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| Why should there be an AWA compliance audit every year? | |
Australian Institute of Building Surveyors (AIBS)
Private building certifiers/surveyors sign off on in
excess of 100 standards when approving buildings.
The AWA accreditation program provides a simple and
verifiable means of proving the performance of a
window.
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| Can I buy windows that will reduce the noise from outside my home? | |
Yes, but unfortunately, resolution of noise problems is often a complex issue. The most effective barrier against noise is to have 2 panes of glass (of different thickness) spaced at 100 – 200mm, but this is often not practical in a normal home. Laminated glass is the next best option to reduce noise but is usually effective only at the high frequencies (eg aircraft noise) – recent technological advances in some PVB interlayers have shown improved acoustic performance for those laminated products using this technology; a thicker interlayer than the regular standard will also be more effective in noise reduction. Always verify the manufacturer’s claims of noise reduction, as you might find that claims are only valid for specific frequencies. In cases where customers seek solutions to specific noise problems we recommend consultation with an acoustic engineer before taking any action. Even when acoustic windows are fitted, if there is even the smallest of air leaks eg under a door, through roof tiles, vents, light fittings, masonry cracks, poorly sealed windows etc, the acoustic windows can be ineffective. |
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| What are the differences between STC & Rw ratings? | |
| Both are laboratory test results and directly equivalent,
however: STC = Sound transmission class that was originally
intended for measuring internal sound transmission
such as the human voice (high frequency).
Rw = Weighted sound reduction index that uses
airborne sound and is viewed as being more
appropriate for rating the attenuation of external low
frequency noise, such as traffic.
This means that a product may have a 30 STC but be
closer to 25 dB in noise. |
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| Which glazed assemblies need to be tested to AS 2047? | |
If located in the external wall of a building, the
following are required to comply:
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| What do I do if a window I have an order to supply is not in AS 2047, is not tested, or does not comply with appendix G Generic timber windows? | |
| Do not supply the window, unless it is a window that
does not have to comply (refer above). |
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| What is a window constructed on site? | |
| A window constructed on site is a
window built in the
structural fabric of the building, using the building’s
structural members as part of the window frame. It is
not a prefabricated window assembled on site. |
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| Can I vary the hardware on a tested product? | |
| Yes, provided that it is judged to be of equivalent
strength to the tested product. |
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| Can I extrapolate and make larger and smaller sizes from the ones tested? How much? | |
| The window manufacturer is responsible for
extrapolation. The design of the product members
limits extrapolation allowance, which varies from
product to product. |
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| Do adjustable louvres with metal blades, or ones with the top half glass and the bottom half metal, need to comply with AS 2047? | |
| YES |
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| How can a toilet window with permanent ventilation meet the waterproofing requirement? | |
| A window containing permanent ventilation cannot
pass the AS 2047 tests and is not an AS 2047
window.
This may be negated by the use of a proprietary
hooded permanent vent. |
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| Is a window fabricated to order by a joinery shop an architectural one off window? | |
| NO |
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| How will I know a window complies with AS 2047 or AS 1288? | |
| An AS 2047 window for housing will be labelled
complying with AS 2047. If there is no label then the
window must certified to comply with AS 1288. |
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| The window has no compliance labelling to either AS 2047 or AS 1288 and it should, what should I do? | |
| Don’t use it. Send it back. |
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| What is a heritage window? | |
| Heritage buildings are normally identified as part
of a
planning instrument. They are usually old buildings
identified as worth preserving for the community.
A new heritage window is a window made to match or
replace an existing window in a heritage building. |
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| Can I make a composite window from windows I have tested? | |
| Yes, provided the members between the windows are
structurally sufficient. |
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| As a glazier currently supplying a certificate for AS 1288, what do I do now? | |
| Continue to supply the certificate as a glazier. The
window manufacturer will label the window if it is for
housing or provide a certificate for other buildings. |
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| Who can tell me what testing rigs are available? | |
| You can use any rig that is NATA certified. The AWA
has a list of testers. |
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| How does a manufacturer certify an exemption? | |
| For windows exempted from AS 2047, including
heritage windows, AS 1288 would still apply and be
certified to. |
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| Who is responsible for certifying an architecturally designed window? | |
| Architecturally designed windows are exempted from
AS 2047. AS 1288 would still apply, particularly safety
glazing. The window needs to be structurally
adequate, be fit for purpose and certified to AS 1288. |
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| Can architects and or owners specify design requirements that do not meet AS 2047? | |
| Generally NO unless the requirements stipulated are
more stringent than the standard specifies. |
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| Are manufacturers protected by a letter or certificate signed off by the architect and or owner? | |
| NO |
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| Can we supply smaller rebates in sills under bi-fold and sliding door systems than those that are required to meet AS 2047? Can we make a door under deemed to comply provisions and extrapolate down? | |
| No. If the sliding door is not tested and passed the AS 2047 tests, and the sliding door does not comply with appendix G, it does not comply with AS 2047. Bi folds are not covered by AS 2047. | |
| Extrapolation is accepted in the standard. Can I add extra hinges and locks to maintain the same unsupported sections as tested units? | |
| NO |
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| If you change anything on a window that has been tested, do you need to retest the whole package? | |
| Generally YES but there may be some exceptions
where the change is minor and does not impact on
performance testing.
If a certain species of timber is specified to
match a tested window can I use any
timber?
The timber should match the structural integrity of the
timber tested. |
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| What should I do if I receive an order to manufacture a frame that has not been tested? | |
| Untested frames should not be supplied, unless it is
for a window that does not have to comply. The
manufacturer may supply the frame without glazing
the window, which may be glazed on site. |
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| If an architect insists on a large window wall and having it installed as drawn, without providing engineer’s calculations to certify it, and the manufacturer makes it, who is responsible for it? | |
| The architect and the window manufacturer. |
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| Can a manufacturer use larger sections than those tested and still achieve the same rating as those tested? | |
| YES |
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| Who is responsible for the windows having the correct wind load rating for a given site? | |
| The designer of the building must select the correct wind loading for the structural parts of the building. A lesser wind loading should be used for the windows. The window manufacturer is responsible for supplying and labelling windows to comply with AS 2047 for housing and certifying windows for other buildings. | |
| There seems to be general industry confusion regarding the actual responsibilities for nominating wind ratings for sites. Who is actually responsible? | |
As AS2047, appendix D and the BCA advise:
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| What is a U-value or U-factor? | |
| U-value measures how well a product prevents heat from escaping. It is a measure of the rate of non solar heat loss or gain through a material or assembly. U-value ratings generally fall between 2.0-10.0 W/m2.K for Australian products. The rate of heat is indicated in the terms of the U-value of a window assembly which includes the effect of the frame, glass, seals and any spacers. The lower the U-value, the greater a window’s resistance to heat flow and the better its insulating value. The U-value for a window takes account of the various U-values for the components making up the window, so you may see these in technical literature; UW is the value for whole window and because of its importance is usually abbreviated to U, UC is the value at the centre of glass, UF is the value for the frame. | |
| What is the difference between R-value and U-value? | |
| R-value and U-value are essentially two sides of the same coin. R-value is usually cited when discussing things such as wall and ceiling insulation values. The term does not translate well to windows and other fenestration products. That industry prefers U-values. The two are actually inversely related. The higher the R-value, the better insulated are the walls and ceilings. The lower the U-value, the better job a window does in keeping out the heat and cold. | |
| What does Solar Heat Gain Co-efficient (SHGC) mean? | |
| SHGC measures how well a product blocks heat caused by sunlight. The SHGC is the fraction of incident solar radiation admitted through a window, both directly transmitted, and absorbed and subsequently released inward. SHGC is expressed as a number between 0 and 1. The lower a window’s SHGC, the less solar heat it transmits. | |
| What is Visible Transmittance (VT)? | |
| Visible transmittance measures how much light comes in through a product. It is an optical property that indicates the amount of visible light transmitted. VT is expressed as a number between 0 and 1. The higher the number, the more light is transmitted. | |
| What is the difference between ANAC and NFRC ratings, and which one should I use? | |
| The ANAC ratings have been available for many years and are based on “Australian National Average Conditions”. This rating system is being replaced by a more advanced and globally acknowledged system developed by the NFRC (National Fenestration Rating Council) in the USA. Unfortunately, the building code called for its use before the “whole of house” rating software (called Accurate - for use in First Rate, BASIX, BERS, etc) was updated. The result is that there are two options available until the transition is complete. Companies can continue with ANAC ratings, and for those with NFRC ratings, as an interim measure, these have been adjusted so that they may run in the “whole of house” software packages. These will be re-rated again when the Accurate software upgrade has been completed, and the ANAC ratings will be discontinued | |
| Why do I need the air infiltration figure from my AS2047 test report for an energy rating? | |
| Air infiltration (or leakage) is indicated on a test report and expressed as L/s m2. Heat loss and gain occur by infiltration through cracks in the window assembly. The lower the air infiltration figure, the less air will pass through the cracks in the window assembly, improving the energy rating. | |
| What is Condensation Resistance (CR)? | |
| CR measures the ability of a product to resist the formation of condensation on the interior surface of that product. The higher the rating, the better the window is at resisting condensation formation. The CR is expressed as a number between 0 and 100. whist this rating cannot predict condensation, it provides a method of comparing the potential of various window types. | |
| What is considered a standard aluminium window frame? | |
| Assume that aluminium frames are standard unless the manufacturer provides a Window Energy Rating (WERS) which demonstrates that better energy performance will be achieved by using the particular frame. Generic Uv for this type of frame = 12.7 | |
| What is considered a thermally improved aluminium window frame? | |
| An aluminium improved frame is defined as one with a U-value of 8.0 W/m2.K or less. This may be achieved by a variety of design improvements, some (or all) of which may be present. Examples include exterior or interior trim made of wood of plastic and attached by clips or adhesives. It is not reliable to estimates the effectiveness of such measures by appearance alone; therefore a U-value of 8 or less, derived from a WERS rating, shall be the sole criterion for classifying a window as 'thermally improved'. | |
| What is considered a thermally broken aluminium window frame? | |
| To be classified as thermally broken, a window must conform
to the following definition by the U.S. National Fenestration Rating Council
(ref: NFRC 100-2001). "Thermal break: a material of low thermal conductivity that is inserted between members of high conductivity in order to reduce heat transfer. Thermal barrier material conductivity shall be no more than 0.5 W/m.K. Thermally broken (TB) members: system members with a minimum
of 5.30mm separation provided by a low-conductance material (where thermal
conductivity (is) less than or equal to 0.5 W/m.K or open air space between
the interior and exterior surfaces. Such systems include members with
exposed interior or exterior trim attached with clips and all skip/debridged
systems".
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| What is spectrally selective glazing? | |
| A coated or tinted glazing with optical properties that is transparent to some wavelengths of energy and reflective to others. Typical spectrally selective coatings are transparent to visible light and reflect short-wave and long-wave infrared radiation. | |
| What effect does the window type have on energy performance? | |
| For operating windows, the operating type has little direct effect on the U-value or SHGC of the unit, but it can have a significant effect on the air leakage and ventilation characteristics. Hinged windows, such as awnings and casements, generally have lower air leakage rates than sliding windows, either horizontal or double hung. A compressive seal and latch increases the effectiveness of the weather stripping in preventing air leakage through hinged windows. | |
| Are there any recommendations I should consider to deliver comfort to my customer? | |
| It is better to install efficient windows than to rely on
heating, ventilation and air conditioning (HVAC) systems to solve thermal
comfort problems. Not only do HVAC systems create non uniform interior
conditions, only partly relieving thermal discomfort, but power outages on
peak days can lead to extremely uncomfortable conditions. In very cold climates, look for windows with very low U-values in order to minimise discomfort. If summer discomfort is expected look for very low SHGC values, but bear in mind that lower SHGCs lead to increased comfort in the summer at the expense of less winter solar warmth. |
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| What is a single hung window? | |
 A single hung window has the upper portion fixed and
only the bottom portion operates. The sash opens
outward pivoting on or near the top rail. |
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| What is a double hung window? | |
 A double hung window has two vertically moving
sashes, controlled by spring balances, each opening
and closing the top and the bottom sash. |
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| What is an awning window? | |
 An awning window is hinged at or near the top and
swings out from the bottom to open. (They do not
open as fully as casement windows and can be left
open in the rain, but allow limited air circulation.) |
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| What is a sliding window? | |
 A sliding window has the opening sash sliding in a
horizontal direction past the other fixed half. |
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| What is a bay window? | |
| A bay window is a series of windows assembled in a
polygon shape that project outward from the face of a
house. |
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| What is a bow window? | |
| Similar to a bay window but usually composed of a
series of window units assembled in an arc, rather
than a polygon. |
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| What is a casement window? | |
 Casement windows pivot on hinges. They can swing
outwards (like a door) and are controlled by a crank
handle fixed to the frame. They can also be hinged at
the sides and swing in the vertical plane to open and
close. |
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| What is a hopper window? | |
 A window where the sash opens inward pivoting at the
bottom rail. |
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| What is a picture window? (Also called fixed lite) | |
 Picture
windows are fixed panes of glass used for light and views only. |
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| What is a roof window? | |
| Roof windows are windows inserted into the roof to
provide additional light to the rooms into which they
are located and are not operable. |
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| What is a skylight? | |
| A skylight is a roof window that can open to provide
ventilation as well as light. |
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| What is a jamb? | |
| Jambs are framing members used to support the
window in a wall and are located at the sides. |
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| What is a head? | |
| The jamb that sits at the top of the frame. |
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| What is a sill? | |
| The framing member at the bottom. |
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| What is a lite? | |
| Lites (lights) are individual panes of glass within a
window. |
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| What is a mullion? | |
| Mullions are vertical members between window units
and are load bearing within the window. |
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| What is a muntin? | |
 A muntin is a framing member that divides multiple
panes of glass in the sash. |
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| What is a sash? | |
| A sash is the operating / moving part of a window,
inclusive of the glass and the surrounding pieces that
hold it together. The sash fits into a frame that is tied
into the surrounding wall and holds the sash into
place. Other parts of the sash include stiles (the
outside vertical members) and rails (the top and
bottom horizontal members). |
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| What is insulated glass? | |
| This term applies to two or more panes of glass
separated by insulation at the edges and air in the
centre to provide greater thermal efficiency to a
window. |
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| What is gas filled glass? | |
| An inert gas, usually argon, is sealed between the
panes of glass in a window instead of air. Gas is a
better insulator than air, increasing the thermal value
of the window. |
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| What is Low-E glass? | |
| Low-E stands for low-emittance. Glass is coated with a
virtually clear material that acts to cut the transmission
of ultra-violet rays that pass through from outside to
inside. Low-E glass further improves thermal
efficiency, cuts glare and prevents the damage that
ultra-violet rays can cause to interior furnishings. |
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| What is a sidelight? | |
| This is typically a fixed, often narrow glass window, located next to a window or door opening. | |
| Can you give me some tips for maintaining my windows? | |
Sure, windows are like any appliance, they need regular care
and maintenance. We suggest a maximum 6 monthly check & clean for windows in
clean air environments, and monthly (maximum 3 monthly) check & clean in
coastal or grimy environments. Some recommendations are:
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| What is an exterior entrance door? | |
| This is a door that allows entrance into a home or non-residential
building. The door must perform in a
manner that allows ingress and egress, but keeps the
elements from penetrating into the interior. |
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| What is a flush door? | |
| Flush doors have a smooth surface with the core
framing of the door covered by two or three layers of
“ply” on either side that form the skin over the core and
frame. The outermost ply is the veneer. |
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| What is a French door? | |
| A French door consists of panes of glass separated by
vertical and horizontal framing members. It opens and
closes in the same fashion as other doors, swinging in
a vertical plane. French doors are often used where
the designer wants to physically define spaces while
still providing a view. |
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| What is a louvre door? | |
| Louvre doors consist of a series of slats, usually
angled horizontally and fastened between vertical
structural pieces. They are frequently employed in
conditions where it is desirable to have air flow
through the door. |
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| What is a bi-fold door? | |
| Bi-fold doors consist of two or more panels. In addition
to being hinged at one side, the panels are hinged
together. These doors are often desirable when there
is a need to fold a door into as small a space as
possible and create an illusion of opening up areas. |
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| Is a 7-ply wood door better than a 5-ply wood door? | |
| A 5-ply door has two layers on each side of the core
(2+core+2) and a 7-ply has three (3+core+3). Since
the thickness of each ply is varied so that the total
thickness of the “skin” remains the same for both,
there is no real difference in the amount of material
provided. The quality of the door is determined by the
strength of the framing and joining used, and the
quality of the materials that make up the skin. |
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| How does a door keep the outside elements from penetrating into the interior? | |
| The door works in concert with weather stripping, the
door frame, and the threshold to keep the elements at
bay. Usually, the door itself has insulating value
provided either by its mass, as in a solid door, or by
insulating material fabricated into the core by its
manufacturer. The weather stripping, doorframe and
threshold prevent air penetration around the door. |
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| What makes an external door different to an internal door? | |
| An exterior door must also be finished to resist the
elements. This requires that the wood be either sealed
or covered with a weather resistant material. The
exterior door must also be manufactured of materials
that are weather resistant. |
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| What is a panel door? | |
| A panel door has several panels, interspersed with
horizontal and/or vertical strips with the result being a
three dimensional appearance. |
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