Catch up with Code changes

This is a part of the Fire feature

By Nick Saunders - 1 October 2012, Build 132

Changes to the Building Code around fire protection aim to give greater certainty to designers and building officials and lead to cost savings, fewer disputes and more creative engineering solutions. So, what’s changed?

ON 10 APRIL 2012 , changes to the Building Code affecting fire design and construction came into effect. The changes were partly in response to the 2007 review of the New Zealand Building Code that found Building Code requirements needed to be clearer, more specific and more accessible.

The Building Code documents that have changed are:

new clause C Protection from fire
new Verification Method C/VM2 Design methodology for specific fire design
revised clause F8 Warning signs
revised and reformatted Acceptable Solutions C/AS1–C/AS7
revised Acceptable Solution F7/AS1 Warning systems
revised Acceptable Solution F8/AS1 Signs.

The existing Verification Method C/VM1 for solid-fuel burning appliances remains unchanged.

Changes clarify requirements

The new protection from fire framework is shown in Figure 1.

Clause C protection from fire

There are now six new Building Code clauses, C1–C6, replacing the previous clauses C1–C4.

While the objectives of the Code clauses remain unchanged, the functional and performance requirements have become more specific, containing metrics that can be shown to have been met, including:

temperatures to which combustible materials must not be raised
criteria for internal surface finishes
maximum doses of harmful fire effects
requirements to provide the Fire Service access to and within a building.

Acceptable Solutions C/AS1–C/AS7

The new Acceptable Solutions C/AS1–C/AS7 replace the existing Acceptable Solution C/AS1. Requirements are laid out in a prescribed way and do not require any complex calculation or fundamental fire engineering knowledge. Designers without fire engineering qualifications can use them for simple buildings with non-complex design features.

The Acceptable Solutions have been reformatted so that one document relates to a defined group of building types. This division is based on risk groups predicated on the risk the building and activity within the building presents to the occupants.

Buildings that potentially present an equal challenge to occupants if a fire was to occur are grouped together. There are seven risk groups in the new format. Users should refer to the scope of each Acceptable Solution to determine which risk group a particular building use is part of.

The scope of Acceptable Solutions also no longer includes complex building features and complex building systems. This means features that are difficult to design with a prescriptive solution, such as atriums, multiple mezzanine floors or large stadiums, are specifically excluded, as are smoke control and pressurisation systems.

Verification Method C/VM2

The new Verification Method (C/VM2) is a methodology akin to NZS 3101 Concrete structures and NZS 3404 Steel structures.

Figure 1: The new protection from fire framework.

It is for use by designers with fire engineering qualifications and requires knowledge and experience in either computational fire modelling or complex calculation. It allows creative and flexible engineering solutions for any building.

C/VM2 specifies the design loads in the form of design fires that need to be applied to a building. It also has the parameters that need to be applied to define how long occupants will need to evacuate the building or space within a building.

The backbone of C/VM2 is a series of 10 design scenarios that require a designer to account for a number of situations in the building design, ensuring that the design meets the requirements for the safety of occupants and protection of other property and aids fire-fighters in the event of a fire.

Option for altering existing buildings

If it is proposed to alter an existing building or change its use and the Code cannot be met entirely using either an Acceptable Solution or the Verification Method C/VM2, it is now possible to show the extent to which the altered building meets the Code requirements for the clause C portion of Means of escape from fire by directly assessing them against the Code requirements.

Guidance on this process is currently being developed. The method of assessment against the other means of escape Code requirements are unchanged.

Warning systems

Minor changes have been made to F7/AS1, the Acceptable Solution for warning systems, aligning it with the new C/AS1–C/AS7 and removing requirements that are already part of either C/AS1–C/AS7 or NZS 4512: 2010 Fire detection and alarm systems in buildings.

Signs

Changes to Building Code clause F8 Signs include updated references to F6 Visibility in escape routes and to the Building Act 2004 that require the use of the international symbol of access to identify accessible routes.

Pictograms and photoluminescent signs are now included in F8/AS1, making signage more universally understood and improving safety.

Transition periods

Until 9 April 2013, use:

either the existing Building Code clauses C1–C4 and Acceptable Solution or the new Building Code clauses C1–C6 and Acceptable Solutions – but not a mix of the two
either the existing or the new F7/AS1.

From 10 April 2013, use only the new:

Building Code clauses C1–C6
Acceptable Solutions C/AS1–C/AS7
F7/AS1.

The new Verification Method C/VM2 can be used for specific design of any building for compliance with the Building Code clauses C1–C6.

F8 and F8/AS1 Signs came into effect on 10 July 2012.

For more

Training organisations will be running education programmes on the new supporting documents, and detailed information on the changes is available at www.dbh.govt.nz/compliance-documents.