Hot Asphalt Fumes - Asphalt Roofing Manufacturers Association

Hot Asphalt Fumes - Asphalt Roofing Manufacturers Association
Recommended Practices for Controlling Asphalt Fume
Exposures during Hot Asphalt Roofing Jobs
Introduction
Effective Temperature Management
Controlling worker exposures to asphalt fumes and
particulates should be a priority on every hot asphalt roofing
job. Although inhalation exposures to fumes in hot asphalt
roofing work are, on average, at or below recommended
health-based limits, higher exposures are not uncommon,
especially for kettle operators but also, to a lesser extent, on
the roof. In addition, asphalt fumes can condense onto the
skin, and some of the chemicals in asphalt can be absorbed
through the skin. ARMA and NRCA recommend the use of
good temperature management and practical exposure
control practices to reduce potential health and safety risks,
minimize odor complaints, and improve working conditions
while ensuring a quality roof installation.
Temperature control is essential on every hot asphalt roofing
job for three reasons: (1) hot asphalt roof construction
requires that the asphalt be applied within a specified
temperature range in order to reduce the risk of roof failure
or reduced service life; (2) overheating the asphalt can cause
kettle fires or explosions; and (3) health scientists agree that
heating asphalt to higher temperatures results in significantly
higher worker exposures to fumes – scientific studies indicate
that, at the temperatures needed for commercial application
of hot asphalt, roofer exposure to asphalt fumes can be cut
in half by reducing temperatures by 50°F [28°C]. Effective
temperature management involves the following steps:
Continued on pg 2
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Recommended Practices for Controlling Asphalt Fume Exposures during Hot Asphalt Roofing Jobs
„„ At the start of every job the supervisor or foreman should
identify two important temperature targets: (1) the
maximum kettle temperature, and (2) the recommended
application temperature.
zz The maximum kettle temperature is intended primarily
to minimize the risks of kettle fires and explosions that
can occur if asphalt is overheated. In the great majority
of cases, the maximum kettle temperature will be
550°F [288°C] as recommended in the current ASTM
specification for roofing asphalt (ASTM D312-15).
zz The recommended application temperature refers to
the temperature of the asphalt taken at the point of
application on the roof (such as the mop bucket or
mechanical spreader). On built-up roofing (BUR) jobs, the
recommended application temperature is the “equiviscous
temperature,” or EVT, and the application temperature
target is expressed as EVT ± 25°F [EVT ± 14°C]. EVTs can
vary. On jobs involving hot application of other asphalt
roofing products such as modified bitumen and fleecebacked membranes, observe the application temperature
specified by the product manufacturer.
„„ The job supervisor or foreman should always assign the
kettle operator and a member of the rooftop crew to
work together to help ensure that the proper asphalt
temperatures are maintained in the kettle and at the point
of application on the roof.
zz Prior to the beginning of the job, the supervisor
or foreman should inform the kettle operator and
responsible member of the rooftop crew of the asphalt
application temperature and maximum kettle temperature
which will be used for the job.
zz The responsible member of the rooftop crew should take
temperature readings from the application equipment
(mop buckets or the reservoirs of mechanical asphalt
spreaders and asphalt felt-laying machines) as needed
to ensure that proper application temperature is being
maintained, and report the readings to the job supervisor
or foreman. NOTE: Temperatures should be taken
after the application equipment has been in use long
enough to reach the same temperature as the asphalt.
Temperatures should be measured with a properly
calibrated immersion probe or kettle thermometer. If
a thermocouple or thermometer is used, it should be
inserted into the asphalt long enough to reach a constant
temperature. The use of infrared thermometers is not
recommended because they measure surface rather than
internal temperature, which is necessary for proper EVT
application.
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zz The kettle operator should always keep the kettle
temperature below the maximum kettle temperature.
However, based on the readings at the point of
application, the kettle operator should wherever possible
reduce the kettle temperature even further, and set it at
the lowest temperature that maintains the recommended
application temperature.
zz The kettle operator should observe the following guidelines
to monitor the temperature of the asphalt in the kettle:
• Always skim the asphalt in the kettle before taking
temperature readings to avoid stagnant layers. Do not skim if
using a fume-suppressing asphalt.
• If the kettle is controlled manually, monitor the temperature
of the asphalt at least every 30 minutes.
• Take manual temperature readings using a stem thermometer
inserted just below the surface of the asphalt. Avoid hot
spots inside the kettle such as the heating coil.
• Verify temperature readings with the temperature gauge
on the kettle by using a hand-held immersion probe
(thermocouple or thermometer).
„„ All members of the crew working with hot asphalt should
follow simple steps to minimize heat loss. By keeping
heat loss to a minimum, the kettle can be operated at a
lower temperature while maintaining the recommended
temperature at the point of application.
zz On the roof, always keep the lids closed on reservoirs of
luggers, mechanical asphalt spreaders, and asphalt feltlaying machines except when necessary to re-fill them.
zz When transferring hot asphalt from the hot lugger to
mop carts, spreaders or felt-laying machines on the roof,
use the lugger’s draw-off valve/spigot at the proper height
to avoid splash hazards and reduce heat loss.
zz Keep the kettle lid closed except when performing
necessary operations such as refilling the kettle, skimming,
and taking temperature readings. This not only reduces
heat loss but also reduces fume exposures from the kettle.
zz Minimize the frequency of kettle lid opening by:
• Filling the kettle to the maximum recommended fill level
(usually within 4 to 6 inches of the top).
• Chop the asphalt keg into small, manageable pieces before
the refill operation to allow the asphalt to melt more quickly.
• When reloading, spread the asphalt chunks throughout the
kettle so they will melt evenly and rapidly. This prevents “cold
spots” which can cause the temperature control feature of
the kettle to keep the burners fired, resulting in overheating.
• Combine tasks so the lid does not need to be opened more
often than necessary: For example, when the lid is opened
for reloading, skim the asphalt as needed and take a manual
temperature reading.
Recommended Practices for Controlling Asphalt Fume Exposures during Hot Asphalt Roofing Jobs
Job-SetUp
„„ Choice of Asphalt: Wherever possible, always choose an
asphalt that meets ASTM D312-15 specifications.
CAUTION: If an asphalt not complying with ASTM D31215 specifications is used, it is critical to recognize that
ASTM D312-15 specifies a minimum flashpoint of 575°F
[302°C]. Noncompliant asphalts – including asphalts
meeting previous versions of ASTM D312, and other ASTM
and manufacturer specifications, as well as Canadian
and other international standards – may allow lower
flashpoints. The new 550°F [288°C] maximum kettle
temperature specified in ASTM D312-15 would pose
significant safety risks if used for asphalts with flashpoints
below 575°F [302°C]. Kettle temperatures should be
maintained at least 25°F [14°C] below the flashpoint
whenever using noncompliant asphalts with flashpoints
lower than 575°F [302°C].
„„ Kettle Size: Always use a kettle with a capacity
appropriate to the job. Kettles that are too small must be
refilled more often. In addition, introducing cold asphalt
into an undersized kettle can have a bigger impact on the
overall asphalt temperature in the kettle, making control
more difficult.
„„ Prevent Overheating: Whenever available, choose
kettles that –
zz are insulated, and
zz have working thermometers, thermostatic controls, and
automatic shutoff mechanisms.
„„ Reduce Heat Loss: Whenever possible –
zz choose kettles with higher pumping speeds that reduce
heat loss during transfer;
zz insulate the hot pipe; and
zz use insulated rooftop containers such as the lugger and
reservoirs on asphalt spreaders and felt-laying machines.
„„ Kettle/Tanker Location: Consider the following factors:
zz Distance to Roofing Work: Reducing the distance from
kettle/tanker to point of application minimizes heat
loss, permitting the kettle to be operated at lower
temperature.
zz Prevailing Wind Direction: Whenever practical, place the
kettle/tanker downwind from the building being roofed to
reduce worker exposure and odor complaints.
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zz Kettle Orientation: For the same reasons, always locate the
kettle so that, when open, the inside of the kettle lid faces
away from the building being roofed.
„„ Restrict access to the area surrounding the kettle/tanker
using warning tape, traffic cones, and/or signs. The
restricted area should be large enough to keep the public
and other employees away from contact with the kettle/
tanker and to allow sufficient space for the kettle/tanker
operator to work.
„„ Work with building management to ensure that
appropriate measures are taken to prevent asphalt fumes
from entering the building through windows and other
air intakes, for example, by covering or closing such
intakes and/or temporarily shutting down the heating and
ventilation system.
„„ Kettle Maintenance:
zz Inspect thermometers, thermostats and automatic
shutoffs before each job and daily when in use.
zz Calibrate these devices in accordance with manufacturer
instructions. If manufacturer recommendations are
unknown, calibrate at least monthly.
zz Make sure the kettle lid fits tightly.
„„ Poorly Ventilated Spaces: For work in partially confined
or poorly ventilated spaces (such as under eaves),
consider using fans to blow asphalt fumes away from the
work area. Fans should be electrically grounded and kept
out of walking paths and areas where contact with hot
asphalt may occur. Inspect fans and other devices daily
when in use.
„„ SDSs and Manufacturer Recommendations: Observe
recommended precautions for asphalt and non-asphalt
components of the product in SDSs and product
installation guides.
Work Practices for Reducing
Worker Asphalt Exposures
„„ Kettle operators should work upwind of the kettle
opening wherever possible.
„„ Workers applying hot asphalt on the roof should work
upwind of fume sources whenever possible. Rooftop fume
sources include hot luggers, mop carts, spreaders, feltlaying machines and roof surfaces where hot asphalt is
being applied.
Recommended Practices for Controlling Asphalt Fume Exposures during Hot Asphalt Roofing Jobs
„„ On re-roofing jobs involving the removal of an existing
asphalt roof, observe the equipment and work practice
recommendations in the companion ARMA/NRCA
publication: “Recommended Practices for Controlling
Asphalt Exposures during Tear-Offs of Asphalt Roofs”
Fume Emission Controls
Where feasible and appropriate for the job, use one or more
of the following controls:
„„ Fume-Suppressing Asphalt: These products, which
are made by adding small amounts of polymer to the
asphalt, have been shown by the National Institute for
Occupational Safety and Health (NIOSH) to reduce worker
fume exposure and energy loss.
„„ Wax Modified Asphalt: Some BUR asphalts on the market
are formulated for application at temperatures lower than
standard products. This allows the kettle to be operated at
lower temperatures, resulting in reduced fume emissions
both at the kettle and on the roof.
„„ Kettle Engineering Controls: Kettles can be equipped
with several different types of emission control systems,
including:
zz loading devices allowing the kettle to be refilled without
opening the lid; or
zz afterburner and filtration systems which burn or condense
fumes collected from the headspace inside the kettle.
Regardless of which system is used, manufacturer
instructions on use and maintenance of the equipment must
be strictly followed to minimize fire and explosion risks.
Protective Clothing and Equipment
All employees working with hot asphalt should wear:
„„ Goggles or safety glasses with side shields; consider
safety glasses that have added protection from airborne
emissions, such as foam padded safety glasses.
NOTE: Kettle operators should wear full-face shields
attached to their hard hats over their safety goggles/
safety glasses.
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„„ Nonskid shoes with leather uppers that cover the ankles
„„ Long cuff-less pants
„„ A long-sleeved shirt made from cotton or other materials
that will not melt. Do not wear materials, such as nylon
and polyester, which can melt.
„„ Leather or thick cotton gloves with cuffs tight at the wrist
„„ Hard hats where designated by the site safety plan.
Personal Hygiene Practices
„„ Work clothing that comes into contact with asphalt
fumes should be removed as soon as possible after each
workday, should be kept separate from other clothing,
and should not be re-worn unless laundered.
„„ Workers should wash exposed areas of the skin with
soap and water as soon as possible after each shift and,
if possible, before eating, drinking, smoking, chewing
tobacco or gum, applying cosmetics, or using toilet
facilities. Fuels, solvents and other industrial chemicals
should never be used to clean condensed fumes or asphalt
from the skin.
„„ Employees should not eat, drink, smoke, chew tobacco or
gum, apply cosmetics, or have open or exposed food and
beverages, in areas where fumes are present or may have
condensed on surfaces.
Education and Training
„„ In addition to complying with the provisions of the OSHA
Hazard Communication Standard, contractors should
ensure that workers assigned to jobs involving potential
asphalt fume exposure in hot asphalt roofing operations
are adequately educated about all health and safety
hazards of working with hot asphalt during roofing,
including burn and fall hazards. This document addresses
fume-related hazards and workers should also be
specifically trained in the operational practices, protective
equipment and precautions recommended here.
Recommended Practices for Controlling Asphalt Fume Exposures during Hot Asphalt Roofing Jobs
If you need more information, or have any questions or concerns, please feel free to contact us:
Asphalt Roofing Manufacturers Association
750 National Press Building
529 14th Street, NW
Washington, D.C. 20045
(202) 207-0917
www.asphaltroofing.org
National Roofing Contractors Association
Suite 600
10255 West Higgins Rd
Rosemont, IL 60018-5607
(847) 299-9070
www.nrca.net
Publication Date: May 2016
This publication is disseminated for informational purposes only, and is intended to provide a general resource for roofing contractors and workers
on jobs involving the use of hot asphalt. It is based on information that is published in the open literature or otherwise readily available to the
general public and believed to be reliable. Although every reasonable effort has been made to be accurate as of the publication date, ARMA and
NRCA cannot accept responsibility for any inaccuracies or omissions this brochure may contain. This publication addresses only certain hazards
associated with exposures to asphalt and asphalt emissions. Workers on asphalt roofing jobs may be exposed to a variety of other health and safety
hazards. THE USER IS RESPONSIBLE FOR ASSURING COMPLIANCE WITH ALL APPLICABLE LAWS AND REGULATIONS, WIDELY-ACCEPTED GUIDELINES,
AND INDUSTRY STANDARDS OF CARE INTENDED TO PROTECT WORKERS AND OTHERS AGAINST HEALTH AND SAFETY HAZARDS. Contractors
and roofing workers also should observe the warnings and recommended precautions on product labels and in safety data sheets and other
manufacturer publications relating to such hazards. ARMA and NRCA are not engaged in the rendering of legal or medical advice or services.
If expert assistance is required, the services of a competent professional should be sought. Nothing contained herein shall be interpreted as a
warranty by ARMA or NRCA, either express or implied, including but not limited to the implied warranties of merchantability, fitness for a particular
purpose or non-infringement. IN NO EVENT SHALL ARMA OR NRCA BE LIABLE FOR ANY DAMAGES WHATSOEVER, including special, indirect,
consequential or incidental damages or damages for loss of profits, revenue, use or data, whether claimed in contract, tort or otherwise. Where
exclusion of implied warranties is not allowed, the liability of ARMA and NRCA shall be limited to the maximum extent permitted by law.
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