Gaskets and Seals

DOE-STD-3020-97

5.3.5

Gaskets and Seals. Two methods are currently employed for sealing

the filter to its mounting frame, flat gaskets, and "fluid" seals. The

two methods shall not be used on the same mounting frame.

Flat Gasket. Gasket materials shall be oil and

5.3.5.1

ozone-resistant, made of synthetic rubber, closed cell

sponge Grade 2C3 or 2C4 in accordance with ASTM D

1056, and shall be 1/4 in. (6 mm) thick by 3/4 in. (19 mm)

wide with split or cut surfaces (i.e., no mold skin).

Fluid Seal. Fluid seals require a specially designed

5.3.5.2

mounting frame that is not compatible with flat-gasketed

sealed filters. The sealant shall be nonflammable as

defined in ASTM D092; e.g., no flash at 4500 F (2320 C) or

below; with a fire retardant rating of V-0, per UL-94;

hardness, as determined by Brookfield LTV Penetrometer #

3, of 0.14-0.24 in. (3.5-6.0 mm); and allowing no biological

growth. Fluid seals must be a non-evaporating, highly

viscous, self-healing non-Newtonian substance. The fluid

seal substance shall be corrosion resistant, shall not relax,

crack, separate, or stick or adhere to the knife-edge, and

shall be insoluble in water. The substance shall be

thermally stable with a serviceable range of from 400 F

(40 C) to 4500 (2320 C). If the fluid seal substance is a

grease, the substance shall have a National Lubricating

Grease Institute (NLGI) consistency number 2 or 3 as

determined by ASTM D 217. Evaporation shall be less than

2% when tested in accordance with MIL-S-8660C for 24

hours at 3900 F (1980 C).

Face Guards. Face guards, if required by the filter purchase order,

5.3.6

shall be corrosion resistant and nonflammable.