NFPA 271-1998 Standard Method of Test for Heat and Visible Smoke Release Rates for Materials and Products Using and Oxygen Consumption Calorimeter

NFPA 271-1998 Standard Method of Test for Heat and Visible Smoke Release Rates for Materials and Products Using and Oxygen Consumption Calorimeter. 1-3.2 If delamination of the specimen occurs, the test results shall be considered suspect and this shall be described in the test report. 1-3.3* This test method shall be performed in a controlled environment under controlled laboratory conditions in order to obtain material properties data for use in evaluating the fire hazard of materials. These data alone do not describe the fire hazard of a material’s specific end use or predict its response to real fires. The data obtained by this test method have not yet been correlated with the real-world fire performance for most materials. Thus, caution shall be used when utilizing such data to evaluate the full-scale fire performance of the end use of materials tested in accordance with this method. 1-4 Summary of Test Method. 1-4.1 This test method shall be based on the observation that the net heat of combustion is directly related to the amount of oxygen necessary for combustion. Approximately 13.1 × 10 3 kJ of heat are released per 1 kg of oxygen consumed. Specimens in the test shall be combusted in ambient air conditions while being subjected to a predetermined external radiant heat flux, which ranges from 0 kW/m 2 to 100 kW/m 2 . Combustion shall be initiated with or without a spark ignition. 1-4.2 The primary measurements, as a function of time, shall be oxygen concentration and exhaust gas flow rate (for assessing heat release rate). Additional measurements shall include specimen mass, for assessing mass loss rate and smoke obscuration, both of them as a function of time, and time to sustained flaming, which is a measure of ignitibility. The test method shall also be suitable for other measure- ments, as required in the relevant material or performance standard. 2-4 Exhaust System. 2-4.1 The exhaust-gas system shall consist of a high-tempera- ture centrifugal exhaust fan, a hood, intake and exhaust ducts for the fan, and an orifice plate flowmeter as shown in Figure 2-4.1. The exhaust system shall be capable of developing flows from 0.012 m 3 /sec to 0.035 m 3 /sec. 2-4.2 A restrictive orifice (57-mm I.D.) shall be located between the hood and the duct to promote mixing. 2-4.3 A ring sampler for gas sampling shall be located in the fan intake duct 685 mm...