WINDOWS | TECHNICAL
AWA TECHNICAL COMMITTEE
INSTALLATION PROJECT
RUSSELL HARRIS
Technical Manager,
Australian Window
Association
Following the successful launch
of the AWA installation videos,
work continues on this project
to develop appropriate training
and technical manuals. The
Technical Committee recently
reached another key milestone
with the completion of the
draft handbook which will be
published later this year. The
Technical Committee’s focus will
now turn to the development of
course content for the training
modules.
AS 1530.8
Public Comment on Draft
Australian Standard (AS) 1530.8
Parts 1 and 2 Methods for fire
tests on building materials,
components and structures
recently closed. In response
to a number of changes in the
draft standard, the Technical
Committee formed a working
group of R&D specialists
to review and comment on
the proposed changes. This
work culminated in an AWA
submission to Standards
Australia on behalf of all
members. There is no indication
at this time from Standards
Australia as to when this revision
will be published.
AS 2047
Amendment 2 of Australian
Standard (AS) 2047 Windows
and external glazed doors in
buildings was recently published.
The pertinent changes in this
amendment are:
• Correction of unit-of-measure
for the Charpy Impact Test.
• Update references to
AS 4420.1.
DOCUMENT NO. 201706/01
VERSION 1
RELEASED JUNE 2017
KEY MESSAGE
WIND LOADS FOR RESIDENTIAL AND COMMERCIAL
BUILDINGS
Clause 2.3.1 Housing
• Clause 2.3.2 Residential and Commercial
WIND SPEED AND WIND PRESSURE
All buildings are subject to the elements of extreme
weather which includes high wind speeds. Wind loads
on buildings can be substantial and in many cases
will act as one of the most significant forces that the
building will be subjected to. Wind speed and wind pressure are closely related, but
are not the same.
Wind load is considered to be a dynamic force as it
varies greatly in intensity over time. As wind flows around
a building, it exerts high pressure on the windward face
and low pressure (suction) on the leeward face. Leading
edges (corners) experience the greatest force due to
wind acceleration.
Wind speed is an expression of the velocity of the air
moving past a stationary object. It is most commonly
measured in metres per second (m/s).
Site wind speeds are derived from recorded regional
wind speed data, the local effects of terrain (height,
topography and shielding) and the relevant annual
probability of exceedance. Site wind speeds are the
predicted speed of wind over the building site, and are
determined without consideration of the effects of the
building itself (ie calculated as if the building does not
exist).
Wind pressure is the force per unit area exerted over
a structure by moving air. The pressure varies with the
velocity of the air (both wind speed and direction) and
the aerodynamic shape and orientation of the structure.
Different parts of the same building experience different
wind pressures given the same site wind speed.
Differential wind pressure is the difference in pressure
between the inside and outside of a building surface (for
example, a window). Pressure is measured in pascals
(Pa).
Figure 1
KEY MESSAGES
The AWA has recently published
a Key Message to provide
information and guidance on
wind loads for commercial and
residential buildings (image 01).
The Key Message discusses
relevant aspects of wind loading
such as:
• Regulatory requirements of
the National Construction
Code (NCC) and Australian
Standard (AS) 2047 Windows
and external glazed doors in
buildings.
The purpose of this Key Message is to provide general information about wind load requirements for windows in
residential and commercial buildings.
ABOUT WIND LOADS
Public Comment on Draft
Australian Standard (AS) 2688
Timber and composite doors
closed in early June. The AWA
sought comments from members
which were considered by the
Technical Committee prior
to a submission to Standards
Australia on behalf of all
members. An important note
is that the draft standard now
includes an option for voluntary
testing to AS 4420.1 in an
informative appendix. There is
no indication at this time from
Standards Australia as to when
this revision will be published.
• Wind speed and pressure.
AS 2047:2014 sets out the performance criteria for all windows in all buildings. These requirements fall into two
categories based on building type and purpose:
•
AS 2688
Airflow over a House
REGULATORY REQUIREMENTS
• Determination of Wind
Actions according to
Australia/New Zealand
Standard (AS/NZS) 1170.2
Structural Design Actions –
Part 2 Wind Actions.
• Responsibilities for
determining wind loads under
Australian Standard (AS)
2047 Windows and external
glazed doors in buildings.
The National Construction Code (NCC) prescribes that
a building must perform adequately under all reasonably
expected design actions and withstand extreme or
frequently repeated design actions, including the effects
of wind loads.
The NCC references Australian/New Zealand Standard
(AS/NZS) 1170.2 Structural Design Actions – Part 2 Wind
Actions as the primary engineering standard used in the
des