Features and Test Criteria

DOE-HDBK-1092-98

atmosphere. Enclosures shall meet operation and temperature-design tests. Enclosures intended for

outdoor use shall also meet the rain test (See #4 in Section 5.8.2).

5.8.2 FEATURES AND TEST CRITERIA

When completely and properly installed, Type 8 enclosures:

1. Provide, by oil immersion, a degree of protection to a hazardous gas environment from

operation of internal equipment

2. Do not develop surface temperatures that exceed prescribed limits for the specific gas

corresponding to the atmospheres for which the enclosure is intended when internal equipment

is at rated load

3. Withstand a series of operation design tests with oil levels arbitrarily reduced

and with flammable gas-air mixtures introduced above the oil

4. When intended for installation outdoors, exclude water when subjected to a water spray

design test simulating a beating rain

5. Are marked with the appropriate class and groups for which they have been qualified.

5.9 TYPE 9 ENCLOSURES

Type 9 enclosures are designed for indoor use in locations classified as Class II Groups E or G as

defined in the NEC.

5.9.1 DESCRIPTION AND APPLICATION

Type 9 enclosures shall prevent the entrance of dust. Enclosed heat-generating devices shall not

cause external surfaces to reach temperatures capable of igniting or discoloring dust on the enclosure

or igniting dust-air mixtures in the surrounding atmosphere. Enclosures shall meet dust-penetration

and temperature-design tests and prevent aging of gaskets (if used).

5.9.2 FEATURES AND TEST CRITERIA

When completely and properly installed, Type 9 enclosures:

1. Provide a degree of protection to a hazardous dust environment from operation of internal

equipment

2. Do not develop surface temperatures that exceed prescribed limits for the group corresponding

to the atmospheres for which the enclosure is intended when internal equipment is operated

at rated load

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