C22.2 No 30 M1986 (2003)

C22.2 No. 30-M1986 (Reaffirmed 1992) Explosion-Proof Enclosures for Use in Class I Hazardous Locations Industrial Products

Copyright Canadian Standards Association Provided by IHS under license with CSA Sold to:GE SENSING, W0341746

Not for Resale,2006/7/27 16:53:14 GMTNo reproduction or networking permitted without license from IHS

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Matt Roberts

(Reaffirmed 2003)

General Instruction No. 2 C22.2 No. 30-M1986 November 1988

CSA Standard C22.2 No. 30-M1986, Explosion-Proof Enclosures for Use in Class I Hazardous Locations, was published in November 1986; it consisted of 35 pages, each of which was dated November 1986.

Amendments to Clauses 4.1.2, 4.2, 4.3.1 (a), 6.5.1, 6.5.2, 6.5.3, 6.6.1, 6.6.3 and Table 1

and the addition of Clause 6.5.3A and Table 14 have been formally approved and are incorporated (and identified by a vertical line in the margin) in the attached replacement pages.

CSA Standard C22.2 No. 30-M1986 now consists of the following pages: 3—8, 13—16, 21—26, 29—35 dated November 1986; 9-12, 17—20, 27, 27A, and 28 dated November 1988. These replacement pages are to be inserted into your copy of the Standard; the

pages replaced should be kept for reference.



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General Instruction No. I C22.2 No. 30-M1986 November 1986

CSA Standard C22.2 No. 30-M1986, Explosion-Proof Enclosures for Use in Class I

Hazardous Locations, consists of 35 pages, each dated November 1986. This Standard, like all CSA Standards,. is subject to periodic review, and amendments

in the form of replacement pages may be issued from time to time; such pages will be mailed automatically to those purchasers who complete and return the attached card.* Some Standards require frequent revision between editions, whereas others require none at all. It is planned to issue new editions of the Standard, regardless of the amount of revision, at intervals not greater than 5 years. Except in unusual

circumstances, replacement pages will not be issued during the last year of that edition. * This card will appear with General Instruction No. 1 only.

Although any replacement pages that have been issued will be sold with the Standard, it is for the purchaser to insert them where they apply. The responsibility for ensuring that his or her copy is complete rests with the holder of the Standard, who should, for the sake of reference, retain those pages which have been replaced. Note: A General Instruction sheet will accompany replacement pages each time they are issued and will list the latest date of each page of the Standard.

Cut along dotted line.

Name

Organization

Address

City

Prov./State

Country________________ CSA Standard Postal/Zip Code ____________________ C22.2 No. 30-M 1986



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C22.2 No. 30-M1986 Explosion-Proof Enclosures for Use in Class I Hazardous Locations

Industrial Products

Forming Part of Canadian Electrical Code, Part II Safety Standards for Electrical Equipment

ISSN 031 7-5669 Published in November 1986

by Canadian Standards Association (Incorporated 1919) 178 .Rexdale Boulevard Rexdale (Toronto), Ontario Canada M9W 1R3



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Canadian Standards Association—i 986 All rights reserved. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior permission of the publisher.



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Contents

Contents

Technical Committee on Industrial Products 04

Subcommittee on C22.2 No. 30 05

Preface 07

Foreword 08

1. Scope 09

2. Definitions 09

3. General Requirements 09

4. Construction 10 4.1 General 10 4.1.1 Materials 10 4.1.2 Strength 10 4.1.3 Cleaning 10 4.1.4 Quality of Cast Enclosures 10 4.2 Corrosion Protection 11 4.3 Joints 11 4.3.1 General 11 4.3.2 Plain and Stepped Joints 11 4.3.3 Threaded Joints 11 4.3.4 Operating Rod Joints 12 4.3.5 Power Shaft Joints 12 4.4 Inspection Windows 12 4.4.1 Material 12 4.4.2 Window Joints 12 4.5 Flame Arrestors 12 4.6 Breathers and Drains 12 4.7 Cover Bolts 12 4.7.1 General 12 4.7.2 Joints 12 4.7.3 Depth of Tapping 12 4.8 Fastenings 12 4.8.1 General 12 4.8.2 Removable Fastenings 12 4.8.3 Nonremovable Fastenings 13 4.8.4 Nameplate Fastenings 13 4.9 Conduit or Cable Openings 13 4.10 Seals 13 4.10.1 General 13 4.10.2 Poured Seals 13 4.10.3 Fabricated Seals 13 4.10.4 Compression Seals 13

4.10.5 Gastight Joints 14 4.10.6 Explosive Fluid Seals 14 4.11 Grounding and Bonding 14

5. Marking 14

6. Tests 15 6.1 General 15 6.2 Impact 15 6.2.1 General 15 6.2.2 Test Procedure 16 6.3 Explosion Pressure Test 16 6.4 Arc-Rupturing 17 6.5 Explosion Flame Propagation Test 17 6.5.1 General 17 6.5.2 Flameproof Test Using a More Sensitive Gas/Air Mixture 17 6.5.3 Flameproofness Using Enlarged Gaps 17 6.5.4 Flame Arrestors 17 6.6 Overpressure 17 6.6.1 General 17 6.6.2 Routine Tests 18 6.6.3 Type Test 18 6.7 Temperature 18 6.8 Temperature (Abnormal) 18 6.9 Flammability 18 6.10 Gastight Joints 18 6.10.1 Gastight Joint Pressure Routine Test 18 6.10.2 Gastight Joint Type Tests 18 6.11 Overpressure Test for Fittings 19 6.12 Adhesive Nameplates 19 6.13 TestforSealing Compounds 19

Tables 20

Figures 28

Appendix A—Explosion and Flameproof Testing 34

Explosion-Proof Enclosures for Use in Class I Hazardous Locations November io 3



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Technical Committee

Technical Committee on Industrial Products

C.E. McRoberts Thornhill, Ontario Vice-Chairman Representing Manufacturers

B. Dyczkowsky Canadian Standards Association, Standards Rexdale, Ontario Administrator,

Nonvoting

Representing Regulatory Authorities

F.M. Bragg City of Halifax, Halifax, Nova Scotia

D.H. Dunsire Manitoba Hydro, Winnipeg

M. Riendeau Ministère de l'Habitation et de Ia Protection du consommateur, Montréal, Québec

G.A.H. Ward British Columbia Ministry of Labour, Vancouver

Representing Manufacturers

R.D. Colvin Allen-Bradley Canada Ltd., Cambridge, Ontario

R.A. Wilson Westinghouse Canada Inc., Hamilton, Ontario

Representing General Interests

C. Allan Etobicoke, Ontario Representing Canadian Electrical Contractors Association

G.E. Davidson Toronto, Ontario Consumer Representative

R.E. Dowling Canadian Standards Association, Alternate Rexdale, Ontario

M.D. Skinner Public Works Canada, Ottawa, Ontario

R.H. Smith Canadian Standards Association, Rexdale, Ontario

C222 No. 30-M1986 4 November 1986



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Sutxommittee

Subcommittee on C22.2 No. 30

R.D. Colvin Allen Bradley Canada Ltd., Chairman Cambridge, Ontario

J.A. Bossed Energy, Mines & Resources Canada, Ottawa, Ontario

R.L. Carruthers Square D Canada, Waterloo, Ontario

T.R. Doucet Foxboro Canada Inc., LaSalle, Quebec

D.H. Dunsire Manitoba Hydro, Winnipeg

J.M. Gallagher Union Carbide Canada Limited, Sarnia, Ontario

W.F. Horvath Killark Electric Mfg. Co., St. Louis, Missouri, USA

A. Kassabian Crouse-Hinds Canada Limited, Scarborough, Ontario

K.V. Knudsen Vic Knudsen Electrical Consultants Ltd., Calgary, Alberta

R.A. Neil Esso Petroleum Canada, Toronto, Ontario

R. Polimine O-Z/Gedney, Brooklyn, New York, USA

E.J. Power Prince Edward Island Dept. of Community and Cultural Affairs, Charlottetown

E.D. Robertson Appleton Electric Limited, Cambridge, Ontario

W.W.M. Shao Canadian Standards Association, Rexdale, Ontario

J.O. Shaughriessy Canadian General Electric Company Limited, Peterborough, Ontario

L.M. Sison Ontario Hydro, Toronto

Explosion-Proof Enclosures for Use in Class I Hazardous Locations November 1986 5



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Subcommittee

C.M. Speers Alberta Department of Labour, Edmonton

R.C. Gilmour Canadian Standards Association, Standards Rexdale, Ontario Administrator

C22.2 No. 30-M1986 6 November 1986



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Preface

Preface

This is the third edition of No. 30 of a series of Standards issued by Canadian Standards Association under Part II of the Canadian Electrical Code. It supersedes previous editions published in 1970 and 1984.

This edition includes requirements for sealing fittings to retain the sealing compound, requirements for the sealing compounds, and requirements for enclosures that involve explosive fluids.

For general information on the Standards of the Canadian Electrical Code, Part II, see the Preface of CSA Standard C22.2 No. 0, General Requirements—Canadian Electrical

Code, Part II. This Standard was prepared by a Subcommittee of the Technical Committee on

Industrial Products under the jurisdiction of the Standards Steering Committee on Canadian Electrical Code, Part II, and was formally approved by the Technical Committee.

November 1986 Note: Although the intended primary application of this Standard is stated in its Scope, it is important to note that it remains the responsibility of the user of the Standard to judge its suitability for his or her particular purpose.

CSA Standards are subject to periodic review and suggestions for their improvement will be referred to the appropriate committee. All enquiries regarding this Standard, including requests for interpretation, should be addressed to Canadian Standards Association, Standards Division, 178 Rexda/e Boulevard, Rexdale (Toronto), Ontario M9W 1R3. Requests for interpretation should (a) define the problem, making reference to a specific Clause, and, where appropriate, include an illustrative sketch; (b) provide an explanation of circumstances surrounding the actual field condition; and (c) be phrased, where possible, to permit a specific "yes" or "no" answer.

Interpretations are published in "CSA In formation Update' For subscription details and a free sample copy, write to CSA Marketing or telephone (416) 747-2292.




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Foreword

Foreword

The Canadian Standards Association provides certification services for manufacturers who, under license from CSA, wish to use the appropriate registered CSA Marks on certain products of their manufacture to indicate conformity with CSA Standards.

CSA Certification for a number of products is provided in the interest of maintaining agreed-upon standards of quality, performance, interchangeability and/or safety, as appropriate. Where applicable, certification may form the basis for acceptance by inspection authorities responsible for enforcement of regulations. Where feasible, programs will be developed for additional products for which certification is desired by producers, consumers or other interests.

In performing its functions in accordance with its objectives, CSA does not assume or undertake to discharge any responsibility of the manufacturer or any other party. The opinions and findings of the Association represent its professional judgement given with due consideration to the necessary limitations of practical operation and state of the art at the time the Standard is processed.

Products in substantial accord with this Standard but which exhibit a minor difference or a new feature may be deemed to meet the Standard providing the feature or difference is found acceptable utilizing appropriate CSA Certification Division Operating Procedures. Products which comply with this Standard shalt not be certified if they are found to have additional features which are inconsistent with the intent of this Standard. Products shall not be certifiable if they are discovered to contravene applicable laws or regulations.

Testing techniques, test procedures and instrumentation frequently must be prescribed by the CSA Certification Division in addition to the technical requirements contained in Standards of CSA.

In addition to markings specified in the Standard the CSA Certification Division may require special cautions, markings and instructions that are not specified by the Standard.

Some tests required by CSA Standards may be inherently hazardous. The Association neither assumes nor accepts any responsibility for any injury or damage that may occur during or as the result of tests, wherever performed, whether performed in whole or in part by the manufacturer or the Association, and whether or not any equipment, facility or personnel for or in connection with the test is furnished by the manufacturer or the Association.

Manufacturers should note that, in the event of the failure of the GSA Certification Division to resolve an issue arising from the interpretation of requirements, there is an appeal procedure: the complainant should submit the matter, in writing, to the Secretary of the Canadian Standards Association.

If this Standard is to be used in obtaining GSA Certification please remember, when making application for certification, to request all current Amendments, Bulletins, Notices and Technical Information Letters that may be applicable and for which there may be a nominal charge. For such information or for further information concerning details about CSA Certification please address your inquiry to the Applications and Records Section, Canadian Standards Association, 178 Rexdale Boulevard, Rexdale (Toronto), Ontario M9W 1R3. Publication Date—November 30, 1986 (ie, the date on or after which this Standard may, at the discretion of the applicant, be used for certification). Effective Date—November 30, 1986* (ie, the date on which this Standard shall be applicable to equipment being submitted for certification and to equipment already certified and manufactured on or after that date). * Unless otherwise noted in the text or Genera! Instruction.

C22.2 No. 30-M1986 8 November 1986



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Scope—Definitions—General Requirements


1. Scope 1.1 This Standard covers the details of construction and tests for explosion-proof enclosures for electrical

equipment to be used in Class I, Division 1,

Groups A, B, C, and D hazardous locations and in

gaseous mines in accordance with the Rules of the Canadian Electrical Code, Part I and the requirements of CSA Standard CAN3-M421-M85.

1.2 Other Standards for hazardous location equipment covering specific types of equipment shall take precedence over this Standard.

1.3 Unless otherwise marked, this Standard applies to enclosures intended for use in ambient temperatures of (a) —50 to +40°C for Class I, Groups A, B, C, and

D; (b) 0 to +40°C for gaseous mines; (c) an oxygen concentration of approximately 21%

by volume; and

(d) a pressure of not more than 106 kPa.

2. Definitions 2.1 The following definitions apply in this Standard:

Explosion-proof enclosure means an enclosure for electrical equipment that is capable of withstanding, without damage, an explosion within it of a specified gas or vapour and is capable of preventing ignition of the same gas or vapour surrounding the enclosure caused by sparks or flames from the explosion within the enclosure (synonymous with "flameproof enclosure"asdefinedinlEC Publication 79-1, Part I).

Gap means the distance between the corresponding surfaces at a joint measured normal to the surfaces. For cylindrical surfaces, the gap is the difference between the two diameters (diametrical clearance).

Gastight joint means a joint that prevents gases or vapours from passing from one section of an enclosure to another or to the surrounding atmosphere.

Joint means the place where corresponding surfaces of the different parts of an enclosure come together and where paths from the inside to the outside of the enclosure occur.

Labyrinth gland joint means a joint having at least 2

axial paths in series, interrupted by at least 1 radial path,thelatterhavingaminimumlengthofl.58 mm.

Operating rod means a rod or shaft operating at less than 100 cycles/mm.

Powershaft means ashaft operating at 100 cycles/mm or greater.

Width of joint means the shortest distance from the inside of the enclosure to the outside of the enclosure through the joint (dimension W in Figure 2).

3. General Requirements 3.1 General requirements are given in CSA Standard C22.2 No. 0, General Requirements—Canadian Electrical Code, Part II.

3.2 Electrical equipment contained in explosion-proof enclosures shall meet the requirements of all applicable CSA Standards of the Canadian Electrical Code, Part (I.

3.3 CSA Standard CAN3-M421 restricts the use of exposed light-weight alloys in gaseous under- ground mines.

3.4 Where reference is made to CSA Standards of the Canadian Electrical Code, Parts I and II, such reference shall be considered to refer to the latest edition and revision thereto, unless otherwise specified.

Explosion-Proof EncIosurs for Use in Class I Hazardous Locations

November1986 9 Copyright Canadian Standards Association Provided by IHS under license with CSA Sold to:GE SENSING, W0341746


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General Requirements—Construction

This Standard makes reference to the following such Standards and the year dates shown indicate the latest editions available at the time of printing:

C22.1 -1986, Canadian Electrical Code, Part I; C22.2 No. 0-M1982, General Requirements—Canadian Electrical Code, Part II; C22.2 No. 0.4-M 1982, Bonding and Grounding of Electrical Equipment (Protective Grounding); C22.2 No. 0.5-1 982, Threaded Conduit Entries; C22.2 No. 0.6-M1982, Flammability Testing of Polymeric Materials; C22.2 No. 14-M1985, Industrial Control Equipment for Use in Ordinary (Non-hazardous) Locations; C22.2 No. 55-1957, Snap Switches; C22.2 No. 111-1956, Manually-Operated General-Purpose A-C Switches; C22.2 No. 157-M1979, Intrinsically Safe and Non-incendive Equipment for Use in Hazardous Locations.

3.5 Where reference is made to the following publi- cations not under the jurisdiction of the Committee on Part II, such reference shall be considered to refer to the edition listed below:

CSA Standards Bi i-1949, Unified and American Screw Threads;

B95-1 962, -

Surface Texture (Roughness, Waviness, and Lay);

CAN3-C235-83, Preferred Voltage Levels for AC Systems, 0 to 50 000 V;

CAN3-M421 -M85, Use of Electricity in Mines.

ASTM Standards E499-73, Standard Methods of Testing for Leaks Using the Mass Spectrometer Leak Detector in the Detector Probe Mode;

E51 5-74, Standard Method of Testing for Leaks Using Bubble Emission Techniques.

IEC* Publication 79-1 (1971), Part 1, Construction and Test of Flameproof Enclosures of Electrical Apparatus. *International Electrotechnical Commission.

4. Construction 4.1 General

4.1.1 Materials Details throughout this Standard are based upon enclosures constructed of iron, copper, aluminum, or their alloys. The use of other materials shall be the subject of investigation with respect to factors such as the physical and chemical stability, strength, resistance to impact, and resistance to flame of these materials.

4.1.2 Strength Enclosures shall have adequate mechanical strength for the intended use and shall be capable of withstanding either the routine overpressure test (Clause 6.6.2) or the type overpressure test (Clause 6.6.3) without rupture. The permanent distortion of walls and covers may be allowed if the enclosure is capable of passing the explosion flame propagation test (Clause 6.5) aftertheoverpressure tests. As an alternative to the overpressure tests, calculations may be used to determine the strength of the enclosure, in which case the factor of safety shall be five times the measured explosion pressure.

4.1.3 Cleaning All particles shall be removed from the enclosure and joints after all machining operations have been

completed. (See also Clause 5.3.)

4.1.4 Quality of Cast Enclosures

4.1.4.1 General The following criteria are intended to provide guidance in acceptance of castings and flat explosion-proof joints, machined or as cast.

4.1.4.2 Surface Roughness A metal joint surface shall have an arithmetical average roughness of not more than 0.0063 mm when measured in accordance with CSA Standard B95.

C22.2 No. 30—M1986

10 November 1986



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4.1.4.3 Casting Imperfections Blowholes orfissures are permitted in the machined

joint surface of explosion-proof joints provided that the castings comply with the following: (a) blowholes or fissures not in the joint surface shall be not over 2.4 mm wide and not over 1.6 mm

deep. These holes shall not be considered as affecting the minimum thicknesses, unless the wall from the bottom of the hole to the opposite surface is less than 3.2 mm; and (b) blowholes or fissures in the joint surface that are over 0.4 mm in width shall not be included in the effective joint width. The orientation of such holes shall not lessen the joint width in any direction.

4.1.4.4 Repairs Blowholes or fissures may be repaired in aluminum castings by heli-arc welding using an aluminum

welding rod or in iron castings by means of brazing. Welding or brazing shall be done before the final machining operation.

4.2 Corrosion Protection Ferrous alloys other than stainless steel shall have a protective coating that will resist rust and corrosion in accordance with CSA Standard C22.2 No. 0. The protective coating shall be applied to both inside and outside surfaces of the enclosure before visible rusting has occurred. Joints shall be

protected by means of a suitable anticorrosive material such as light grease or electrically or chemically deposited metallic plating not exceeding 0.0075 mm thick. Joints shall not be plated by the hot dip method nor shall they be painted.

4.3 Joints

4.3.1 General Joints between covers or other removable parts and the body of the enclosure shall be of the metal-to- metal type and (a) for Class I, Group A, shall be threaded or comply with Clause 6.5.4; and

(b) for other Groups, may be plain, stepped, or threaded.

4.3.2 Plain and Stepped Joints The minimum joint width in plain or stepped joints shall be in accordance with Table 1, 2, 3, or 4 as applicable. The maximum gap shall be in accordance with Table 1, 2, 3, or 4 as applicable except that the gap may be larger providing the enclosure meets the test of Clause 6.5 with an additional

safety factor of 1.2. There shall be no intentional gaps at cover joints. Compliance of the gap will be indicated if a feeler gauge having a thickness equal to the maximum gap will not enter the joint for a distance of more than 3.2 mm at any point or, in the case of a cylindrical joint, if the difference in the diameters of the two parts is smaller than the gap. In the case of stepped joints for Groups C and D enclosures, the clearance for the cylindrical portion of the joint may be considered as the difference in the radii of thetwo parts iftheclamped radial section is not less than one-quarter of the minimum width of the joint.

4.3.3 Threaded Joints

4.3.3.1 General Unless otherwise specified, the threads in threaded joints shall be not finerthan 32 threads per inch. A joint of the serrated type with thread contour shall not have more than 20 serrations per inch and shall have at least 5 fully engaged and tightly clamped serrations.

4.3.3.2 Class I, Groups A and B A cover joint shall not have a standard tapered pipe thread and shall have (a) at least the following number of fully engaged threads not finer than 20 threads per inch:

(i) 8 with a Class 1 fit; (ii) 7 with a Class 2 fit; or (iii) 6 with a Class 3 fit; and

(b) a minimum width (direct axial length of thread engagement*) of

(I) 9.5 mm for internal volumes of enclosures up to and including 500 cm3; or

(ii) 12.5 mm for internal volumes of enclosures over 500 cm3 up to and including 6000 cm3.

Classes of fits are defined in CSA Standard Bi .1. *See Figure 2(e).

4.3.3.3 Class I, Groups A and B Threaded joints other than cover joints shall (a) have standard tapered pipe threads with 5 fully engaged threads; or (b) comply with Clause 4.3.3.2.

4.3.3.4 Class I, Groups C and D A threaded cover joint for use in Class I, Groups C and D hazardous locations shall have (a) not fewer than 5 fully engaged threads; and

(b) a minimum width (direct axial length of thread engagement) of 8 mm. *See Figure 2(e).

Explosion-Proof Enclosures for Use in Class I Hazardous Locations

November 1986 11

Construction



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Construction

4.3.4 Operating Rod Joints

4.3.4.1 Joints for an operating rod shall comply with one of the following requirements: (a) the requirements for plain and stepped joints (Clause 4.3.2), except that the length of flame path (dimension "w" shown in Figure 1) shall be at least equal to the diameter of the rod but it need not exceed 25 mm; (b) the requirements for threaded joints (Ciause 4.3.3), except that threads shall be not finer than 24 threads per inch; or (c) the joints shall be of the labyrinth gland joint type (see definitions), in which case the gap may be increased, provided that the design successfully passes the test of Clause 6.5 with an additional safety factor of 1.2.

4.3.4.2 Operating rods shall have mechanical means to prevent accidental or inadvertent removal (ie, to prevent any movement that would impair the effectiveness of the joint).

4.3.5 Power Shaft Joints Where a shaft for transmitting power is provided on rotating or reciprocating machinery, the joint widths and gaps shall conform to the requirements given in Tables 5, 6, and 7 for plain joints and in Table 8 for labryinth joints. The joint shall include any protection afforded by a sleeve bearing.

4.4 Inspection Windows

4.4.1 Material Windows shall be glass or equivalent. The use of materials other than glass shall be the subject of investigation to determine physical and chemical stability, resistance to impact, resistance to flame, etc, of these materials.

4.42 Window Joints The joint between a window and its housing shall have the width of joint required in Clause 4.3.2, or the window shall be cemented into a removable part. The cement shall also be investigated for resistance to flame and chemical and physical stability.

4.5 Flame Arrestors Where air, gas, or liquid lines enter or leave an explosion-proof enclosure, a suitable flame arrestor shall be provided at the entrance to the enclosure.

4,6 Breathers and Drains Breathers and drains shall be flame arresting and shall be constructed of corrosion resistant material.

4.7 Cover Bolts

4.7.1 General Bolts for securing covers and other removable parts shall be such that they will ensure the effectiveness of the joint.

4.7.2 Joints If a joint surface is interrupted by a cover bolt, the flame path (cv),as shown in Figure 2, measured from the inside of the enclosure shall be not less than the value specified in Table 9.

4.7.3 Depth of Tapping 4.7.3.1 The tapping for cover bolts shall be deep enough to allow for nominal variations in standard bolt lengths. Washers on cover bolts are optional, but if washers are used, the bolts shall be capable of securing the cover tightly without them.

4.7.3.2 Except as permitted by Clause 4.7.3.3, tapped holes for cover bolts shall be bottomed if the holes enter the enclosure.

4.7.3.3 Tapped holes for cover bolts for enclosures having an internal volume of 2000 cm3 or less need not be bottomed but the bolts shall engage at least 5 full threads in the enclosure.

4.8 Fastenings 4.8.1 General All unused holes through the walls of an explosion- proof enclosure shall be plugged so as to meet the requirements for joints, and the plugs shall be secured against removal from the outside of the enclosure.

4.8.2 Removable Fastenings Fastenings other than cover bolts, such as removable bolts, screws, and studs, shall not leave an opening in the enclosure wall when they are omitted. The minimum thickness of metal around the hole shall be not less than 3.2 mm or 1/3 of the diameter of the hole, whichever is greater. The minimum thickness of metal at the bottom of the hole shall be not less than 1/2 the untapped diameter.

C22.2 No. 30-MI 986 12 November 1986



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4.8.3 Nonremovable Fastenings Bolts, screws, studs, etc, for securing component parts that pass through the enclosure walls shall engage at least5 full threads with a threaded hole in the enclosure and be secured against removal by peening, staking, welding, or other means. The threads shall be not finer than 32 threads per inch. If the means for securing is not obvious, it must withstand the following torques without loosening: for screw size No. 4, 2.8 Nm; No. 5, 4 Nm; No. 6, 4.5 N•m; No. 8, 8.5 Nm; and No. 10, 13.5 Nm.

4.8.4 Nameplate Fastenings Holes for screws or rivets for securing nameplates shall not pass through the enclosure walls unless they comply with Clause 4.8.3, except that the threads shall be not finer than 40 threads per inch.

4.9 Conduit or Cable Openings

4.9.1 Enclosures shall be equipped with threaded conduit entries complying with the requirements of CSA Standard C22.2 No. 0.5, shall have provision for cable entries, or shall have wall sections of sufficient thickness to permit conduit entries meeting the requirements of CSA Standard C22.2 No. 0.5 to be added in the field. Any thickened sections for conduit entries shall be located to provide con- venient access to wiring terminals.

4.9.2 If more than the minimum number of conduit or cable openings for the proper wiring of the device are provided, pipe plugs shall be supplied in the extra openings that shall engage at least 5 full threads.

4.10 Seals

4.10.1 General Where a seal is provided to separate two compart- ments of an enclosure or for the conduit or cable entry, it shall be constructed so that it will effectively prevent the passage of an explosion from one compartment to another or from the enclosure to the supply conduit. The seal may be of the poured type, a machined fit, or a compression gland.

4.10.2 Poured Seals

Construction

4.10.2.1 The compound of a poured seal shall not be affected by any of the solvents likely to be present, shall be compatible with any conductors passing through it, and shall not have a softening point of less than 93°C for Class A insulated equipment. Equipment with insulation systems having higher temperature ratings shall have sealing compounds that will not soften at correspondingly higher temperatures (eg, Class B insulation, 113°C).

4.10.2.2 Poured seals shall have a minimum depth of 16 mm or the inside diameter of the opening, whichever is greater, unless they are reinforced by metal, in which case the depth may be reduced by 6 mm.

4.10.2.3 Where a seal is required immediately adjacent to a conduit entrance in order to reduce the explosion pressure, it shall be an integral part of the enclosure or permanently secured in place, or the enclosure shall be marked in accordance with Clause 5.5.

4.10.2.4* Sealing fittings for seals of the poured type shall incorporate means to prevent movement of the sealing compound during an explosion. The means shall be in the form of at least one ridge with minimum dimensions of 3 mm high (deep) and 3 mm wide extending completely around the fitting or it shall have an equivalent restraining feature such as a double taper. *Effective Date—May 31, 1988.

4.10.3 Fabricated Seals In order to be considered a seal, an assembly of moulded or machined parts with explosion-proof joints shall comply with Clause 4.3.2 or 4.3.3.

4.10.4 Compression Seals Compression seals shall be of resilient or compres- sible material that is not affected by any of the solvents present and they shall be reinforced by metal on all sides. The effective length of a compression seal shall be a minimum of 16 mm or the inside diameter of the opening, whichever is greater.




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Construction—Marking

410.5 Gastight Joints An assembly of nonresilient parts that cannot be disassembled without destruction of one or more parts and does not comply with Clause 4.3.2 or 4.3.3 shall be capable of withstanding the leakage test (Clause 6.10.2(a) or (b)) and, in addition, each device at the completion of manufacture and before shipment shall withstand the pressure routine test (Clause 6.10.1).

4.10.6* Explosive Fluid Seals

4.10.6.1 Where electrical equipment contains an explosive fluid seal intended to prevent explosive fluids from reaching the electrical housing or conduit system, it shall comply with either Clauses 4.10.6.3 and 4.10.6.4, or Clauses 4.10.6.5 and 4.10.6.6.

4,10.6.2 Where electrical equipment contains an explosive fluid in contact with electrical parts or wiring, explosive fluid seals shall be installed to prevent the explosive fluid from entering the supply conduit or cable and shall comply with Clauses 4.10.6.5 and 4.10.6.6.

4.10.6.3 The pressure seal shall withstand for 1 mm without visible leakage the following overpressure test:

(a) 2.0 times the maximum working pressure for working pressures equal to or less than 14 MPa; (b) 1.75 times the maximum working pressure plus 3500 kPa for working pressures over 14 MPa and up to 70 MPa; or (c) 1.3 times the maximum working pressure plus 35 000 kPa for working pressures over 70 MPa.

4.10.6.4 The pressure seal shall withstand for 1 mm without rupture the following overpressure test: (a) 3.0 times the maximum working pressure for working pressures equal to or less than 14 MPa; (b) 2.5 times the maximum working pressure plus 7000 kPa forworking pressures over 14 MPa and up to 70 MPa; or (C) 2.0 times the maximum working pressure plus 42 000 kPa for working pressures over 70 MPa.

4.10.6.5 There shall be two independent seals preventing passage of the explosive fluid to the electrical

housing. Each seal shall be capable of withstanding for 1 mm without visible leakage 1.5 times the marked maximum working pressure.

4.10.6.6 During normal operation, failure of the seal con- tacting the process explosive fluid shall cause a signal audible or visible to plant personnel. Note: Process explosive fluid venting through a flame arrestor is one example of such a signaL * Effective Date—November 30, 1987.

4.11 Grounding and Bonding

4.11.1 A grounding terminal means shall be provided in accordance with CSA Standard C22.2 No. 0.4.

4.11.2 The number and sizes of the conductors to be accommodated shall comply with the requirements applicable to comparable equipment in general purpose enclosures.

4.11.3 The bonding path between the terminating means and the enclosure shall comply with the requirements of CSA Standard C22.2 No. 0.4.

4.11.4 The terminating means shall be factory installed, except that for switches, circuit breakers, panel- boards, junction boxes, and other cases where it is not possible to predetermine the number and sizes of conductors, the terminating means may be field installed, but the mounting means shall not require any drilling of the enclosure walls in the field.

4.11.5 Field-installed terminating means in the form of kits shall comply with the applicable requirements for kits to be used with comparable equipment installed in general purpose enclosures as specified in other Part II Standards.

5. Marking 5.1 The enclosure shall be plainly marked in a permanent manner in a place where the details will be readily visible after installation with the following details, where applicable: (a) manufacturer's name, trademark, tradename, or other recognized symbol of identification;

C22.2 No. 30-M1986 14 November 1986



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Marking—Tests

(b) catalogue, style, model, or other type designation; (C) hazardous location designation (eg, Class I, Groups A, B, C, and D Hazardous Locations); (d) cautions on use in hazardous locations (eg, OPEN CIRCUIT BEFORE REMOVING COVER and OUVRIR LE CIRCUIT AVANT D'ENLEVER LE

COUVERCLE, or KEEP COVER TIGHT WHILE CIRCUITS ARE ALIVE and GARDER LE COUVERCLE BIEN FERME TANT QUE LES CIRCUITS SONT SOUS TENSION or the equivalent); (e) electrical ratings and other designations, as required by the applicable CSA Standard of the Canadian Electrical Code, Part II, for the equipment enclosed; (f) the words FACTORY SEALED or SEAL NOT REQUIRED; and (g) the maximum external temperature or the code numberas specified in Table 10 to indicate the maximum external temperature if the external temperature exceeds 100° C. (h)* for equipment intended to contain fluids under pressure, the maximum working pressure (MWP) in pascals. *Effective Date—November 30, 1987.

5.2 External markings required by the Standard shall be (a) embossed, die-stamped, cast, moulded, etched, or the equivalent, in the enclosure material; (b) on a metal plate or plates at least 0.5 mm thick permanently attached to the enclosure by means of drive pins or screws; except that metal of lesser thickness may be used provided that it is secured in a mannerthat will prevent damage ordistortion (eg, secured in each corner); or (c) on a metallic or nonmetallic adhesive label, subject to the additional tests of Clause 6.12.

5.3 When aluminum or aluminum parts are used, instructions pertaining to the cleaning of flat joints shall appear in a permanent manner on all enclosures that are intended for Class I, Group B hazardous locations. Similar instructions, which may be in the form of a tag, shall appear on aluminum enclosures intended for use in Class I, Group C or D hazardous locations if the internal free volume exceeds 6000 cm3. The actual marking shall be the following or the equivalent: COVER JOINTS MUST BE CLEANED BEFORE REPLACING COVER and

NETTOYER LES SURFACES DE CONTACT DU COUVERCLE AVANT DE LE REMETTRE EN PLACE. Notes: (1) The permanent markings specified in Clause 5.3 may Consist of a self-adhesive, nonmetallic label on the inside of the enclosure or an external marking in accordance with Clause 5.2. (2) Aluminum housings for Class I, Group B with flat joints are particularlysusceptible to hot particle ejections and special care must be taken to ensure that these joints are free from metallic particles each time that the enclosure is opened.

5.4 Enclosures for equipment that has been shown to be non-ignition capable under normal conditions shall be marked SEAL NOT REQUIRED. Note: Examples of this type of equipment are those which have successfully passed the tests of Clauses 6.6 and 6.7 of CSA Standard C22.2 No. 157.

5.5 Enclosures that permit conduit entries to be added in the field and must comply with Clause 4.10.2.3 shall have the following marking or the equivalent: A SEAL SHALL BE INSTALLED WITHIN 50 mm OF THE ENCLOSURE and UN SCELLEMENT DOlT ETRE INSTALLEA MOINS DE 50 mm DU BOITIER.

This marking shall comply with Clause 5.2.

6. Tests 6.1 General Enclosures shall be capable of withstanding the applicable tests in Clause 6. The tests shall be conducted at normal room temperature, atmospheric pressure, and humidity unless otherwise specified.

6.2 Impact 6.2.1 General Inspection windows, thin sections, and enclosures made of materials other than metal shall be capable of withstanding the impact specified in Tables 11

and 12. Chips and cracks that do not extend through the enclosure shall not be considered a

failure, provided that the same sample passes the remaining tests.

Explosion-Proof Enclosures for Use in Class I Hazardous Locations November 1986 1 5



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Tests

6.2.2 Test Procedure

6.2.2.1 Normally, the tests shall be made on the enclosure completely assembled and ready for use. Where this is not possible for light-transmitting parts, the tests shalt be made with the parts removed but fixed in their mounting frame or on an equivalent frame. Where cement or bonding is used, the same materials shall be used to fix the transparent parts to the equivalent frame.

6.2.2.2 For light-transmitting parts made of glass, the tests shall be made once on each of 3 samples. In all other cases, 2 tests shall be made on 1 sample. The points of impact shall be the places considered to be the weakest by the certification agency.

6.2.2.3 Enclosures shall be mounted on a steel base (see Figure 5) so that the direction of the impact is normal to the surface being tested if it is flat, or normal to the tangent of the surface at the point of impact if it is not flat. The base shall have a mass of at least 20 kg or shall be rigidly fixed or inserted in the floor (secured in concrete).

6.2.2.4 For suspended enclosures, the direction of impact shall be normal to a flat surface or, if the surface is not flat, normal to the tangent at the point of impact.

6.2.2.5 The test shall be carried out at an ambient temperature of 25 10°C except where the enclosure or part of the enclosure is made of polymeric material; in this case it shall be made at a temperature 10°C above the surface temperature of the enclosure orat50°C, whichever is higher, and, if necessary, on another sample at a low temperature of 0 3°C for gaseous mines and —50 3°C or at the lowest marked temperature for other applications.

6.2.2.6 Enclosures to be tested at a temperature different from the ambient temperature shall be placed in an environmental chamber at a temperature 10°C higher than the prescribed value when this is above the ambient temperature and 5°C lower than the prescribed value when this is below the ambient temperature. After the temperature of the sample has stabilized, it shall be removed from the chamber,

placed on the base, and submitted to the test at the moment when the temperature reaches that prescribed.

6.2.2.7 An example of the standard free-fall test apparatus for enclosures is shown in Figure 5. When the conditions are such that this method cannot be used, a pendulum method may be used instead. In this case, the striking element, including the support rods or cords, shall have a mass as specified in Table 12 and this mass shall be distributed so that the impact point is on the trajectory of the centre of gravity of the moving system.

6.3 Explosion Pressure Test The enclosure shall be tested for resistance to explosion pressure with all the internal apparatus in position, or, if it is designed to be used with part of the internal apparatus removed, under the conditions considered to be the most severe. One or more points of ignition and one or more points of pressure measurement, depending upon the shape of the enclosure, shall be provided at the discretion of the certification agency. The mixtures to be used are as follows: (a) Class I, Group A—14.5 0.5% acetylene (C2H2) mixed with air; (b) Class I, Group B—32.0 1% hydrogen (H2) mixed with air; (c) Class I, Group C—8.0 0.5% ethylene (C2H4) mixed with air; (d) Class I, Group D—4.6 0.3% propane (C3H8) mixed with air; and (e) gaseous mines—9.8 0.5% methane (CH4) mixed with air.

The maximum explosion pressure shall be recorded by a suitable pressure transducer and recording device, and ignition of the mixture shall be by a suitable spark plug, unless the enclosure contains one of the devices described in the arc-rupturing test (Clause 6.4), in which case some of the tests may be performed using the arc rupturing device as a source of ignition. There shall be no rupture of the enclosure as a result of these tests and the same sample shall subsequently pass the flameproof test (Clause 6.5). For conduit-connected enclosures having no ignition sources and for factory-sealed devices, the tests shall be done with 2.5 and 3.33 m lengths of conduit of the largest size permissible in the enclosure up to and including 1-1/2 trade size. Forall otherenclosures, aO.5 m length of the largest permissible size of conduit shall be used.

C22.2 No. 30-M1986 16 November 1986



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6.4 Arc-Rupturing If the enclosed device consists of a motor controller having contacts rated between 1 and 100 hp inclusive, it shall be subjected to a series of overload tests (at least 15 operations) with the load specified in CSA Standard C22.2 No. 14 in the presence of the specified gas or vapour/air mixtures. If the device contains a snap switch, the load shall be in accordance with CSA Standard C22.2 No. 55. If the device contains a manually operated general purpose ac switch rated at greater than 20 A but not more than 400 A, the load shall be in accordance with GSA Standard C22.2 No. 111. Pressures recorded during these tests shall be included in the analysis of the explosion tests. A3 A fuse connected between the side of the line least likely to arc to ground and the enclosure shall not rupture. Note: Until adequate short-circuit test facilities are available, no electrical tests are required on circuit breakers during the explosion tests.

6.5 Explosion Flame Propagation Test

6.5.1 General The enclosure shall be tested for flameproofness in accordance with either Clause 6.5.2 or Clause 6.5.3. Clause 6.5.2 is the preferred method for Class I, Groups C and D and gaseous mines.

6.5.2 Flameproof Test Using a More Sensitive Gas/Air Mixture The enclosure as received shall be placed in an

explosion chamber and the test shall be made with the same flammable mixture inside and surrounding the enclosure. The inside mixture shall be ignited by means of a spark plug, unless the enclosure contains a switching device as described in Clause 6.4, in which case the switching device may be the means of ignition. The mixture inside the enclosure shall be ignited at least 5 times without ignition of the external mixture. The following gas/air mixtures shall be used: (a) Class I, Group C—37 0.5% hydrogen .(H2) mixed with air; (b) Class I, Group 0—55 0.5% hydrogen (H2) mixed with air; and (C) gaseous mines—12.5 0.5% methane-hydrogen (58 1% methane (CH4) and 42 1% hydrogen (H2)) mixed with air.

6.5.3 Flameprootness Using Enlarged Gaps All enclosures for Class I, Groups A and B, and enclosures for Groups C and D that could be damaged bythe test mixtures specified in Clause 6.5.2 shall have their gaps enlarged by a factor of 1.42 above the maximum values specified by the manufacturer and shall be tested in accordance with the method described in Clause 6.5.2, except that the following gas/air mixtures shall be used: (a) Class I, Group A—8.5 0.5% acetylene (C2H2) mixed with air; (b) Class I, Group B—24 1% hydrogen (H2) mixed with air; (c) Class I, Group C—6.5 0.5% ethylene (C2H4) mixed with air or 19 1% hydrogen-methane (hydrogen (H2) to methane (CH4) ratio, (85/15)) mixed with air; and (d) Class I, Group D—4.2 0.1% propane (C3H8) mixed with air.

6.5.4 Flame Arrestors For flame arrestors in Class I, Groups A, B, C, and D, oxygen-enriched gas/air mixtures shall be used in both inside and surrounding atmospheres in accordance with the method described in Clause 6.5.2 using the following mixtures: (a) Class I, Group A—17% acetylene (C2H2), 22% oxygen, 61% air; (b) Class I, Group B—48% hydrogen (H2), 13.8% oxygen, 38.2% air; (c) Class I, Group C—37 0.5% hydrogen (H2) mixed with air; and (d) Class I, Group D—55 0.5% hydrogen (H2) mixed with air.

If a flame arrestor is submitted for test without an enclosure, it shall be tested in a standard enclosure measuring 300 mm on each side.

6.6 Overpressure 6.6.1 General The overpressure tests shall be based on the maximum explosion pressure recorded in the explosion test except as outlined in Clauses 6.11.1 and 6.11.2. This test may be used as a type test or a routine test at the option of the manufacturer. The pressure shall be applied at the rate of approximately 690 kPa/min until the required internal pressure is reached. If necessary, gaskets or other means may be employed to prevent leakage of fluid during the application of pressure.


Tests



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Tests

If permanent deformation of walls or covers occurs, the distortion shall not affect the flameproofness of the enclosure. The flameproofness of the enclosure shall be investigated by inspection or by test. Elongation of fasteners shall not be permitted. Note: It is recommended that the tests be done with a noncom pressible fluid.

6.6.2 Routine Tests The routine overpressure tests shall be performed on all explosion-proof enclosures manufactured unless permission is obtained from the certification agency to make these tests on a portion of the production. The routine test may be waived if the original prototype is capable of passing the type test (Clause 6.6.3) and the minimum thickness of the prototype enclosure is maintained on all production samples. The pressures may be applied statically or dynamically and shall have the following values: (a) 2.25 times the maximum recorded pressure developed in the explosion tests, or not less than 340 kPa, when the pressure rise time (see Figure 4) is not less than 5 ms; (b) 3 times the maximum recorded pressure developed in the explosion tests, or not less than 340 kPa, when the pressure rise time (see Figure 4) is less than 5 ms; (c) 1.5 times the maximum recorded pressure developed in the explosion tests for equipment intended for gaseous mines when the pressure rise time (see Figure 4) is not less than 5 ms.

6.6.3 Type Test This test is an alternative to the routine tests described in Clause 6.6.2. A sample enclosure shall be subjected to an overpressure of the following values applied hydrostatically: (a) for enclosures of fabricated rolled steel, 2.25 times the maximum explosion pressure without rupture or distortion; (b) for enclosures of fabricated rolled steel for equipment intended for gaseous mines, 2 times the maximum explosion pressure without rupture or distortion; and (c) for other than fabricated rolled steel enclosures, 4 times the maximum explosion pressure without rupture.

6.7 Temperature A temperature test, if required by the certification agency, shall be conducted on the complete assembly to ensure that the temperatures on the enclosed equipment, when tested at the upper limit

of the normal operating conditions as defined in CSA Standard C235 and based on an ambient temperature of 40° C, do not exceed the allowable temperatures given in the relevant CSA Standard of the Canadian Electrical Code, Part II. Note: The temperature test may be made at any room temperature between 10°C and 40°C, and the variation below 40°C is to be added to the observed temperatures.

6.8 Temperature (Abnormal) If the enclosed equipment can be overheated by means of an overload or by shorting out an operating thermostat, an abnormal temperature test shall be conducted to determine whether the maximum allowable surface temperatures given in Clause 6.7 might be exceeded under abnormal conditions. If a limit thermostat (approved for 100 000 operations) is provided, it shall not be defeated when conducting this test.

Tests shall be conducted at the upper limit of the normal operating conditions as defined in CSA Standard C235 and at the lowest marked frequency and with conditions most liable to cause high temperatures, eg, the armature of a solenoid blocked in its normally de-energized position.

6.9 Flammability Materials for enclosures other than metal and materials for viewing windows other than glass shall be subjected to Test A of CSA Standard C22.2 No. 0.6. After the fifth application of the flame, the material shall not have burned through nor have supported combustion for more than 1 mm.

6.10 Gastight Joints

6.10.1 Test

Gastight Joint Pressure Routine

A gastight joint shall be capable of being subjected to a pressure test of 4 times the maximum explosion pressure without rupture or visible leakage. The test pressure may be reduced to 1.5 times the maximum operating pressure if the higher pressure would result in damage to items in the equipment not critical to the explosion-proof enclosure.

6.10.2 Gastight Joint Type Tests The joint under investigation shall be subjected to either of the following sensitive leakage tests: (a) Helium Mass Spectrometer Leakage Test. Helium at 1-1/2 times the maximum explosion pressure shall be applied to one side of the joint and any leak rate, as determined in accordance with ASTM Standard E449 shall be less than 1 X 10 cm3/s.

18 C22.2 No. 30-M1986

Nomber 1986



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(b) Nitrogen Gas Leakage Test. Nitrogen gas at 4 times the maximum explosion pressure shall be applied to one side of the joint when immersed in silicone oil having a kinematic viscosity of 0.2 cm2/s or less at 25 mm below the surface and at a temperature of approximately 25° C. The leak rate when tested in accordance with ASTM Standard E515 shall be less than 1 bubble every 10 mm

(1 X 10—6 cm3/s).

6.11 Overpressure Test for Fittings

6.11.1 A conduit union, a conduit elbow, and any other similarfitting, including a flexible connection fitting or flexible fixture fitting, that does not increase the internal cross-sectional area of the conduit on which it is intended to be installed need not be subjected to an explosion test if the fitting is subjected to a pressure test in accordance with Table 13 without rupturing or permanent deformation.

A flexible connection fitting or a flexible fixture fitting shall withstand the internal hydrostatic pressure specified in Table 13 without damage or leakage.

6.11.2 A box or a fitting subjected to explosion tests shall withstand, without rupture or permanent distortion, an internal hydrostatic test pressure not less than 4 times the maximum internal pressure obtained in the device during the explosion tests.

6.11.3* The maximum explosion pressure shall be measured

by a suitable pressure transducer installed at the fitting and ignition of the mixture shall be by a

suitable spark plug installed in a 28 300 cm3 box. There shall be no rupture of the fitting as a result of these tests. For fittings up to and including 1-1/2 trade size, the tests shall be done with 2.5 and 3.3 m

lengths of conduit. For larger fittings, a 0.5 m

length of conduit shall be used. The test gas mixtures shall be in accordance with Clause 6.3. * Effective Date—May 31, 1988.

6.12 Adhesive Nameplates

6.12.1 The nameplate shall be installed on the intended panel or part of the equipment. The panel or part shall be finished with the paint or coating normally applied.

6.12.2 The installation shall be exposed to a 50% saturated atmosphere of the following vapours for a period of 10 d: ethanol, ethyl acetate, ethyl ether, gasoline, methyl ethyl ketone, toluene, and vinyl acetate. It shall then be examined for lack of firmness of attachment or other deleterious effects. A fresh

sample shall be used for each test.

6.13* Test for Sealing Compounds

6.13.1 A sealing compound shall be capable of withstanding a pressure of 140 kPa (20 psi) without leakage in excess of 100 cm3/min and of withstanding a

pressure of 5500 kPa (800 psi) without failure when tested in accordance with Clauses 6.13.2 and 6.13.3. The sealing compound shall remain intact and in place.

6.13.2 The test apparatus shall consist of (a) a commercial iron pipe reducing coupling of 1/8 X 1/2 trade size; (b) a commercial pipe plug of 1/8 trade size; and

(c) a hydrostatic pressure test apparatus with a pressure rating of 7000 kPa (1000+ psi) at a discharge rate greater than 100 cm3/min.

6.13.3 The following test method shall be used: (a) the pipe plug shall be fitted into the corresponding opening of the reducing coupling until it is flush with the inner surface of the coupling; (b) the sealing compound shall be prepared according to the manufacturer's directions and poured into the reducing coupling to a depth of 16 mm (just below the 1/2 trade size thread); (c) the sealing compound shall be cured for 24 h

at room temperature or according to the manufacturer's instructions; (d) the pipe plug shall be removed and visually examined for integrity of the seal; (e) the 1/2 trade sizeend of the reducing coupling shall be connected to the hydrostatic test machine;

(f) the pressure shall be slowly increased to 140 kPa; (g) the pressure shall be maintained at this value for 1 mm and the leakage measured; and

(h) the pressure shall be slowly increased to 5500 kPa and maintained for 1 mm. * Effective Date—November 30, 1987.


Tests



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Table 1

Joint Widths and Gaps for Enclosures for Class I, Group B Hazardous Locations

(See Clause 4.3.2 and Table 5.)

Size of enclosure*

Dimensions of joint, mm

Minimum of joint

width Maximum gap

Plain Stepped Plain Stepped

Up to and including 100 cm3

9.5 9.5 0.1 0.1

Above 100 cm3 and up and including 500 cmt

to 9.5 19 25

9.5 0.04 0.05t 0.08t

0.1

Above 500 cm3 and up and including 2000 cm3

to 16 9.5 0.04 0.1

Above 2000 cm3 and up to and including 6000 cmj

25 9.5 0.04 0.1

* The size of the enclosure shall be taken as the free internal volume (with the apparatus installed unless the enclosure is likely to be used without the apparatus). tin order to qualify for this joint, the cover or removable part shall have a thickness of at least 9.5 mm at the joint unless stiffened or reinforced metal of a lesser thickness has been found acceptable with respect to its physical strength and resistance to opening of the gap under internal pressure.

This maximum gap applies to operating rods only. §Enclosures larger than 6000 cm3 shall be the subject of investigation.

C22.2 No. 30-M1986 20 November 1986

Table I



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Table 2 Joint Widths and Gaps for Enclosures

for Class I, Group C Hazardous Locations (See Clause 4.3.2.)

Size of enclosure*


Minimum of joint

width Maximum gap

Up to and including 100 cm3 6 0_i

Above 100 cm3 and including 500 cm3t

up to and 9.5 0.04

Above 500 cm3 and including 6000 cm31

up to and 9.5 0.04


up to and 12.5 0.1

Above 2000 cm3 12.5 25

0.08 0.1

The size of the enclosure shall be taken as the free internal volume (with the apparatus installed unless the enclosure is likely to be used without the apparatus). tin order to quality for this joint, the cover or removable part must have a thickness of at least 9.5 mm at the joint unless stiffened or reinforced metal of a lesser thickness has been found acceptable with respect to its physical strength and resistance to opening of the gap under internal pressure. tIn order to qualify for this joint, the cover or removable part must have a thickness of at least 9.5 mm at the joint.


Table 2



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Table 3 Joint Widths and Gaps for Enclosures

for Class I, Group D Hazardous Locations (See Clause 4.3.2.)

Size of enclosure*


Minimum of joint

width Maximum gap

Up to and including 100 cm3 6 0.15

Above 100 cm3 and including 500 cm3t

up to and 9.5 0.04


up to and 9.5 0.04


up to and 12.5 0.15

Above 2000 cm3 12.5 25

0.1 0.2

*The size of the enclosure shall be taken as the free internal volume (with the apparatus installed unless the enclosure is likely to be used without the apparatus). tIn order to qualify for this joint, the cover or removable part must have a thickness of at least 9.5 mm at the joint unless stiffened or reinforced metal of a lesser thickness has been found acceptable with respect to its physical strength and resistance to opening of the gap under internal pressure. In order to qualify for this joint, the cover or removable part must have a thickness of at least 9.5 mm at the joint.

Table 4 Joint Widths and Gaps for Enclosures for Gaseous Mines

(See Clause 4.3.2.)

Size of enclosure*


Minimum of joint

width Maximum gap

Up to and including 100 cm3 6 0.15


up to and 9.5 0.04


up to and 12.5 0.2

Above 2000 cm3 25 0.25

*The size of the enclosure shall be taken as the free internal volume (with the apparatus installed unless the enclosure is likely to be used without the apparatus).

C22.2 No. 30-Mi 986 22 November 1986

Table 3



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Table 5 Joint Widths and Gaps for Power Shafts—

Enclosures for Class I, Group B Hazardous Locations (See Clause 4.3.5 and Figure 6.)

Tables 5 and 6


Maximum gap diametrical

Minimum of joint

width (2 X B in Figure 6)

Ball and (A in Sleeve roller

Size of enclosure* Figure 6) bearings bearings

Up to and including 100 cm3 12.5 25

0.1 0.15

0.15 0.2

Above 100 cm3 and up to and 25 t t including 2000 cm3

Above 2000 cm3 t t t *The size of the enclosure shall be taken as the free internal volume (with the apparatus installed unless the enclosure is likely to be used without the apparatus). f Where no values are specified in Table 5, the values in Table 1 apply; except that special joints such as labyrinth gland joints are permissible subject to investigation.

Table 6 Joint Widths and Gaps for Power Shafts for

Enclosures for Class I, Group C Hazardous Locations (See Clause 4.3.5 and Figure 6.)


Maximum gapt diametrical

Minimum of joint




Up to and including 100 cm3 6 12.5 25 40

0.2 0.25 0.3 0.4

0.3 0.4 0.45 0.6

Above 100 cm3 and up to and 12.5 0.2 0.3 including 2000 cm3 25

40 0.25 0.3

04 0.45

Above 2000 cm3 12.5 25 40

0.15 0.2 0.25

0.2 0.3 0.4

* The size of the enclosure shall be taken as the free internal volume. I-For Class I, Group C labyrinth gland joints see Table 8.




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Table 7 Joint Widths and Gaps for Power Shafts for Enclosures for Class I, Group D Hazardous Locations and Gaseous Mines

(See Clause 4.3.5 and Figure 6.)


Maximum gap diametrical

Minimum of joint





6 12.5 25 40

0.3 0.35 0.4 0.5

0.46 0.5 0.6 0.75

Above 100 cm3 and 6 — 0.38 up to and including 1050 cm3

12.5 25 40

0.3 0.4 0.5

0.46 0.6 0.75

Above 1050 cm3 and 12.5 0.3 0.46 up to and including 2000 cm3

25 40

0.53 0.64

0.6 0.75

Above 2000 cm3 and 12.5 0.2 0.3 up to and including 6000 cm3

25 40

0.53 0.64

0.6 0.75

Above 6000 cm3 with 25 0.4 0.6 joint length up to 40 0.64 0.75 and including 63 0.75 — 2300 mm

Above 6000 cm3 with 25 0.4 0.6 joint length greater 40 0.5 0.75 than 2300 mm

* The size of the enclosure shall be taken as the free internal volume.

C22.2 No. 30-M1986 24 November 1986

Table 7



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Tables 8 and 9

Table 8 Widths and Gaps of Labyrinth Joints for Power Shafts for Enclosures for Class I, Groups C and D Hazardous Locations and Gaseous Mines

(See Clause 4.3.5, Table 6, and Figure 3.)

Dimensions of joint, mm (see Figure 3)

Maximum gap Minimum total Minimum width Minimum difference (diametrical) width of of shortest between diameters ball, sleeve, and labyrinth joint section at step roller bearings

Size of enclosure* (W) (w) (D—E) (F—D) or (G—E)

Up to and including 6000 cm3 with end shield joint length 29 3.2 3.2 0.53 not greater than 810 mm 41 3.2 3.2 0.64

Above 6000 cm3 with joint length greater than 810 mm but 41 3.2 6 0.64 not greater than 2300 mm 67 3.2 6 0.75

Above 6000 cm3 with 50 6 6 0.64 joint length greater than 2300 mm 75 25 6 0.75

* The size of the enclosure shall be taken as the free internal volume.

Table 9 Minimum Flame Path

at Bolt Holes (See Clause 4.7.2 and Figure 2.)

Requi width mm

red of

minimum joint (W),

Minimum flame path (w), mm

6 6 9.5 8

12.5 8 16 or wider 9.5




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Tables 10 and 11

Table 10 Temperature-Indicating Code Numbers

(See Clause 5.1 (g).)

Code number Maximum external temperature, °C

Ti 450 T2 300 T2A 280 T2B 260 T2C 230 T2D 215 T3 200 T3A 180 T3B 165 T3C 160 T4 135 T4A 120 T5 100 T6 85

Table 11 Tests of Resistance to Impact

(See Clause 6.2.1.)

Group

Impact energy (E), J

Mines Others

1 Light-transmitting parts with guard (tested without guard)

4 2

2 Light-transmitting parts without guards

7 4

3 Other enclosures or parts of enclosures (including guards and fan hoods)

20 7

Note: The electrical apparatus is submitted to the effect of a test mass of M falling vertically from a height h, the values of M and h being dependent on the impact energy required as listed in Table 12. The test mass shall be fitted with an impact head of hardened steel in the form of a hemisphere of 25 mm diameter.

C22.2 No. 30-M1986 26 November 1986



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Table 12 Impact Test Levels

Tables 12 and 13

(See Clauses 6.2.1 and 6.2.2.7, Table 11, and Figure 5.)


Mass (M), kg

Height (h), m

2 0.25 0.8

4 7 1.0

0.4 0.7

20 2.0 1.0

Note: h = E/Mg

where g 10 rn/s2 h is in metres E is in joules M is in kilograms

Table 13 Overpressure Test Values, kPa

(See Clause 6.11.1.)

Type of fitting Class I, Groups A and B

Class I, Groups C and D

Conduit fitting up to 8000 4000 1-1/2 trade size

Conduit fitting 2 8000 4000 trade size and larger




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Figure 1

Typical Operating Rods (See Clause 4.3.4.1.)

C222 No. 30-M1986 28 November 1986

Figure 1

I_I- w

(a) (b)

C__ I

(C) C!

(d)



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Figure 2

0)

Figure 2 Method of Measuring Width of Typical Joints

(See Clauses 2.1, 4.3.3, and 4.7.2.)

Explosion-Proof Endosures for Use in Class I Hazardous Locations November 1986 29

(a) (b) (c)

w=z±x+Y wX+Y

(d) (e) (f)



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Figure 3

Exterior

Figure 3 Method of Measuring Labyrinth Joints for Shafts

(See Table 8.)

C222 No. 30-M1986 30 November 1986

End shield or bearing cover

Interior

F G

Note: WA—X A



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a)

CI) U) a)

C-

Figure 4 Method of Evaluation of Pressure Rise Time

(See Clause 6.6.2.)

Explosion—Proof Enclosures for Use in Class I Hazardous Locations

November 1986

Figure 4

31

Maximum rate of rise

Explosion pressure curve

Pressure



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Figure 5

Legend: 1 = adjustment pin 2 = plastics guide tube 3 = test piece 4 = steel base (mass � 20 kg) 5 = steel mass (see Table 12) 6 = hardened steel impact head 25 mm in diameter h = height of fall (see Table 12)

4

5

Figure 5 Example of Free Fall Test Apparatus for Impact Test

(See Clauses 6.2.2.3 and 6.2.2.7.)

C22.2 No. 30-M1986 32 November 1986

1

6

2

/3/

h



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0— A —I

Figure 6

Sleeve bearing

Ball bearing

Figure 6 Typical Power Shafts (See Tables 5, 6, and 7.)

Explosion-Proof Endosures for Use in Class I Hazardous Locations November 1986 33



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Appendix A

Appendix A Explosion and Flameproof Testing

Note: This Appendix is not a mandatory part of this Standard.

Al - General A1.1 The following information is extracted directly from the International Electrotechnical Commission Publication 79-1, Amendment No. 1, dated September 1979, Electrical Apparatus for Explosive Gas Atmospheres, which describes the interna- tionally recognized method of explosion and flameproof testing. This information is reproduced verbatim except that the numbers of the clauses have been changed and certain information is shown in brackets where reference is made to International Groupings (which do not agree with Canadian Groupings at present). Testing by other agencies such as UL Inc. may be considered equivalent.

A2. Determination of Explosion Pressure A2.1 The test consists of igniting an explosive mixture inside the enclosure and recording the pressure caused by the explosion.

The mixture to be used at atmospheric pressure is as follows (in a volumetric ratio with air): (a) for Group I enclosures (Gaseous Mines) (9.8 0.5)% methane; (b) for Group hA enclosures (Class I, Group D) (4.6 0.3)% propane; (c) for Group lIB enclosures (Class I, Group C) normally the test mixture is (8 0.5)% ethylene. In cases where pressure piling may occur the test shall be made at least 5 times with a mixture of (8 0.5)% ethylene and it shall be repeated afterwards at least 5 times with a mixture of (24 1 )% hydrogen- methane (85-15).

The enclosure shall be tested with all the internal apparatus or its equivalent in position, but if it is so designed that it can be used with part of the internal apparatus removed, the tests shall be made under the conditions which the certification agency con- siders to be the most severe.

The mixture shall be ignited by one or more high- voltage sparking plugs or other low-energy sources of ignition. Alternatively, where the enclosure contains a switching device that produces sparks capable of igniting the explosive mixture, then this device may be used to initiate the explosion. The pressure developed during the explosion shall be measured and recorded in the course of each test.

The siting of the sparking plug or plugs, and of the pressure gauge or gauges, is left to the discretion of the certification agency.

The tests described in this Clause shall be made at least 3 times except when 5 tests are required where pressure piling occurs in Group IIB (Class I, Group C) enclosures.

A3. Overpressure Test There are two alternative methods of test.

A3.1 First Method For this method it is necessary to know the pressure as recorded during the explosion pressure test under Clause A2. The test may be either a static test or a dynamic test subject to an agreement between the certification agency and the manufacturer.

In the dynamic test, the enclosure shall be submitted to a pressure test such that the maximum pressure applied is equal to 2 times the maximum smoothed pressure obtained in the tests made in accordance with Clause A2, hereafter referred to as the reference pressure, with a minimum of 250 kPa, and such that the rate of pressure development is reasonably similar to that during the determination of explosion pressure.

In the static test, the test pressure shall be raised to 2 times the reference pressure, with a minimum of 350 kPa. The pressure shall be applied for not less than 10 s and not more than 1 mm.

Samples of the enclosures over 10 cm3 not subjected to the routine test specified in Clause 6.6.2 shall be submitted to either a static test or a dynamic test in which the pressure shall be raised to 4 times the reference pressure.

34 C22.2 No. 30-M1986

November 1986



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Flameproof enclosures for storage batteries which are fitted with ventilating devices are exempt from the requirementfora minimum pressure of 350 kPa.

A3.2 Second Method This method may be used only when it is not practicable to measure the explosion pressure in the test specified in Clause A2.

For this method the testing procedure as given in Clause A2 is used, except that the explosion pressure is not measured.

The test consists of filling the enclosure with a

prescribed explosive mixture at an initial pressure of 50% above the atmospheric pressure and igniting the precompressed mixture.

A4. Test to Determine Whether the Enclosure is Flameproof A4.1 The enclosure shall be placed in an explosion chamber. The test shall be made with the same explosive mixture inside the enclosure and in the explosion chamber.

The mixture inside the enclosure shall be ignited by means of a high-voltage sparking plug or other low-energy source of ignition. Alternatively, where the enclosure contains a switching device that produces sparks capable of igniting the explosive mixture, then this may be used to initiate the explosion. The test is considered satisfactory if the mixture in the explosion chamber is not ignited.

At least 5 tests shall be made, the mixture in the enclosure and, if necessary, in the explosion chamber being renewed for each.

The enclosure is tested in its normal condition without creating an artificial gap (the joints being within the manufacturing tolerances indicated in the descriptive documents).

Detachable sealing gaskets which do not contri- bute to the explosion protection shall be removed.

The explosive mixtures to be used, in volumetric ratio with air, are as follows: (a) electrical apparatus of Group I (Gaseous Mines): 12.5 0.5% methane-hydrogen (58 1% methane and 42 1% hydrogen) (equivalent to a maximum experimental safe gap (M ESG) of approximately 0.8 mm); (b) electrical apparatus of Group lIA (Class I, Group D): 55 0.5% hydrogen (equivalent to a MESG of approximately 0.65 mm);

(c) electrical apparatus of Group IlB (Class I, Group C): 37 0.5% hydrogen (equivalent to a MESG of approximately 0.35 mm). Note: The explosive mixtures chosen for this test ensure that the joints prevent the transmission of an internal ignition, with a known margin of safety. This margin of safety, K, is the ratio of the maximum experimental safe gap of the representative mixture of the Group concerned to the maximum experimental safe gap of the chosen test mixture. Electrical apparatus of Group / (Gaseous Mines):

1.14 K = 1.42 (methane)

0.8

Electrical apparatus of Group hA (Class I, Group D):

0.92 K=

06 =1.42 (propane)

Electrical apparatus of Group FIB (Class I, Group C):

0.65 K = = 1.85 (ethylene)

0.35

If enclosures of Groups hA and IIB (Class I, Groups C and 0) could be destroyed or damaged by this test, however, it is permitted that the test be made by increasing the gaps above the maximum values specified by the manufacturer. The enlarge- ment factor of the gap is 1.42 for Group IlA electrical apparatus and 1.85 for Group lIB electrical apparatus. The explosive mixtures to be used in the enclosure and in the test chamber, in volumetric ratio with air and at atmospheric pressure, are as follows: (a) electrical apparatus of Group II A: 4.2 0.1% propane; (b) electricalapparatusof Group IIB: 6.5 0.5% ethylene or 19 1% hydrogen-methane (85/15) mixture.

The test result is considered satisfactory if ignition is not transmitted to the test chamber.


Appendix A



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Proposal for Change

To help our volunteer members to assess proposals to change requirements we recommend that each

proposal for change be submitted in writing and identifr the

(a) Standard number; (b) Clause number; (c) proposed wording of the Clause (requirement, test, or pass/fail criterion) using mandatory language and underlining those words changed from the existing Clause (if applicable); and

(d) rationale for the change, including all supporting data necessary to be considered.

The proposal should be submitted to the Standards Administrator at least one month prior to the next

meeting of the Committee. It is CSA Committee practice that only those proposals sent out to members

prior to a meeting can be the subject of discussion and action. This is to allow the members time to consider the proposal and to do any research they may feel necessary.

Date: ____ - ____ - ____ YY MM DD

To: The Standards Administrator of CSA Standard _________________

From: ________________________________________________________

Affiliation: ___________________________________________

Address: _______________________________________________

Phone: _______________________________ Fax: __________

Re: Request for an Amendment, Deletion, or Addition to Clause(s)

Proposed change:

(Use reverse and additional pages as required.) Copyright Canadian Standards Association Provided by IHS under license with CSA Sold to:GE SENSING, W0341746


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Association Activities

The Canadian Standards Association is a not-for-profit, independent, private sector organization that serves the public, governments, and business as a forum for national consensus in the development of standards, and offers them certification, testing, and related services. It is a

membership Association open to any individual, company, or organization interested in standards activities. The more than 1000 standards published by CSA are written, reviewed, and revised by over 7000

committee members, who represent users, producers, and regulatory authorities in all regions of Canada. In addition to these volunteers, some 2000 representatives from industry, labour, governments, and the public participate in the work of the Association through sustaining memberships. Approximately one-third of CSA's standards have been referenced into law by provincial and federal authorities. Activities in the standards field cover a number of program areas: lifestyles and the environment,

electrical/electronics, construction, energy, transportation/distribution, materials technology, business/production management systems, communications/information technology, and welding. These are all listed in our catalogue, which is available on request. We welcome your comments and inquiries. Further information on standards programs may be

obtained by writing to

The Director, Standards Programs Standards Development Canadian Standards Association 178 Rexdale Boulevard Rexdale (Toronto), Ontario Canada M9W 1R3



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PLEASE NOTE:

THE PAGES APPEARING AFTER THIS PAGE

ARE NO LONGER CURRENT.

THEY HAVE BEEN WITHDRAWN, AND REPLACED.

THEY ARE RETAINED FOR YOUR REFERENCE ONLY.



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Scope—Definitions—General Requirements


1. Scope 1.1 This Standard covers the details of construction and tests for explosion-proof enclosures for electrical equipment to be used in Class I, Division 1, Groups A, B, C, and D hazardous locations and in gaseous mines in accordance with the Rules of the Canadian Electrical Code, Part I and the requirements of CSA Standard CAN3-M421 -M85.

1.2 Other Standards for hazardous location equipment covering specific types of equipment shall take precedence over this Standard.

1.3 Unless otherwise marked, this Standard applies to enclosures intended for use in ambient temperatures of (a) —50 to +40° C for Class I, Groups A, B, C, and D; (b) 0 to +40°C for gaseous mines; (c) an oxygen concentration of approximately 21% by volume; and (d) a pressure of not more than 106 kPa.

2. Definitions 2.1 The following definitions apply in this Standard:

Explosion-proof enclosure means an enclosure for electrical equipment that is capable of withstanding, without damage, an explosion with in it of a specified gas or vapour and is capable of preventing ignition ofthesame gas orvapoursurrounding the enclosure caused by sparks or flames from the explosion with in the enclosure (synonymous with "flameproof enclosure" as defined in IEC Publication 79-1, Part I).

Gap means the distance between the corresponding surfaces at a joint measured normal to the surfaces. For cylindrical surfaces, the gap is the difference between the two diameters (diametrical clearance).

Gastight joint means a joint that prevents gases or vapours from passing from one section of an enclosure to another or to the surrounding atmosphere.

Joint means the place where corresponding surfaces of the different parts of an enclosure come together and where paths from the inside to the outside of the enclosure occur.

Labyrinth gland joint means a joint having at least 2 axial paths in series, interrupted by at least 1 radial path, the latterhaving a minimum length of 1.58 mm.

Operating rod means a rod or shaft operating at less than 100 cycles/mm.

Power shaft means a shaft operating at 100 cycles/mi n or greater.

Width of joint means the shortest distance from the inside of the enclosure to the outside of the enclosure through the joint (dimension W in Figure 2).

3. General Requirements 3.1 General requirements are given in CSA Standard C22.2 No. 0, General Requirements—Canadian Electrical Code, Part II.

3.2 Electrical equipment contained in explosion-proof enclosures shall meet the requirements of all applicable CSA Standards of the Canadian Elec- trical Code, Part II.

3.3 CSA Standard CAN3-M421 restricts the use of exposed light-weight alloys in gaseous underg round mines.

3.4 Where reference is made to CSA Standards of the Canadian Electrical Code, Parts I and II, such reference shall be considered to refer to the latest edition and revision thereto, unless otherwise specified.


November 1988 (Replaces p. 9. November 1986) 9 Copyright Canadian Standards Association Provided by IHS under license with CSA Sold to:GE SENSING, W0341746


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General Requirements—Construction

This Standard makes reference to the following such Standards and the year dates shown indicate the latest editions available at the time of printing:

C22. 1-1986, Canadian Electrical Code, Part I; C22.2 No. 0-M1982, General Requirements—Canadian Electrical Code, Part II; C22.2 No. 0.4-M1982, Bonding and Grounding of Electrical Equipment (Protective Grounding); C22.2 No. 0.5-1 982, Threaded Conduit Entries; C22.2 No. 0.6-M1982, Flammability Testing of Polymeric Materials; C22.2 No. 14-M1985, Industrial Control Equipment for Use in Ordinary (Non-hazardous) Locations; C22.2 No. 55-1 957, Snap Switches; C22.2 No. 111-1 956, Manually-Operated General-Purpose A-C Switches; C22.2 No. 157-M1979, Intrinsically Safe and Non-incendive Equipment for Use in Hazardous Locations.

35 Where reference is made to the following publi- cations not under the jurisdiction of the Committee on Part II, such reference shall be considered to refer to the edition listed below:

CSA Standards Bi .1-1949, Unified and American Screw Threads; B95-1 962, Surface Texture (Roughness, Waviness, and Lay); CAN3-C235-83, Preferred Voltage Levels for AC Systems, 0 to 50 000 V; CAN3-M421 -M85, Use of Electricity in Mines.

ASTM Standards E499-73, Standard Methods of Testing for Leaks Using the Mass Spectrometer Leak Detector in the Detector Probe Mode; E51 5-74, Standard Method of Testing for Leaks Using Bubble Emission Techniques. IEC* Publication 79-1 (1971), Part 1,

Construction and Test of Flameproof Enclosures of Electrical Apparatus. *lnternational Elect rotechnical Commission.

4. Construction 4.1 General

4.1.1 Materials Details throughout this Standard are based upon enclosures constructed of iron, copper, aluminum, or their alloys. The use of other materials shall be the subject of investigation with respect to factors such as the physical and chemical stability, strength, resistance to impact, and resistance to flame of these materials.

4.1.2* Mechanical Strength 4.1.2.1 Enclosures shall be capable of withstanding the applicable explosion pressure test of Clause 6.3, without rupture, and the joint gaps shall not exceed the values specified in Tables 1, 2, 3, and 4, as applicable.

4.1.2.2 The enclosure shall be capable of withstanding the overpressure test of Clause 6.6.

4.1.2.3 As an alternative to the overpressure test of Clause 4.1.2.2, calculations may be used to determine the strength of the enclosure, in which event the factor of safety shall be 4 times the measured explosion pressure when tested in accordance with Clause 6.3.1 for fabricated rolled metal and 5 times that pressure for other than fabricated rolled metal. *Effective Date—November 30, 1988

4.1.3 Cleaning All particles shall be removed from the enclosure and joints after all machining operations have been completed. (See also Clause 5.3.)

4.1.4 Quality of Cast Enclosures

4.1.4.1 General The following criteria are intended to provide guidance in acceptance of castings and flat explosion-proof joints, machined or as cast.

4.1.4.2 Surface Roughness A metal joint surface shall have an arithmetical average roughness of not more than 0.0063 mm when measured in accordance with CSA Standard B95.

C22.2 No. 30-M1986 10 November 1988 (Replaces p. 10. November 1986)



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4.1.4.3 Casting Imperfections Blowholes orfissures are permitted in the machined joint surface of explosion-proof joints provided that the castings comply with the following: (a) blowholes or fissures not in the joint surface shall be not over 2.4 mm wide and not over 1.6 mm deep. These holes shall not be considered as affecting the minimum thicknesses, unless the wall from the bottom of the hole to the opposite surface is less than 3.2 mm; and

(b) blowholes or fissures in the joint surface that are overO.4 mm in width shall not be included in the effective joint width. The orientation of such holes shall not lessen the joint width in any direction.

4.1.4.4 Repairs Blowholes or fissures may be repaired in aluminum castings by heli-arc welding using an aluminum welding rod or in iron castings by means of brazing. Welding or brazing shall be done before the final machining operation.

4.2* Corrosion Protection Ferrous alloys otherthan stainless steel shall have a protective coating that will resist rust and corrosion in accordance with CSA Standard C22.2 No. 0. The protective coating shall be applied to both inside and outside surfaces of the enclosure before visible rusting has occurred. Joints shall be protected by means of a suitable anticorrosive material such as light grease or electrically or chemically deposited metallic plating not exceeding 0.0075 mm thick. Joints shall not be plated by the hot dip method nor shall they be painted. Conduit threads with fine particles of paint caused by overspraying, where the base metal is plainly visible underneath, shall not be considered to be painted. *Effective Date—November 30, 1988

4.3 Joints

4.3.1* General Joints between covers or other removable parts and the body of the enclosure shall be of the metal-to- metal type and (a) for Class I, Group A, shall be threaded; and (b) for other Groups, may be plain, stepped, or threaded. *Eflective Date—November 30, 1988

4.3.2 Plain and Stepped Joints The minimum joint width in plain or stepped joints shall be in accordance with Table 1, 2, 3, or 4 as applicable. The maximum gap shall be in accordance with Table 1, 2, 3, or 4 as appiicable except

Explosion-Proof Enclosures for Use in Class I Hazardous Locations November 1988 (Replaces p. II, November 1986)

that the gap may be larger providing the enclosure meets the test of Clause 6.5 with an additional safety factor of 1.2. There shall be no intentional gaps at coverjoints. Compliance of the gap will be indicated if a feeler gauge having a thickness equal to the maximum gap will not enter the joint for a distance of more than 3.2 mm at any point or, in the case of a cylindrical joint, if the difference in the diameters of the two parts is smaller than the gap. In the case of stepped joints for Groups C and D enclosures, the clearance for the cylindrical portion of the joint may be considered as the difference in the radii of the two parts if the clamped radial section is not less than one-quarter of the minimum width of the joint.

4.3.3 Threaded Joints

4.3.3.1 General Unless otherwise specified, the threads in threaded

joints shall be not finer than 32 threads per inch. A joint of the serrated type with thread contour shall not have more than 20 serrations per inch and shall have at least 5 fully engaged and tightly clamped serrations.

4.3.3.2 Class I, Groups A and B A cover joint shall not have a standard tapered pipe thread and shall have (a) at least the following number of fully engaged threads not finer than 20 threads per inch:

(i) 8 with a Class 1 fit; (ii) 7 with a Class 2 fit; or (iii) 6 with a Class 3 fit; and

(b) a minimum width (direct axial length of thread engagement*) of

(i) 9.5 mm for internal volumes of enclosures up to and including 500 cm3; or

(ii) 12.5 mm for internal volumes of enclosures over 500 cm3 up to and including 6000 cm3.

Classes of fits are defined in CSA Standard Bi .1. *See Figure 2(e).

4.3.3.3 Class I, Groups A and B Threaded joints other than cover joints shall (a) have standard tapered pipe threads with 5 fully engaged threads; or (b) comply with Clause 4.3.3.2.

4.3.3.4 Class I, Groups C and D A threaded cover joint for use in Class I, Groups C and D hazardous locations shall have (a) not fewer than 5 fully engaged threads; and (b) a minimum width (direct axial length of thread engagement*) of 8 mm. *See Figure 2(e).

11

Construction



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Construction

4.3.4 Operating Rod Joints

4.3.4.1 Joints for an operating rod shall comply with one of the following requirements: (a) the requirements for plain and stepped joints (Clause 4.3.2), except that the length of flame path (dimension cv shown in Figure 1) shall be at least equal to the diameter of the rod but it need not exceed 25 mm; (b) the requirements for threaded joints (Clause 4.3.3), except that threads shall be not finer than 24 threads per inch; or (c) the joints shall be of the labyrinth gland joint type (see definitions), in which case the gap may be increased, provided that the design successfully passes the test of Clause 6.5 with an additional safety factor of 1.2.

4.3.4.2 Operating rods shall have mechanical means to prevent accidental or inadvertent removal (ie, to prevent any movement that would impair the effectiveness of the joint).

4.3.5 Power Shaft Joints Where a shaft for transmitting power is provided on rotating or reciprocating machinery, the joint widths and gaps shall conform to the requirements given in Tables 5, 6, and 7 for plain joints and in Table 8 for labryinth joints. The joint shall include any protection afforded by a sleeve bearing.

4.4 Inspection Windows

4.4.1 Material Windows shall be glass or equivalent. The use of materials other than glass shall be the subject of investigation to determine physical and chemical stability, resistance to impact, resistance to flame, etc, of these materials.

4.4.2 Window Joints The joint between a window and its housing shail have the width of joint required in Clause 4.3.2, or the window shall be cemented into a removable part. The cement shall also be investigated for resistance to flame and chemical and physical stability.

4.5 Flame Arrestors Where air, gas, or liquid lines enter or leave an

explosion-proof enclosure, asuitableflame arrestor shall be provided at the entrance to the enclosure.

4.6 Breathers and Drains Breathers and drains shall be flame arresting and shall be constructed of corrosion resistant material.

4.7 Cover Bolts

4.7.1 General Bolts for securing covers and other removable parts shall be such that they will ensure the effectiveness of the joint.

4.7.2 Joints If a joint surface is interrupted bya cover bolt, the flame path (cv), as shown in Figure 2, measured from the inside of the enclosure shall be not less than the value specified in Table 9.

4.7.3 Depth of Tapping 4.7.3.1 The tapping for cover bolts shall be deep enough to allowfor nominal variations in standard bolt lengths. Washers on cover bolts are optional, but if washers are used, the bolts shall be capable of securing the cover tightly without them.

4.7.3.2 Except as permitted by Clause 4.7.3.3, tapped holes for cover bolts shall be bottomed if the holes enter the enclosure.

4.7.3.3 Tapped holes for cover bolts for enclosures having an internal volume of 2000 cm3 or less need not be bottomed but the bolts shall engage at least 5 full threads in the enclosure.

4.8 Fastenings

4.8.1 General All unused holes through the walls of an explosion- proof enclosure shall be plugged so as to meet the requirements for joints, and the plugs shall be secured against removal from the outside of the enclosure.

4.8.2 Removable Fastenings Fastenings other than cover bolts, such as removable bolts, screws, and studs, shall not leave an opening in the enclosure wall when they are omitted. The minimum thickness of metal around the hole shall be not less than 3.2 mm or 1/3 of the diameter of the hole, whichever is greater. The minimum thickness of metal at the bottom of the hole shall be not less than 1/2 the untapped diameter.

C22.2 No. 30-M1986 12 November 1988 (Replaces p. 12, November 1986)



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6.4 Arc-Rupturing If the enclosed device consists of a motor controller having contacts rated between 1 and 100 hp inclusive, it shall be subjected to a series of overload tests (at least 15 operations) with the load specified in CSA Standard C22.2 No. 14 in the presence of the specified gas or vapour/air mixtures. If the device contains a snap switch, the load shall be in accordance with CSA Standard C22.2 No. 55. If the device contains a manually operated general purpose ac switch rated at greater than 20 A but not more than 400 A, the load shall be in accordance with CSA Standard C22.2 No. 111. Pressures recorded during these tests shall be included in the analysis of the explosion tests. A 3 A fuse connected between the side of the line least likely to arc to ground and the enclosure shall not rupture. Note: Until adequate short-circuit test facilities are available, no electrical tests are required on circuit breakers during the explosion tests.

6.5 Explosion Flame Propagation Test

6.51* General The enclosure shall be tested for flame-proofness in accordance with Clauses 6.5.2, 6.5.3, or 6.5.3A. The test method described in Clause 6.5.2 is the preferred method for Class I, Groups C and 0 and gaseous mines. The test method described in Clause 6.5.3 is the preferred method for Class I,

Groups A and B.

6.5.2* Flameproof Test Using a More Sensitive Gas/Air Mixture The enclosure as received shall be placed in an explosion chamber and the test shall be made with the same flammable mixture inside and surrounding the enclosure. The inside mixture shall be ignited by means of a spark plug, unless the enclosure contains a switching device as described in Clause 6.4, in which case that device may be the means of ignition. Table 14 indicates the number of tests and the explosive gases to be used in volumetric ratio with air at atmospheric pressure.

6.5.3* Flameproofness Using Enlarged Gaps All enclosures for Class I, Groups A and B, and enclosures for Groups C and D that could be

damaged by the test mixtures specified in Clause 6.5.2 shall have their gaps enlarged above the maximum values specified by the manufacturer by a factor of 1.42 and shall be tested in accordance with the method described in Clause 6.5.2. Table 14

indicates the number of tests and the explosive gases to be used in volumetric ratio with air at atmospheric pressure.

6.5.3A* Flameproof Test Using a Pre- Pressurized Gas/Air Mixture The enclosure, as received, shall be placed in an explosion chamber and the test shall be made with the same flammable mixture inside and surrounding the enclosure at an initial pressure of 1.5 times the atmospheric pressure. The test shall otherwise be conducted as in Clause 6.5.2 using the following gas/air mixtures: (a) Class I, Group A—14 1% Acetylene (C2H2) mixed with air; (b) Class I, Group B—31 1% Hydrogen (H2) mixed with air. Note: The volume ratio of the test chamber to the enclosure should be at least 5 to 1 for this test.

*Effective Date—November 30, 1988

6.5.4 Flame Arrestors For flame arrestors in Class 1, Groups A, B, C, and D, oxygen-enriched gas/air mixtures shall be used in both inside and surrounding atmospheres in accordance with the method described in Clause 6.5.2 using the following mixtures: (a) Class I, Group A—17% acetylene (C2H2), 22%

oxygen, 61% air; (b) Class I, Group B—48°h hydrogen (H2), l3.8% oxygen, 38.2% air; (c) Class I, Group C—37 0.5% hydrogen (H2) mixed with air; and (d) Class I, Group D—55 0.5°h hydrogen (H2) mixed with air.

If a flame arrestor is submitted for test without an enclosure, it shall be tested in a standard enclosure measuring 300 mm on each side.

6.6 Overpressure 6.6.1* General The overpressure tests shall be based on the maximum explosion pressure recorded in the explosion test except as outlined in Clauses 6.11.1 and 6.11.2. At the option of the manufacturer, this test may be done as a type test or a routine test. The pressure is to be applied at the rate of approximately 690 kPa/min until the required internal pressure is reached. The pressure shall be maintained at this value for at least 10 s. Gaskets or other means may be employed if necessary to prevent leakage of fluid during application of pressure.

Explosion-Proof Enclosures for Use in Class I Hazardous Locations November 1988 (Replaces p. 17. November 1986) 1 7

Tests



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Tests

If the cover of the enclosure is designed to include operator or device holes that may weaken the cover, the overpressure test shall be conducted with the maximum number of holes that the cover is designed to accommodate. Note: It is recommended that the tests be done with a noncom pressible fluid. *Effective Date—November 30, 1988

6.6.2 Routine Tests The routine overpressure tests shall be performed on all explosion-proof enclosures manufactured unless permission is obtained from the certification agency to make these tests on a portion of the production. The routine test may be waived if the original prototype is capable of passing the type test (Clause 6.6.3) and the minimum thickness of the prototype enclosure is maintained on all production samples. The pressures may be applied statically or dynamically and shall have the following values: (a) 2.25 times the maximum recorded pressure developed in the explosion tests, or not less than 340 kPa, when the pressure rise time (see Figure 4) is not less than 5 ms; (b) 3 times the maximum recorded pressure developed in the explosion tests, or not less than 340 kPa, when the pressure rise time (see Figure 4) is less than 5 ms; (c) 1.5 times the maximum recorded pressure developed in the explosion tests for equipment intended for gaseous mines when the pressure rise time (see Figure 4) is not less than 5 ms.

6.6.3* Type Test This test is an alternative to the routine tests described in Clause 6.6.2, and shall be done once only. A sample enclosure shall be subjected to an overpressure of the following values applied hydrostatically. For enclosures employing more than one type of construction material, eg, a cast metal body with fabricated rolled metal cover, each component shall be tested to the following values: (a) for components of rolled metal, 2.25 times the maximum explosion pressure; (b) for components of rolled metal for gaseous mines, 2 times the maximum explosion pressure; and (c) for components of other than rolled metal, 4 times the maximum explosion pressure. Note: When enclosures are constructed with more than one type of material, it maybe necessary to also submit an enclosure having components of the same material in order to test the components as required in item (c). *Effective Date—November 30, 1988

6.7 Temperature A temperature test, if required by the certification agency, shall be conducted on the complete assembly to ensure that the temperatures on the enclosed equipment, when tested at the upper limit of the normal operating conditions as defined in CSA Standard C235 and based on an ambient temperature of 40°C, do not exceed the allowable temperatures given in the relevant CSA Standard of the Canadian Electrical Code, Part II. Note: The temperature test may be made at any room temperature between 10°C and 40° C, and the variation below 40°C is to be added to the observed temperatures.

6.8 Temperature (Abnormal) If the enclosed equipment can be overheated by means of an overload or by shorting out an operating thermostat, an abnormal temperature test shall be conducted to determine whether the maximum allowable surface temperatures given in Clause 6.7 might be exceeded under abnormal conditions. If a limit thermostat (approved for 100000 operations) is provided, it shall not be defeated when conducting this test.

Tests shall be conducted at the upper limit of the normal operating conditions as defined in CSA Standard C235 and at the lowest marked frequency and with conditions most liable to cause high temperatures, eg, the armature of a solenoid blocked in its normally de-energized position.

6.9 Flammability Materials for enclosures other than metal and materials for viewing windows other than glass shall be subjected to Test A of CSA Standard C22.2 No. 0.6. After the fifth application of the flame, the material shall not have burned through nor have supported combustion for more than 1 mm.

6.10 Gastight Joints

6.10.1 Gastight Joint Pressure Routine Test A gastight joint shall be capable of being subjected to a pressure test of 4 times the maximum explosion pressure without rupture or visible leakage. The test pressure may be reduced to 1.5 times the maximum operating pressure if the higher pressure would result in damage to items in the equipment not critical to the explosion-proof enclosure.

6.10.2 Gastight Joint Type Tests The joint under investigation shall be subjected to either of the following sensitive leakage tests: (a) Helium Mass Spectrometer Leakage Test. Helium at 1-1/2 times the maximum explosion

C22.2 No. 30-M1986 18 November 1988 lReplaces p. 18. November 1986)



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pressure shall be applied to one side of the joint and

any leak rate, as determined in accordance with ASTM Standard E449 shall be less than 1 X 10—6 cm3/s. (b) Nitrogen Gas Leakage Test. Nitrogen gas at 4 times the maximum explosion pressure shall be

applied to one side of the joint when immersed in silicone oil having a kinematic viscosity of 0.2 cm2/s or less at 25 mm below the surface and at a temperature of approximately 25° C. The leak rate when tested in accordance with ASTM Standard E515 shall be less than 1 bubble every 10 mm (1 X 10—6 cm3/s).

6.11 Overpressure Test for Fittings

6.11.1 A conduit union, a conduit elbow, and any other similarfitting, including a flexible connection fitting or flexible fixture fitting, that does not increase the internal cross-sectionai area of the conduit on which it is intended to be installed need not be

subjected to an explosion test if the fitting is

subjected to a pressure test in accordance with Table l3withoutrupturing orpermanentdeformation.

A flexible connection fitting or a flexible fixture fitting shall withstand the internal hydrostatic pressure specified in Table 13 without damage or leakage.

6.11.2 A box or a fitting subjected to explosion tests shall withstand, without rupture or permanent distortion, an internal hydrostatic test pressure not less than 4 times the maximum internal pressure obtained in the device during the explosion tests.

6.11.3* The maximum explosion pressure shall be measured

by a suitable pressure transducer installed at the fitting and ignition of the mixture shall be by a suitable spark plug installed in a 28 300 cm3 box. There shall be no rupture of the fitting as a result of these tests. For fittings up to and including 1-1/2 trade size, the tests shall be done with 2.5 and 3.3 m

lengths of conduit. For larger fittings, a 0.5 m

length of conduit shall be used. The test gas mixtures shall be in accordance with Clause 6.3. *Effective Date—May 31, 1988.

6.12 Adhesive Nameplates

6.12.1 The nameplate shall be installed on the intended panel or part of the equipment. The panel or part

shall be finished with the paint or coating normally applied.

6.12.2 The installation shall be exposed to a 50% saturated atmosphere of the following vapours for a period of 10 d: ethanol, ethyl acetate, ethyl ether, gasoline, methyl ethyl ketone, toluene, and vinyl acetate. It shall then be examined for lack of firmness of attachment or other deleterious effects. A fresh

sample shall be used for each test.

6.13* Test for Sealing Compounds

6.13.1 A sealing compound shall be capable of withstanding a pressure of 140 kPa (20 psi) without leakage in excess of 100 cm3/min and of withstanding a pressure of 5500 kPa (800 psi) without failure when tested in accordance with Clauses 6.13.2 and 6.13.3. The sealing compound shall remain intact and in

place.

6.13.2 The test apparatus shall consist of (a) a commercial iron pipe reducing coupling of 1/8 X 1/2 trade size; (b) a commercial pipe plug of 1/8 trade size; and

(C) a hydrostatic pressure test apparatus with a

pressure rating of 7000 kPa (1000+ psi) at a discharge rate greater than 100 cm3/min.

6.13.3 The following test method shall be used: (a) the pipe plug shall be fitted into the corresponding opening of the reducing coupling until itis flush with the inner surface of the coupling; (b) the sealing compound shall be prepared according to the manufacturer's directions and

poured into the reducing coupling to a depth of 16 mm (just below the 1/2 trade size thread); (c) the sealing compound shall be cured for 24 h at room temperature or according to the manufacturer's instructions; (d) the pipe plug shall be removed and visually examined for integrity of the seal; (e) the 1/2 trade size end of the reducing coupling shall be connected to the hydrostatic test machine; (f) the pressure shall be slowly increased to 140 kPa; (g) the pressure shall be maintained at this value for 1 mm and the leakage measured; and (h) the pressure shall be slowly increased to 5500 kPa and maintained for 1 mm. *Effective Date—November 30, 1987.

Explosion-Proof Enclosures for Use in Class I Hazardous Locations November 1988 (Replaces p. 19, November 1986 19

Tests



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Table I

Table 1* Joint Widths and Gaps for Enclosures

for Class I, Group B Hazardous Locations (See Clause 4.3.2 and Table 5.)

Size of enclosuret


Minimum of joint

width Maximum gap

Plain Stepped Plain Stepped


6.0 9.5

— 9.5

0.05 0.10

— 0.1

Above 100 cm3 and up and including 500 cm'

to 9.5 19 25

9.5 0.04 0.05 008

0.1

Above 500 cm3 and up and including 2000 cm3

to 16 9.5 004 0.1

Above 2000 cm3 and up to and including 6000 cmJ**

25 9.5 0.04 0.1

*Eflective Date—November 30, 1988 t The size of the enclosure shall be taken as the free internal volume (with the apparatus installed unless the enclosure is likely to be used without the apparatus). ln order to qualify for this joint, the cover or removable part shall have a thickness of at least 9.5 mm at the joint unless stiffened or reinforced metal of a lesser thickness has been found acceptable with respect to its physical strength and resistance to opening of the gap under internal pressure. § This maximum gap applies to operating rods only. **Enclosures larger than 6000 cm3 shall be the subject of investigation.

20 C22.2 No. 30-M1986

November 1988 (Replaces p. 20. November 1986)



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2

Table 12

Impact Test Levels (See Clauses 6.2.1 and

6.2.2.7, Table 11, and Figure 5.)

Tables 12 and 13

4 0.4 7 1.0 0.7

20 2.0 1.0

Note: h = E/Mg

where g 10 rn/s2 Ii is in metres E is in Iou/es M is in kilograms

Table 13 Overpressure Test Values, kPa

(See Clause 6.11.1.)

Type of fitting Class I, Groups A and B

Class I, Groups C and D

Conduit fitting up to 8000 4000 1-1/2 trade size

Conduit fitting 2 8000 4000 trade size and larger

Explosion-Proof Enclosures for Use in Class I Hazardous Locations November 1988 (Replaces p. 27, November 1986) 27

Mass (M), kg

0.25

Height (h), m

0.8



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Table 14* Explosion Tests

(Per Cent Test Mixture Mixed with Air)t (See Clauses 6.3.2, 6.3.3, 6.5.2, and 6.5.3.)

Explosion pressure test (Clause 6.3)

Flameproof test (Clause 6.5.2)

Flameproof test (Clause 6.5.3)

Class and group

Number of tests

Explosive test mixture

Number of tests


Number of tests


Class 1

Group A 5 Acetylene (C2H2)

14.5 0.5% — — 5 Acetylene (C2H2)

8.5 0.5%

Class 1

Group B 5 Hydrogen (H2)

32.0 1%

— — 5 Hydrogen (H2) 24.0 1.0%

Class 1

Group C 5 Ethylene (C2H4)

8.0 0.5% 5 Hydrogen (H2)

37.0 0.5% 5 Ethylene (C2H4)

6.5 0.5%

Class 1

Group D 5 Propane (C3H8)

4.6 0.3% 5 Hydrogen (H2)

55.0 0.5°Io

5 Propane (C3H8) 4.2 0.1%

Gaseous mines

5 Methane (CH4) 9.8 0.5%

5 Methane (CH4) Hydrogen (H2) 12.5 0.5% Ratio 58 1% CH4 42 1% H2

— —

* Effective Date—November 30, 1988 tMeasured by volumetric ratio at atmospheric pressure.


November 1988 27A

Table 14



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Figure 1

28

(C)

Figure 1

Typical Operating Rods (See Clause 4.3.4i.)

C22.2 No. 30-M1986 November 1988 (Replaces p. 28, November 1986)

(a) (b)



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General Instruction No. I C22.2 No. 30-M1986 November 1986

CSA Standard C22.2 No. 30-M1986, Explosion-Proof Enclosures for Use in Class I

Hazardous Locations, consists of 35 pages, each dated November 1986. This Standard, like all CSA Standards,. is subject to periodic review, and amendments

in the form of replacement pages may be issued from time to time; such pages will be mailed automatically to those purchasers who complete and return the attached card.* Some Standards require frequent revision between editions, whereas others require none at all. It is planned to issue new editions of the Standard, regardless of the amount of revision, at intervals not greater than 5 years. Except in unusual

circumstances, replacement pages will not be issued during the last year of that edition. * This card will appear with General Instruction No. 1 only.

Although any replacement pages that have been issued will be sold with the Standard, it is for the purchaser to insert them where they apply. The responsibility for ensuring that his or her copy is complete rests with the holder of the Standard, who should, for the sake of reference, retain those pages which have been replaced. Note: A General Instruction sheet will accompany replacement pages each time they are issued and will list the latest date of each page of the Standard.

Cut along dotted line.

Name

Organization

Address

City

Prov./State

Country________________ CSA Standard Postal/Zip Code ____________________ C22.2 No. 30-M 1986



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A not-for-profit private sector organization 178 Rexdale Boulevard, Rexdale (Toronto), Ontario, Canada M9W 1 R3

(416) 747-4000 Regional offices in Vancouver, Edmonton, Winnipeg, Montreal, Moncton

Printed in Canada



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C22.2 No 30 M1986 (2003)

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