Section B Structure
Part B1 Structural provisions
NT B1.4 Determination of structural resistance of materials and forms of construction
Termite Risk Management: Where a primary building element is subject to attack by subterranean termites—
AS 3660.1 with additional protection measures to be used in areas where Mastotermes Darwiniensis are prevalent; and
for the purpose of this provision, a primary building element consisting entirely of, or a combination of, any of the following materials is considered not to be subject to termite attack:
Steel, aluminium or other metals.
Timber in areas where Mastotermes Darwiniensis are not prevalent—naturally termite resistant in accordance with Appendix C of AS 3660.1.
Timber — preservative treated in accordance with Appendix D of AS 3660.1; and
where a termite risk management system in accordance with AS 3660.1 is used, a durable notice must be permanently fixed to the building in a prominent location, such as a meter box or the like, indicating—
the method of termite risk management; and
the date of installation of the system; and
where a chemical barrier is used, its life expectancy as listed on the appropriate authority's pesticide register label; and
the installer's or manufacturer's recommendations for the scope and frequency of future inspections for termite activity.
NT Addition to Specification B1.2
NT3 Strengthened area
Where a residential building of Class 2, 3, 9a or 9c, in Region C as defined by AS/NZS 1170.2, is designed to be used by the Aged or Infirm it shall incorporate a “strengthened area” for use as shelter during cyclonic conditions and must comply with the following criteria:
(“strengthened area” is defined as the strengthening of an area to increase its potential to facilitate debris protection)
The floor area of the “strengthened area” is to be calculated at the rate of 1.2 m2 per person normally accommodated within the building.
The design wind pressure for the overall "strengthened area" is for an Importance Level 3 building.
The minimum standard of debris protection to walls, floors and ceilings (or roof) bounding the "strengthened area" shall be that which resists (without complete penetration) the impact loading specified in AS/NZS 1170.2, using a regional wind speed associated with an Importance Level 3 building.
All doors, windows, vents and the like in walls bounding the "strengthened area" are to be protected against windborne debris with permanently installed screens in accordance with (c).
Consideration must be given to the selection of materials and fittings to ensure doors, windows and vents can withstand the required design wind pressures.
All doors serving as required entries/exits to a "strengthened area" are to be inward opening with locking devices suitably noted for use in a cyclone emergency.
NT4 Masonry veneer construction
Masonry veneer construction must be designed so that the structural framing, to which the masonry veneer is tied, will ensure the stability of the masonry veneer.