ES&H Manual Flammable Gas Supplement

Chapter 5 – Electrical Installation

1.0 Purpose

This appendix is an index of Article 501 which may pertain to Jefferson Lab flammable gas systems. The guidelines in this appendix are supplementary to those provided in ES&H Manual Chapter 6230 Electronic Equipment Safe Work Policy and ES&H Manual Chapter 6240 Electronic Equipment – Construction and Modification Safety. The National Electrical Code (NEC) article covers both Divisions 1 and 2. The general plan for the gas systems is that electrical devices will be kept out of Division 1 areas when possible and that the gas sheds will be Division 2. Division 2 is applicable when a flammable mixture is likely to be present less than ten hours per year.

Table 1: Ignition Temperature per National Fire Protection Association (NFPA),

Fire Protection Guide to Hazardous Materials, 13th Edition

Gas	Ignition Temperature	80% of Ignition Temperature (for reference)
ethane	472oC	378oC
methane	537oC	430oC
iso butane	460oC	368oC
isopropyl alcohol	399oC	319oC
ethyl alcohol	363oC	290oC

NOTE: This appendix is based on NFPA-70, Article 501 as of 2002; the NFPA standard is typically revised every three years. You are responsible for meeting the version of the standard that is current at the time of approval of your gas system. We provide this material here to indicate the scope and content of the standard.

2.0 Index of Article 501 Class I Locations

501.1 General

501.2 Transformers and Capacitors

501.3 Meters, Instruments, and Relays

501.4 Wiring Methods

501.5 Sealing and Drainage

501.6 Switches, Circuit Breakers, Motor Controllers, and Fuses

501.7 Control Transformers and Resistors

501.8 Motors and Generators

501.9 Lighting Fixtures

501.10 Utilization Equipment

501.11 Flexible Cords, Class I Divisions 1 and 2

501.12 Receptacles and Attachment Plugs, Class I, Divisions 1 and 2

501.13 Conductor Insulation, Class I, Divisions 1 and 2

501.14 Signals, Alarms, Remote-Control, and Communication Systems

501.15 Live Parts, Class I, Divisions 1 and 2

501.16 Grounding, Class I, Divisions 1 and 2

501.17 Surge Protection

501.18 Multi-Wire Branch Circuits

3.0 Revision Summary

Periodic Review – 05/06/16 – No changes per TPOC

Revision 1.0 – 06/05/11 – New content

ISSUING AUTHORITY	TECHNICAL POINT-OF-CONTACT	APPROVAL DATE	REVIEW DATE	REV.
Flammable Gas - Physics	Jack Segal	05/06/16	05/06/21	1.0

This document is controlled as an on line file. It may be printed but the print copy is not a controlled document. It is the user’s responsibility to ensure that the document is the same revision as the current on line file. This copy was printed on 5/26/2016.