FAR 25.853 Part IV OSU Heat Release Rate Test Apparatus

Introduction:

The OSU heat release rate test apparatus, originally designed by Smith of Ohio State University in 1972, became FAA's designated combustion tester. The test standards are FAR Part 25 Appendix F Part IV, Airbus AITM 2.0006, Boeing BSS 7322 and ASTM E906.

The Heat Release Rate (OSU) test is used by the aerospace/aviation industry to determine the heat release rate of cabin compartment materials when exposed to radiant heat. It is most commonly used to show compliance with 14 CFR 25.853(d).

A test sample is placed into a chamber with a constant flow of air. A radiant heat source is applied to the exposed surface of the sample. The changes in temperature of the gas are monitored and recorded. The pass/fail criterion is based on the heat release rate calculated from this data.

Standard:

FAR 25.853 Part IV:Heat release rates by materials and products when exposed to one level of radiant heat

Airbus AITM 2.0006,

Boeing BSS 7322,

ASTM E906:Standard Test Method for Heat and Visible Smoke Release Rates for Materials and Products Using a Thermopile Method SUPERSEDED

Features

1. The main components of OSU heat release rate apparatus are adiabatic outer box, electric heating radiation device, ignition device and constant temperature and current device. During the test, the air passes through the cabinet at a constant flow rate from the inlet. The temperature of the air inlet and outlet and the temperature of the cabinet wall are recorded by the data acquisition system. The heat release rate is calculated according to the energy per unit of exposed surface. OSU heat release rate tester can also measure toxic gases, such as CO, CO 2, NO x, HCN, Hbr, HCL, etc. by adding FTIR infrared flue gas toxicity testing device.

2.Three samples were used, with a surface area of 15cm x 15cm and a thickness of use. The samples were placed vertically. The ignition source is a radiation device with a medium flame, which is located at the lower end of the sample. The heat flow intensity is 35kW/m2, and the applied ignition source time is 5min. It is required that the PHRR of qualified materials within 5min of the test head should not be greater than 65kW/m2, and the total heat release of the first 2min should not be greater than 65W min/cm2.

It can adopt different incident heat flux (such as 20kW/m2, 50kW/m2, etc.), and the measured data includes the heat release rate PHRR, and the total heat release THR15 after 15min of the test.

Structure Characteristics

1.Stainless steel combustion chamber with high temperature glass observation window

2.The thermal radiation source is four Glowbars heating rods, which can provide the maximum heat radiation flux of 100KW/M2.

3.The heating rod is 508 mm in length and 16 mm in diameter. The nominal resistance is 1.4 ohms.

4.The air distribution system is made of 6.3mm thick aluminium plate.

5.The flue is made of stainless steel. The cross-sectional area is 133 mm X70 mm and the length is 254 mm.

6.Stainless steel is used to make upper and lower ignition burners. Outer diameter 6.3 mm, wall thickness 0.8 mm; upper ignition burner length 360 mm, lower ignition burner length 400 mm

7.Gas flow rate of induced gas: methane 120cm³/min, air 850 cm³/min

8.Imported gas and air flowmeters with accuracy of 2%.

9.Two independent PID temperature controllers are used for heating temperature control.

10.OSU heat release rate test apparatus is equipped with fully automatic sample propulsion device and shielding door device;

11.OSU heat release rate test apparatus is supplied with upper burner and movable lower burner;

12.Imported rotor flowmeter can be used to adjust gas flow rate of upper and lower burners.

13.OSU has movable T-type calibration burner device and flow controller

14.Methane Mass Flow Controller Imported from Japan Used for Thermopile Temperature Calibration

15.Water-cooled heat flow meter is equipped with self-circulating water cooling system to measure the heat radiation flux of the fire surface without external water source.

16.Air temperature control device, which can provide constant temperature and constant flow air for test chamber

Test system

1.Metherm heat flow meter imported from the United States - used to set the radiation level on the surface of the sample; and equipped with water cooling system to protect the heat flow meter safely. The design range is 0~100k W/m², the accuracy of heat flow meter is 3% and the repeatability is 士0.5%.

2.Using orifice flowmeter to measure flow pressure entering test bin.

3.Micro-differential pressure sensors imported from the United States. Accuracy: ±1%FS, hysteresis ±0.1%FS, maximum linear pressure 69Kpa;

4.Computer + Labview equipped with data acquisition system and heat release standard test software

Specifications