1、MIL-STD-LOBE- NOTICE I EN m 77777LL 0033706 L m c “ 08“ 4 August 1966 SUPERSEDING 27 June 1958 MIL-STD-108D MILITARY STANDARD DEFINITIONS OF AND. BASIC REQUIREMENTS FOR ENCLOSURES FOR ELECTRIC AND ELECTRONIC EQUIPMENT - c i. - .r . THIS DOCUMENT CONTAINS a, E PAGES Provided by IHSNot for ResaleNo re
2、production or networking permitted without license from IHS-,-,-I MIL-STD-LOBE NOTICE L EN W 77777LL 0033707 3 W . MIL-STD-108E 4 August 1966 J DEPARTMENT OF DEFENSE WASHINGTON, D.C. 20301 Definitions of and Basic Requirements for Enclosures for Electric and Electronic %quipment MIG-STD-1OSE . . 1.
3、This Military Standard is mandatory for use by all Departments and Agencies of the Department of Defense. f I 2. Recommended corrections, additions, or deletions should be addressed to Commander, . Naval Ship Engineering Center, Washington, D.C. 20360. Provided by IHSNot for ResaleNo reproduction or
4、 networking permitted without license from IHS-,-,-7 MIL-STD-LOBE NOTICE I EN 99979LL 0033708 5 W FOREWORD - ”-” MIGSTD-108E 4 August 1966 An enclosure is a mechanical item which wholly or partly surrounds some electrical or electronic item or group of items and is an integral part of the equipment,
5、 It is used herein in a general sense to include such items as cabinet and housing which are defined in the Federal Item Identification Guide for Supply Cataloging. It may per- form any or all of the following functions: 4 (a) Provide physical protection to the enclosed items. (b) Provide physical p
6、rotection from -items within the enclosure to personnel or ob- (c) Provide means for ventilating items within the enclosure, (d) Provide means for cooling items within the enclosure. (e) Provide external facilities for mounting on, or securing to, a structure, such as (f) Provide interior support fo
7、r subassemblies, parts and similar items. (g) Provide reduction of radiated audible noise or radio interference. jects outside the enclosure. a wall or bulkhead. I This standard defines the enclosure by the environmental protection that it provides to its contents. In some cases, this standard cover
8、s physical protection to the equipment or to personnel. Specific requirements for ventilation, cooling, mounting, support and re- duction of audible noise or radio interference should be covered by equipment specifiw- tions. i Provided by IHSNot for ResaleNo reproduction or networking permitted with
9、out license from IHS-,-,-MIL-STD-108E NOTICE l. 19 September 1985 - MILITARY STANDARD DEFINITIONS OF AND BASIC REQUIREMENTS FOR ENCLOSURES POR-ELECTRIC AND ELECTRONIC EQUIPMENT TO THE HOLDERS.OF MIL-STD-108E: “ 1. -THE FOLLOWING PAGES- TH33 STANDARD HAVE BEEN REVISED AND SUPERSEDE THE PAGES LISTED:
10、NEW PAGE DATE SUPERSEDED PAGE DATE 1 19 September la 19 September. 2 19 September 9 19 September 9a 19 September 10 19 September 10a 19 September 11 19 September 12 19 September .1985. 1985 1985 1985 1985 1985 1985 1985 1985 -1 - 4 August 1966 1. 4 August 1966 2 REPRINTED WITHOUT CHANGE 9 REPRINTED
11、WITHOUT CHANGE 9 REPRINTED WITHOUT CHANGE 10 4 August 1966 10 4 August 1966 11 4 August 1966 12 4 August 1966 2. RETAIN THIS NOTICE PAGE AND INSERT BEFORE THE TABLE OF CONTENTS. 3. Holders of MIL-Sm-108 will verify that page changes and additions indicated above has been entered. This notice page wi
12、ll be retained as a check sheet. This issuance, together with the appended pages, is a separate publication. Each notice is to be retained by stocking points until the Military Standard is com- pletely revised or canceled. Custodians: Army - TE Navy - SH Preparing activity: Navy - SH (Project ENVR-0
13、018) PSC ENVR DISTRIBUTION STATEMENT A Approved for public release; distribution unlimited Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-i “ .- . MIL-STD-I 08E 4 August -1966 CONTENTS TABLES Provided by IHSNot for ResaleNo reproduction or networkin
14、g permitted without license from IHS-,-,-m e m flIL-STD-LOBE NOTICE 1 EN W 7777711 0033711 5 9 MIL-STD-108E 19 September 1985 DEFINITIONS OF AND BASIC REQUIREMENTS FOR ENCLOSURES FOR ELECTRIC AND ELECTRONIC EQUIPMENT 1. SCOPE 1.1 SCOF This standard establishes definitions and basic requirements for
15、enclosFes for environmental protection of electrical and electronic equip- ment. The use of these definitions for parts intended for mounting in enclosures is also described (see 6.1). 2. REFERENCED DOCUMENTS 2.1 The issues of the following documents in effect on the date of invita- tion for bids fo
16、rm a part of this standard to the extent specified herein: SPECIFICATIONS MILITARY MIL-E-2036 - Enclosures for Electric and Electronic Equipment, Naval Shipboard. STANDARDS MILITARY MIL-STD-810 - Environmental Test Methods. 2.2 Other publications. The following documents form a part of this standard
17、 to the extent specified herein. Unless otherwise indicated, the issue in effect on date of invitation for bids or request for proposal shall apply. AMERICAN NATIONAL STANDARDS INSTITUTE International Electrotechnical Commission Publication 144 (Application for copies should be addressed to American
18、 National Standards Institute, 1430 Broadway, New York, NY 10018.) NATIONAL FIRE PROTECTION ASSOCIATION National Electric Code (Application for copies should be addressed to the National Fire Protection Association, Battery-march Park, Quincy, MA 02269.) 3. REQUIREMENTS 3.1 Definitions, basic requir
19、ements and tests. Degrees of enclosures for environmental protection of electrical and electronic equipment are defined in Table I. The basic design requirements and tests applicable to a particular degree of enclosure shall be as specified in Table I. Enclosures are defined by either of two general
20、 methods which are consistent with industry practice: Supersedes page 1 of 4 August 1966. r Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-108E 19 September 1985 (a) Enclosures defined solely in terms of protection provided by the enclosure
21、itself; the function of the enclosure being to exclude the undesirable or harmful element. All degrees of enclosure having the suffix “tight“ fall in this category. (b) Enclosures defined in terms of specified environmental con- ditions under which the enclosed equipment (equipment with its enclosur
22、e) will operate satisfactorily. The ability of such enclosed equipment to perform under the specified con- ditions is not necessarily wholly dependent on the Supersedes page 1 of 4 August 1966. la Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-S
23、TD-LOBE NOTICE L EN m 7777733 0033733 7 m MIL-STD-108E 4 August 1966 enclosure itself, but may also depend upon the characteristics of the equipment. All degrees of enclosure having the suffix “proof“ fall in this category. 3.2 Supplementary enclosure identification by cooling method. The degrees of
24、 enclosure listed in Table I are commonly used without supplementary identi- fication, but it is also a frequent practice to further identify enclosed equip- ment by the method of cooling. Standard terms used for this purpose are listed below. When these terms are used with reference to enclosures,
25、they should be in combination with and following the degree of environmental protection (example: totally enclosed, fan-cooled). (a) Air-to-air cooled. Equipment is cooled by circulating the internal air through a heat exchanger which, in turn, is cooled by circulating external air, An air-to-air he
26、at exchanger, a fan or fans for circulation of internal air and a fan for circulation of external air are provided. cooled by air flow over the enclosed machine. Air flow is produced by a fan or fans attached to the equipment shaft. Protective covers are provided for fans (see 3.4). (c) Ventilated.
27、Equipment is cooled by air passing through the enclosure. Specific terms used to describe ventilated equipment are: (b) Fan-cooled (used for rotating equipment only). Equipment is (1) Natural-convection ventilated. Air circulation through (2) Self-ventilated (generally used for rotating machines the
28、 enclosure by natural convection. such as motors and generators). Air is circulated through the enclosure by a means integral with the equipment. used for other than rotating equipment) Air is circulated through the enclosure by a fan or blower located within the enclosure. by separately supplied fo
29、rced air from a source other than the atmosphere surromding the enclosure. Enclosure is provided with inlet and outlet air duct connections. (3) Forced-air-ventilated, Forced-draft-ventilated. (Generally (4) Separately ventilated. Equipment is intended for cooling (d) Non-ventilated (generally used
30、for rotating equipment such as motors and generators). Enclosure has no ventilation openings or provisions for air flow other than natural air convection over the enclosed equipment. Rotating equipment may be provided with an internal fan (or fans) attached to the shaft to recircu- late air within t
31、he enclosure. water or water conductors coming in direct contact with parts to be coo.led. in turn, is cooled by circulating water. A water-cooled heat exchanger and a fan or fans for circulating the air are provided. (e) Water-cooled. Equipment is cooled by circulating water, the (f) Water-air-cool
32、ed. Equipment is cooled by circulating air which, REPRINTED WITHOUT CHANGE -2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-c. MIL-STD-LOBE NOTICE L EN m mwm 003371 o m 8 f C t #. . a. 3.3 Design requirements for hazardous atmospheres. 3.3.1 Dust-i
33、gjtitio)l pwof. The purchaser shall indicate the type of hazardous dust in- volved. Applicability of the National Elec- tric Code, if required, shall also be specified by purchaser. 3.3.2 Explosionproof. The purchaser shall indicate the specific hazardous gas or vapor involved. In addition, the purc
34、haser shall designate which of the following require- ments apply. (a) National Electric Code. (b) MIGSTD-810. (c) Special Kaval shipboard require- ments (See MILE-2036). 3.4 Protection against contact with ex- ternal fans. Fans which are external to the basic equipment enclosure (example : totally
35、enclosed, fan-colled motor) shall have protective covers, grilIs or screens to pre- vent accidental contact with the moving parts. Openings in the covers, grills or screens shall be of such size that a 0.50 inch diameter rod will not pass through. On spraytight, fan-cooled and watertight fan- cooled
36、 machines drain holes shall be pro- vided to prevent accumulation of water in the fan housing. 3.5 Construction. Enclosures, including protective covers, grills and screens shall be of rigid construction, inflexible to the firm touch. 4. TESTS AND DEFINITIONS 4.1 Procedures. The following test pro-
37、cedures are applicable to specific degrees of enclosure for environmental protection. Tests shall be conducted to the extent speci- fied by the equipment specification or as otherwise required by the contract or order, - I -7 , / MIL-STD-108E . - -. 4 August 1966 - and when so specified shall form a
38、 part of the inspection procedure for the equipment. Tests apply to the enclosed equipment (en- closure with contents) except that dust- tight and watertight enclosures for portable equipment may be tested without the con- . tents, provided that the contents are not to be attached to the enclosure,
39、Failure to meet the specified requirements, including the di-electric and insulation resistance re- quirements of the equipment specification following enclosure tests described herein shall be cause for rejection. 4.2 Airtight. Tests for airtightness shall be conducted with both of the following in
40、i- tial conditions. (a) Internal air pressure 10 p.s.i. aI:v+- external air pressure. (b) Internal air pressure 10 p.s.i. be- low external air pressure. Total time of each test shall be 24 hours minimum. The equipment operating sequence shall be as follows: ON-8 hours, OFF-4 hours minimum, ON4 hours
41、; OFF4 hours minimum. A change in pressure difference (internal minus external or external minus internal pressure) of more than 0.6 p.s.i.g. during either test, after corrections for changes in barometric pressure and tem- perature, shall be cause for rejection 4.3 Dripproof (15 degrees) and drippr
42、oof (45 degrees). Visual examination or actual drip test may be used to determine the abil- ity of the enclosed .equipment to operate satisfactorily under the defined conditions. If neither method is specified in the equip- +ment specification or by the contract or or- der,either may be used. Visual
43、 examina- tion is intended to determine the ability of the enclosure to exclude falling drops of -liquid or solid particles. Such exclusion is not necessarily required of the enclosure (see Table I), If the enclosed is of such design that falling drops of liquid or solic1 3 .f , Provided by IHSNot f
44、or ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-I 08E 4 August 1966 particles appear to be able to enter, the ability of the enclosed equipment to operate Satisfactorily under the defined conditions can be determined only by further examina- tion of equipment wi
45、thin the enclosure or by actual drip test. (a) Visual examinatimt. E n c 1 o S e d equipment shall be visually ex- amined for the presence of the following features and character- istics when in its normal posi- tion or inclined in any direction at angles not exceeding the spe- cified 15“ or 45“. (1
46、) There are no openings directly exposed to falling drops of water or solid particles. Openings where provided on exposed surfaces shall be protected by louvers or suit- ably covered. (2) All removable access plates or covers on enclosure surfaces exposed to falling drops of water shall have gaskets
47、. Doors and door openings on exposed enclosure surfaces shall be of such design as to prevent the entry of falling drops of water. (3) There shall be no paths on the surface of the enclosure which drops of liquid or solid particles will follow and run into the enclosure. (b) Drip test. The enclosed
48、equipment shall be placed below a device that drips or sprinkles wder over the entire enclosed equip- ment. (Examples of suitable test devices are the test equipment described in International Elec- trotechnical Commission Publica- tion 144 and the rain chamber 4 ,. used for MIL-STD-810, Method 506
49、tests.) The minimum amount of water shall be 1000 cubic inches per square foot of area covered by the drip or sprinkle in 60 minutes. The drip- ping or sprinkle rate and distri- bution shall be approximately uniform. The enclosed equipment shall be oriented in 5 different PO- sitions during the test; normal - position and inclined at the maxi- mum angle (15“ or
