Constructions Database User Guide

Constructions Database User Guide
Constructions Database User Guide
IES Virtual Environment
Copyright © 2015 Integrated Environmental Solutions Limited. All rights reserved.
No part of the manual is to be copied or reproduced in any form without the express agreement
of Integrated Environmental Solutions Limited.
Contents
CONSTRUCTIONS DATABASE USER GUIDE ...................................................................... 1
1 INTRODUCTION .................................................................................................................... 3
2 UNITS ................................................................................................................................... 4
3 MAIN DIALOG – PROJECT CONSTRUCTIONS ........................................................................... 5
3.1
3.2
3.3
3.4
3.5
3.6
4
5
6
7
8
9
10
11
OUTLINE................................................................................................................................................... 5
CONSTRUCTION CLASSES & CATEGORIES ......................................................................................................... 6
PROJECT CONSTRUCTION COLUMNS ............................................................................................................... 8
MAIN MENU ............................................................................................................................................. 9
TOOLBAR ................................................................................................................................................ 13
SIDE PANEL ............................................................................................................................................. 14
EDITING AN OPAQUE PROJECT CONSTRUCTION................................................................... 15
EDITING A GLAZED PROJECT CONSTRUCTION ...................................................................... 20
CONSTRUCTION ORIENTATION ........................................................................................... 29
PROJECT MATERIALS........................................................................................................... 30
SYSTEM OR LIBRARY CONSTRUCTIONS ................................................................................ 34
SYSTEM OR LIBRARY MATERIALS......................................................................................... 35
SHADING DEVICES ........................................................................................................... 36
DERIVED PARAMETERS ................................................................................................... 42
11.1
11.2
12
13
13.1
13.2
13.3
13.4
14
15
16
16.1
16.2
DERIVED PARAMETERS (OPAQUE CONSTRUCTION) .......................................................................................... 42
DERIVED PARAMETERS (GLAZED CONSTRUCTION)............................................................................................ 44
CONDENSATION ANALYSIS .............................................................................................. 46
HINTS & TIPS................................................................................................................... 48
MANUFACTURERS’ DATA ........................................................................................................................... 48
INTERSTITIAL BLINDS AND VENTILATED CAVITIES .............................................................................................. 49
AIR PARTITIONS ....................................................................................................................................... 49
EDITING MATERIALS .................................................................................................................................. 50
COMPOSITE LAYERS ........................................................................................................ 51
BRE MATERIALS .............................................................................................................. 52
COST PLANNING AND LIFE CYCLE SOFTWARE ................................................................... 56
CONSTRUCTION DIALOGS ........................................................................................................................... 56
MATERIALS DIALOGS ................................................................................................................................. 56
1 Introduction
This User Guide explains how to use the Constructions Database user interface.
The Constructions Database (formerly called ApCDB) provides facilities for viewing and editing
constructions used throughout the VE (e.g. the thermal applications ApacheCalc, ApacheLoads,
ApacheSim, Part L/J and other compliance and ratings applications; lighting, cost planning and
life cycle applications; etc.).
A construction defines the thermal properties of a building element such as a wall, ceiling or
window. It consists of a number of layers of different materials, together with thermal
properties of the materials, surface properties and other attributes used in thermal analysis.
There are two main thermal classes of construction, Opaque and Glazed, with different
parameter sets. Two extra classes are defined for use in the cost planning and life cycle
software – Hard landscaping and Misc. Further classes may be added in future. These classes
are further broken down into categories – external walls, partitions, internal windows, roof
lights and so on.
The purpose of the Constructions Database is to assemble a set of constructions for use in the
project. It provides facilities for creating, viewing, editing and copying constructions, aided by
access to central ‘system’ and ‘library’ databases of constructions and materials. It also provides
facilities for condensation analysis.
Project constructions created in the Constructions Database may be assigned to building
elements, individually or collectively, in the Apache View (and other thermal compliance views).
At the room creation stage, in ModelIT, constructions may also be set using a Construction
Template, which assigns a pre-set construction to each category of building element in the new
room.
Routes into the Constructions Database are provided from the Apache View (and other thermal
compliance views) and the Template Manager. The Template Manager provides a facility for
transferring constructions from one project to another.
Accurate construction data is critically important for the integrity of the thermal model. The
function of the Constructions Database is to facilitate the process of setting up and checking
this data.
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2 Units
Construction attributes in the Constructions Database are displayed in the current Units System
(metric or IP). The Units System may be changed using the <VE> menu option Tools >>
Preferences >> Units.
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3 Main dialog – Project constructions
3.1 Outline
The main dialog, headed Project constructions, displays tabular edit grids of the constructions in
the project, organised in tabs. These tabs are usually filtered to individual categories or classes,
but there are also other special tabs with different filters, e.g. the In-project tab lists all
constructions in use in the project. By double-clicking on a construction ID you can display its
properties and edit them. Options, in the side pane, main menu or context menu, provide
further operations on the project constructions such as creating, deleting, copying and pasting.
The main menu also provides access to features such as the system and library databases of
constructions and materials, printing options and condensation analysis.
When you first enter the Constructions Database with a new project you will see a list of default
constructions, together with any additional constructions that have been brought into the
project via templates. The Constructions Database facilities allow you to add to and edit these
constructions so that they accurately reflect the thermal properties of the elements in the
building.
Figure 1 Constructions database main dialog – Project constructions
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3.2 Construction classes & categories
Constructions are divided into classes with different thermal property sets. There are two
thermal classes – Opaque and Glazed. If particular cost planning and life cycle software is
licensed, there are two other non-thermal classes – Hard landscape and Misc. In the case of
opaque constructions thermal capacity, as defined by density and specific heat capacity, is
important. Glazed constructions, by contrast, are to a good approximation massless, but they
require properties characterizing their solar transmission properties. Hard landscape and Misc.
constructions have similar properties to Opaque constructions plus some specific extra
properties.
The classes of construction are further broken down into categories, as follows:
Opaque constructions:
 External Wall
 TSC Wall
 Internal Partition
 Ground/Exposed Floor
 Roof
 Active Thermal Roof
 Internal Ceiling/Floor
 Active Thermal Ceiling/Floor
 Door
Glazed constructions:
 External Window
 Internal Window
 Roof Light
Hard landscape constructions:
 Pavement/sidewalk (private)
 Site hard landscape
 Site parking
 Site pervious hard landscape
 Site road
Misc. constructions:
 Double facade
 Foundation
 Gutter
 Shape beam
 Shape column
 Shape lintol
 Shape stairs
 Solid beam
 Solid column
 Solid lintol
 Solid stairs
 Structural frame
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The construction categories in the Opaque and Glazed classes correspond to categories of
building element used for construction assignment in the Apache View. The thermal parameter
sets for constructions are broadly similar for categories belonging to the same class (Opaque or
Glazed), but in some cases differ in respect of their Building Regulations parameters and default
values for surface resistance.
Tabs on the tabular edit grid are arranged to give access to the following:
Tabs for constructions in the Opaque class - separate tabs for each category:

External Wall – Opaque class, Wall category

TSC Wall – Opaque class, Wall category

Partition – Opaque class, Partition category

Ground floor – Opaque class, Ground floor category

Roof – Opaque class, Roof category

Active Thermal Roof – Opaque class, Roof category

Internal Ceiling/Floor – Opaque class, Internal Ceiling/Floor category

Active Thermal Ceiling/Floor – Opaque class, Internal Ceiling/Floor category

Door – Opaque class, Door category
Tabs for constructions in the other classes - single tabs covering all categories in the class:

Glazed – Glazed class, all categories

Hard landscape – Hard landscape class, all categories

Misc. – Misc. class, all categories
Tabs for constructions in any class or category:

Assigned (thermal) shows constructions that are assigned to thermally active elements
in the model.

Assigned (non-thermal) shows constructions that are assigned to thermally inactive
elements in the model.

Costs/LCA shows only those constructions that have Data source BRE Impact, with extra
columns showing the data related to costing and life cycle analysis.

UK Part L shows only those constructions that have Data source UK NCM – this shows all
constructions that have been automatically added from UK NCM templates for use in UK
Part L analysis.
NB this document describes the default tab status and dialog size. As with other tabular edit
dialogs the tabs, columns and filtering can be customized and the dialog can be resized. These
changes are saved between sessions for your particular Windows username.
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3.3 Project construction columns
Within each tab a list of project constructions is displayed, with the following columns of
summary information:
ID
A unique identifier assigned to the construction when it is created.
Category
The construction category (only displayed if the tab is not filtered to just one
category).
Assigned
Whether this construction is assigned to elements in your project (not displayed
– because not necessary – on the In-project tab).
Description
The description assigned to this construction.
Data source
the construction may be generic or specific to a particular regulation or rating
system (e.g. NCM, Green Mark).
U-value
The U-value of the construction may be calculated by several methods:
currently CIBSE, EN-ISO or ASHRAE. In the case of glazed constructions the Uvalues are net U-values including the effect of the frame.
Thickness
The overall thickness of the construction.
Notes etc.
This field is available for your notes but is also written to by various compliance
converters when creating new constructions that they may need.
(Other
columns)
Various other columns are also displayed for specific tabs, e.g. the Ground floor
tab has a Ground contact floor column, and the Doors tab has a Door type
column. Some of the tabs, specific to particular cost planning and life cycle
software, display a considerable number of extra columns with data needed by
various parts of this software. See the documentation for this software.
To edit a construction, double-click the grid row on the ID cell. Alternatively select the
construction and then use one of four Edit construction options (the button, the side panel
option, the main menu option or the context menu option).
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3.4 Main menu
When editing project constructions a main menu is available. When editing system or
library constructions only a context menu is available. Some of the menu options are
also available on the side panel, the toolbar or the context (right-click) menu.
3.4.1 File menu
Save: Saves the project constructions and materials.
Properties…: Displays the project pathname and statistics on the project constructions and
materials.
Close Window: Exits the Constructions Database. You will be prompted to save your edits.
3.4.2 Edit menu
Find construction…: Displays a dialog where you can search for project, system or library
constructions containing particular text strings in either their IDs or descriptions. Constructions
containing the search strings are then listed and may be selected for editing.
Add new construction: Creates a new construction in the current category (or the most sensible
category for a multi-category tab). Not available from the tabs displaying more than one
category such as Hard landscape or Misc. The exception, for convenience, is the Glazed tab,
where it is enabled but will always create a construction in the External Window category (this
category can be changed after creation).
Duplicate construction: Creates a copy of the currently selected construction.
Delete construction(s): Removes the selected constructions from the project unless they are
assigned to elements in the model.
Edit construction…: Displays a dialog to edit the construction.
Preferences…: Displays a dialog where you can set grid colours.
Copy construction to project: Copies the construction to the project. This is only enabled when
editing system or library constructions.
3.4.3 View menu
Toolbar: Toggles the displays of the toolbar.
Side panel: Toggles the displays of the side panel.
Status bar: Toggles the displays of the status bar.
Refresh: Refreshes the display of the grid.
System materials…: Displays the materials in the system database and allows them to be
copied to the clipboard for pasting into a project construction. See System materials below.
System constructions…: Displays the constructions in the system database and allows these
constructions and their materials to be copied to the clipboard for pasting into a project
construction. See System constructions below.
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Project materials…: Displays the materials used in the project constructions and allows them to
be copied to the clipboard for pasting into another project construction. See Project materials
below.
Review manager…: Provides facilities for viewing, printing or copying a textual description of
selected project constructions.
Construction usage…: Displays a list of elements in the model that use the currently selected
construction.
Library (constructions and materials): Displays a sub-menu giving you access to any of the
library materials or constructions. For example there is an IMPACT library for use in the cost
planning and life cycle software.
3.4.4 Settings menu
Wind exposure…: Allows you to set the wind exposure index used in ApacheCalc to calculate
external surface resistances. Choose from the following options:
 Sheltered: sheltered from the wind
 Normal: typical wind exposure
 Severe: severe wind exposure (e.g. coastal)
The wind exposure index is used in ApacheCalc to calculate the external surface resistance of
walls, windows, roofs etc. when a value is not explicitly entered in APcdb. This parameter may
also be set in ApLocate. Note that ApacheSim has its own method for calculating external
surface heat transfer.
Enable composite layers: Allows you to be able to create composite layers in a construction
layer, where a single layer is composed of 2 or 3 separate materials in give proportions.
Therefore this should be enabled if you need to create constructions with composite layers.
Composite layers are generated in certain ASHRAE wizard-generated constructions. However
these do not normally require subsequent editing. See Composite layers for details.
Composite layers are also used in the cost planning and life cycle software where sub-layers
using real materials can be used to increase the accuracy of material usage. This software
imposes certain rules on allowed combinations of BRE materials in a composite layer; after any
such edit any rule violations will be checked and if necessary a validation window will display
showing the rule violations and inviting you to fix them or enter a justification for the edit. See
BRE materials for details.
3.4.5 Calculations menu
Derived parameters…: Displays a set of derived parameters summarising the characteristics of
the currently selected construction. See Derived parameters below.
Condensation prediction…: Accesses a facility for performing condensation analysis on the
currently selected construction. See Condensation analysis below.
3.4.6 Actions menu
Purge unused project constructions: Removes all constructions that are not assigned to any
elements in your model.
Delete selected constructions: Identical to Delete constructions in the Edit menu.
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3.4.7 Tools menu
Manage Filters…: Displays the standard tabular edit feature which allows you to manage the
filters controlling each tab.
Configure tabs and columns…: Displays the standard tabular edit feature which allows you to
edit the columns that appear on this tab.
ASHRAE construction wizard…: Displays the ASHRAE Assembly Wizard dialog, where you can
create constructions suitable for use in ASHRAE compliance. Some of these may generate
constructions with composite layers (see Composite layers). See also ASHRAE 90.1 tables
(A3.1a/b etc.).
Figure 2 ASHRAE Assembly Wizard
Create target construction…: Displays the Target construction creator dialog, where you can
create a construction with a desired category, description, U-value and cM value. . The rules
for calculating the cM value (the effective thermal capacity) of a wall floor, ceiling etc. can be
found in the CEN standard: prEN 13790.
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Figure 3 Target construction creator dialog
Ground contact floorplans…: Displays the Ground-contact Floorplans dialog. This allows you to
manually add details of levels of the building which are in contact with the ground, for use in UK
Part L where these details are essential for ensuring an adequate U-value for ground-contact
walls and floors. The details may also be created automatically from examination of the
building geometry. This is calculated as a function of the ratio of exposed perimeter to floor
area and the thermal transmittance of the floor construction.
Figure 4 Ground-contact Floorplans dialog
3.4.8 Help menu
User guide…: Displays this document.
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3.5 Toolbar
A toolbar is available with several commands. When editing system or library
constructions only a subset of the commands is available. All the commands are also
available on the side panel, the main menu or the context (right-click) menu.
Figure 5 Toolbar
Save the database – same as File->Save on the main menu.
Open review manager to review or print constructions
manager… on the main menu.
– same as View->Review
Open a dialog to find constructions – same as Edit->Find construction… on the main menu.
Add a copy of the selected constructions – same as Edit->Duplicate construction on the
main menu.
Add a new construction – same as Edit-> Add new construction on the main menu.
Edit selected construction – same as Edit->Edit construction… on the main menu.
Delete selected constructions – same as Edit->Delete construction(s) on the main menu.
View where this construction is used in the model – same as View->Construction usage…
on the main menu.
View the system materials – same as View ->System materials… on the main menu.
View the system constructions – same as View ->System constructions… on the main
menu.
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3.6 Side panel
A side panel is available with several commands. When editing system or library
constructions only a subset of the commands is available. All the commands are also
available on the toolbar, the main menu or the context (right-click) menu.
Save project – same as File->Save on the main menu.
Add new construction – same as Edit-> Add new construction
on the main menu.
Duplicate construction – same as Edit->Duplicate construction
on the main menu.
Delete construction(s) – same as Edit->Delete construction(s)
on the main menu.
Edit construction – same as Edit->Edit construction… on the
main menu.
Purge unused project constructions – same as Actions->Purge
unused project constructions on the main menu.
View system materials… – same as View ->System materials…
on the main menu.
View system constructions… – same as View ->System
constructions… on the main menu.
View user guide... – same as Help->User guide… on the main
menu.
Refresh – same as View->Refresh on the main menu.
Figure 6 Side panel
Manage filters... – same as Tools->Manage Filters… on the
main menu.
Configure tabs and columns... – same as Tools->Configure
tabs and columns… on the main menu.
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4 Editing an Opaque Project Construction
This dialog appears when an opaque project construction is selected for editing by means of a
double click or the Edit selected construction icon. It displays the properties of an opaque
construction and allows them to be edited. The dialog includes tabbed sections containing the
various settings for the construction. Note: The Functional Settings and Frame tabs are only
displayed if they have relevant data for the category of construction being displayed:
Figure 7 Opaque construction
The fields and buttons displayed on the dialog are described below. Fields appearing on a white
background are editable. When setting this data it is important to understand the conventions
applied to the orientation of constructions and the ordering of their layers, which are described
in the section headed Construction orientation.
Description: a description of the construction in words.
ID: a unique identifier assigned to the construction when it is created.
External: Shows the colour used by Radiance for the internal surface when this construction is
assigned. When clicked, displays a colour picker allowing the assigned colour to be changed.
Internal: Shows the colour used by Radiance for the internal surface when this construction is
assigned. When clicked, displays a colour picker allowing the assigned colour to be changed.
Performance: The type of U-value calculation used (CIBSE, EN-ISO or ASHRAE). Note that the
EN-ISO method does not take account of the entered values for emissivity, surface resistance or
wind exposure.
U-value: the U-value of the construction, calculated by the selected method.
Thickness (non-editable): the thickness of the construction, calculated as the sum of the layer
thicknesses. This is used in the setting of room inner volumes and surface areas in rooms for
which the Inner Volume flag is turned on.
Thermal mass Cm (non-editable): the thermal capacity per unit area and temperature rise.
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Total R-value (non-editable): total resistance of all layers (does not include inside and outside
surface resistances)
Mass (non-editable): the area density of the construction, mass per unit area, calculated from
the densities and thicknesses of the construction layers.
Weight category: a field describing the Thermal mass Cm above:

Very lightweight – thermal mass less than 95 kJ/m2K

Lightweight – thermal mass less than 137.5 kJ/m2K

Mediumweight – thermal mass less than 212.5 kJ/m2K

Heavyweight – thermal mass less than 315 kJ/m2K

Very heavyweight – thermal mass greater than or equal to 315 kJ/m2K
Surfaces Tab
Outside surface:
Emissivity: the emissivity of the outside surface of the construction. Values are provided in
Table 23 in the Apache Tables document. Most materials have an emissivity of about 0.9. Lower
values apply to unpainted metals.
Resistance: the thermal resistance between the outside surface and its environment. This is the
reciprocal of the outside heat transfer coefficient, which is made up of convective and radiative
components. Ticking the default box displays a standard value determined from the
construction category, together with the Wind exposure in the case of external adjacency. The
default value is used in the ApacheCalc programs. In ApacheSim it is replaced by algorithms that
take account of the changing heat transfer conditions at every time step. If the default box is
not ticked, the entered value is used by all programs.
Solar absorptance: the fraction of incident solar radiation absorbed by the surface. This is a
function of the colour and surface finish. Typical values are given in Table 14 in the Apache
Tables document or CIBSE Guide A.
Inside surface:
Emissivity: the emissivity of the inside surface of the construction.
Resistance: the thermal resistance between the inside surface and its environment. This is the
reciprocal of the inside heat transfer coefficient, which is made up of convective and radiative
components. Ticking the default box displays a standard value determined from the
construction category. The displayed default value is used in the ApacheCalc programs. In
ApacheSim it is replaced by algorithms dependent on simulation options. If the default box is
not ticked, the entered value is used by all programs.
Solar absorptance: the fraction of incident solar radiation absorbed by the surface. This is a
function of the colour and surface finish. Typical values are given in Table 14 in the Apache
Tables document or CIBSE Guide A.
Functional Settings Tab
This tab is only displayed if the construction belongs to the Ground Floor, External Wall or TSC
Wall categories.
Ground-contact floor: a construction can be identified as a ground-contact floor or wall. In
either case, additional parameters must be set (using the Adjust button) for compliance testing
against Part L2 of the UK Building Regulations. The rules for the notional building state that
where the U-value of an un-insulated floor of the same area and exposed perimeter is less than
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0.25 W/m2K a floor with this U-value must be used in the notional building. In accordance with
this the following inputs are requested (they will not be calculated automatically):
 Floor area: The total internal area of the floors to which this construction is assigned.
 Exposed floor perimeter: The exposed perimeter length of the floors to which this
construction is assigned.
 External wall thickness: The average thickness of the external walls along the floor
perimeter.
 Ground conductivity: The thermal conductivity of the ground under the building.
Using these parameters the software will calculate and display the CIBSE uninsulated U-value. If
this is less than 0.25 W/m2K it will be used to create a bespoke floor construction that will be
assigned to the relevant floors in the notional building.
CIBSE un-insulated U-value (read-only): The calculated value.
Regulations Tab
This tab is only displayed if you have a licence for the UK Building Regulations compliance
application. The parameters are required only for UK Building Regulations compliance testing.
Thermal bridging coefficient: Part L2 (2006) requires an allowance to be made for nonrepeating thermal bridging. In the <VE> implementation this is handled via a coefficient
expressing this component of heat loss as a multiple of element area. This can be thought of as
an addition to element U-value. The default value of 0.035 W/m2K represents a typical value for
office spaces built to the standards of the Robust construction details defined in IP 17/01. In the
notional building, thermal bridging coefficients are set to standard values laid down in the NCM
methodology document.
Metal cladding: Constructions can be identified as metal clad. This is used for thermal bridging
in SBEM compliance testing.
Curtain wall: If the construction belongs to the Wall category it can be identified as a curtain
wall. This is used for UK Building Regulations compliance testing.
Standard: Generic, UK NCM, etc.
Retain in notional/reference building: If the construction belongs to the Partition or
Floor/ceiling categories this additional parameter must be set for UK Building Regulations
compliance testing.
Door Type: If the construction belongs to the Door category an additional parameter must be
set for UK Building Regulations compliance testing.
Select from the following options
 Personnel door: standard door.
 Vehicle access or similar large door: a category of door to which special rules, including
more stringent U-value requirements, are applied in the Building Regulations.
 Wall or roof element: select this option if you have used a door to represent elements
of a wall or roof. This will place these elements in the correct category for Building
Regulations purposes.
 Smoke vent: select this option for a roof ventilator.
 High usage entrance door: select this option to represent the entrance to a building
with a high throughput of people (e.g. shopping centre, airport).
Frame Tab
This tab is only displayed if the construction belongs to the Door category.
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LCA frame materials: The assigned list of special LCA frame materials is displayed. The Edit
button displays a dialog allowing you to edit this list of special LCA frame materials to your
construction. This is only relevant to users of the cost planning and life cycle software where
the datasets include some special materials with quantity method set to length instead of area.
These are used in LCA to account for the environmental impact or costs of frame materials.
Construction Layers (Outside to Inside) grid
The construction may consist of up to 10 homogeneous layers, which are listed in order from
outside to inside. With the exception of air gaps, each layer has a thickness and a material. The
material has a set of properties which are stored in the Project Materials database, but which
may be edited within the layer. Any new materials created by edits of this kind will be added to
the list of Project Materials. Air gaps (which can include cavities filled with other gases such as
argon) are assigned a thermal resistance in place of a material.
Material: the id and description of the material composing the layer, or alternatively ‘Cavity’.
Thickness: the thickness of the layer.
Conductivity: the thermal conductivity of the material. Values for commonly used building
materials are listed in Table 6 in the Apache Tables document and in CIBSE Guide A.
Density: the density of the material. Values for commonly used building materials are listed in
Table 6 in the Apache Tables document and in CIBSE Guide A.
Specific heat capacity: the specific heat capacity of the material. Values for commonly used
building materials are listed in Table 6 in the Apache Tables document and in CIBSE Guide A.
Resistance: (cavity only) the thermal resistance of the cavity or air gap, taking account of both
convection and radiation across the gap.
Vapour Resistivity: the vapour resistivity of the material or air gap. This field is blank for many
materials, but a value must be supplied before condensation analysis is carried out. Values for
commonly used building materials are listed in Table 16 in the Apache Tables document.
Category: the material category from the materials database.
Layer buttons
The following buttons, which are mostly also available as context menu (right-click) options, are
provided for tasks related to layer editing:
Copy: copies the properties of the selected layer to the clipboard. This is the same as Copy
Layer on the context menu.
Paste: copies the material properties (but not the layer thickness) from the clipboard to the
selected layer. The contents of the clipboard may have been copied from another layer, from a
layer of a system construction or from a project or system material. This is the same as Paste
Layer on the context menu.
Cavity: creates an air gap adjacent to and on the outer side of the selected layer. This is the
same as Insert Cavity on the context menu.
Insert: inserts a layer adjacent to the selected layer on its outer side and assigns it the material
properties stored in the clipboard. If the clipboard contains a construction layer, the new layer
is also assigned the copied thickness. This is the same as Insert Layer on the context menu.
Add: adds a layer to the inside surface of the construction and assigns it the material properties
stored in the clipboard. If the clipboard contains a construction layer, the new layer is also
assigned the copied thickness. This is the same as Add Layer on the context menu.
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Delete: deletes the selected layer. This is the same as Delete Layer on the context menu.
Flip: reverses the order of the layers. There is no equivalent option on the context menu.
Composite: converts a non-composite layer to a composite layer with two sub-layers, or a
composite layer with two sub-layers to a composite layer with three sub-layers. Sub-layers
initially use “in-line” data instead of real materials, but they can be “promoted” to using real
materials. There is no equivalent option on the context menu.
Composite layers are generated in certain ASHRAE wizard-generated constructions. However
these do not normally require subsequent editing. See Composite layers for details.
Composite layers are also used in the cost planning and life cycle software where sub-layers
using real materials can be used to increase the accuracy of material usage. This software
imposes certain rules on allowed combinations of BRE materials in a composite layer; after any
such edit any rule violations will be checked and if necessary a validation window will display
showing the rule violations and inviting you to fix them or enter a justification for the edit. See
BRE materials for details.
NB A composite layer cannot be turned back into a non-composite layer – you would have to
delete the layer and re-add it.
Additional context menu options
U-Value adjustment: Sets the selected layer as the layer to be adjusted in the U-value
adjustment calculation, and displays a dialog allowing you to select whether to adjust
conductivity or thickness to achieve the desired U-value.
Make real material (only available when you right-click on a composite layer sub-layer): displays
a sub-menu where you can select from project, system or library materials, to “promote” the
“in-line” data for the selected sub-layer into a reference to a real material. See Composite
layers for details.
NB A sub-layer using a real material cannot be turned back into a sub-layer using “in-line” data.
Materials buttons
System Materials…: display the materials used in the system database, with the option of
copying them into the construction. See System Materials for details.
Project Materials…: display the materials in the project database, with the option of copying
them into the construction. See Project Materials for details.
NB Library materials cannot be viewed from a button on this dialog.
Calculation buttons
Two further buttons perform analysis functions on the selected construction:
Condensation analysis: carries out an analysis of condensation risk for the construction under
given temperature and humidity conditions. See Condensation Analysis for details.
Derived parameters: displays, in a separate window, a set of derived parameters for the
selected construction. These include U-values and parameters relating to the CIBSE admittance
procedure. The derived parameters will be dynamically updated as the construction is edited.
See Derived Parameters for details.
OK/Cancel buttons
The construction editing session is completed by clicking on either the OK or the Cancel button:
OK: Exits the opaque construction dialog and keeps any changes.
Cancel: Exits the opaque construction dialog and discards any changes.
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5 Editing a Glazed Project Construction
This dialog appears when a glazed project construction is selected for editing by means of a
double click or the Edit selected construction icon. It displays the properties of a glazed
construction and allows them to be edited. The dialog includes tabbed sections, as shown
below:
Figure 8 Glazed construction
All transparent constructions of whatever material, including transparent doors, should be
defined as glazed constructions.
The fields and buttons displayed on the dialog are described below. Fields appearing on a white
background are editable. When setting this data it is important to understand the conventions
applied to the orientation of constructions and the ordering of their layers, which are described
in the section headed Construction orientation.
Description: a description of the construction in words.
ID: a unique identifier assigned to the construction when it is created.
External: Shows the colour used by Radiance for the internal surface when this construction is
assigned. When clicked, displays a colour picker allowing the assigned colour to be changed.
Internal: Shows the colour used by Radiance for the internal surface when this construction is
assigned. When clicked, displays a colour picker allowing the assigned colour to be changed.
Performance: The type of U-value calculation used (CIBSE, EN-ISO or ASHRAE). Note that the
EN-ISO method does not take account of the entered values for emissivity, surface resistance or
wind exposure.
Net U-value (including frame): the net U-value of the construction, calculated as an average of
the centre-pane and frame U-values, weighted according to the frame percentage. Calculated
using the selected method (CIBSE, EN-ISO or ASHRAE).
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U-value (glass only): the centre-pane U-value of the construction, calculated using the selected
method (CIBSE, EN-ISO or ASHRAE).
CIBSE shading coefficient: The ratio of the instantaneous heat gain at normal incidence
transmitted by a particular glass/blind combination to that transmitted by a reference glass,
usually 3 mm or 4 mm thick clear glass. See CIBSE Guide A section5.
Net R-value: total thermal resistance of all the glazed layers (including surface resistances).
g-value (BS EN 410): the solar transmittance (between 0 and 1)
Visible light normal transmittance: the proportion of normally incident visible light that is
transmitted by the glazed portion of the construction.
Surfaces Tab
Outside surface:
Emissivity: the emissivity of the outside surface of the construction. If the construction involves
low-emissivity coatings these are usually applied to surfaces facing into an air gap, and do not
therefore affect the outside or inside surface emissivities. If the outer pane has an emissivity for
its outside surface, this sets the construction outside surface emissivity automatically.
Resistance: the thermal resistance between the outside surface and its environment. This is the
reciprocal of the outside heat transfer coefficient, which is made up of convective and radiative
components. Ticking the default box displays a standard value determined from the
construction category and, in the case of external adjacency, the Wind exposure. The displayed
default value is used in the ApacheCalc programs. In ApacheSim it is replaced by algorithms that
take account of the changing heat transfer conditions at every time step. If the default box is
not ticked, the entered value is used by all programs.
Inside surface:
Emissivity: the emissivity of the inside surface of the construction. If the construction involves
low-emissivity coatings these are usually applied to surfaces facing into an air gap, and do not
therefore affect the outside or inside surface emissivities. If the inner pane has an emissivity for
its inside surface, this sets the construction inside surface emissivity automatically.
Resistance: the thermal resistance between the inside surface and its environment. This is the
reciprocal of the inside heat transfer coefficient, which is made up of convective and radiative
components. Ticking the default box displays a standard value determined from the
construction category. The displayed default value is used in the ApacheCalc programs. In
ApacheSim it is replaced by algorithms dependent on simulation options. If the default box is
not ticked, the entered value is used by all programs.
Frame Tab
Percentage: The material percentage of the glazing element taken up by the frame. This is used
in solar calculations and affects net U-value.
U-value: The U-value of this window including the frame, calculated using the selected method
(CIBSE, EN-ISO or ASHRAE). U-values for various types of window frame and sash are given in
CIBSE Guide A Table 3.25 and are based on data given in BS EN ISO 10077-1.
Absorptance: The absorptance of this frame. Absorptance is defined as the ratio of the amount
of radiation absorbed by a surface to the amount of radiation incident upon it. Standardised
values can be assumed as follows:
- dark coloured surface = 0.9
- light coloured surface = 0.5.
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Resistance: The resistance of this frame. The resistance is expressed in m2K/W and is the
reciprocal of thermal conductance.
Outside surface area ratio: The outside surface area ratio of this frame. This is the material
percentage of the outside surface taken up by the frame.
Inside surface area ratio: The inside surface area ratio of this frame. This is the material
percentage of the inside surface taken up by the frame.
Type: The type of frame material selected from a list. The list includes softwood, hardwood,
steel, aluminium, PVC and metal and this is used in UK Part L compliance testing.
LCA frame materials: The assigned list of special LCA frame materials is displayed. The Edit
button displays a dialog allowing you to edit this list of special LCA frame materials to your
construction. This is only relevant to users of the cost planning and life cycle software where
the datasets include some special materials with quantity method set to length instead of area.
These are used in LCA to account for the environmental impact or costs of frame materials.
Shading Device Tab
Local shade: Click on the question mark to specify a local shading device. See Shading devices
for details.
External shade: Click on the question mark to specify an external shading device (shutter or
louvre). See Shading devices for details.
Internal shade: Click on the question mark to specify an internal shading device (curtain or
blind). See Shading devices for details.
Regulations Tab
These parameters are required only for UK Building Regulations compliance testing.
Data Source: Generic, NCM, etc.
Surface area ratio: The surface area ratio of this window. This is the “developed area to
projected area” ratio for the window or rooflight. The developed area is the total area of the
glass plus the frame, and the projected area is the area of the opening in the wall/roof.
Therefore, for domed or conical rooflights, for example, this ratio would be larger than 1. It
cannot have a value which is less than 1.
Thermal bridging coefficient: Part L2 (2006) requires an allowance to be made for nonrepeating thermal bridging. In the <VE> implementation this is handled via a coefficient
expressing this component of heat loss as a multiple of element area. This can be thought of as
an addition to element U-value. The default value of 0.035 W/m2K represents a typical value for
office spaces built to the standards of the Robust construction details defined in IP 17/01. In the
notional building, thermal bridging coefficients are set to standard values laid down in the NCM
methodology document.
Type: select a window type.
BFRC Data Values: tick if you wish to add values as defined under the conventions of the British
Fenestration Rating Council. If so, enter g-value and Light transmittance.
Display Window?: tick if this is a display window.
UK Dwellings Tab
These parameters are required only for dwellings under UK Building Regulations compliance
testing.
Glazing type: select a glazing type.
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% Sky blocked: select a category from the list to indicate the degree of shading.
Electrochromic Glazing Tab
These parameters determine the controller for an electrochromic glazed construction. This tab
is only displayed if the glazed construction contains an Electrochromic layer.
Control Profile: Select a modulating profile to determine when the electrochromic glazing is
active. When inactive (profile value of 0), the pane will be in its clear state. When active (profile
value of 1), the pane will interpolate between the specified clear and dark states based on the
value of its control function. If the profile takes a value between 0 and 1, then the control
function will be weighted by the control profile..
Control Function: The control function is a formula, much like those used in formula profiles.
However, the control function is different in that it stands on its own; it is not attached to a
profile. When a simulation runs and the electrochromic glazed element is active, the control
function (whose value, once evaluated, is clamped between 0 and 1) determines the tint of the
glazing by linearly interpolating between 0 (clear) and 1 (dark). The variables that may be used
in the control function are the same as those in any other function, with the addition of the
incident solar irradiance variable, ii, as noted in the ApPro documentation.
The default formula in Metric is “(ii – 400.0)/400.0” (with an equivalent default for projects
using imperial units). This linearly interpolates between 0 at 400W/m2 and 1 at 800W/m2. The
syntax of the formula follows that used in ApPro for formula profiles – an indicator to the right
of the text box will show whether the formula is valid (
) or invalid (
). If an invalid
formula is entered, the construction window’s OK button is disabled.
Metric / Imperial: These buttons set the units of the control function variables. When the
formula is evaluated, the variables are replaced by their values in whichever system of units is
specified. However, switching between Metric and IP does not convert constants to the
specified units. As an example, consider the default metric formula of (ii - 400.0)/400.0. At ii =
800W/m2, it evaluates to 1, if the formula is evaluated as metric. However, if it is evaluated as
IP, it evaluates to -0.37 (clamped to 0 during simulation) because 800W/m2 is the same as
253.6Btu/(h.ft2). It is important, therefore, to consider the physical dimension of constants in
an expression and convert them accordingly.
?: This button opens the ApPro user guide at the formula syntax section, for guidance on
possible values that could be used for the Control Function formula.
The control signal for the layer is determined by multiplying the Control Profile by the Control
Function – this will allow the true state of the Electrochromic Layer to be determined during
simulation (the value will be appropriately interpolated between fully transparent and fully
opaque).
Construction Layers (Outside to Inside) grid
The construction may consist of up to 4 glazing panes separated by air gaps. The panes are
listed in order from outside to inside. With the exception of air gaps, each layer is assigned a
pane type, consisting of a description and a set of optical properties describing the pane. Unlike
an opaque material, a pane type describes the properties of the layer (pane) rather than the
substance of which it is made. The pane properties are stored in the Project Materials
database, but may be edited within the layer. Any new pane type created by edits of this kind
will be added to the list of Project Materials. Cavity layers (air gaps and other gas-filled cavities)
can be described in three different ways: in terms of a gas, a convection coefficient or a cavity
resistance.
Material: the id and description of the material composing the layer, or alternatively ‘Cavity’.
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Thickness: the thickness of the layer.
Conductivity: the thermal conductivity of the material. Values for commonly used building
materials are listed in Table 6 in the Apache Tables document and in CIBSE Guide A.
Angular dependence: specifies the angular dependence of the pane’s optical properties. The
options are as follows:
‘Fresnel’: Calculates the angular dependence using the Fresnel equations and the
specified refractive index, with adjustments to cater for special coatings.
’Explicit’: Explicit user-specified angular dependence (see ‘More data’).
‘Constant’: Optical properties are independent of incidence angle.
‘LBNL’: Uses standard profiles for angular dependence, as specified by Lawrence
Berkeley National Laboratory.
Gas (optional): gas type of the cavity. If set, this is used to calculate the cavity convection
coefficient.
Convection coefficient (optional): the convection coefficient for heat transfer across the cavity.
If set (or calculated from Gas), this is used, with the adjacent pane surface emissivities, to
calculate the cavity resistance.
Resistance (optional, air gap only): the thermal resistance of the air gap, taking account of both
convection and radiation across the gap. The air gap resistance will be higher if a low-emissivity
coating is applied to either of the surfaces facing into the cavity. If Cavity convection coefficient
is set, it is used, with the adjacent pane surface emissivities, to calculate the cavity resistance.
For guidance on setting air gap resistance and other glazing parameters, see the Hints & Tips
section.
Transmittance: The transmittance of the pane for solar radiation at normal incidence.
Outside reflectance: the reflectance of the outside surface of the pane for solar radiation at
normal incidence.
Inside reflectance: the reflectance of the inside surface of the pane for solar radiation at normal
incidence.
Refractive index: The refractive index of the material composing the pane. Editable only if the
angular dependence is set to ‘Fresnel’.
Outside emissivity: the emissivity of the outside surface of the pane. This is used to calculate
the thermal resistance of the adjacent surface or cavity (unless this resistance has been
specified explicitly).
Inside emissivity: the emissivity of the inside surface of the pane. This is used to calculate the
thermal resistance of the adjacent surface or cavity (unless this resistance has been specified
explicitly).
Visible light specified (not currently used): Indicates whether the pane data contains visible light
parameters (which in due course will provide an alternative route to deriving the construction’s
visible light transmittance).
Note: For an Electrochromic Layer, the values for Thickness, Conductivity and Angular
Dependence must match on both the Clear and Dark sub-layers. When these values differ, the
Electrochromic Layer will be highlighted red, the OK button on the construction window
disabled and the Derived Parameters window hidden:
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Layer buttons
The following buttons, some of which are also available as context menu (right-click) options,
are provided for tasks related to layer editing:
Copy: copies the properties of the selected layer (pane) to the clipboard. This is the same as
Copy Layer on the context menu.
Paste: copies the material properties from the clipboard to the selected layer. The contents of
the clipboard may have been copied from another layer, from a layer of a system construction
or from a project or system material. This is the same as Paste Layer on the context menu.
Insert: inserts a layer adjacent to the selected layer on its outer side and assigns it the material
properties stored in the clipboard. If the clipboard contains a construction layer, the new layer
is also assigned the copied thickness. This is the same as Insert Layer on the context menu.
Add: adds a layer to the inside surface of the construction and assigns it the material properties
stored in the clipboard. If the clipboard contains a construction layer, the new layer is also
assigned the copied thickness. This is the same as Add Layer on the context menu.
Delete: deletes the selected pane and an adjacent air gap. If the pane is enclosed within the
construction the deleted air gap will be the one to its inside. This is the same as Delete Layer on
the context menu.
Flip: reverses the order of the panes and air gaps. There is no equivalent option on the context
menu. Note that the order of the sub-layers within an Electrochromic Glazing layer will not be
affected – these are always displayed as the Clear state followed by the Dark state.
Electrochromic: transforms the selected pane into an electrochromic pane (see below). A
maximum of one electrochromic pane can exist in a given construction. When an
electrochromic pane exists, the Electrochromic Control tab is made available.
More Data…: opens the ’Glazing material (pane)’ dialog (see below)
Electrochromic button
This button converts the selected glazing layer to be an Electrochromic glazing layer, consisting
of Clear and Dark sub-layers. This button will be disabled if the construction already contains an
electrochromic layer, or a cavity (air gap) layer is selected.
When the Electrochromic button is clicked, the Electrochromic Glazing tab is automatically
selected and the previously selected layer material is used for both the Clear and Dark state
sub-layers. The standard Paste functionality can be used to change the material assigned on
either of the sub-layers.
Materials buttons
System Materials: display the materials used in the system database, with the option of copying
them into the construction. See System Materials for details.
Project Materials: display the materials in the project database, with the option of copying
them into the construction. See Project Materials for details.
NB Library materials cannot be viewed from a button on this dialog.
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Calculation buttons
Two further buttons perform analysis functions on the selected construction:
Condensation analysis: carries out an analysis of condensation risk for the construction under
given temperature and humidity conditions. See Condensation Analysis for details.
Derived parameters: displays, in a separate window, a set of derived parameters for the
selected construction. These include U-values and optical properties. The derived parameters
will be dynamically updated as the construction is edited. See Derived Parameters for details.
OK/Cancel buttons
The glazed construction editing session is completed by clicking on either the OK or the Cancel
button:
OK: exits the glazed construction dialog and keeps any changes.
Cancel: exits the glazed construction dialog and discards any changes.
More Data… button
When the button ‘More Data…’ is clicked the dialog in Fig 11 appears, displaying data for the
selected layer. These variables include those which appear in the ‘Glazed construction’ dialog.
Figure 11 Glazing material (pane) with the relative angular values
Thermo-Optical properties grid
These properties, with the exception of the last three, are also displayed on the ‘Glazing
material (pane)’ dialog.
Thickness: the thickness of the layer.
Conductivity: the thermal conductivity of the material. Values for commonly used building
materials are listed in Table 6 in the Apache Tables document and in CIBSE Guide A.
Outside emissivity: the emissivity of the outside surface of the pane. This is used to calculate
the thermal resistance of the adjacent surface or cavity (unless this resistance has been
specified explicitly).
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Inside emissivity: the emissivity of the inside surface of the pane. This is used to calculate the
thermal resistance of the adjacent surface or cavity (unless this resistance has been specified
explicitly).
Angular dependence: pane angular dependence behaviour. The default value is set to ‘Fresnel’,
the other options are: ’Explicit’, ‘Constant’ and ‘LBNL’.
Refractive index: The refractive index of the material composing the pane. Editable only if the
angular dependence is set to ‘Fresnel’.
Transmittance: The transmittance of the pane for solar radiation at normal incidence.
Outside reflectance: the reflectance of the outside surface of the pane for solar radiation at
normal incidence.
Inside reflectance: the reflectance of the inside surface of the pane for solar radiation at normal
incidence.
Visible Transmittance (not currently used): The transmittance of the pane for visible solar
radiation at normal incidence.
Outside visible reflectance (not currently used): the reflectance of the outside surface of the
pane for visible solar radiation at normal incidence.
Inside visible reflectance (not currently used): the reflectance of the inside surface of the pane
for visible solar radiation at normal incidence.
Optical properties – angular dependence grid
Solar spectrum
When ‘Angular dependence’ is set to ‘Explicit’ this grid allows the specification of explicit values
for solar transmittance (tau), outside reflectance (rho_o) and inside reflectance (rho_i) for a
range of incidence angles (0°-90°). For other settings of ‘Angular dependence’ only the normal
incidence value can be edited (these being duplicates of the values appearing in the ‘Thermooptical properties’ grid). The values must be between 0 to 1.0 and the sum of transmittance and
inside reflectance or transmittance or outside reflectance cannot exceed 1.0.
Visible spectrum (not currently used)
When ‘Angular dependence’ is set to ‘Explicit’ this grid allows the specification of explicit values
for visible light transmittance (tau), outside reflectance (rho_o) and inside reflectance (rho_i)
for a range of incidence angles (0°-90°). For other settings of ‘Angular dependence’ only the
normal incidence value can be edited (these being duplicates of the values appearing in the
‘Thermo-optical properties’ grid). All the values must be between 0 to 1.0 and the sum of
transmittance and inside reflectance or transmittance or outside reflectance cannot exceed 1.0.
Radiance properties grid (not currently used)
For more information see: ‘Radiance’ manual.
Surface type: ‘plastic’, ‘metal’, ‘glass’ or ‘trans’.
Roughness: the roughness of the pane surface. Roughness range value 0.0-1.0.
Overall transmissivity: the ratio of the directly transmitted light after passing through the pane
to the amount of light that would have passed the same distance through a vacuum.
Transmitted specularity: is the ratio between the reflected light by specular mechanisms and
the diffuse light.
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Specularity: the amount of light reflected by specular mechanisms (basically how shiny a
surface is).
Red transmittance: pane transmittance in the Red spectrum.
Green transmittance: pane transmittance in the Green spectrum.
Blue transmittance: pane transmittance in the Blue spectrum.
Red reflectance: pane reflectance in the Red spectrum.
Green reflectance: pane reflectance in the Green spectrum.
Blue reflectance: pane reflectance in the Blue spectrum.
Red transmissivity: pane transmissivity in the Red spectrum.
Green transmissivity: pane transmissivity in the Green spectrum.
Blue transmissivity: pane transmissivity in the Blue spectrum.
Miscellaneous properties grid
For more information see: ‘Life Cycle Analysis’ (LCA) manual.
Service life (years): expected pane service life.
Site wastage %: How much wastage is produced when installing.
Adjust factor: to account for instances where adjustment is required e.g. overlapping roof
slates.
BRE material #: read only – unique BRE id used when calculating the LCA.
BRE category 1 ID: read only – used when constructing composite constructions.
BRE category 2 ID: read only – used when constructing composite constructions.
Last edited: date when this material was last edited.
Info/Notes: user notes on the pane.
Quantity method: default value ‘Area’.
Overall mass: gives the kg/m value of the material.
Generic/Certified: Generic or certified – generic is a BRE generic construction, certified is
generally a specific construction (see description of construction for more details).
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6 Construction orientation
The orientation of both opaque and glazed constructions is important thermally and is
governed by the following rules.
1. The layers of a construction are listed in order from outside to inside.
2. For Roofs, External walls, Ground/Exposed Floors, External Windows and Rooflights,
the outside of the construction faces the external environment (or in the case of a
Ground Floor the ground).
3. Internal Ceiling/Floors are defined as ceilings, so the outside of the construction is the
upper side. Note that as a consequence, these constructions are displayed in the
reverse orientation to ground or exposed floors.
4. The orientation of Internal Partitions and Internal Windows depends on the particular
instance in the building, and is determined from the relative ordering of the adjacent
spaces in the room browser. The convention is that the inside of the Internal Partition
or Window, as defined in the Constructions Database, is the side facing the space that
appears first on the browser.
5. Doors are treated in the same way as external constructions or internal partitions,
depending on whether they have internal or external adjacency.
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7 Project materials
The project materials dialog provides a list of materials used in the project. It is accessed via the
Project materials option on the View menu, or alternatively from buttons on the construction
editing dialogs.
Figure 12 Project materials dialog with extra section hidden
This dialog has an extra section which is only of interest to the LCA or LCC software (see BRE
materials and Cost planning and lifecycle software for details):
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Figure 13 Project materials dialog with extra section visible
Materials in the database are organised in categories such as Concretes, Insulating Materials
and Glass. The Material category is selected from a list. Two new categories are added, Floor
finishes and Suspended ceilings, of interest only to the cost planning and life cycle software. You
can also choose Show all opaque categories if you prefer to see materials from all opaque
categories together (Glass is not included because the columns are different for Glass).
The materials in the chosen category, together with their properties, are displayed in a grid
with columns for each property. The materials may be sorted according to any of their
properties. For example to sort concretes by density click on the Density column. The first click
arranges the materials in ascending order, the second in descending order.
Icons on the toolbar provide the following options operating on the selected construction:
Copy material: Copies the selected material to the clipboard, ready for pasting into a
project construction.
Show material references: Displays the Material References dialog, with a list of project
constructions referencing the selected material:
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Figure 14 Material References dialog
Compact materials database: Compact the materials database will remove duplicate
materials.
Delete material: Delete the material from the project material database.
NB When the Project materials dialog is opened from the Project materials button in the
Project construction dialog (with a layer row selected), the Project materials dialog selects the
appropriate material category and material for your convenience.
If a material has been edited in the Materials dialog and you move on to another material or
close the dialog, a check is made to see how many constructions reference that material. If only
one construction references the material, the material is updated with the same ID. If more
than one construction references the material, a dialog is displayed where you can select which
constructions are to be updated to use the new material:
Figure 15 Dialog to handle multiple references to an edited material
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If you select all of them, again the material is updated with the same ID. If you select some but
not all, a new material is created with a new, automatically generated, ID, and only the selected
constructions will reference the new ID. If you select none, you are prompted that if you
continue the changes will be discarded:
Figure 16 Confirmation dialog
Press Yes to discard the changes or No to reselect constructions to update.
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8 System or library constructions
The system constructions database is a central store of constructions available for copying into
projects. Materials and glazing pane types in the system constructions may also be copied. This
database is accessed via the System constructions option on the View menu. You can keep the
database open while you work on project constructions.
Figure 17 System constructions dialog
The Library constructions dialog is identical apart from the caption which displays the name of
the library (e.g. “Library constructions (non-editable) [IMPACT_CMP_Dataset_V15]”). The
library databases are accessed via the menu options ending in “ constructions…” under the
Library (constructions and materials) option on the View menu.
This dialog works in a similar way to the main Project constructions dialog and organises the
constructions using the same classes and categories. The main difference is that, unlike project
constructions, system constructions may not be edited, only viewed and copied. Therefore
many functions are unavailable (not shown, or disabled if shown) and a Copy construction to
project option is now enabled.
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9 System or library materials
The system materials database is a central store of materials and glazing pane types available
for copying into projects. This database is accessed via the System materials option on the View
menu, or alternatively from buttons on the construction editing dialogs. You can keep the
database open while you work on project constructions.
Figure 18 System materials dialog
The Library materials dialog is identical apart from the caption which displays the name of the
library (e.g. “Library materials (non-editable) [IMPACT_CMP_Dataset_V15]”). The library
databases are accessed via the menu options ending in “ materials…” under the Library
(constructions and materials) option on the View menu.
Materials in the database are organised in categories such as Concretes, Insulating Materials
and Glass. The Material Category is selected from a list.
This dialog works in a similar way to the main Project materials dialog and organises the
materials using the same categories. The main difference is that, unlike project materials,
system materials may not be edited, only viewed and copied. Therefore many functions are
unavailable (not shown, or disabled if shown) and a Copy material to project option is now
enabled.
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10 Shading Devices
Shading devices of three kinds – internal, external and local – may be attached to glazed
constructions. This is a quick way to specify shading features to all instances of a glazing
construction. The results of the shading calculations performed for these shading devices are
combined with those carried out by SunCast.
The three types of shading device are suitable for representing the following types of shading:
Internal:
curtains, blinds.
External: shutters, louvres, brise soleils.
Local:
side-fins, overhangs, balconies, window recesses.
10.1.1 Internal Shading
The input dialog window for an internal shading device is shown below. Descriptions of the data
fields are given below.
Figure 19 Internal Shading Device dialog
10.1.1.1 Device:
Selecting Curtains or Blinds activates the device and allows the parameters to be edited.
No distinction is made between curtains and blinds in terms of the performance of the
device.
10.1.1.2 Percentage Profile Group:
A percentage profile specifying the timing of the blind operation. Percentage values
greater than 50% are interpreted as ‘on’ and other values as ‘off’. When the profile is on,
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the device operates (i.e. is lowered into position). When the profile is off, or set to ‘none’,
the device is controlled by incident solar radiation, as specified by the following two
parameters.
10.1.1.3 Incident Radiation to Lower Device:
This parameter comes into play when the profile is off. The shading device starts operating
(i.e. is lowered into position) when the total incident solar radiation flux rises through this
value. If Incident Radiation to Raise Device and Incident Radiation to Lower Device are both
set to zero the device is assumed to operate only according to the timed operation profile
and its operation is not affected by solar radiation.
10.1.1.4 Incident Radiation to Raise Device:
This parameter comes into play when the profile is off. The shading device stops operating
(i.e. is raised) when the intensity of total incident solar radiation falls below this value. This
value must be less than or equal to the Incident Radiation to Lower Device. For incident
radiation fluxes between the two thresholds the blind remains in its previous state. If
Incident Radiation to Raise Device and Incident Radiation to Lower Device are both set to
zero the device is assumed to operate only according to the timed operation profile and its
operation is not affected by solar radiation.
10.1.1.5 Night-time Resistance:
The additional thermal resistance (if any) associated with the device when it is in operation
at night (taken to be when the sun is below the horizon). This parameter allows you to
make allowance for the night-time closing of curtains or blinds.
A value of zero is appropriate in most cases. Net curtains and most types of blind have
minimal insulation effect on the glazing. They can therefore be ignored for most
applications. However, the effect of heavyweight curtains and blinds should be included.
10.1.1.6 Daytime Resistance:
The additional thermal resistance (if any) associated with the device when it is in operation
during the day (taken to be when the sun is above the horizon). This extra resistance
affects not only the U-value, but also the retransmitted component of absorbed solar
radiation.
A value of zero is appropriate in most cases. Net curtains and most types of blind have
minimal insulation effect on the glazing. Their thermal effect can therefore be ignored for
most applications. However, the effect of heavyweight curtains and blinds should be
included.
10.1.1.7 Shading Coefficient:
Blinds and curtains reduce solar penetration into the space by reflecting and absorbing
short-wave solar radiation. A proportion of the absorbed heat (sometimes called retransmitted heat) is transferred into the room by convection and long-wave radiation.
The shading coefficient specifies the degree to which the blind reduces the short-wave
component of room solar gain that passes through the glazing panes. A value of 1 means
no shading and a value of 0 perfect shading. Typical values are listed in Table 8 of the
Apache Tables document. The internal blind is not considered to affect the long wave
radiation and convective heat transfer from the glazing to the room.
If the solar transmittance (T) and absorptance (A) are known for the blind, values for the
shading coefficient (SC) and short-wave radiant fraction (SWRF) can be obtained using
SC = T + 0.87*A
SWRF = T/SC
These formulae apply to a blind consisting of a single sheet of material, such as a roller
blind or a closed slatted blind. They can be applied to open or partially open slatted blinds
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if an allowance is made in the T and A values for inter-reflection between the slats.
10.1.1.8 Short-Wave Radiant Fraction:
The short-wave radiant fraction specifies the proportion of the room heat gain associated
with the blind that passes through it as short-wave radiation.
Typical values are listed in Table 8 in the Apache Tables document. A method for deriving
values from blind properties is described under Shading Coefficient.
10.1.1.9 Building Regulations L1:
Used for defining local shading in conjunction with Part L1 for dwellings. See the SAP 2005
document for more details on these settings in relation to overheating.
10.1.2 External Shading
The input dialog window for an external shading device such as a shutter, louvre or brise soleil
is shown below. Descriptions of the data fields are given below.
Figure 20 External Shading Device dialog
10.1.2.1 Device:
Selecting Shutters or Louvres activates the device and allows the parameters to be edited.
No distinction is made between shutters and louvres in terms of the performance of the
device.
10.1.2.2 Percentage Profile Group:
A percentage profile specifying the timing of the operation of the shade. Percentage values
greater than 50% are interpreted as ‘on’ and other values as ‘off’. When the profile is on,
the device operates (i.e. is lowered into position). When the profile is off, or set to ‘none’,
the device is controlled by incident solar radiation, as specified by the following two
parameters.
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10.1.2.3 Incident Radiation to Lower Device:
This parameter comes into play when the profile is off. The shading device starts operating
(i.e. is lowered into position) when the total incident solar radiation flux rises through this
value. If Incident Radiation to Raise Device and Incident Radiation to Lower Device are both
set to zero the device is assumed to operate only according to the timed operation profile
and its operation is not affected by solar radiation.
10.1.2.4 Incident Radiation to Raise Device:
This parameter comes into play when the profile is off. The shading device stops operating
(i.e. is raised) when the intensity of total incident solar radiation falls below this value. This
value must be less than or equal to the Incident Radiation to Lower Device. For incident
radiation fluxes between the two thresholds the blind remains in its previous state. If
Incident Radiation to Raise Device and Incident Radiation to Lower Device are both set to
zero the device is assumed to operate only according to the timed operation profile and its
operation is not affected by solar radiation.
10.1.2.5 Night-time Resistance:
The additional thermal resistance (if any) associated with the device when it is in operation
at night (taken to be when the sun is below the horizon). This parameter allows you to
make allowance for the night-time closing of shutters. A value of zero is appropriate in
most cases.
10.1.2.6 Daytime Resistance:
The additional thermal resistance (if any) associated with the device when it is in operation
during the day (taken to be when the sun is above the horizon). This extra resistance
affects not only the U-value, but also the retransmitted component of absorbed solar
radiation. A value of zero is appropriate in most cases.
10.1.2.7 Ground diffuse transmission factor:
The degree to which the ground is shaded by the device as viewed from the glazing
construction. This affects the amount of diffuse ground-scattered solar radiation incident
on the window. Ticking the Calculate check box sets a default value of 1.
10.1.2.8 Sky diffuse transmission factor:
The degree to which the sky is shaded by the device as viewed from the window. This
affects the amount of diffuse solar radiation incident on the window from the sky. Ticking
the Calculate calculates a value for this parameter as a suitably weighted average of the
transmission factors for direct solar radiation.
10.1.2.9 Transmission Factors at 15 degree increments:
Values of the transmittance of the shading device for direct solar radiation, at 15 degree
angular increments. The angle in question is the solar altitude measured in a vertical plane
perpendicular to the glazing construction.
10.1.3 Local Shading
The input dialog window for local shading features such as projections and window recesses is
shown below. Descriptions of the data fields are given below.
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Figure 21 Local Shading Device dialog
10.1.3.1 Device:
Selecting Projections or Window Recesses activates the device and allows the parameters
to be edited. No distinction is made between projections and window recesses in terms of
the performance of the device. Enter the value 0 for parameters relating to any shading
features that are not present.
10.1.3.2 Window width:
The width of the windows to which the construction is to be assigned. The shading
calculations will only be correct if applied to a rectangular window of the given dimensions.
10.1.3.3 Window height:
The height (top to bottom) of the windows to which the construction is to be applied. The
shading calculations will only be correct if applied to a rectangular window of the given
dimensions.
10.1.3.4 Balcony projection:
If there is a balcony, enter the distance it projects from the plane of the window.
10.1.3.5 Balcony height:
The height of the top edge of the balcony measured from the lower edge of the window.
10.1.3.6 Overhang projection:
If there is an overhang or recess soffit, enter the distance it projects from the plane of the
window.
10.1.3.7 Overhang offset:
The distance between the overhang and the top of the window.
10.1.3.8 Left fin projection:
If there is a left side-fin or a left wall of a window recess (as viewed from the outside),
enter the distance it projects from the plane of the window.
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10.1.3.9 Left fin offset:
The distance between the left fin or left recess wall from the adjacent window edge.
10.1.3.10 Right fin projection:
If there is a right side-fin or a right recess wall (as viewed from the outside), enter the
distance it projects from the plane of the window.
10.1.3.11 Right fin offset:
The distance between the right fin or right recess wall from the adjacent window edge.
10.1.3.12 Building Regulations L1:
Used for defining local shading in conjunction with Part L1 for dwellings. See the SAP 2005
document for more details on these settings in relation to overheating.
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11 Derived parameters
By clicking on the Derived Parameters button on a Construction dialog or using the Derived
Parameters option on the Calculations menu, you can bring up a window displaying parameters
derived from the current construction’s data. These include U-values, CIBSE admittance
parameters and optical properties of glazed constructions. The derived parameters are
dynamically updated in response to edits made to the construction.
11.1 Derived parameters (opaque construction)
Figure 22 Derived Parameters (Opaque) dialog
The derived parameters for an opaque construction are as follows:
Outside surface resistance: the thermal resistance between the outside surface and its
environment, as set in the construction data.
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Inside surface resistance: the thermal resistance between the inside surface and its
environment, as set in the construction data.
Outside convective heat transfer coefficient: the convective heat transfer coefficient for the
outside surface, calculated from the surface resistance and emissivity.
Inside convective heat transfer coefficient: the convective heat transfer coefficient for the inside
surface, calculated from the surface resistance and emissivity.
Outside radiative heat transfer coefficient: the radiative heat transfer coefficient for the outside
surface, calculated from the emissivity.
Inside radiative heat transfer coefficient: the radiative heat transfer coefficient for the inside
surface, calculated from the emissivity.
CIBSE U-Value: the U-value of the construction as calculated by the CIBSE method.
EN-ISO U-Value: the U-value of the construction as calculated by the EN-ISO method.
Admittance: the CIBSE admittance of the construction, which relates inside surface heat
transfer to inside environmental temperature.
Admittance time lead: the time lead associated with the admittance
Internal admittance: (for partitions and ceilings only) the combined admittance of both surfaces
of the construction, which features in CIBSE calculations for partitions contained entirely within
a room.
Decrement factor: the CIBSE decrement factor, which, taken together with the admittance,
relates inside surface heat transfer to outside environmental temperature.
Decrement factor time lag: the time lag associated with the decrement factor.
Surface factor: the CIBSE surface factor for the inside surface of the construction.
Internal surface factor: (for partitions and ceilings only) the combined surface factor of both
surfaces of the construction, which features in CIBSE calculations for partitions contained
entirely within a room.
Checkbox
Include construction properties in printed output?: adds the construction to the list of those to
be printed from the main Print facility.
Buttons
Copy: copies the derived parameters to the clipboard for pasting into other applications.
Print: prints the derived parameters.
Close: closes the dialog.
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11.2 Derived parameters (glazed construction)
Figure 23 Derived Parameters (Glazed) dialog
The derived parameters for a glazed construction are as follows:
Calculate values based on Electrochromic Clear State/Dark State: this option is only displayed if
the construction includes an Electrochromic Glazing layer – it allows you to choose whether to
display the optical properties based on the clear or the dark state of the glazing (the radio
controls default to “Clear State”).
Outside surface resistance: the thermal resistance between the outside surface and its
environment, as set in the construction data.
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Inside surface resistance: the thermal resistance between the inside surface and its
environment, as set in the construction data.
Outside convective heat transfer coefficient: the convective heat transfer coefficient for the
outside surface, calculated from the surface resistance and emissivity.
Inside convective heat transfer coefficient: the convective heat transfer coefficient for the inside
surface, calculated from the surface resistance and emissivity.
Outside radiative heat transfer coefficient: the radiative heat transfer coefficient for the outside
surface, calculated from the emissivity.
Inside radiative heat transfer coefficient: the radiative heat transfer coefficient for the inside
surface, calculated from the emissivity.
CIBSE U-value (glass only): the centre-pane U-value of the construction as calculated by the
CIBSE method.
CIBSE net U-value (including frame): the U-value as calculated by the CIBSE method with a
correction applied for the effect of the frame.
EN-ISO U-value: the U-value centre-pane as calculated by the EN-ISO method.
EN-ISO net U-value (including frame): the U-value as calculated by the EN-ISO method with a
correction applied for the effect of the frame.
g-value (BS EN 410): the g-value of the glazing construction as calculated by BS EN 410. This is
the total solar transmittance at normal incidence under specified conditions.
g-value (BFRC): the g-value of the glazing construction as defined under the conventions of the
British Fenestration Rating Council:
g-value (BFRC) = 0.9 * (1 – frame fraction) * g-value (BS EN 410)
Frame occupies...: the percentage of the glazing element taken up by the frame
T(D): the short wave solar transmittance at 10 angles of incidence
T(R): the solar transmittance at 10 angles of incidence arising from absorption in the glazing
construction and subsequent conduction, convection and long-wave radiation into the room.
Short-wave shading coefficient: the shading coefficient for directly transmitted short-wave solar
radiation, defined as T(D)/0.87, where T(D) is the value at 0° (normal) incidence.
Long-wave shading coefficient: the shading coefficient for absorbed solar that enters the room
by conduction, convection and radiation, defined as T(R)/0.87, where T(R) is the value at 0°
(normal) incidence.
Total shading coefficient: the sum of the short-wave and the long-wave shading coefficients.
Checkbox
Include construction properties in printed output?: adds the construction to the list of those to
be printed from the main Print facility.
Buttons
Copy: copies the derived parameters to the clipboard for pasting into other applications.
Print: prints the derived parameters.
Close: closes the dialog.
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12 Condensation analysis
This facility allows you to perform a condensation analysis on the currently selected
construction. It is accessed either from the Calculations menu option Condensation analysis or
by a button on the construction editing dialog.
Before condensation analysis can be carried out, all layers of the construction must be assigned
a vapour resistivity. You will be prompted to supply any missing values:
Figure 24 Vapour Resistance dialog
Figure 25 Condensation Analysis dialog
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Edit boxes (with spin buttons)
Conditions on each side of the construction can be specified:
Ext. T:
The external air temperature to be used in the analysis
Ext. RH:
The external air relative humidity to be used in the analysis
Int. T:
The internal air temperature to be used in the analysis
Int. RH:
The internal air relative humidity to be used in the analysis
Chart
If condensation is predicted, a chart is displayed showing the variation of the following
variables through the construction:
VP:
Vapour pressure
Dry Bulb Temp.:
Dry bulb temperature
Sat. VP:
Saturated vapour pressure
A blue dot indicates where condensation occurs.
Toolbar icons
Copy to clipboard:
Copy the condensation chart to the clipboard.
Save condensation chart: Save the condensation chart as a bitmap file.
Print condensation chart: Print the condensation chart.
Text representation:
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Display the results in text form (with options to copy and print).
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13 Hints & Tips
13.1 Manufacturers’ data
The properties of glazing panes and constructions are published by manufacturers. The salient
properties for an individual pane are the solar direct transmittance, reflectance and
absorptance. These values should sum to one.
When creating a glass pane type (material) the direct transmittance, reflectance and
absorptance may be used directly with no modification. However, for a double glazed unit you
will find that the solar radiant properties are usually given for the full unit rather than the
individual layers. The properties given are typically U-value, short-wave shading coefficient and
total shading coefficient. Separate U-values may be specified for the mid-pane properties and
the unit as a whole, including the frame.
The procedure for matching glazing properties for a complete glazing unit is as follows:
1. For any known glazing panes (for instance 6mm clear float), assign properties from the
materials database.
2. Make a guess for the properties of panes for which no specific data is available.
3. Match the manufacturer’s mid-pane U-value by suitable choice of air gap resistance.
The air gap resistance includes the effect of low emissivity coatings facing into the
glazing cavity. Do not adjust the CIBSE Net U-value (including frame) or the emissivities
of the outside or inside surface.
4. Click on Derived Parameters to display the derived properties of the glazing and
compare the shading coefficients displayed with those provided by the manufacturer.
Adjust the reflectance, absorptance and transmittance of the unknown panes to match
these parameters. Be careful to ensure that the sum of the reflectance, absorptance
and transmittance is 1. If the manufacturer’s data is in the form of transmittances
rather than shading coefficients, use the displayed values for T(D) and T(R) at 0º
incidence. These transmittances are related to the shading coefficients by a factor of
0.87.
5. Adjust the CIBSE Net U-value (including frame) to match the manufacturer’s value for
this parameter. This operation must be done last, as the Net U-value is automatically
updated to the calculated mid-pane U-value after edits to any other parameters.
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13.2 Interstitial blinds and ventilated cavities
Blinds within a glazing cavity (which may be ventilated) can be modelled in one of two ways.
The example given below assumes triple glazing:
Method 1
The blind may be modelled by using a fourth layer of glass but assigning the properties of the
blind to this pane.
Using a fourth pane of glass to model the blind. In this case, the manufacturer's blind
transmittance, absorptance, reflectance data can be used to set up a glazing material. Set the
refractive index to 1.0.
The manufacturers' blind transmittance of short-wave solar radiation value can be entered
directly as the transmittance of the blind material.
The absorptance is calculated by reducing the absorptance of the actual blind by a factor to
account for the convection of the absorbed heat by natural ventilation in the cavity.
If the ventilation is 100% effective in removing heat absorbed by the blind, enter 0.0 as the
absorptance of BLIND.
If there is no ventilation enter the manufacturers’ value directly. The actual value will lie
somewhere between 0 and 100% of the manufacturer's value.
You will have to estimate the actual value to use based on the likely flow of air through the
cavity and the heat removal rate from the blinds.
It is likely that the proper value to use is between 40 and 95% of the manufacturers'
absorptance value.
Method 2
Alternatively, the outer cavity may be modelled as a separate room. In this case the blind can
be modelled in the normal way, by attaching an internal shading device to the outer pane.
The double-glazed unit between the outer cavity and the room is now an internal window.
13.3 Air partitions
If a space is subdivided with the option Remove partition set, the partition between the spaces
is automatically replaced by a hole. Holes are completely transparent to solar radiation and
MacroFlo treats them as open to the passage of air. In some instances it is appropriate to adjust
the MacroFlo characteristics of such an opening (as described in the MacroFlo Methods
manual), and to make this possible the hole must be replaced by a window. To ensure the
correct characteristics for solar and long-wave radiation exchange the window should be
constructed as a single pane with the following properties:
General
Outside surface emissivity: 1.0
Inside surface emissivity: 1.0
Frame: 0.0
Construction layer
Reflectance: 0.0
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Transmittance: 1.0
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13.4 Editing materials
It is possible to edit certain material properties in two places: the Construction layers grid in the
Project construction dialog (Sections 4 and 5) and the dedicated Project materials dialog
(Section 7).
Material changes are not synchronised between these dialogs when both are visible so making
changes in both places may result in those changes being lost.
In general, it is recommended that changes to materials are made using the Materials dialog.
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14 Composite layers
The Enable composite layers menu option on the main dialog allows you to be able to create
composite layers in a construction layer, where a single layer is composed of 2 or 3 separate
materials in given proportions. Therefore this should be enabled if you need to create
constructions with composite layers.
The Composite button in the Project construction dialogs is only available if you have already
enabled composite layers (see above). It converts a non-composite layer to a composite layer
with two sub-layers. If it is already a composite layer with two sub-layers it adds another sublayer, i.e. converts it to a composite layer with three sub-layers. There is a maximum of three
sub-layers. Sub-layers initially use “in-line” data instead of real materials, but they can be
“promoted” to using real materials.
NB Previously only one composite layer was allowed per construction. This restriction is now
lifted because some constructions using BRE materials may need several composite layers.
Composite layers are generated in certain ASHRAE wizard-generated constructions. However
these do not normally require subsequent editing.
Composite layers are also used in the cost planning and life cycle software where sub-layers
using real materials can be used to increase the accuracy of material usage. This software
imposes certain rules on allowed combinations of BRE materials in a composite layer; after any
such edit any rule violations will be checked and if necessary a validation window will display
showing the rule violations and inviting you to fix them or enter a justification for the edit. See
BRE materials for details.
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15 BRE materials
Some of the cost planning and life cycle software is used to best advantage when you use the
BRE materials from the IMPACT libraries. These can be copied from the IMPACT library to your
project. Often they can be used in a non-composite layer just like any other materials. However
some of these materials have extra validation rules imposed:
15.1.1 Extra validation rules when editing BRE materials
Percentage change from original material
The service life, density, adjustment percentage and site wastage percentage must not differ by
more than 10% from the original library material from which this project material was copied.
Figure 26 Percentage change validation
The user is allowed to enter a justification for not conforming to this rule.
Transport distance
If the transport distance has been modified compared to the original library material from
which this project material was copied, the user must confirm that all future added project
materials will have user entered transport distances.
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Figure 27 Transport distance validation
The user is allowed to enter a justification for not conforming to this rule.
15.1.2 Extra validation rules when editing BRE constructions
Appropriate material
Each BRE material has an allowed construction categories list (e.g. Roof) for which it is allowed
to be added as a layer. Any BRE material used in a layer (or composite sub-layer) of this
construction you are editing, must include the construction’s category in its allowed
construction categories list:
Figure 28 Appropriate material validation
The user is allowed to enter a justification for not conforming to this rule.
Valid co-layer
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This is the most complex validation. Some (but not all) BRE materials have a list of valid BRE
Category 1 or 2 IDs required in co-layers (i.e. the other sub-layers in a composite layer). This
means that each material that needs valid co-layer materials (i.e. has a list of valid BRE Category
IDs) must be used in a sub-layer of a composite layer in the construction, and that the other
sub-layers in the same composite layer must match all of, and only, the valid materials in that
list. Several validation checks are carried out on the materials in this construction:
a. Each material that needs valid co-layer materials must be in a composite layer.
b. Each co-layer must use a real material.
c. Each co-layer material must have a valid BRE Category ID.
d. All valid co-layer material BRE Category IDs must be present in one and only one co-layer.
e. No other materials must be present in the composite layer.
Figure 29 Valid co-layer validation
The user is allowed to enter a justification for not conforming to this rule. This is particularly
important as there are some combinations of co-layers that are impossible to satisfy.
BRE Category 1 and 2 IDs are shown as columns in the materials dialog. The “P” types are
Category 1 IDs, and the “L” types are Category 2 IDs.
Hint – sort on the appropriate column to make it easier to search for a required co-layer
material. E.g. a type “L61” is required here, so click on the column header for Category 2 ID to
sort these into alphabetical order to make it easier to see materials with this Category 2 ID.
Percent change in co-layer service life
The service life of all BRE materials must be the same to within 10% for all co-layers in each
composite layer:
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Figure 30 Percent change in co-layer service life validation
The user is allowed to enter a justification for not conforming to this rule. Again, the contents
of the BRE database make it sometimes difficult to conform.
Adjustment percentage total
BRE materials to be used in co-layers have an adjustment percentage. E.g. brick and mortar
would be maybe 90% and 10%. This validation checks that the total adds up to 100%.
Figure 31 Adjustment percentage total validation
The user is allowed to enter a justification for not conforming to this rule. Again, the contents
of the BRE database make it sometimes difficult to conform.
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16 Cost planning and life cycle software
Some extra data is available when you are licenced to use some of the cost planning or life cycle
software, which show extra properties available in the BRE materials or constructions using
these.
16.1 Construction dialogs
The Project, System and Library construction dialogs have extra columns, and extra “IMPACT”
tabs.
Extra columns
It is beyond the scope of this document to give details of these columns. Please refer to the cost
planning or life cycle documentation.
Extra tabs
It is beyond the scope of this document to give details of these tabs. Please refer to the cost
planning or life cycle documentation.
16.2 Materials dialogs
The Project, System and Library materials dialogs have extra columns, and an extra Additional
LCC/LCA fields section.
Extra columns
It is beyond the scope of this document to give details of these columns. Please refer to the cost
planning or life cycle documentation.
Additional LCC/LCA fields section
These are visible only for materials with category Floor finishes or Suspended ceilings.
It is beyond the scope of this document to give details of these columns. Please refer to the cost
planning or life cycle documentation.
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