12-7A-4A.7 Under-Deck Flame Test
- Burner. A 12- × 12-inch (300 x 300 mm) diffusion burner shall be used. Natural gas, methane or propane shall be supplied to the burner through a metered control system. The gas supply to the burner shall produce a net heat output of 80 ± 4 kW throughout the flame exposure. Burner output can be determined from HRR or calculated from the gas flow rate, temperature, and pressure.
- Oxygen depletion calorimeter. The equipment shall include a hood, associated ducting, and instrumentation to provide HRR data by oxygen depletion calorimetry.
See 12-7A-4 Figure No. 1.
- Deck support assembly. Assembly that holds the test deck over the burner.
- Baffle panels and joist support. Horizontal metal plates to support the deck joists along their full length, and also to confine burner flames to the underside of the deck boards located between the support joists.
- Back wall. Ceramic fiber board or another noncombustible panel product for the back wall material. Total height of the back wall is 8 feet (2.4 m).
- Ledger board. A 4-foot-long (1.2 m) simulated 2 x 6 ledger board shall be constructed of layers of ceramic fiber board (or other noncombustible panel product) and attached to the wall at a height slightly below the overhang of the rear deck board of the test deck.
- Airflow. The test is conducted under conditions of ambient airflow.
- Number of tests. Conduct the test on three replicate assemblies.
- Burner output verification. Without a deck in the apparatus, set the output of the burner to 80 ± 4 kW. Conduct a verification run of 3 minutes to ensure the heat release rate, and then turn off the burner.
- Measurement of heat release rate. HRR is measured during the tests with a properly calibrated oxygen depletion calorimeter. Since HRR is typically a post-test analysis, this criterion for Acceptance may be determined at the end of the test.
- Burner positioning. Center the burner directly under the middle deck board, midway between the joists. The distance from the top of the burner to the bottom of the deck boards shall be 27 inches (690 mm).
- Moisture content. Measure the moisture content of the wooden members of the assembly using a moisture meter (ASTM D 4444).
- 7.1. Ignition. Ignite the burner, controlling for a constant 80 ± 4 kW output.
- 7.2. Flame exposure. Continue the exposure for a 3-minute period. Extinguish the burner.
- 7.3. Continued combustion. Continue observation for an additional 40 minutes or until all combustion has ceased. The test shall be terminated immediately if flaming combustion accelerates uncontrollably (runaway combustion) or structural failure of any deck board occurs.
- Observations. Note physical changes of the deck boards during the test, including structural failure of any deck board, location of flaming and glowing ignition, and loss of material (i.e., flaming drops of particles falling from the deck). It is desirable to capture the entire test with a video recorder to allow review of the details of performance.
Should one of the three replicates fail to meet the Condition of Acceptance, three additional tests may be run. All of the additional tests must meet the Condition of Acceptance with an effective peak heat release rate of less than or equal to 25 kW/ft2 (269 kW/m2).
SFM STANDARD 12-7A-5