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What does Group 2 mean and what is required to comply.

The National Construction Code of Australia (NCC) and AS 5637.1:2015 stipulates the classification of materials by Group Number, which indicates the amount of time taken for the material being tested to reach flashover under AS ISO 9705 — 2003 test conditions.


The NCC and AS 5637.1:2015 define flashover to be a Heat Release Rate of 1 MW, so materials are classified, in accordance with NCC 2016 spec Cl.10 and AS 5637.1 2015, by the time taken for the Heat Release Rate, as measured during the AS ISO 9705 test, to reach 1 MW per the scheme below.

Group 1

Materials that does not reach flashover when exposed to 100 kW for 600s followed by exposure to 300 kW for 600s.


Group 2

Materials that reaches flashover following exposure to 300 kW within 600s after not reaching flashover when exposed to 100 kW for 600s.


Group 3

Materials that reaches flashover in more than 120s but within 600s when exposed to 100 kW.


Group 4

Materials that reach flashover within 120s when exposed to 100 kW.

The NCC and AS 5637.1:2015 also define the smoke growth rate index, or SMOGRARC as a quantity which may be obtained from the smoke obscuration measurements obtained in the AS ISO 9705 test


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