For an Authority Having Jurisdiction, combustibility is defined by the local code. In the National Building Code of Canada, it is defined as follows:
*Combustible: A material that fails to meet acceptance criteria of [https://web.archive.org/web/20061003193651/http://www.ulc.ca/About_ulc/Publication_Notice_Detail.asp?PN_ID=31 CAN/ULC-S114, Standard Method of Test for Determination of Non-combustibility in Building Materials].
*Non-combustible: means that a material meets the acceptance criteria of [https://web.archive.org/web/20061003193651/http://www.ulc.ca/About_ulc/Publication_Notice_Detail.asp?PN_ID=31 CAN4-S114, "Standard Method of Test for Determination of Non-Combustibility in Building Materials]".
BS 476-4:1970 defines a test for combustibility in which a technician heats three specimens of a material in a furnace. Combustibile materials are those for which any of the three specimens either:
* Makes the temperature reading from either of two thermocouples rise by 50 degrees Celsius or more above the initial furnace temperature
* Flame continuously for 10 seconds or more inside the furnace
Otherwise, the material is classified as non-combustible.