UL 72:2015 pdf download – Tests for Fire Resistance of Record Protection Equipment.
8 Explosion Test
8.1 General
8.1. Record protection equipnient snai, wiulsianu me exp.osion lesI WnhUUI inernia uamage 10 uie contents.
82 Samples
8.2.1 Samples are to be selected in the same manner as for the fire endurance test.
8.2.2 The test sample fo the explosion test is able to be provided with lifting hooks to facilitate the handling and insertion of the sample into the furnace.
8.3 Method
8.3.1 The sample is to be prepared as for the fire endurance test, except that no temperature- ohumidity-measuring equipment is to be installed inside the test sample. The procedure is to be as follows:
a) The empy. closed furnace is to be heated to a temperature of approximately 2000°F
(1090°C).
b) The furnace door is to be opened momentarily and the test sample inserted. (During
insertion of the test specimen, the temperature of the furnace drops several hundred degrees,)
C) The furnace fire is to be maintained at 2000°F (1090°C) for 30 mm (20 mm for units rated 112-h) after insertion of the test specimen. All surfaces of the sample are to be exposed to the temperature. If no explosion results, the sample is to remain in the closed furnace until
sufficiently cool to handle.
8.3.2 Alter the test sample has cooled sufficiently to permit handling, the doors, drawer heads, or other closures are to be opened and the assembly dismantled. Examinations are to be made as to the heat-Insulating properties of the sample, as evidenced by the usability of the paper contents (see 5.2). Observations are to be made of the integrity of the closure mechanism (latched, locked, or both latched and locked).
9 Combined Explosion Impact Test
9.1 At the option of the manufacturer, the fire-impact test and the explosion test may be combined and
conducted on one sample of the equipment.
9.2 In the combined test, the explosion test as described in 8.3.1 is to be conducted.
9.3 II no explosion results during 30 mm at 2000°F (1090°C), the furnace temperatures are to be reduced
to those specified in Appendix A and the fire continued for an additional 30 mm for equipment to be rated
4 or 3 h, and for an additional 15 mm for equipment to be rated 2 h. No additional exposure is required
for equipment to be rated 1 or 112 h. After exposure to the fire for the total period required for the desired
classihcation, the furnace fire is to be extinguished and the test sample withdrawn,
9.4 The Impact test is then to be continued as described In 7.3.3 — 7.3.5.
10 Gasket Materials
10.1 Neoprene or rubber gaskets (except those made of foamed material), when employed, are to be tested to demonstrate compliance with the following properties:
a) Minimum tensile strength — 850 pounds per square in (psi) (586 MPa) and minimum ultimate elongation — 250 percent (1 to 3-112 units);
b) Maximum set of 1/4 in (6,4 mm) when 1 In (25.4 mm) marks are stretched to 2-112 in (64 mm), held for 2 mm. and measured 2 mm after release;
C) After 70 Ii In an air oven at 100°C ±2°C (212F ±3.6°F):
1) Minimum percent of original tensile strength — 75.
2) Minimum percent of original elongation — 65.
10.2 Foamed neoprene or rubber gaskets, when employed, are to be tested to demonstrate compliance with the following properties:
a) Minimum tensile strength — 65 psi (0.45 MPa) and minimum ultimate elongation — 100 percent,
b) After 70 h In an air oven at 100°C ±2°C (212°F ±3.6°F):
1) Minimum percent of original tensile strength — 75.
2) Minimum percent of original elongation — 65.
10.3 Thermoplastic gaskets, if employed, are to be tested to demonstrate compliance with the following properties:
a) Minimum tensile strength 1200 psi (8.27 MPa) and minimum ultimate elongation — 250 percent (1 to 3-112 units).
b) After 7 days in air at 87°C (189°F).