ISrM24=196!I (ltemnd1993)

Indian Standard SPECIFICATION FOR

RUBBER MATS FOR ELECTRICAL PURPOSES

Seve~lth Reprint JANUARY 1998

( Incorporating Amendment No. t )

UDC 678.4- 494 : 621.315.616

@I copyright 1975

BUREAU OF INDIAN STANDARDS MANAK BHAVAN, PBAHADUR SHAH ZAFAR MARG

NEW DELHI lloo(n

Gr2 Ftbruat) 1970

15:!5424-1969

Indian Standard ( Remmd1993J)

SPECIFICATION FOR RUBBER MATS FOR ELECTRICAL PURPOSES

H&her Products Sectional Committee, CDC 6

Chabmon

DR D. RANWRJRR

H*prrscntinR

National Rubber Manufacturers Ltd, Calcutta; and Association of Rubber Manufacturers of India. Calcutta

Mcmbtrs

DR B. B. BHATIA I.C.I. ( India) Private Ltd? Calcutta SHRI D. K. CHATERJEE ( Alfernate )

Stunt S. K. BoSE National Test House, Calcutta Soar A. Gttostt ( Altemot~)

SHRI DALIP KUMAR Railway Board ( Ministry of Railways 1 SERI G. C. DE Export Inspection Council of India, Calcutta

S~trr P. K: CAATTERJEB ( Alfern&) SBRI S. L. GANDHI

SIIUI B. H. DALAL ( Ahnate) Ministry of Defence ( DC1 )

SHBI K. K. GANOULY Ministry of Defence ( R 8t D ) SRIII N. S. BANXER ( Altemofs)

DR P. Jortrr JACOB Rubber Board, Kottayam SHRI G. C. JAIN Hindustan Steel Ltd, Ranchi SRRI LALIT MoHAN JA?dNADAb The Cosmos India Rubber Works Private Ltd,

Bombay Snnt P~JLIN L. KINARIWALA ( Altmuf~ )

SHRI S. R. KOOHEAR Inspection Win

f;” l4

, Dis sals,

Directorate General of Supplies& ew Delhi

DR K. N. MODAX Indian ubber Manufacturers Research Associition, Bombay; and Indian Rubber Industries Associa- tion, Bombay

SHRI K. R. SENOUPTA (Alfmutr ) Indian Rubber Industries Association, Bombay SHRI S. MUKIIERJEE

SHRI G. P. DUTTA (Al&mats) The Dunlop India Ltd, Calcutta

SHRI S. C. NANDY Bata Shoe Co Private Ltd, Calcutta SARI M. M. PATaL Synthetics and Chemicals Ltd, Bombay DR A. SEETHARAMIAH Directorate General of Technical Development,

New Delhi DR N. A. C. RAO ( Altmafe)

( Confinurd 011 page 2 )

BUREAU OFINDIAN STANDARDS MANAK BHAVAN. 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

IS 1.5424 - 1969

Members

Sstax D. D. TALWALKAR

Rlplrmlin~

All India Automobile & Ancillary Industries Asmcia- tion, Bombay

SHRI R. M. KAALADKAR ( Alfcmafr ) SARI A. R. YAJNIK Indian Oii Gorporation Ltd ( Marketing Division )+

Bombay SHRI M. K. jAIN ( Al;emo* )

SABI D. DAM GUPTA, Director General, ISI ( fi-&io Membtr ) Director ( Chem )

secretary SHRI N. R. SRINIVASAN

Deputy Director ( Chem I, ISI

General Rubber Products Subcommittee, CIX 6 : 4

DB M. L. BEAUMIX

MNmbers

National Rubber Manufacturers Ltd, CaIcutta

SRBI D. Boss Bengal Waterproof Works ( 1940 ) Ltd, Calcutta SHaI A. BoaIs (Allemu&)

SEBI S. K. Boat National Test House, Calcutta Sanr A. GHO~A ( Altema&)

SBBI S. L. GANDRI Ministry of Dcfence ( DGI ) SARI B. H. DALAL ( Altmafr )

SHBI L. G. JAIN Central Water EL Power Commission, New DeIhi SHRI R. C. THUKRAL

SHBI S. V. LATHIA ( Altemuk

t thin Rubber Works Private Ltd, Bombay SBBI D. P. LATHIA ( Alfemate)

CAPX P. R. MAHAJAN SRRI V. P. CHADWA ( Ahmafe )

Ministry of Dcfence ( K UK D )

DR K. N. MODAK Indian Rubber IndusrriesAssociatinn. Bombay SHRI C. A. FAIEULI.BIIOY ( Alkmdc)

Sam S. C. NANDY Bata Shoe Co Private Ltd, Calcutta SHRI MANUBHAI M. PAT~L Rubbrex Industries Private Ltd. B&bay

SHIII K. C. SHAH (hmatr) SHRI M. M. PATP.L Syntbetica and Chemicals Ltd, Bombay SKUS V. D. PINDSE Swastik Rubber Products Ltd, Poona

SARI D. D. TALWALSAR ( Altmtar~) DR V. B. PHADKE National ChemicaI Laboratory ( CSIR ). P00rv

SHHX R. G. GOKHALE ( Alfmnc DB N. V. C. RAO &rectorate General of TechnicaI DeveIqsnast,

New Delhi SARI G. K. INAMIuR ( Altematr )

SRRI B. N. KAY The Dunlop Indii Ltd, Calcutta SHRI S. C. MUUX~AB ( Altemalr)

SERX B. ROY The East Indii Rubber Works Private Ltd. Calcutta &tar A. R. YAJNIK Indian Oil Corporation Ltd ( I&rketing -Division ).

fS:5424h69

Indian Standard SPECIFICATION FOR

RUBBER MATS FOR ELECTRICAL PURPOSES

0. FOREWORD

0.I This Indian Standard was adopted by the Indian Standards Institution on 24 October 1969, after the draft finalized by the Rubber Products Sectional Committee had been approved by the Chemical Division Council.

0.2 The need for standard on rubber mats for electrical purposes has been felt for quite a long time. This standard is expected to furnish the rubber industry with properties, test methods and sampling of rubber mats used as a floor covering around electrical apparatus whose voltage rating is 3 300 volts. It is not intended to imply that rubber mats should afford the sole means of protection for those working on electrical circuits. Wherever possible, further adequate precautions should be taken against the risk of shock and short circuit.

0.3 This standard is based on the following standards:

B.S. 921 : 1952 Rubber mats for electrical purposes. British Standards Institution.

ASTM Designation : D178-24 Rubber matting for use around electrical apparatus. American Society for Testing and Materials.

ZZ-M-8la : 1961 Matting: Rubber. and plastics ( for use around elec- trical apparatus or circuits not exceeding 3000 volts to ground). General Service Administration, US Federal Supply Service.

0.4 This standard comains clauses 2.2.2 and 3.2 which call for agreement between the purchaser and the supplier.

0.5 For the purpose of deciding whether a particular re uirement of this standard is complied with, the final value, observed or ? ca culated, express_ ing the result of a test or analysis, shall be rounded off in accordance with IS: 2-1960’. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

1. SCOPE

1.1 This standard prescribes the requirements, methods of sampling and test for solid rubber insulating mats for use as floor covering around electrical apparatus, not exceeding 3 300 volts to ground.

1.1.1 This standard does not cover perforated matting.

*Rules for rounding off numerical values ( w&d ).

3

IS : 5424 - 1969

2. REQUIREMENTS

2.1 Materials and Manufacture--The mats shall be made from vulcanized rubber compound free from fabric insertions and fibrous materials.

2.1.1 The upper surface may have a ribbed, fluted, or other suitable pattern or may be plain. The lower surface may be finished in cloth imprints. The outside edges, except the butt edges, whtre a mat consists of two or more sections, may be bevelled.

2.2 Dimensions

2.2.1 Thickness-Unless otherwise specified, the thickness of the plain mats shall be not less than 6.5 mm. Patterned mats shall be not less than 6.5 mm thick at the root of the pattern.

2.2.2 Length and IVidth-The length and width of the mats shall be as agreed to between the purchaser and the supplier.

2.3 Colour -The colour of the mats shall be black unless otherwise specified.

2.4 Workmanship and Finish -The material shall be free from blisters, pin holes, cracks, embedded foreign matters and other defects which may impair its serviceability, when visually examined.

2.5 Physical Properties

2.5.1 Tbsile Strength and Elongation at Break-The tensile strength and the elongation at break of the rubber shall be as follows:

Tensile strength, kgf/cm2, Min 50

Elongation at break, percent, Min 250

2.5.2 Comjvession Set- Compression set of the rubber shall not exceed 10 percent.

2.5.3 Ageing Properties - Th e tensile strength and elongation at break of the test samples, when subjected to ageing for 7 days at 70” f 1°C shall not exceed the following !imits of the corresponding values (see 2.5.1 J obtained before ageing:

Characteristic Percent Change from the Original Value

Tensile strength

Elongation at break

i

+ 10 - 25

{

-t 10 - 25

IS : 5424 - 1969

2.6 Electrical Properties

2.6.1 Voltage Z&-The mats shall withstand 15000 volts for 1 minute when tested according to the method prescribed in IS : 2584-1963*. The mats shall not puncture, become appreciably warm at any spot or show any other evidence of weakness. The leakage current shall not exceed 160 mA/m2 ( calculated on the area of the smaller electrode) for any position of the electrodes.

2.6.2 B7cakdown Strength-The mats shall not fail at less than 40000 volts when tested in air between electrodes, the voltage being applied to failure at the rate specified and tested according to IS: 2584-1963*.

2.7 Water Absorption -The mat shall not absorb water more than 4 mg/cmP when tested according to the method prescribed in 5.1.5

3. MARKING AND PACKING

3.1 Marking -Unless otherwise specified, the mats shall be marked with the following information:

a) Size and surface of matting (that is, plain or patterned); b) Rated potential followed by the word ‘Working’ in brackets; c ) Manufacturer’s name or trade-mark, if any; and dj Motith and year of manufacture.

3.1.1 The mats may also be marked with the Standard Mark.

3.1.2 The use of the Standard Mark is governed by the provisions of Bureau of Indian Standards Act, 1986 and the Rules and Regulations made thereunder. The details of conditions under which the licence for the use of Standard Mark may be granted to manufacturers or producers may be obtained from the Bureau of Indian Standards.

3.2 Packing -The mats shall be packed as agreed to between the purchaser and the supplier.

4. SAMPLING

4.1 Scale of Sampling and Criteria for Conformity - For the purpose ofascertaining the conformity ofthe material to this specification, the scaleof sampling alld criteria for conformity shall be as prescribed in Appendix A.

4.1.1 tinless otherwise specified carry out all the tests within three mnnths from the date of supply of the material.

*Method of test for electric strength of solid insulating materials at power frequencies.

5

IS : 5424 - 1969

5. TEST METHODS

5.1 Physical Tests

5.1.1 Tensile Strength and Elongation at Break-Test the material in accordance with the method prescribed in IS : 3400 ( Part I )-1965*.

5.1.2 A~ying-- Age the samples in an air oven at 70’ i 1°C in accordauce with the method specified in IS: 3400 (Part IV)-1965t.

9.1.3 Compression Set-C .arry (Part X)-19692 at 27” f 2°C.

out the test as prescribed in IS: 3400

5.1.4 Ekctrical Tests -Carry out electrical tests as prescribed in IS : 2$84- 19b35.

5.1.5 Water Absorption Test-Weigh a test piece, 2 cm square, with clean cut edges and immerse in distilled water (see IS : !070-19607) at a temperature of 27” f 2°C (see IS : 196 -196611) for 168 hours. Remove and superficially dry with blotting paper and immediately weigh in a stoppered weighing bottle. Express the increase in weight (water absorbed) as mg/cm* of the total surface (top, bottom and edges) of the test piece.

NOTE-III the case of patterned sampled buff off the pattern of the test piece to give a smooth surface before carrying out the test.

APPENDIX A ( Clause 4.1 )

SAMPLING AND CRITERIA FOR CONFORMITY OF RUBBER MATS FOR ELECTRICAL PURPOSES

A-l. PROCESS INSPECTION

A-l.1 Quality and reliability can be built into the product during the course of production by reducing the quality fluctuations td the minimum

*Metho& of test for vulcanized rubben: part I Tensile stress-strain properties. *Methods of test for vulcanized rubk Part IV Accelerated ageing. $Methoda of test for vulcanixxl rubbers: Part X Compression set. IMethod of test for electric strength of solii ins+ing materials at power frequencies. ~Specification for water, distilled quality (rwkd ). I/Atmospheric conditions for testing ( mkd ).

6

IS:!5424-1969

through application of statistical quality control techniques (set IS : 397- 19X*: at all stages of manufacture including the ccjntrol of raw materials. When adequate process control is maintained by the manufacturer, the product will have little chance of rejection during lot inspection.

A-l.2 The requirements like thickness, tensile strength, elongation at break and compression set are suitable for control by the use of control chart for averages and ranges. The surface defects can be controlled by the use of control chart for number of defects.

A-2. LOT INSPECTION

A-2.1 Lot - In a single consignment of rubher mats all the rolls ofthe same colour. size, thickness and rated potential belonging to the same batch of manufacture shall be grouped together to constitute a lot.

A-2.2 For ,judging conformity to this specification each lot shall be considered separately. For this purpose a number of rolls shall be taken at random from the lot .in accordance with rd 1 and 2 of Table 1.

TABLE1 SCALE OFSAMPLING

F;o. OF ROLLS S.4DfPI.E SIZE M THE LOT TOHVlsUAL

ANDDIMEN-

(1) (2)

AOXPTASGE NO.

l .4s agreed to between the purchaser and the rupplier.

SUB-SAXPLE SIZE SUB-SAYPLE SUE

FOR k%lYSlCAL ~ORELECTBICAL CHARACTRRISTIC~ TlCsTs

ANDWATER ABBORPWON

(4) (5)

A-2.2.1 In order to ensure random7 selection of rolls from the lot the random number tables shall be used. In case random number tables are not available the following procedure may be adopted:

Starting from any roll count all the rolls in the lot in one order as 1, 2, 3,. . . . . , etc, up to r and so on where r is the integral part of N/n. Every rth roll thus counted shall be withdrawn to constitute the sample.

Wethod for statistical quality control during production by the use of control chut ( rcntutim 1. ( Since revised ).

t&r ulso IS : 4905 - 1968 Mrthods for random sampling.

7

IS : 5424 - 1969

A-2.3 Number of Tests and Criteria for Conforlihity - Each of tile rolls selected in A-2.2 from the lot shall be inspected for visual and dimensional properties ( see 2.1 to 2.4). The number of defective mats shall not exceed the acceptance number given in co1 3 of Table 1 if the lot is to be accepted under this clause.

A-2.3.1 The lot’ having satisfied the visual and dimensional requirements shall then be tested for physical requirements in 2.5 and 2.7. For this purpose a sub-sample of rolls as in co1 3 of Table 1 shall be taken from the sample already selected. Each of the rolls in the, sub-sample shall 1)~ tested for all the physical requirements in 2.5 and 2.7. The lot shall. be declared to conform to the requirements of this specificatioq if each of the rolls in the sub-sample satisfies all the requirements in 2.5 and 2.7.

A-2.3.2 The number of mats to be tested for electrical properties is given under co1 5 of Table 1. There shall be no failures if the lot is to be declared acceptable for these properties.

BUREAU OF INDIAN STANDARDS

Headquarters Mar& Bhavan, 9 Bahadur Shah Zafar Marg, NEW DELHI 110002 Telephones: 323 0131 I 323 3375.323 9402 Fax t 91 11 3234062, Ql 11 3239399, 91 11 3239382

Central Laboratory : \

Plot No. 20/Q, Site IV, Sahibabad industrial Area, Sahibabad 201010

Regional Offices:

Telegrams : Manaksanstha (Common to all Offices)

Telephone

8-77 06 32

Central : Manak Bhavan, 9 Bahadur Shah Zafar Marg, NEW DELHI 110002 32376 17

*Eastern : l/14 CIT Scheme VII M, V.I.P. Road, Maniktola, CALCUTTA 700054 337 86 62

Northern : SC0 335-336, Sector 34-A, CHANDIGARH 160022 60 38 43

Southern : C.I.T. Campus, IV Cross Road, CHENNAI 600113 23523 15

tWestern : Manakalaya, EQ, Behind Marol Telephone Exchange, Andheri (East), 832 92 95 MUMBAI 400093

Branch Offices::

‘Pushpak’, Nurmohamed Shaikh Marg, Khanpur, AHMEDABAD 380001 550 13 48

$Peenya Industrial Area, 1 st Stage, Bangalore-Tumkur Road, 839 49 55 BANGALORE 560058

Gangotri Complex, 5th Floor, Bhadbhada Road, T.T. Nagar, BHOPAL 462003 55 40 21

Plot No. 62-63, Unit VI, Ganga Nag&, BHUBANESHWAR 751001 40 36 27

Kalaikathir Buildings, 670 Avinashi Road, COIMBATORE 641037 21 01 41

Plot No. 43, Sector 16 A, Mathura Road, FARIDABAD 121001 8-28 88 01

Savitri Complex, 116 G.T. Road, GHAZIABAD 201001 8-71 19 96

53/5 Ward No.29, R.G. Barua Road, 5th By-lane, GUWAHATI 781003 54 11 37

5-8-56C, L.N. Gupta Marg, Nampally Station Road, HYDERABAD 500001 201083

E-52, Chitaranjan Marg, C- Scheme, JAIPUR 302001 37 29 25

117/418 8, Sarvodaya Nagar, KANPUR 208005 21 68 76

Seth Bhawan, 2nd Floor, Behind Leela Cinema, Naval Kishore Road, 23 89 23 LUCKNOW 226001

NIT Building, Second Floor, Gokulpat Market, NAGPUR 440010 52 51 71

Patfiputra Industrial Estate, PATNA 800013 26 23 05

Institution of Engineers (India) Building 1332 Shivaji Nagar, PUNE 411005 32 36 35

T.C. No. 14/l 421, University P. 0. Palayam, THIRUVANANTHAPURAM 695034 621 17

*Sales Cffice is at 5 Chowringhee Approach, P.O. Princep Street, CALCUTTA 700072

tSales Cffice is at Novelty Chambers, Grant Road, MUMBAI 400007

*Sales Cffice is at ‘F’ Block, Unity Building, Narashimaraja Square, BANGALORE 560002

271085

309 65 28

222 39 71

Reprography Unit, BIS, New Delhi, India

AMENDMENT NO. 2 MARCH 1984

TO

IS : 5424 - 1969 SPECIFICATION FOR RUBBER MATS FOR ELECTRICAL PURPOSES

Alteration

( Page 4, clause 2.2.1, seeond line ) - Substitute ’ 6.5 & 0.5 mm ’ for ‘ 6.5 mm ‘.

(PCDC 13)

Reprography Unit, BIS. New Delhi, India

\ At4!NDtZNT NO. 3 MARCH 1986

TO

IS:5424-1969 SPECIFICATION FOR RUBBER MATS FOR ELECTRICAL PURPOSES

This Amendment No. 3 supersedes Amendment No. 2.

(Page 4, c'lause 2.2.1, line 2) - Substitute '6.5 + 0.05 mm' for 'not less than 6.5 mm'. 'ii.

(FCDC 13)

Reprography Unit, BIS, New Delhi, India

AMENDMENT NO. 4 NOVEMBER 1987

TO

IS:5424-1969 SPECIFICATION FOR RUBBER MATS FOR ELECTRICAL PURPOSES

(Page 6, clause 5.1.3) - Substitute the following for the existing clause:

'5.1.3 Compression Set I Carry out the test as pre cribed

8 in IS:3400(Part lOI-1977)-at 2722°C for

2452 hours.' /

I *lethods of test for vulcanized rubbers: Part 10

.’ Compression set at constant strain !,

(first revision).

i

1 (PCDC 13)

Reprography Unit, BIS, New Delhi, India

-- *

i AMENDMENT NO. 5 MARCH 1995

TO ‘IS 5424 : 1969 SPECIFICATION FOR RUBBER MATS

FOR ELECTRICAL PURPOSES

(Page 4, clause 25.2, line 1 ) - Substitute ‘20’ for ‘10’.

PCD 13 ) -- -__ --_- Reprography L!nit, BIS, New Delhi, India