis and Critical Control Point (HACCP) planning to prevent
unintended spread of species and biological contamination. (See 750 FW 1 for more information on
HACCP planning).
B. Focus on conserving more pristine habitats, monitor these areas, and protect them from
C. Design and maintain the stability of structures, museum collections, and developed landscapes,
and restore and maintain habitats to prevent and reduce conditions conducive to the introduction or
spread of pests.
D. Use IPM methods to eliminate or reduce impacts from vertebrate and invertebrate pests to
achieve site-management goals and objectives.
E. Use cost-effective pest management practices that pose the least risk to humans, natural and
cultural resources, facilities, and the environment.
F. Use our best professional judgment and available scientific information to select the lowest risk,
most effective IPM method or combination of methods that is feasible for each pest management
project. When appropriate, we will include IPM methods in short- and long-term management
planning documents such as refuge Comprehensive Conservation Plans, IPM plans, National
Environmental Policy Act (NEPA) documents, and invasive species plans. Service IPM planning
guidance is on the Internet.
G. Encourage pest management activities that benefit natural resources and provide long-term
environmentally sound solutions to pest management problems on and off Service lands. This
includes planting native species that promote beneficial species, like native pollinators, and
promoting beneficial organisms and natural processes that inherently suppress potential pest
H. Complete necessary environmental documentation and procedures before conducting pest
management activities. This may include:
(1) Preparing Pesticide Use Proposals (PUPs) for approval before applying pesticides,
(2) Entering pesticide usage information annually into the online IPM and Pesticide Use Proposal
System (PUPS) database,
(3) Conducting Endangered Species Act consultations, and
(4) Following NEPA requirements.
I. Use and promote pest management research, methods, education, and technical and financial
assistance programs to develop, support, and implement IPM strategies.
J. Use appropriate monitoring techniques before, during, and after any IPM activity to determine
whether we achieved pest management goals and objectives and if the activity caused any
unanticipated impacts.
K. When possible, incorporate IPM principles into procurement activities, contracts, leases, and
agreements, including activities such as:
(1) Cooperative farming,
(2) Construction,
(3) Habitat management,
(4) Fire management,
(5) Grazing,
(6) Forestry,
(7) Operation and maintenance of irrigation systems and dams,
(8) Concessions management,
(9) Road and rights-of-way construction and maintenance,
(10) Public health,
(11) Animal management, and
(12) Fish culture.
1.5 What is the scope of this policy? This chapter applies to all pest management activities we
conduct, approve, or fund on or off Service lands.
1.6 When will the Service manage pests? We will manage pests if:
A. The pest causes a threat to human or wildlife health or private property; action thresholds for the
pest are exceeded; or Federal, State, or local governments designate the pest as noxious;
B. The pest is detrimental to site management goals and objectives; and
C. The planned pest management actions will not interfere with achieving site management goals
and objectives.
1.7 How does the Service choose which pest management methods to use? We choose pest
management methods by considering the following in this order of importance:
A. Human safety,
B. Environmental integrity,
C. Effectiveness, and
D. Cost.
1.8 What are the authorities for this chapter?
A. 517 DM 1, Integrated Pest Management Policy.
B. Noxious Weed Control and Eradication Act (7 U.S.C. 7701 et seq., Subtitle E).
C. Federal Property Management Regulations, Facility Management (41 CFR 102-74.30).
D. Agriculture Risk Protection Act (PL 106-224) (supersedes the Federal Noxious Weed Act, except
Sections 11 and 15).
E. Executive Order 13112, Invasive Species.
F. National Wildlife Refuge System Administration Act (16 U.S.C. 668dd- 668ee), as amended by
the National Wildlife Refuge System Improvement Act (P.L. 105-57).
G. National Invasive Species Act (P.L. 104-332).
H. Aquatic Nuisance Prevention and Control Act (P.L. 101-646).
I. Endangered Species Act (16 U.S.C. 1536).
J. Occupational Safety and Health Act (P.L. 91-596).
K. The National Environmental Policy Act (42 U.S.C. 4321-4370d).
L. Federal Water Pollution Control Act (33 U.S.C. 1251 – 1376) (also known as Clean Water Act).
M. Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) (7 U.S.C. 136).
N. Migratory Bird Treaty Act (16 U.S.C. 703-716).
O. Official Animal Control Operations (50 CFR 31.14).
1.9 Who is responsible for IPM?
A. The Director approves Servicewide IPM policy.
B. The Assistant Director – Fisheries and Habitat Conservation:
(1) Designates a National IPM Coordinator to coordinate a consistent Servicewide approach to pest
(2) Designates a liaison in the Fisheries program to work closely with the National IPM Coordinator
to promote policy compliance and coordination, and
(3) Ensures the development and distribution of information on innovative and updated pest
management techniques.
C. The Assistant Director – National Wildlife Refuge System:
(1) Designates a liaison to work closely with the National IPM Coordinator to ensure the Refuge
System’s policy compliance and coordination,
(2) Supports national IPM activities, including maintenance of the national IPM and PUPS database,
(3) Designates an IPM and PUPS database administrator (owner) for the Refuge System.
D. The Assistant Director – Wildlife and Sport Fish Restoration Program encourages grantees
to implement IPM strategies when managing pest species on projects and lands for which we
provide grants.
E. The Assistant Director – External Affairs ensures that the National Conservation Training
Center develops and offers IPM and other pesticide-related training.
F. The Assistant Director – Business Management and Operations ensures we incorporate IPM
principles into procurement activities, contracts, leases, and agreements.
G. The Regional Directors:
(1) Ensure Regional compliance with this policy.
(2) Designate a Regional IPM Coordinator who informs employees about innovative and new IPM
(3) Ensure that employees receive training necessary to competently develop and implement IPM
programs. Such training may include IPM planning, pesticide applicator certification, and pest
species management.
(4) Ensure that performance plans and annual work activity guidance for employees responsible for
pest management reflect the goals and objectives of this policy.
(5) Use funds allocated for pest management for appropriate pest management projects.
(6) Ensure that staff keep records of IPM techniques, including use of pesticides, biocontrols, and
other pest management tools on lands we manage, and that these records are available as
H. The National IPM Coordinator:
(1) Develops, maintains, and distributes information about innovative and current pest management
techniques to Regional personnel.
(2) Attends and helps organize a national IPM workshop annually or as needed. This workshop is
for national, Regional, and field staff who participate in IPM activities.
(3) Serves on a Federal IPM Coordination Group with IPM Coordinators from many Federal
agencies, including the Environmental Protection Agency, U.S. Department of Agriculture, General
Services Administration, Bureau of Land Management, and the National Park Service. Serves on
other IPM coordination groups as appropriate.
(4) Approves or disapproves IPM plans and PUPs that require Headquarters review and approval to
ensure compliance with applicable laws and other authorities (see section 1.11).
(5) Promotes awareness of and compliance with the Departmental IPM policy to provide a
consistent national approach to pest management.
(6) Reviews annual Regional IPM reports, including pesticide use data, generated by the PUPS
(7) Coordinates closely with field and Regional staff implementing IPM activities to ensure
environmental compliance and to promote the most streamlined procedures and reporting methods.
(8) Works with field and Regional staff implementing IPM to develop updates, as necessary, to
national guidance, including the appropriate review level for different IPM activities (e.g., specific
pesticide applications).
I. Regional IPM Coordinators:
(1) Approve or disapprove IPM plans and PUPs requiring their review to ensure compliance with
applicable laws and other authorities (see section 1.11). This includes reviewing PUPs in an
emergency when an unanticipated outbreak occurs. If a PUP requires Headquarters review, the
Regional IPM Coordinator must send it to Headquarters even in an emergency.
(2) Provide the National IPM Coordinator with information concerning pesticide applications or other
IPM techniques, when requested.
(3) Coordinate with the National IPM Coordinator when the National IPM Coordinator has to review
a PUP from their Region.
(4) Work with the National IPM Coordinator to develop updates, as necessary, to national guidance,
including the appropriate review level for different IPM activities (e.g., specific pesticide
(5) Provide Regional personnel with information about environmental hazards and updated pest
management techniques.
J. Project Leaders:
(1) Ensure that pest management decisions are consistent with this policy, the pesticide safety
policy (242 FW 7), laws, and regulations, including, but not limited to:
(a) Local, State, and Federal requirements for informing employees and visitors of pesticide use,
(b) The Endangered Species Act (for some projects this may include consultation under section 7 of
the Act),
(c) NEPA, and
(d) The Federal Insecticide Fungicide and Rodenticide Act (FIFRA).
(2) Develop IPM plans, as appropriate, consistent with NEPA documentation.
(3) Work with the Regional IPM Coordinator to ensure pest management activities use IPM
strategies consistent with resource management goals and objectives, such as those stated in
Comprehensive Conservation Plans or similar plans.
(4) Promote and encourage IPM practices to land owners and others whose pesticide use may
affect Service lands and resources.
(5) Ensure that anyone applying pesticides, releasing biological control agents, and conducting
other IPM activities has the appropriate training and equipment necessary to protect their safety and
health (also see 242 FW 7).
(6) Ensure we apply pesticides only after the appropriate reviewer (see section 1.11) approves the
PUP. We determine who must review and approve PUPs based on pesticide characteristics and its
usage pattern. The National IPM Coordinator works with a national team of Regional IPM and
Invasive Species Coordinators to determine the level of review and approval each pesticide
(7) Help establish threshold levels of damage or pest populations according to Service or field
station goals and objectives and applicable laws.
(a) Before the treatment, verify that the site has damage levels or pest populations that exceed
threshold levels.
(b) After the treatment, determine whether the pest management action achieved the desired results
and whether there were any unanticipated or non-target impacts.
(8) Provide the Regional IPM Coordinator with summaries of IPM activities at his/her request.
(9) Ensure that staff store, handle, and dispose of pesticides and pesticide containers in accordance
with the label, as required by law, and in a manner that safeguards human, fish, and wildlife health
and prevents soil, air, and water contamination.
1.10 What kind of training do employees need before they can apply pesticides?
A. People who apply pesticides on Service lands must have proper training and pesticide
certification, as required by Federal and State laws.
B. To purchase, use, or supervise the use of Restricted Use Pesticides, the person must be a
Certified Pesticide Applicator (Commercial Applicator), under Section 4 of FIFRA or under the direct
supervision of Certified Pesticide Applicator.
(1) A Restricted Use Pesticide is a pesticide product that has a relatively high degree of potential for
human or environmental hazard even when it’s used according to label directions.
(2) We encourage people who apply general pesticides (non-Restricted Use Pesticides) or
supervise these applications to become Certified Pesticide Applicators (see 242 FW 7), even if
certification is not required by law.
1.11 What do employees have to do before applying pesticides? We may only apply pesticides
after filling out a PUP and getting PUP approval. A PUP is an online document that identifies
important considerations related to a pesticide application (e.g., goals, objectives, IPM techniques,
best management practices, pesticide application rates and methods, etc.).
A. The appropriate field station or facility employee must complete a PUP in the online PUPS
database. We use the PUPS database to develop, duplicate, submit, review, and approve or
disapprove a PUP.
B. PUP reviewer(s) examine the PUP for compliance with applicable regulations to ensure that
employees use the least risk and the most specific and effective pesticide(s) to manage the target
pest. The National IPM Coordinator works with a national team of Regional IPM and Invasive
Species Coordinators to determine the level of review and approval each pesticide receives. The
National IPM Coordinator updates this review and approval hierarchy and the resulting pesticide
lists as needed.
C. Approvals and disapprovals only apply to the specific application regime, time, location, pesticide,
and target pest.
(1) Depending on the PUP, the Project Leader may review and approve it, or he/she may send it to
the Regional IPM Coordinator for review and approval. The Regional IPM Coordinator has to send
some PUPs to the National IPM Coordinator for review and approval.
(2) Regardless of whether the PUP needs just the approval of the Project Leader or the approval of
the Regional or National IPM Coordinator, or both, each approving authority has 30 days to conduct
the review (so a PUP that has to go to the National IPM Coordinator could take up to 90 days).
(3) The review period may take longer depending on what changes the PUP may need and the PUP
workloads at the different reviewer levels. Also, an expedited PUP review may be necessary when
there is an emergency pest outbreak.
1.12 Does the Service require IPM plans for pesticide applications? No. We encourage
employees engaging in pest management practices to include a separate pest management plan or
incorporate IPM strategies into other resource planning documents (e.g., Comprehensive
Conservation Plans, Environmental Assessments, and Environmental Impact Statements). When
developing an IPM plan, we encourage employees to ensure it conforms to the parameters of an
Environmental Assessment or Environmental Impact Statement, as appropriate. Doing this benefits
Project Leaders because they may receive multi-year approvals of certain proposed pesticide uses
that would normally require Regional or national level review.
1.13 What is the relationship among IPM plans, Comprehensive Conservation Plans, and
NEPA? Employees must develop the appropriate level of NEPA documentation (conforming to the
parameters of a categorical exclusion, Environmental Assessment, or Environmental Impact
Statement) and provide public involvement, as needed, when they develop IPM plans. If you have
identified, addressed, and authorized specific pest management strategies in a Comprehensive
Conservation Plan and fully evaluated these strategies in the Comprehensive Conservation Plan’s
NEPA document, you do not need further NEPA documentation. For more information on NEPA
compliance, see Departmental and Service NEPA guidance in 516 DM 6, Appendix 1 and 550 FW
For information on the content of this chapter, contact the Division of Environmental Quality. For
more information about this Web site, contact Krista Holloway in the Division of Policy and
Directives Management.
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242 FW 7
Pesticide Users
Supersedes 242 FW 7, FWM 272,
Date: December 4, 2009
Series: Occupational Safety and
Part 242: Industrial Hygiene
Originating Office: Division of Safety
and Health
PDF Version
7.1 What is the purpose of this chapter? This chapter outlines the Service’s requirements and
responsibilities for implementing a Pesticide Users Safety Program for those involved in pesticiderelated activities on and off Service lands.
7.2 What is the Service policy for pesticide user safety? The Occupational Safety and Health
Administration (OSHA) requires that the Service protect personnel from on-the-job exposure to
pesticides (e.g., insecticides, fungicides, herbicides, or rodenticides) that can cause adverse
health effects.
7.3 To whom does this chapter apply?
A. This chapter applies to the following whose work involves mixing, formulating, loading,
applying, transporting, storing, and disposing pesticides:
(1) Service employees and staff,
(2) Volunteers,
(3) Youth Conservation Corps enrollees and supervisors, and
(4) Seasonal workers.
B. Contractors, such as cooperative farmers, and others, such as Mosquito Abatement Districts,
are responsible for their own safety and health program and must comply with OSHA and
Environmental Protection Agency requirements.
7.4 What is the scope of this chapter?
A. This chapter covers the following pesticide-related activities:
(1) Mixing, formulating, loading, applying, transporting, and storing pesticides;
(2) Disposing of pesticides and emergency spill clean-up activities; and
(3) Developing and monitoring contracts or permits involving the application and use of pesticides
by non-Service personnel on Service-owned or leased property.
B. This chapter does not cover the incidental use of “general use” aerosol pesticides sold for
home use or over-the-counter repellents intended for direct application to humans or pets. All
pesticide uses, including those excluded from this policy, are subject to Departmental and Service
Pesticide and Integrated Pest Management policies.
7.5 What are the authorities for this chapter?
A. Occupational Safety and Health Act of 1970, Section 19, Federal Agency Safety Program and
Responsibilities (Public Law 91-596).
B. Executive Order 12196, Occupational Safety and Health Programs for Federal Employees,
February 26, 1980.
C. Basic Program Elements for Federal Employee Occupational Safety and Health Programs and
Related Matters (29 CFR 1960).
D. Occupational Safety and Health Standards (29 CFR 1910, Table 1000).
E. Pesticide Programs, Worker Protection Standard (40 CFR subchapter E, Part 170).
F. Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) (7 U.S.C. 136-136y).
G. 517 DM 1, Department of the Interior Integrated Pest Management Policy.
H. Department of the Interior’s Occupational Medicine Handbook.
7.6 Who is responsible for the Pesticide Users Safety Program?
A. The Director:
(1) Ensures that we maintain an effective and comprehensive occupational safety and health
program, and
(2) Approves our pesticide users safety policy.
B. The Assistant Director – Business Management and Operations ensures that:
(1) We have a pesticide users safety policy, and
(2) Headquarters provides sufficient support and resources to implement the policy.
C. The Chief, Division of Safety and Health:
(1) Revises and updates this chapter, as necessary, and
(2) Provides interpretation of the requirements of this chapter and serves as a consultant to
resolve Servicewide issues or questions.
D. Regional Directors and the Director, National Conservation Training Center:
(1) Provide sufficient support and resources to effectively implement the requirements of this
chapter within their Regions.
(2) Ensure that staff in their Regions provide the following services:
(a) Evaluate implementation of the requirements of this chapter during safety and environmental
program audits, and
(b) Assist Project Leaders/Supervisors/Facility Managers in developing a pesticide user’s safety
program that includes job hazard assessments, emergency spill response plans, medical
surveillance procedures, storage and disposal procedures, identification of appropriate personal
protective equipment, and proper training.
(3) Ensure that staff implement procedures for protection of personal medical information in
accordance with the Privacy Act and other applicable authorities.
E. The Chief, Division of Environmental Quality provides oversight and recommendations
consistent with the safety and health requirements of this chapter when reviewing Pesticide Use
Proposals (PUPs) that require approval by Headquarters.
F. Regional Integrated Pest Management (IPM) Coordinators provide oversight and
recommendations consistent with the safety and health requirements of this chapter when
reviewing PUPs that require approval by the Regional Office.
G. Regional Safety Managers:
(1) As requested, provide technical support to Project Leaders/Supervisors/Facility Managers,
Regional IPM Coordinators, Regional Environmental Contaminants Coordinators, or other
appropriate personnel to interpret the requirements of this policy and assist with the development
of job hazard assessments; and
(2) Evaluate the implementation of the requirements of this chapter during field station safety
H. Project Leaders/Supervisors/Facility Managers must:
(1) Ensure that:
(a) Pesticide users under their supervision are enrolled in an appropriate medical monitoring
program based on the parameters in section 7.12;
(b) A physician or physician’s assistant has determined that employees who will be mixing,
formulating, loading, applying, transporting, storing, and disposing pesticides are medically able
to accomplish assigned tasks (see section 7.12); and
(c) Staff implement procedures for protecting personal medical information in accordance with the
Privacy Act and other applicable authorities (see section 7.12).
(2) Ensure that pesticide users under their supervision use the appropriate personal protective
equipment as described on the pesticide label and in accordance with an approved job hazard
assessment. If personal protective equipment requirements call for a respirator, see 242 FW 14,
Respiratory Protection for guidance.
(3) Prepare a job hazard assessment (240 FW 1), including tasks to be performed, associated
hazards, and required personal protective equipment for personnel subject to this policy.
(4) Ensure that the Material Safety Data Sheets (MSDSs) for all pesticide products used at the
station are readily available and accessible to all workers. In addition, personnel who are mixing,
formulating, loading, applying, transporting, storing, and disposing pesticides must have
appropriate labels and MSDSs at the job site.
(5) Ensure the proper handling, storage, management, and disposition of pesticides.
(6) Notify their Fire Management Officer or contracted fire fighting entities if a prescribed burn
occurs or is planned to occur or a wildlife occurs in an area treated with pesticides within 90 days
of the treatment.
(7) Consult with the Regional Safety Manager regarding the interpretation of the requirements of
this chapter.
I. Pesticide Users:
(1) Participate in medical monitoring programs (see section 7.12);
(2) Attend required training (see section 7.18) and maintain State-required certification. Provide
training completion information and copies of training certificates to the Project
Leader/Supervisor/Facility Manager;
(3) Follow all policies and procedures required for the tasks assigned;
(4) Wear the appropriate personal protective equipment as described on the pesticide label and in
accordance with an approved job hazard assessment. If personal protective equipment
requirements call for a respirator, see 242 FW 14, Respiratory Protection for guidance;
(5) Notify the Project Leader/Supervisor/Facility Manager if their physical or medical conditions
preclude assignment in pesticide-related field activities involving mixing, loading, formulating,
transporting, applying, storing and disposing pesticides; and
(6) Take corrective action within their limits of authority and report to their Project
Leader/Supervisor/Facility Manager those hazards that they cannot safely abate.
7.7 What terms do you need to know to understand this chapter?
A. Frequent Pesticide Use means when a person applying pesticide handles, mixes, or applies
pesticides, with a Health Hazard rating of 3 or higher, for 8 or more hours in any week or 16 or
more hours in any 30-day period. We consider any less frequent pesticide use to be infrequent
use. Because there are no restrictions on the frequency of using pesticides with a health hazard
rating of 1 or 2 other than what the manufacture requires on the label/MSDS, they aren’t included
when we discuss frequent use.
B. General Use Pesticides are those products that will not cause unreasonable adverse effects
when used according to widespread and commonly recognized practices.
C. Health Hazard is the potential for acute or chronic adverse health effects that can result from
exposure to a chemical or mixture of chemicals as documented through one or more scientific
studies. Chemicals can be hazardous if they are:
(1) Carcinogens;
(2) Reproductive toxins;
(3) Irritants;
(4) Corrosives;
(5) Sensitizers;
(6) Hepatotoxins;
(7) Nephrotoxins;
(8) Neurotoxins;
(9) Agents that act on the blood forming system;
(10) Agents that damage the lungs, skin, eyes, or mucous membranes; and
(11) Other toxic agents.
D. Health Hazard Rating, as defined by the National Fire Protection Association, is the degree of
health hazard of a chemical or material based on the form or condition of the material and its
inherent properties. The degree of health hazard of a material should indicate the degree of
personal protective equipment required for working safely with the material. Health hazard ratings
can be found on most MSDSs in either the “Other Information” or the “Fire & Explosives Hazard”
section. Consult the MSDS for specific health hazards and proper personal protective equipment
to use with all materials.
1 is for slightly hazardous (toxic) material that requires only minimal protection (e.g., safety
glasses and gloves) and normal work clothing to work with safely.
2 is for moderately toxic or a hazardous or moderately toxic material that requires additional
personal protective equipment or other equipment (e.g., chemical goggles, lab/work smock, local
ventilation) in addition to that required for less toxic material. Consult the MSDS for specific health
hazard and proper personal protective equipment to use with this material.
3 or 4 is for highly to extremely toxic (deadly) materials (and any carcinogen, mutagen, or
teratogen). These materials require specialized equipment (e.g., respirator or exhaust hood, full
face shield, rubber apron, specialized gloves, handling tongs, etc.) beyond that required for
moderately toxic material. You must consult the MSDS and other safety information to determine
the hazard (acute or chronic) and the proper personal protective equipment and engineering
controls to safely use this material.
E. Integrated Pest Management (IPM) is a sustainable approach to managing pests by
combining biological (e.g., natural predators), cultural (e.g., crop rotation), physical (e.g., traps),
and chemical tools in a way that minimizes economic, health, and environmental risks.
F. Permissible Exposure Limit (PEL) is the maximum amount of exposure to, inhalation of, or
skin contact with chemical or physical agents under the Occupational Safety and Health Act.
G. Pest is:
(1) Any insect, rodent, nematode, fungus, weed; or
(2) Any other form of terrestrial or aquatic plant or animal life or virus, bacteria, or other
microorganism (except viruses, bacteria, or other microorganisms on or in living man or other
living animals) that the Environmental Protection Agency declares to be a pest under FIFRA.
H. Pesticide is any substance or mixture of substances intended for controlling, preventing,
destroying, repelling, or mitigating any pest, and any substance or mixture of substances intended
for use as a plant regulator, defoliant, or desiccant.
I. Pesticide Users are those whose work involves mixing, formulating, loading, applying,
transporting, storing, and disposing pesticides.
J. Restricted Use Pesticide (RUP) is a pesticide that is available for purchase and use only by
those certified to apply pesticide or people under their direct supervision. Pesticides are
designated as RUPs because of their relatively high degree of potential human or environmental
hazard even when used according to label directions.
K. Threshold Limit Values are airborne concentrations of substances and represent conditions
under which the safety and health industry believes that nearly all workers may be repeatedly
exposed without adverse health effects. The American Conference of Governmental Industrial
Hygienists establishes threshold limit values.
7.8 What are the safety and health issues Service employees should consider when
addressing pesticide user’s safety? All offices involved with pesticide-related activities must
consider a large amount of safety and health information before starting field work.
A. Those applying pesticides and their Project Leaders/Supervisors/Facility Managers must
consider, at a minimum, the following types of health and safety information:
(1) Job hazard assessments,
(2) Pesticide application guidelines,
(3) Medical monitoring programs,
(4) Training,
(5) Certification,
(6) Storage and disposal, and
(7) Documentation.
B. We encourage employees to use pesticide products that deliver the intended effect and pose
the least hazard.
7.9 What are the elements of a Job Hazard Assessment?
A. The Project Leader/Supervisor/Facility Manager evaluates projects requiring the use of
pesticides to identify specific hazards including those related to the pesticide, method of
application, site to be treated, and personal protective equipment required. We must be careful to
ensure that employees and the public are not exposed to harmful quantities of chemicals that are
known or suspected of causing adverse human health. Before using pesticides, managers must
comply with the requirements of this chapter, pesticide labels, and other applicable Service
policies (also see 240 FW 1). For an example of job hazard assessment for pesticide-related
activities see Exhibit 1 (PDF file).
B. Project Leaders/Supervisors/Facility Managers must maintain MSDSs for each hazardous
chemical used during pesticide-related activities and ensure they are readily accessible to
employees engaged in pesticide-related activities.
7.10 What are the guidelines for Service pesticide users? We must:
A. Consider the use of pesticide products that deliver the intended effect and pose the least
hazard to human health.
B. Mix, formulate, load, apply, transport, store, and dispose of pesticides in a manner consistent
with the methods, rates, and equipment specified on the label and applicable State and local
C. Select application methods that minimize exposure to the people applying them, other
employees, the general public, and non-target organisms.
D. Apply pesticides in or around Service residences, dormitories, and offices at a time dictated by
the product’s element of risk (i.e., high risk to low risk). Those products with a high risk to human
health will often have a required “Re-entry Interval” (REI) indicated on the label or MSDS. Those
with a low risk to human health (e.g., ant or cockroach bait traps) will not have such restrictions
and require no occupancy limitations. Project Leaders/Supervisors/Facility Managers at facilities
using products that have an REI indicated on their label must restrict access to that facility or area
for the duration of the REI.
E. Ensure that procedures and necessary supplies are provided at the field stations to address
pesticide mixing and loading areas for containment and cleanup of spilled chemicals and for
backflow prevention (anti-siphoning devices) on water sources so that piped drinking water
supplies aren’t contaminated (see 29 CFR 1910.151).
F. Notify employees, visitors, volunteers, and the public, as appropriate, before applying
pesticides that have a required REI. This notification must be a posting that indicates a point of
contact, the point of contact’s telephone number, and the REI.
7.11 What are the components of our medical monitoring program? We have implemented a
medical program that requires personnel who engage in pesticide-related activities, as described
in section 7.12, to undergo a medical examination and medical monitoring. The examinations are
to assess an individual’s ability to safely perform pesticide-related activities. Subsequent
monitoring (i.e., laboratory testing) assists the occupational health professional to detect any
absorption through the skin, gastrointestinal system, or by inhalation. Occupational health
professionals also use medical examinations and monitoring results to assess body burden,
reconstruct past exposure, monitor work practices, and assess the effectiveness of personal
protective equipment and in-place controls.
7.12 Who is included in the medical monitoring program?
A. We include personnel in the medical examination and monitoring program if they:
(1) Have been exposed or may be exposed to concentrations at or above the published
permissible exposure limits or threshold limit values (see 242 FW 4);
(2) Use pesticides in a manner that that we consider “frequent pesticide use” (see section 7.7); or
(3) Use pesticides in a manner that requires a respirator (see 242 FW 14 for respirator use
B. Under some circumstances, we may include employees who use pesticides infrequently (see
section 7.7), experience an acute exposure (sudden, short term), or use pesticides with a health
hazard ranking of 1 or 2 in the medical examination and monitoring program. We base the
decision about whether or not to include them in medical monitoring on the individual’s health and
fitness level, the pesticide’s specific health risks, and the potential risks from other pesticiderelated activities.
C. If you are using or considering the use of a product that does not have a National Fire
Protection Association health hazard rating, consult with your Regional safety office or the
Division of Safety and Health. Also consider the points in Table 7-1 to make informed decisions
on setting a rating when one doesn’t exist.
Table 7-1: Product Factors for Consideration
Ask the following when a product doesn’t have a
National Fire Protection Association Health Hazard Rating...
Does the product have any constituents that are carcinogens?
Where does the product’s technical information fall within the Health Hazard and Health
Hazard Rating definitions?
How are you applying or planning to apply the product?
How much personal protective equipment is required?
7.13 Who determines if medical monitoring is necessary? The Regional Safety Manager,
Project Leader/Supervisor/Facility Manager, and occupational health professional(s) should
collectively make the decision about whether to include an employee in the medical monitoring
program based on the criteria in section 7.12.
7.14 How does the Service use the results of medical monitoring? We use the results of
medical monitoring to identify whether an employee has been exposed to pesticides, reevaluate personal protective equipment selection and handling procedures, and determine if an
employee is eligible for continued participation in pesticide-related activities. If examinations or
monitoring test results indicate that an employee is not physically able to participate in routine
pesticide-related activities because of occupational exposure to pesticides or other medical
conditions, we remove the employee from exposure. These activities may not be resumed without
a medical release.
7.15 Where do personnel go for pesticide-related medical services? We encourage the
Regions to use the Federal Occupational Health (FOH) units of the U.S. Public Health Service
(USPHS) to the extent possible. You can use other sources of occupational health services (i.e.,
local clinics or private physicians) if available. See Exhibit 2 for guidance on the examination
7.16 What are the requirements of medical examinations?
A. We require an exam (baseline, periodic, and termination) that constitutes a medical history,
exposure history, and complete physical examination for all participants in the medical monitoring
program. Typically the frequency of monitoring (e.g., blood counts) is annual, but the occupational
health professional may require more or less.
B. Not participating in any phase of a required medical examination/monitoring program may
result in disciplinary action, reassignment, or in a worse case scenario, dismissal from the job.
C. A Reviewing Medical Officer uses examinations and laboratory test results to determine
whether to issue clearance for an employee to conduct pesticide-related activities. The clearance
states whether or not the person is physically and medically able to perform his/her duties. If the
official determines an employee is unable to perform his/her duties or places restrictions on
activities, the clearance document states this and identifies the reasons.
D. See Table 7-2 for a list of the forms we use for pesticide medical exams.
Table 7-2: Medical Exam-Related Forms
FWS Form 3-2395, Recommended Exams & Tests for Pesticide Users
FWS Form 3-2396, Pesticide Use Profile
FWS Form 3-2397, Pesticide Exam Medical Release & Physician Clearance
FWS Form 3-2399, FOH Medical History and Examination Form for Pesticide Workers
E. We set up these exams as a joint protocol so that we can also use them for people with
additional duties, such as Arduous Duty Wildland Fire Fighters. (The requirements meet those of
the fire medical standards annual exam.) The employee should take Exhibit 3 (PDF file) with them
to the doctor as well as the other forms listed in Table 7-2.
F. Employees who have participated in the medical monitoring program described in this chapter
must be provided with a termination physical examination before their separation date from the
G. All examination and laboratory test results must be sent to the Service’s Reviewing Medical
Officer for Pesticide Applicators for review (see Exhibit 2).
7.17 What are the requirements for mixing, storing and disposing of pesticides? We must:
A. Mix and store all pesticides in accordance with the pesticide labels and applicable Federal,
State, and local laws and regulations.
B. Separate pesticides from flammable or incompatible chemicals and secure them from
unauthorized access. Provide good ventilation and secondary containment in the storage,
preparation, and mixing areas. Maintain in an accessible location chemical spill kits that are
compatible for the pesticides stored or used.
C. Label portable pesticide containers with the name of the chemical and appropriate hazard
D. Dispose of all pesticide containers in accordance with the pesticide label. This may involve
triple rinsing containers into the sprayer, if possible.
E. Protect storm and sanitary drains from spillage. Never put pesticides into the sewer or trash
without proper clearance from regulatory agencies.
F. Ensure expired or unneeded pesticides are properly identified, managed, and disposed of in
accordance with Federal, State, and local regulations. Contact local and State regulatory
agencies for approved disposal options and facilities.
G. Maintain an inventory of pesticides, their use, and a record of the final disposition of any
7.18 What are the training requirements for applying pesticides? We must train personnel
before they begin work with pesticides.
A. Pesticide users must have pesticide training and certification required by applicable policies
and regulations. The Environmental Protection Agency (EPA) regulations require that people
applying pesticides be certified as competent to apply Restricted Use Pesticides. States,
territories, tribes, and some Federal agencies have EPA-approved certification programs. For
safety reasons, we also encourage all personnel who conduct pesticide-related activities with
general use pesticides to acquire pesticide applicator certification. Verify with the applicable State
whether the certification requirement is for a commercial or private applicator.
B. Project Leaders/Supervisors/Facility Managers and other employees involved in pesticiderelated activities (i.e., general use application) must be trained to recognize potential hazards and
minimize personal exposure by using proper procedures and personal protective equipment. We
achieve this through a comprehensive hazard communication program (see 242 FW 2). The
hazard communication program must specifically address:
(1) Signs and symptoms of over-exposure to pesticides;
(2) Appropriate selection and use of personal protective equipment;
(3) Proper type and limitations for pesticide applications as outlined in an applicable job hazard
(4) Proper use, storage, spill containment, and disposal of pesticides. The Regional Spill
Coordinators can give you information on spill response training;
(5) Legal requirements for following all instructions on the pesticide label; and
(6) Users’ ability to read and understand MSDSs.
7.19 Are there any other safety requirements associated with applying pesticides? All
personnel must follow these additional safety requirements and personal safety practices to
minimize the risk of exposure during pesticide-related activities:
A. Employees must not eat, drink, chew gum or tobacco, smoke, etc. while conducting pesticiderelated activities.
B. After conducting pesticide-related activities, employees must thoroughly wash their hands and
face. If applying pesticides at a field location where there is no access to hand washing facilities,
the applicators should carry hand wipes in their vehicle so they can wipe off their hands and face
before eating and drinking.
C. We do not allow employees to apply pesticides that require tight-fitting, negative pressure
respirators (see 242 FW 14) if their facial hair interferes with the mask-to-face seal.
D. Avoid contact with pesticide-contaminated surfaces or treated areas. For example, do not walk
through puddles or other discolored surfaces, kneel on the ground, or place equipment on
containers or on visibly contaminated surfaces. Adhere to a pesticide’s REI.
E. Provide suitable facilities for quick drenching or flushing of the eyes and body within the
immediate work area where contact with materials occurs.
7.20 What are the personal protective equipment requirements? Personal protective
equipment selection and use varies depending on the chemical you are mixing, loading, or
applying; where it is used; and how it is used. Employees may use more personal protective
equipment than what is required as long as it does not create additional hazards.
A. All personal protective equipment use and maintenance, including cleaning and storage, must
comply with the pesticide label and 241 FW 3, Personal Protective Equipment.
B. Employees required to wear respirators during pesticide application must comply with all
elements of their station’s Respiratory Protection Program (see 242 FW 14 and 29 CFR
C. If personnel wear non-disposable clothing (i.e., uniforms or coveralls, etc.) when applying
pesticides, they must keep that clothing separate from the clothing they take home, and they must
not wash that clothing at home. If suitable laundry equipment is not provided, then personnel who
conduct pesticide-related activities must use disposable clothing (e.g., coveralls).
D. Personnel must change clothing they wear during applications before using vehicles or
entering office locations. Personal protective equipment and other equipment must be
decontaminated when operations are complete.
7.21 What are the documentation requirements for this chapter?
A. Project Leaders/Supervisors/Facility Managers must retain:
(1) A written record of all pesticide-related training and other training that addresses safe handling
of pesticides that employees receive (see section 7.18),
(2) Job hazard assessments for as long as the related projects last,
(3) Exposure sampling results for a minimum of 30 years [29 CFR 1910.1048(o)],
(4) Respirator fit testing and medical clearance records until replaced by a more recent record,
(5) Medical clearance for doing pesticide-related activities until a new clearance is received, and
(6) A written record of routine monthly flushing of eyewashes and emergency showers, and any
periodic maintenance performed per the manufacturer’s standards for portable eyewash units.
B. The servicing Human Resources office must retain all medical evaluations such as physician
opinions, physical exam results, physical exam supporting documentation, etc. for, at a minimum,
the length of employment plus 30 years. Human Resources should retain these documents in the
employee’s Employee Medical Records, SF-66D.
C. We must collect and maintain records containing personal information (e.g., medical
evaluations and physician statements, etc.) in compliance with 5 U.S.C. 552a (The Privacy Act of
1974). Employees tasked with storing and maintaining such records must read and be familiar
with OPM/GOVT-10. These records:
(1) Are sensitive and protected by The Privacy Act (see 204 FW 1 – 8 for more information on the
Privacy Act),
(2) Must only be available to staff on a need-to-know basis,
(3) If electronic, must be password protected and only used in accordance with the routine uses
identified in “OPM/GOVT-10, Employee Medical File System Records,” and
(4) If hard copy, protected in a locked file and locked room that is available only to staff who have
a need to know this information in accordance with OPM/GOVT-10.
For information on the content of this chapter, contact the Division of Safety and Health. For
information about this Web site, contact Krista Holloway in the Division of Policy and Directives
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FTS 27: O&M Best Practices for
Small-Scale Photovoltaic Systems
PV Corrective Maintenance - Service Descriptions
Service Description
Dispatch contractor in response to alarms,
alerts, or contact by others
As needed
Warranty coordination: adminster timely
response for claims and repairs
As needed
Admin Asst
AC wiring
Replace inverter AC fuse(s)
As needed
AC wiring
Replace protective devices (breakers) in
building panel
As needed
AC wiring
Replace broken/crushed AC wiring conduit
and fittings
As needed
AC Wiring
Repair line-to-line fault
As needed
AC Wiring
Locate line-to-line fault
As needed
DC Wiring
Replace failed fuses in combiner box.
As needed
DC Wiring
Replace any electrical boxes that have
extensive corrosion, make sure junction boxes
are sealed.
As needed
DC wiring
Replace MC Connectors between modules
As needed
DC wiring
Replace MC connector lead to combiner box
As needed
DC wiring
Replace failed fuses in combiner box
As needed
DC wiring
Replace fuse(s) on DC source circuits to
As needed
DC wiring
Re-route conduit
As needed
DC wiring
Replace broken/crushed Dc wiring conduit
and fittings
As needed
DC Wiring
Repair ground fault
As needed
DC Wiring
Locate ground fault
DC wiring
Locate underground DC wiring
As needed
Replace fuse
As needed
Start/stop inverter
(reboot to clear unknown error)
As needed
Replace inverter fan motor
As needed
Replace inverter data acquisition card/board
(also called system input module); diagnose with
fault code
As needed
Replace inverter data acquisition card/board;
diagnose with fault code
As needed
Service Description
Replace inverter control card (PWM signal,
voltage, phase, frequency, shut-down);
diagnose with fault code
As needed
Replace IGBT driver card/board; diagnose with
fault code
As needed
Replace maximum power point tracker card/
board; diagnose with fault code
As needed
Replace AC contactor in inverter
As needed
Replace IGBT matrix in inverter
As needed
Replace 24VDC power supply for inverter
As needed
Replace DC contactor in inverter
As needed
Replace surge protection in inverter
As needed
Replace GFI components in inveter
As needed
Replace capacitors in inverter
As needed
Replace inductors (coils) in inverter
As needed
Replace fuses internal to inverter
As needed
Replace inverter relay/switch
As needed
Replace overvoltage surge suppressors for
As needed
RE-install inverter control software
As needed
Restore lost internet connection
As needed
PV Array
Repair or replace rack parts damaged by
corrosion or physical damage
As needed
PV Array
Excavate and replace failed foundation element
As needed
PV module
Replace modules failing performance test after
showing cracks in glazing, discoloration of
metallic contacts, delamination or signs of water
As needed
PV module
Clean, re-do connections, and re-seal junction
box showing corrosion of connections.
As needed
PV module
Replace modules showing delamination of
encapsulant and back sheet
As needed
PV module
Repair cracking of PV module back sheet
As needed
PV Module/
Array Specialist
PV module
Repair or replace damage to module frame
As needed
Repair roof leaks
As needed
Service Description
Re-roof (new roof)
As needed
Roof leak repair
As needed
roof tile repair
As needed
Roof replacement; re-roof
As needed
Repair/replace tracker drive shaft
As needed
Replace tracker drive bearing
As needed
Replace tracker mount bearing
As needed
Replace tracker motor controller
As needed
PV Module/
Array Specialist
Replace/upgrade tracker control software
As needed
PV Module/
Array Specialist
Replace transformer
As needed
Re-tap transformer
As needed
Replace terminal block
As needed
Upgrade inverter control software
5 Years
PV module
Tighten loose mounting hardware
As needed
AC wiring
Locate underground AC wiring
As needed
Utilities Locator
federal energy management program
Federal energy management program
FTS 27: O&M Best Practices for
Small-Scale Photovoltaic Systems
Federal Legislation and Executive Orders
Energy Policy Act of 2005
EPAct 2005 defines “renewable energy” as electric energy generated from solar, wind, biomass, landfill gas, ocean (including tidal,
wave, current, and thermal), geothermal, municipal solid waste, or new hydroelectric generation capacity achieved from increased
efficiency or additions of new capacity at an existing hydroelectric project.
The Act requires the Secretary of Energy to ensure that, to the extent economically feasible and technically practicable, that not
less than 7.5% of the total electricity consumed by the Federal Government come from renewable energy by fiscal year 2013
and thereafter.
EPAct provides a bonus to federal agencies by allowing them to double count renewable energy if it is produced:
On-site and used at a federal facility
On federal lands and used by a federal facility
On Native American land and used at afederal facility
Energy Independence and Security Act of 2007
EISA 2007 requires new buildings and major renovations of federal buildings to reduce fossil fuel consumption relative to 2003 by:
65% by 2015
80% by 2020
100% by 2030
Another section of EISA 2007 requires that 30% of the hot water demand in new federal buildings (and major renovations) be met
with solar hot water equipment provided it is life-cycle cost-effective.
EISA 2007 also makes it easier for federal agencies to finance renewable energy projects through energy savings performance
contracts (ESPCs) through the following:
Project funding flexibility is increased by allowing agencies to combine appropriated funds and private financing.
Contract length limitations to less than 25 years are also restricted, as are total obligation amount limitations.
In addition, EISA 2007 expanded the definition of ESPC to address the use of excess electrical or thermal energy generated from
on-site renewable sources.
Executive Order (EO) 13423, Strengthening Federal Environmental, Energy, and Transportation Management
Executive Order 13423 reinforces previous legislative renewable goals. Specifically, the order mandates that at least half of renewable
energy used by the Federal Government must come from new renewable sources (in service after January 1, 1999).
Non-electric renewable resources (e.g., solar water heating) can be used to meet this requirement, but all of the EPAct 2005 goal must
be met with renewable electricity.
Consider this example: if an agency met the 7.5% by 2013 EPAct goal with wind turbines that was built before 1999, then they it
could use new solar water heaters to meet the E.O 13423 requirement that 3.75% be new (after 1999).
federal energy management program
Federal Leadership in Environmental, Energy & Economic Performance (E.O. 13514)
Executive Order 13514 makes reduction of greenhouse gas (GHG) emissions a priority for federal agencies. The goal is to reduce
GHG emissions 28% by 2020, with the baseline year of 2008. This EO also sets non-numerical targets that agencies must reach that
include increasing renewable energy and renewable energy generation on agency property.
E.O. 13514 requires federal agencies to annually assess, measure, and report Scope 1, 2, and 3 GHG emissions. It allows Agencies to
see what has been achieved, and offers a great opportunity to show energy use and costs reductions
Presidential Memorandum on Federal Leadership on Energy Management
The Presidential Memo issued in 2013 states that each agency shall ensure that the percentage of the total amount of electric energy
consumed by that agency that is renewable energy is not less than:
10% in fiscal year 2015;
not less than 15 percent in fiscal years 2016 and 2017;
not less than 17.5 percent in fiscal years 2018 and 2019; and
not less than 20 percent in fiscal year 2020 and each fiscal year thereafter.
This should be accomplished by (in order of priority):
Installing agency-funded renewable energy on-site at federal facilities and retain renewable energy certificates;
Contracting for energy that includes the installation of a renewable energy project on-site at a federal facility or off-site from
a federal facility and the retention of renewable energy certificates for the term of the contract;
Purchasing electricity and corresponding renewable energy certificates;
Purchasing renewable energy certificates.
FTS 27: O&M Best Practices for
Small-Scale Photovoltaic Systems
Federal Funding Opportunities
Congressional Appropriations
Congressional appropriations allow the government to have control over, and responsibility for the site’s PV project. A site should
look to round out appropriations with private sector project funding when possible through proven contract vehicles, such as ESPCs
and UESCs.
Congressional appropriations can include: Capital Construction, Energy Efficiency and Renewable Energy Funding, or Operations
and Maintenance Funding.
There are advantages to appropriated funding. It provides the lowest cost of funding: and there are no financing charges, overhead
charges, or other associated charges. The agency also retains all of the cost savings and other environmental attributes associated
with the power generated.
GSA procurement schedules include several qualified bidders that provide solar panels, inverters, and complete systems, including
professional services that provide turn-key operations.
Utility Energy Service Contracts, or UESCs
With a UESC, photovoltaic projects can be bundled with energy efficiency projects, into a long-term contract with a serving utility.
In these contracts, the capital cost of PV systems can be offset by less-expensive efficiency projects and amortized over a long period
of time.
Utility Energy Service Contracts are authorized by the Energy Policy Act of 1992 and the National Defense Authorization Act of 2007.
Under a UESC, the serving utility arranges to provide funding to cover the costs of the project, which are then repaid over the contract
term from the cost savings that are generated by the project’s energy efficiency measures.
There are three types of UESCs that can fund renewable technologies: A GSA Areawide Contract, a Basic Order Agreement, and a
Separate Contract. Specific Task Orders for projects can be placed under these contracts or agreements.
There are advantages of using a UESC contracting vehicle. First, the utility and agency may already have an existing relationship and
the utility may have a good knowledge of the needs of the site. Second, the UESC can provide a streamlined acquisition process to
contract for energy management services. And third, utilities have high credit ratings, low costs of financing, and low risks for longterm investments.
Energy Savings Performance Contracts, or ESPCs
With ESPCs, PV can be developed as an energy conservation measure (ECM) and be included within the ESPC contract.
ESPCs are authorized by EPAct, and can be an excellent way to finance photovoltaic systems. Within an ESPC, it is possible for PV
technology and equipment to be “bundled” with other energy conservation measures.
The advantages to implementing a PV project as part of an ESPC is that it requires no up-front capital investment by the government;
the ESPC Energy Service Company guarantees performance, and the contract can extend to a 25-year term. Long-term ESPCs allow
the initial cost of the renewable energy technology to amortize over a longer period of time.
ESPC ENABLE offers the same benefits as a conventional ESPC while at the same time, taking advantage of the GSA Schedule and
its set of pre-qualified vendors and pre-negotiated pricing. This allows for a faster selection process so that a project can be designed
and installed quickly.
Through the ESPC ENABLE program, smaller federal facilities now have the opportunity to upgrade old equipment and finance
renewable systems such as photovoltaics
ESPC ENABLE now includes two new ECMs: solar photovoltaic (PV) and simple one-for-one heating, ventilation, and air
conditioning (HVAC) system replacement (small building systems). Examples of equipment that may be installed under these
new ECMs include:
- Solar PV,
- Ground, roof, or parking canopy mounted,
- Fixed and tracking arrays, and
- Grid-tied and off-grid.
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