ASTM E69 Combustible Properties of Treated Wood by the Fire-Tube Apparatus

Scope:

The goal of ASTM E69 is to determine the combustibility of fire-retardant-treated wood specimens based on their weight loss % during controlled fire exposure settings. Other possible data include weight loss rate, blazing and after glowing time, temperature increase, and maximum vertical flame progress. This test method has proven valuable in comparing the effectiveness of fire-retardant chemicals and treatment formulations for wood and wood products in terms of fire performance.

Procedure

After conditioning, there are two main procedures for ASTM E69. Procedure A is used to determine the percentage loss of weight of specimens following flame exposure. The test is carried out in a laboratory hood or a room with no severe drafts. The burner is put within the empty fire tube, and the burner and gas regulator is set to produce a blue flame with a tall unclear inner cone that is roughly 11 in. (279 mm) in height. After this, the fire-tube weighing apparatus is adjusted, and the percentage loss of weight sustained by the test specimen is recorded at 30 second intervals. Only the final percentage loss of weight of specimens exposed to the flame is reported using procedure B. It’s a condensed version of procedure A.

Video 01: Pressure treatment process of wood

Specimen size:

At the top of the fire tube, the flame is adjusted to create a temperature of 356 6 9°F (180 6 5°C).

Data

The following data is calculated in ASTM E69:

% Weight loss =  (Wi 2 Wf)/ Wi/3 ×100 

where:

Wi = initial weight, lb(g), and

Wf = final weight, lb(g).

Conclusion:

The goal of ASTM E69 is to determine the combustibility of fire-retardant-treated wood specimens based on their weight loss % during controlled fire exposure settings.