Fire Penetrations and C3.15

Understanding Fire Penetrations and the Application of C3.15

One of the questions we get asked the most is in relation to Fire Penetrations and C3.15 and its application. Clause C3.15 in the NCC deals with openings for service installations (fire penetrations).

In simple terms this part of the NCC relates to fire stopping service penetrations and whether the required FRL is to have integrity and insulation (-/120/120 for example for 2 hours) or integrity only (-/120/-).

This part of the NCC outlines how to achieve compliance in relation to the insulation criteria of an FRL for a service penetration. The below is an extract from C3.15 and our options for compliance. To comply we need to meet one of the options below in full.

(a) Tested systems

(i) The service, building element and any protection method at the penetration are identical with a prototype assembly of the service, building element and protection method which has been tested in accordance with AS 4072.1 and AS 1530.4 and has achieved the required FRL or resistance to the incipient spread of fire.

(ii) It complies with (i) except for the insulation criteria relating to the service if—

(A) the service is a pipe system comprised entirely of metal (excluding pipe seals or the like); and

(B) any combustible building element is not located within 100 mm of the service for a distance of 2 m from the penetration; and

(C) combustible material is not able to be located within 100 mm of the service for a distance of 2 m from the penetration; and

(D) it is not located in a required exit.

(b) Ventilation and air-conditioning – In case of ventilating or air-conditioning ducts or equipment, the installation is in accordance with AS/NZS 1668.1.

The simplest way to comply with C3.15 is to provide integrity and insulation to the service that is penetrating a fire wall and or floor. This would comply with C3.15(a) (i). If you are going to attempt to waive the insulation criteria you need to comply with C3.15(a) (ii) and in full with all sub clauses A,B,C,D. In our opinion this is very hard to do due to the routing of other services. In particular we find it hard to demonstrate how you will continue to comply with part C of this part of the clause.

The NCC gives an option to comply to the Specification C3.15 if the clause is not able to be met. The specification C3.15 is a lot more difficult to comply with compared with meeting the requirements outlined in C3.15(a) (i) – a tested system. Most services when complying with the Specification call for separation of services by 200 mm, in separately cut tight holes with one service per penetration. These services are also not allowed to penetrate more than 2 fire compartments in addition to any fire-resisting service shafts- hence making it a more difficult install.