The annual changes to the National Construction Code (NCC) took effect on 1 May 2018.
Here’s a snapshot of what changed for builders and trade contractors in Queensland.
Fire safety and wall cladding
The Australian Building Codes Board (ABCB) has developed a comprehensive package of measures designed to address fire safety in high rise buildings, including fire safety related to the combustibility of external walls.
Amongst these measures are the amendments to Volume One of the NCC which took effect from 12 March 2018 - Amendment 1.
The changes introduced a new verification method for testing external wall assemblies for fire spread, which references AS 5113. The Deemed to Satisfy provision for bonded laminated materials was also changed to require any core to be non-combustible. In addition, changes proposed to NCC 2019 will remove the Deemed to Satisfy provision for bonded laminated materials altogether.
The effect of the changes is that external wall systems will need to be verified using a fully assembled prototype wall test in accordance with AS 5113. This will affect the construction of units, health care and aged care buildings two storeys or more in height (classes 2, 3 or 9) and office, retail or commercial buildings three storeys or more in height (classes 5, 6, 7 or 8).
Specifically, Amendment 1 includes the following:
- The introduction of a new Verification Method (CV3) for testing of external wall assemblies for fire propagation. CV3 references a new testing standard, AS 5113-2016 Fire propagation testing and classification of external walls of buildings, and in most circumstances requires additional measures (e.g. enhanced sprinkler protection) to mitigate the hazard presented by a combustible façade.
- Clarification of provisions, including provisions relating to external wall claddings and attachments, provisions that provide exemption to the non-combustibility requirements, and provisions that control the fire hazard properties of building elements.
- Increased stringency for the sprinkler protection of balconies of residential high rise buildings through referencing an updated sprinkler standard, AS 2118.1-2017 Automatic fire sprinkler systems – General systems.
The Amendment also revised the NCC’s evidence of suitability provisions in Volume One Part A2.2. This included:
- clarification of the application and language
- strengthened wording of the current options, and
- a new requirement to consider the ‘appropriateness’ of the evidence being presented to support the use of the material, product, design or form of construction.
The Evidence of Suitability Handbook 2018 accompanies the Amendment and provides guidance for applying the provisions of Part A2.2.
Advisory Note 2016-3 ‘Fire Performance of External Walls and Cladding’ has also been revised in line with the Amendment. Editions of this advisory note dated to prior 2018 are not applicable to NCC 2016 Volume One Amendment 1.
Slip-resistance requirements for housing
AS 4586-2013 'Slip-resistance classification of new pedestrian surface materials' applies to all classes of buildings under the BCA and is required for:
- Floor surfaces of a ramp
- The surface of a tread or the nosing strip on the tread
- The surface of a landing or the strip at the edge of the landing.
The application of finishes to these areas must have documentary evidence to prove the classification. This applies to all finishes and surface types.
What do you have to do?
- Identify the slip-resistance classification for stair treads, ramps and landings in wet or dry surface conditions
- Source and install products with the correct classification
- Get documentary evidence that states classification, as per AS 4586, that’s from an organisation registered by the National Association of Testing Authorities (NATA), or a product certification body accredited by the Joint Accreditation Scheme of Australia and New Zealand (JAS–ANZ)
- Provide a copy of documents to the Building Certifier.
The Building Code references two types of classifications:
- The wet pendulum test gives a slip-resistant value as a P classification, ranging from P0 to P5.
- The oil wet inclining test gives a slip-resistant value as an R classification ranging from R9 to R13.
Higher classifications indicate a good slip-resistance value.
Volume 1 – Class 2 to 9
This requires a classification not less than that listed in Table D2.14 for:
Ramp steeper than 1:14
P4 or R11
P5 or R12
Ramp steeper than 1:20 but not steeper than 1:14
P3 or R10
P4 or R11
Tread or landing surface
P3 or R10
P4 or R11
Nosing or Landing edge strip
Volume 2 – Class 1 & 10
Requires a classification not less than that listed in Table 126.96.36.199:
Ramp not steeper than 1:8
P4 or R10
P5 or R12
P3 or R10
P4 or R11
Nosing or landing edge strip
Is the product compliant?
For products like carpet, tiles, slate, vinyl, concrete and metal, not altered during installation, the manufacturers laboratory test, as per AS 4586, could be appropriate.
Always get evidence of a test report (from a NATA organisation or a JAS–ANZ certification body) before purchasing any product. Non-compliant test reports are unacceptable to building certifiers and in-situ wet pendulum testing may be required. Depending on the location this could be impractical with no guarantee that the classification can be achieved.
For timber surfaces any pre‐coated finish supplied by the manufacturer could be pre‐tested to AS 4586.
Requirements for eaves gutters
A slotted gutter system may not always be sufficient for class 1 and 10 buildings without using additional measures.
The Code’s provisions are used to determine overflow volumes required for the specific building design and the available options to remove the specified volume of water.
The overflow volume is calculated using a series of reference tables in the Code, with an option between two systems:
- Continuous – a continuous overflow measure operates over the entire length of the gutter, such as a slotted gutter system.
- Dedicated – a dedicated overflow measure is one which removes water in a given location, such as a rainhead.
Options include measures such as:
- Slotted gutters
- Rear gaps to eaves gutter
- Reduced bead heights
- End stop weirs and rainheads.
You can use a combination of these options to achieve the overflow volumes.
The changes don’t apply to eaves gutters fixed to a verandah or an eave that is greater than 450mm in width, which:
- Has no lining; or
- Is a raked verandah or a raked eave with a lining sloping away from the building.
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