Australian Window Association

FAQ'S

ACCREDITATION

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.

• LITIGATION The AWA's use of a third party NATA accredited program minimises the legal liability of the window manufacturer.

• QUALITY ASSURANCE The AWA's third party NATA accreditation program meets the requirements of government and other bodies that require quality assurance when choosing a supplier. NATA mandates an annual audit as part of its ongoing accreditation of the AWA compliance program.

•  MARKETING The AWA accreditation program provides a measurable independent means of promoting the performance of your window against those not in the program.

• COST The AWA has streamlined the operation of the audit process so that it is conducted at the minimum (self funded) costs possible to its members.

ACOUSTICS

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.

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.

STANDARDS AND COMPLIANCE

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:

• All windows except for:

- those in other than the vertical plane,

- those containing fixed louvres'

- windows constructed on site,

- architectural one off windows,

- second hand, re-used, recycled and replacement windows,

- heritage windows

-Sliding doors with a frame.

-Adjustable louvres.

-Shopfronts.

-Window walls with one-piece framing.

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).

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.

Can I vary the hardware on a tested product?
Yes, provided that it is judged to be of equivalent strength to the tested product.

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.

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

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.

Is a window fabricated to order by a joinery shop an architectural one off window?
NO

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.

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.

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.

Can I make a composite window from windows I have tested?
Yes, provided the members between the windows are structurally sufficient.

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.

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.

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.

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.

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.

Are manufacturers protected by a letter or certificate signed off by the architect and or owner?
NO

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

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.

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.

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.

Can a manufacturer use larger sections than those tested and still achieve the same rating as those tested?
YES

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:

• For housing and other residential buildings the purchaser should nominate the window ratings when ordering the window assemblies
• For all other buildings the purchaser should nominate the design wind pressure for the window assemblies when ordering the windows
• The manufacturer of standard window assemblies should verify the window rating or design wind rating

ENERGY EFFICIENCY

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".
Generic Uv = 3.8.

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.

WINDOWS GENERAL

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.

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.

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.)

What is a sliding window?
A sliding window has the opening sash sliding in a horizontal direction past the other fixed half.

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.

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.

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.

What is a hopper window?
A window where the sash opens inward pivoting at the bottom rail.

What is a picture window? (Also called fixed lite)
Picture windows are fixed panes of glass used for light and views only.

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.

What is a skylight?
A skylight is a roof window that can open to provide ventilation as well as light.

What is a jamb?
Jambs are framing members used to support the window in a wall and are located at the sides.

What is a head?
The jamb that sits at the top of the frame.

What is a sill?
The framing member at the bottom.

What is a lite?
Lites (lights) are individual panes of glass within a window.

What is a mullion?
Mullions are vertical members between window units and are load bearing within the window.

What is a muntin?
A muntin is a framing member that divides multiple panes of glass in the sash.

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).

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.

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.

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.

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:

• All dirt, sand and rubbish should be vacuumed out of the bottom of glider windows and sliding doors.

• Clean Aluminium windows with a non abrasive pH neutral detergent solution. Rinse clean to remove residue. Do not use solvents or abrasive cleaners eg Jiff

• We suggest cleaning uPVC windows as above, however they are more tolerant of harsher cleaners such as turps or Jiff. Rinse clean to remove residue.
• Do not hose down your windows, they are not designed for this and high pressure water may leak inside, or worse - break the glass.
• Check and clear any debris from weepholes in the windowsills - these holes allow water to drain out of the window system when it rains.
• Check the surface finish of timber windows on a regular 6 monthly basis, re-coat as necessary.
  
• If your windows are subjected to spillage of cement, render or other waste, you must wash them clean immediately or you may risk a permanent stain or damage to your window frames.
• Avoid using metal scrapers to remove paint etc from glass surfaces as many of the new high performance glass options have surfaces that are readily scratched or damaged if not properly cared for.
• Lubricate moving parts such as rollers, locks, hinges with a silicone based spray.

DOORS - GENERAL

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.

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.

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.

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.

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.

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.

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.

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.

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.