NCC 2016 Volume One
Search the National Construction Code editions
Specification A1.1 Fire-Protected Timber
To set out the requirements for fire-protected timber.
includes the requirements for fire-protected timber and procedures for determining the time at which the temperature at the interface between the protection system and a fire-protected timber element is exceeded.
General requirements
To specify the protection requirements for fire-protected timber.
Where fire-protected timber is used, it must be provided with protection so as to achieve the FRL required of the building element.
In addition, the timber must have either of the following:
Figure Spec A1.1 FIRE PROTECTED TIMBER |
---|
|
The covering required by part or all of the system used to protect the timber in order to achieve the required FRL of the building element.
separates the testing requirements into two sub-clauses; for horizontal elements and for other elements.
For testing of horizontal elements, the test must be conducted in accordance with Section 4 of AS 1530.4. The resistance to the incipient spread of fire is deemed to have failed at the time when the maximum temperature recorded by thermocouples located on the unexposed face of the element lining exceeds 250°C.
The requirements for the testing of other than horizontal elements are contained in . For the purpose of measuring temperatures in accordance with this Clause, thermocouples complying with clause 2.2.3.1 of AS 1530.4 shall be positioned at the following locations:
For wall systems and the like:
For column systems and the like:
For all systems:
The testing must be carried out in accordance with the Standard Fire Test, or an equivalent or more severe test on the timber element with the proposed non-combustible fire-protective covering fixed in a representative manner and confirmed in a report from a Registered Testing Authority.
Massive timber
To specify alternative protection requirements for fire-protected timber which is massive timber.
Fire-protected timber which is massive timber need not comply with Clause 2.1 if it complies with Clause 2.2. Compliance with Clause 2.2 is achieved when all of the following is applied:
The covering required by may form part or all of the system used to protect the timber in order to achieve the required FRL of the building element.
The option provided under requires a test to be carried out on a representative specimen. Refer to Clause 3 for test procedures.
Fire-protected timber must—
utilise a non-combustible fire-protective covering fixed in accordance with the system requirements to achieve an FRL not less than that required for the building element; and
have a non-combustible fire-protective covering fixed in accordance with system requirements—
to achieve a resistance to the incipient spread of fire of not less than 45 minutes when tested in accordance with—
for horizontal elements — Section 4 of AS 1530.4; and
for other elements — the relevant test procedures from Section 4 of AS 1530.4 applied to the element lining; or
which consists of not less than 2 layers of 13 mm thick, fire-protective grade plasterboard.
For the purposes of (a), the non-combustible fire-protective covering provided under (a)(ii) may form all or part of the non-combustible fire-protective covering provided under (a)(i).
Fire-protected timber, where the timber is massive timber, need not comply with Clause 2.1 if the fire-protected timber—
utilises a non-combustible fire-protective covering fixed in accordance with system requirements to achieve an FRL not less than that required for the building element; and
has a non-combustible fire-protective covering fixed in accordance with system requirements—
so as the temperature at the interface between the protection system and the timber does not exceed 300°C during a fire resistance test performed in accordance with Clause 3 for the application and periods listed in Table 1; or
not less than that specified by ; and
has no cavities—
between the surface of the timber and the fire-protective covering; or
between timber elements within the fire-protective covering.
For the purposes of (a), the non-combustible fire-protective covering provided under (a)(ii) may form all or part of the non-combustible fire-protective covering provided under (a)(i).
Table 1 INTERFACE TEMPERATURE AND MINIMUM FIRE-PROTECTIVE GRADE PLASTERBOARD THICKNESS
Application | Time – minutes without timber interface exceeding 300°C | Minimum thickness of fire-grade plasterboard (mm) |
---|---|---|
Inside a fire-isolated stairway or lift shaft | 20 | 13 |
External walls within 1 m of an allotment boundary or 2 m of a building on the same allotment | 45 | 2 x 13 |
All other applications | 30 | 16 |
Form of test
To provide a test procedure for massive timber.
specifies the testing requirements for fire-protected timber. requires the test to be in accordance with the Standard Fire Test, or to apply an equivalent or more severe test method. The Registered Testing Authority must also provide a report to confirm the time at which the timber interface temperature exceeded 300°C.
The remaining Clauses are specific requirements on how to conduct the test. requires the test specimen to incorporate representative joints used in the proposed system. The locations where interface temperatures are measured during the test is specified by . The final sub-clause, , specifies the method of measuring the temperature; which is in accordance with AS 1530.4.
Smaller specimen permitted
To allow a smaller test specimen to be tested.
permits the Registered Testing Authority to conduct a test using a smaller test sample than that required by , provided:
Acceptance criteria
To specify the acceptance criteria of the test.
specifies that the acceptance criteria is the time at which any of the thermocouples (specified in ) exceeds 300°C during the test.
Tests must be carried out in accordance with the Standard Fire Test, or an equivalent or more severe test, on the timber element with the proposed non-combustible coverings fixed in a representative manner, with the time the timber interface temperatures exceeded 300°C confirmed in a report from a Registered Testing Authority.
If a fire protection system incorporates joints, the test specimens must incorporate representative joints.
Interface temperatures must be measured over the following features by a minimum of two thermocouples:
At joint positions in the protection systems.
At least 200 mm from any joint.
At service penetrations.
At any other locations where, in the opinion of the Registered Testing Authority, the interface temperature may be higher than the above positions.
The temperatures must be measured in accordance with Appendix C1 and Section 2 of AS 1530.4 as appropriate.
A Registered Testing Authority may carry out the test specified in Clause 3.1 at pilot scale provided—
a specimen (which must be not less than 1000 mm x 1000 mm) adequately represents the proposed construction in the building; and
the fire resistance of the specimen has already been determined in a full scale test performed in accordance with AS 1530.4 to demonstrate adequate retention of the fire protection system in conjunction with the timber elements being protected; and
the results of the test do not apply to construction larger than limits defined by the Registered Testing Authority conducting the pilot examination.
The time the timber interface temperature exceeds 300°C must be taken as the minimum time any of the thermocouples specified in Clause 3.1 exceeded 300°C.