ATIS T1 TR 1-1986 Status of the Compatibility Standard for the Interface between a Cellular Mobile Carrier and a Wireline Exchange Carrier (C-E Interface).pdf

1、KSC-STD-E-0002E MARCH 12, 2009 Supersedes KSC-STD-E-0002D June 11, 2007 HAZARDPROOFING OF ELECTRICALLY ENERGIZED EQUIPMENT, STANDARD FOR EAR 99 NO LICENSE REQUIRED The information contained in the document is technical in content, but not technical data as defined by the International Traffic in Arm

2、s Regulations (ITAR) or the Export Administration Regulations (EAR), and therefore is EAR 99 NLR, no export license required, suitable for public release. General Prohibition Six (Embargo) applies to all items subject to the EAR, i.e. items on the CCL and within EAR 99 NLR. You may not make an expor

3、t or re-export contrary to the provisions of part 746 (Embargos and Other Special Controls) of the EAR and 22 CFR part 126.1 of the ITAR. KSC EDDR #09186 ENGINEERING DIRECTORATENational Aeronautics and Space Administration John F. Kennedy Space Center KSC FORM 16-12 (REV. 6/95) PREVIOUS EDITIONS ARE

4、 OBSOLETE (CG 11/95) KSC-STD-E-0002E MARCH 12, 2009 Supersedes KSC-STD-E-0002D June 11, 2007 KSC Form 7-657 NS (01/09) KSC-STD-E-0002E March 12, 2009 CONTENTS 1. PURPOSE AND SCOPE.1 2. APPLICABLE DOCUMENTS .1 2.1 Governmental.1 2.1.1 Specifications.1 2.1.2 Standards2 2.1.3 Handbooks .2 2.2 Nongovern

5、mental.2 2.3 Order of Precedence.3 3. DEFINITIONS.3 4. GENERAL REQUIREMENTS.4 5. GUIDELINES4 5.1 Hazardous Locations and Classifications 4 5.2 Purging and Pressurizing .5 5.3 Equipment for Hazardous Areas6 5.3.1 Class and Properties.6 5.3.2 Cable Wiring Methods.6 5.4 Electrical Connections for Meter

6、s, Instruments, and Relays.8 6. QUALITY ASSURANCE PROVISIONS 8 7. PREPARATION FOR DELIVERY 8 8. NOTES.9 8.1 Intended Use 9 8.2 Notice.9 APPENDIX A. SPACE SHUTTLE ELECTRICAL-POWER HAZARDOUS-ZONE DOCUMENTATION 11 KSC-STD-E-0002E_DD_03122009.doc iii KSC-STD-E-0002E March 12, 2009 This page intentionall

7、y left blank. iv KSC-STD-E-0002E March 12, 2009 HAZARDPROOFING OF ELECTRICALLY ENERGIZED EQUIPMENT, STANDARD FOR 1. PURPOSE AND SCOPE This standard sets forth requirements for hazardproofing electrical installations and equipment located in hazardous (classified) and other locations designated as ha

8、zardous by the authority having jurisdiction (AHJ) at Kennedy Space Center (KSC) to prevent ignition of flammable liquids or hazardous fluids, gases, or vapors. This document defines the minimum requirement that KSC ground systems and equipment must meet. This document does not define how to design

9、systems and equipment, or encompass hazardproofing requirements associated with lightning protection, grounding, operational safety, toxicity, or chemical reactions. This standard does not apply to locations made hazardous because of the presence of high explosives (such as blasting agents or muniti

10、ons) or pyrophoric materials (those that ignite spontaneously in air). 2. APPLICABLE DOCUMENTS The following documents form a part of this document to the extent specified herein. When this document is used for procurement, including solicitations, or is added to an existing contract, the specific r

11、evision levels, amendments, and approval dates of said documents shall be specified in an attachment to the solicitation/statement of work/contract. Unless a specific edition is cited, the latest released edition applies. 2.1 Governmental 2.1.1 Specifications John F. Kennedy Space Center (KSC), NASA

12、 KSC-SPEC-E-0031 Cables, Electrical, Specification for 1 KSC-STD-E-0002E March 12, 2009 Military MIL-DTL-5015 Connectors, Electrical Circular Threaded, AN Type, General Specification for MIL-DTL-22992 Connectors, Plugs and Receptacles, Electrical, Waterproof, Quick Disconnect, Heavy Duty Type, Gener

13、al Specification for 2.1.2 Standards John F. Kennedy Space Center (KSC), NASA KSC-STD-132 Potting and Molding Electrical Cable Assembly Terminations, Standard for KSC-STD-E-0006 Instrumentation and Communications Cable Applications, Standard for KSC-STD-E-0011 Electrical Power Receptacles and Plugs,

14、 Standard for KSC-STD-E-0014 Wire and Cable Applications, Standard for 2.1.3 Handbooks John F. Kennedy Space Center (KSC), NASA GP-864, Volume IIA Electrical Ground Support Equipment Cables Handbook 2.2 Nongovernmental National Fire Protection Association NFPA 70 National Electric Code NFPA 430 Code

15、 for the Storage of Liquid and Solid Oxidizers NFPA 496 Standard for Purged and Pressurized Enclosures for Electrical Equipment 2 KSC-STD-E-0002E March 12, 2009 NFPA 497 Recommended Practice for the Classification of Flammable Liquids, Gases or Vapors and of Hazardous (Classified) Locations for Elec

16、trical Installations in Chemical Process Areas 2.3 Order of Precedence In the event of conflict between the documents cited herein and the contents of this document, the contents of this document shall supersede, except where otherwise noted. The NASA contract, purchase order, or program-level docum

17、entation shall take precedence over the contents of this document in the event of conflicting requirements. Nothing in this document supersedes applicable laws and regulation unless a specific exemption has been obtained. 3. DEFINITIONS For the purpose of this document, the following definitions sha

18、ll apply. a. authority having jurisdiction (AHJ): Organization, office, or individual responsible for approving equipment, materials, an installation, or a procedure. At KSC, the NASA Fire and Rescue Office is the AHJ. b. control drawing: Drawing or other document provided by the manufacturer of the

19、 intrinsically safe or associated apparatus (or of the nonincendive field wiring apparatus or associated nonincendive field wiring apparatus) that details the allowed interconnections between the intrinsically safe and associated apparatus or between the nonincendive field wiring apparatus or associ

20、ated nonincendive field wiring apparatus. c. facility: Structure or building that serves a particular purpose. d. hazardous location: Location where fire or explosion hazards may exist because of the presence of flammable gases, vapors, or liquids; combustible dust; or ignitable fibers or flyings. T

21、he area is classified in accordance with properties of the material responsible for the potential hazard and with the likelihood of the hazard actually being present. e. purged and pressurized: Condition achieved by (1) purging, or supplying an enclosure with a protective gas at a sufficient flow an

22、d positive pressure to reduce the concentration of any flammable gas or vapor initially present to an acceptable level; and (2) pressurizing, or supplying an enclosure with a protective gas, with or without continuous flow, at sufficient pressure to prevent the entrance of flammable gas or vapor, co

23、mbustible dust, or ignitable fibers. (For further information, see NFPA 496.) 3 KSC-STD-E-0002E March 12, 2009 f. intrinsically safe: “An assembly of interconnected intrinsically safe apparatus, associated apparatus, and interconnecting cables in that those parts of the system that may be used in ha

24、zardous (classified) locations are intrinsically safe circuits” (NFPA 70). 4. GENERAL REQUIREMENTS Design for all new electrical equipment to be used in hazardous (classified) locations shall comply with the intent of the applicable guidelines of NFPA 70 (latest released edition), NFPA 430 (latest r

25、eleased edition), NFPA 496 (latest released edition), and NFPA 497 (current version at start of project unless otherwise stated in project documentation). The lead design engineer shall coordinate the design and implementation of hazardproofing for electrically energized equipment with the NASA Fire

26、 and Rescue Office, the AHJ over such activities at KSC. 5. GUIDELINES Guidelines have been extracted from the NFPA 70A, Article 500, and have been tailored to KSC-specific environment and requirements. 5.1 Hazardous Locations and Classifications All areas designated as hazardous (classified) locati

27、ons shall be properly documented in KSC drawings (see Appendix A). This documentation shall be available to those authorized to design, install, inspect, maintain, or operate electrical equipment at the location. Hazardous locations are where fire or explosion hazards may exist because of the presen

28、ce of flammable gases, vapors, or liquids; combustible dust; or ignitable fibers or flyings. Although combustible dust and flammable gases and vapors exist almost everywhere, they are usually present in only minute quantities, much less than necessary for a fire or explosion hazard to exist. Thus, t

29、he presence of flammable gases or vapors or combustible dust does not in itself define a hazardous location. These materials must be present in sufficient quantities (concentrations) to present a potential explosion hazard. Hazardous locations at KSC involve the storage, handling and distribution of

30、 liquid oxygen, liquid hydrogen, nitrogen tetroxide, monomethylhydrazine, and open-grain solid propellants. NFPA 497 does not assign the following items as hazardous substances nor does it assign an NEC group classification. The substances shall be treated as follows: nitrogen tetroxide Class I, Gro

31、up C oxygen Class I, Group D methane Class I, Group D 4 KSC-STD-E-0002E March 12, 2009 In North America, hazardous (classified) locations are divided into three classes, based on the explosive characteristics of the material. The classes of material are further divided into divisions or zones, based

32、 on the risk of fire or explosion that the material presents. Zones have three levels of hazard, whereas divisions have two levels. Table 1Table 1. Classes, Divisions, and Zones of Hazardous Materials illustrates the relationships among classes, divisions, and zones. Hazardous Material Class, Divisi

33、on Zone Gases or vapors Class I, Division 1 Zone 0 and Zone 1 Gases or vapors Class I, Division 2 Zone 0 Locations shall be classified depending on the properties of the flammable vapors, liquids, or gases, or the combustible dust or fibers that may be present, and the likelihood that a flammable or

34、 combustible concentration or quantity is present. Where pyrophoric materials are the only materials used or handled, these locations shall not be classified. Each room, section, or area shall be considered individually in determining its classification. 5.2 Purging and Pressurizing Purging is the p

35、rocess of supplying an enclosure with a protective gas at a sufficient flow and positive pressure to reduce the concentration of any flammable gas or vapor initially present to an acceptable level. This technique can be used to change a Class I or Class II, Division 1, location into a nonhazardous l

36、ocation or into a Division 2 location, or to change a Class I or II, Division 2, location into a nonhazardous location. It requires a noncombustible enclosure (which may be a control room or a machine room) that is first purged of any combustibles or flammables and then maintained at a positive pres

37、sure sufficient to prevent combustibles or flammables from entering the enclosure and being ignited by electrical equipment within the enclosure. The purging may be a continuous process or a single operation with a positive pressure maintained to make up for leaks. The pressurizing medium may be eit

38、her air, commonly used in control rooms where people will be working, or a nonflammable gas. In instrument enclosures in locations with corrosive atmospheres, specially processed and dried air or gas is used to protect the enclosed equipment against corrosion, as well as to prevent ignition of exter

39、ior flammable gases and vapors or combustible dust. (See NFPA 496.) Where possible, enclosures and distributors that are required by the system should be located outside a hazardous area and an intrinsically-safe design for energized electrical equipment is preferred. 5 KSC-STD-E-0002E March 12, 200

40、9 5.3 Equipment for Hazardous Areas 5.3.1 Class and Properties Equipment shall be identified for not only the class of location but also the explosive, combustible, or ignitable properties of the specific gas, vapor, dust, fiber, or flyings that will be present. In addition, Class I equipment shall

41、not have any exposed surface that operates at a temperature in excess of the ignition temperature of the specific gas or vapor. Class II equipment shall not have an external temperature higher than that specified. Class III equipment shall not exceed the maximum surface temperatures specified in NFP

42、A 70, Article 503.5. 5.3.2 Cable Wiring Methods Cable shall be protected from spillage of liquid oxygen, hydrogen, or other propellants and from mechanical damage. No electrical lines of any type shall be located in trenches containing propellant lines. Instrumentation, communication, control, and a

43、ssociated power equipment at KSC may be connected by hard-service cabling/cords as specified in GP-864, Volume IIA; KSC-SPEC-E-0031; KSCSTD-E-0006: or KSC-STD-E-0014. 5.3.2.1 Mineral-Insulated Cable Mineral-insulated cable is suitable for Division 1 locations and for all Class I and Class II locatio

44、ns. (See GP-864, Volume IIA; KSC-STD-E-0014; KSC-SPEC-E-0031; and KSC-STD-E-0006.) 5.3.2.2 Metal-Clad Cable Metal-clad cable (Type MC) is permitted for application in Class I, Division 2, locations. Use of this type of cable is not limited to any voltage class. Under restrictions, metal-clad cable (

45、Type MC-HL) and instrumentation tray cable (Type ITC-HL) are permitted in Class I, Division 1, locations. (See NFPA 70; GP-864, Volume IIA; KSC-STD-E-0014; KSC-SPEC-E-0031; and KSC-STD-E-0006.) 5.3.2.3 Tray Cable Power and control cable (Type TC) and other cable assemblies that do not permit gas mig

46、ration are permitted in Class 1, Division 2, locations where (1) the overall sheath is compatible with materials within the hazardous area, (2) the conditions of maintenance and supervision ensure that only qualified persons service the installation, and (3) the cable is continuously supported and p

47、rotected against physical damage using mechanical protection, such as struts, angles, or channels. 6 KSC-STD-E-0002E March 12, 2009 5.3.2.4 Flexible Cords: Class I, Divisions 1 and 2 5.3.2.4.1 Permitted Uses Flexible cords are permitted for a. connection between portable lighting equipment or other

48、portable equipment and the fixed portion of their supply circuit; b. that portion of the circuit where the fixed wiring methods cannot provide the necessary degree of movement for fixed and mobile electrical equipment, where the flexible cord is protected from damage by location or by a suitable gua

49、rd, and only in an industrial establishment where conditions of maintenance and engineering supervision ensure that only qualified persons install and service the installation; c. electric submersible pumps with means for removal without entering the wet-pit (the extension of the flexible cord within a suitable raceway between the wet-pit and the power source is permitted); and d. electric mixers intended for travel into and out of open-type mixing tanks or vats. 5.3.2.4.2 Required Characteristics Where flexible cords are used, they shall a. be a type listed in NFPA 70 fo