Standard Test Method for Ignition Sensitivity of Nonmetallic Materials and Components by Gaseous Fluid Impact

Importancia y uso:

4.1 This test standard describes how to evaluate the relative sensitivity of materials and components to dynamic pressure impacts by various gaseous fluid media (can include gas mixtures).

4.2 Changes or variations in test specimen configurations, thickness, preparation, and cleanliness can cause a significant change in their impact ignition sensitivity/reaction. For material tests, the test specimen configuration shall be specified on the test report.

4.3 Changes or variation in the test system configuration from that specified herein may cause a significant change in the severity produced by a dynamic pressure surge of the gaseous media.

4.4 A reaction is indicated by an abrupt increase in test specimen temperature, by obvious changes in odor, color, or material appearance, or a combination thereof, as observed during post-test examinations. Odor alone is not considered positive evidence that a reaction has occurred. When an increase in test specimen temperature is observed, a test specimen reaction must be confirmed by visual inspection. To aid with visual inspection, magnification less than 10× can be used.

4.5 When testing components, the test article must be disassembled and the nonmetallic materials examined for evidence of ignition after completion of the specified pressure surge cycles.

4.6 Ignition or precursors to ignition for any test sample shall be considered a failure and are indicated by burning, material loss, scorching, or melting of a test material detected through direct visual means. Ignition is often indicated by consumption of the non-metallic material under test, whether as an individual material or within a component. Partial ignition can also occur, as shown in Fig. 3a, b, and c, and shall also be considered an ignition (failure) for the purpose of this test standard.

FIG. 3 a Untested PCTFE (10X Magnification) (Polychlorotrifluoroethylene) Sample.

FIG. 3 b Untested Nylon (PA, polyamide) Valve Seat (10X magnification) (continued)

FIG. 3 c Untested Pin-Index Sealing Washer (10X magnification) (continued)

Note 1: For the purpose of this standard, test samples that visually appear in these conditions, or similar, are considered to be representative of ignition.

FIG. 3 Photographs Representing Partial Reactions Including Scorching, Discoloration, Melting and Material Loss or Material Consumption. For the purpose of this standard, test samples that visually appear in these conditions, or similar, are considered to be representative of ignition.

Note 2: A representative (exemplar) material or component may be requested by the test laboratory personnel for visual comparison with the post-test condition of the test samples.

4.7 For material testing, the prescribed procedure is conducted on multiple samples until a statistically significant number of ignitions or no-ignitions, or both, are achieved at various test pressures. The data is then analyzed by a procedure that calculates the median failure pressure (i.e., the 50 % reaction pressure) or the functional form of the ignition probability versus pressure by logistic regression analysis. Materials tested in a similar configuration can be ranked against each other by either of these two criteria. The initial test gas temperature may be varied as required depending on the requirements of the test.

4.8 For component testing, a specified number of pressure surge cycles are conducted at a defined test pressure, usually specified by a particular industry test standard. Usually, this pressure is 1.2 times the maximum allowable working pressure of the component. The initial test gas temperature may be varied depending on the requirements of the test; however, most commonly the initial test gas temperature is 60 ± 3 °C.

Subcomité:

G04.01

Referida por:

G0126-16R23, G0128_G0128M-15R23, G0127-15R23, G0063-15R23, G0088-21, G0114-21

Volúmen:

14.04

Número ICS:

13.220.40 (Ignitability and burning behaviour of materials and products), 13.230 (Explosion protection)

Palabras clave:

component adiabatic compression test; gaseous fluid impact; ignition sensitivity; material oxygen compatibility test; oxygen enriched environment; oxygen qualification test; oxygen valve test;