BUREAU OF INDIAN STANDARDS

Transcription

1 Manak Bhavan, 9 Bahadur Shah Zafar Marg New Delhi 000 BUREAU OF INDIAN STANDARDS Phones Etn 484 TeleFa Website : eetd@bis.org.in य प च ल म स द स द भ र ख रषण स ञ म ईट ड 0/ट -54 ददम प तपम प सम तत ई ट ड 0 र षत :. ईट ड 0 क सभ सद य. व य त तकन क व भ ग पर षद क सभ सद य त 3. च खन ल अ य सभ नक य मह दय, क य न नललखखत मस द स ल न ह : रल ख श षषक ईट ड 0 व ध त रय नम प म ए व ध त ध ट व म टट (आई एस 565 प ह म षण ) (668) अपन स म तय यह तत त ह भ औ क अ तत: य द यह म नक क प म रक लशत ह स प अमल क न मऔ आपक य स य अ क त मऔ य क न य आ सकत ह क य त स मस द क अ ल कन क औ स म तय भ न क अ तम त ख : य _ स म तय य द क ई ह त क य अगल प प द प मऔ अ ह त क रपर ललखखत पत प भ य द क ई स म त र त नह ह त अ स म त मऔ क ल भ ष स त दऔ ट ह ई त रप त रल ख क य त अ त म प दय ग य द क ई स म त तकन क रक त क ह ई त व षय सलम त क अ य क प मशष स अ रनक प आग क क यष ह क लल व षय सलम त क भ न क त द रल ख क अ त म प द दय ग य द, भ द य, न भ ञ नक फ रम ख (व य त तकन क ) स ल न : रपर ललखखत

2 BUREAU OF INDIAN STANDARDS Manak Bhavan, 9 Bahadur Shah Zafar Marg New Delhi 000 Phones Etn 484 TeleFa Website : eetd@bis.org.in DRAFTS IN WIDE CIRCULATION Document Despatch Advice REFERENCE DATE ETD 0/ T TECHNICAL COMMITTEE: ETD 0 ADDRESSED TO:. All Members of Solid Electrical Insulating Materials and Insulating Systems Sectional Committee, ETD 0;. All Members of Electrotechnical Division Council; and 3. All other Interested. Dear Sir(s), Please find enclosed a copy of the following draft Indian Standard: Doc No. Title: ETD 0(668) Insulating Mats For Electrical Purposes Specification (First Revision of IS (565) Kindly eamine the draft standard and forward your views stating any difficulties which you are likely to eperience in your business or profession, if these are finally adopted as Indian Standards. Comments, if any, may please be made in the format given overleaf and mailed to the undersigned. Last date for comments: _ In case no comments are received or comments received are of editorial nature, you will kindly permit us to presume your approval for the above document as finalized. However, in case of comments of technical in nature are received then it may be finalized either in consultation with the Chairman, Sectional Committee or referred to the Sectional Committee for further necessary action, if so desired by the Chairman, Sectional Committee. Thanking you, Yours faithfully (Rajeev Sharma) Sc E & Head (Electrotechnical) Encl: As above

3 Manak Bhavan, 9 Bahadur Shah Zafar Marg New Delhi 000 BUREAU OF INDIAN STANDARDS Phones Etn 484 TeleFa Website : eetd@bis.org.in Date Sl. No. Name of the Organization Clause/ Subclause Paragraph/ Figure/Table Type of Comment (General/ Technical/ Editorial Document No. Doc: ETD 0(668) Comments Proposed Change

4 Solid Electrical Insulating Materials and Insulating Systems Sectional Committee, ETD 0 FOREWORD This draft Indian Standard (first revision) is proposed to be adopted by the Bureau of Indian Standards, after the draft finalized by the Solid Electrical Insulating Materials and Insulation Systems Sectional Committee is approved by the Electro technical Division Council. The Standard was first published in 006. This revision is being carried out to incorporate the amendments published subsequently as well as for updating the standard in line with the IEC 6 : 009. The significant changes in this revision include addition of new requirements viz. compression set, mechanical puncture resistance and slip resistance. For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, epressing the result of a test or analysis, shall be rounded off in accordance with IS : 960 Rules for rounding off numerical values (revised). The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard. i

5 Doc: ETD 0(668) BUREAU OF INDIAN STANDARDS DRAFT FOR COMMENTS ONLY (Not to be reproduced without the permission of BIS or used as Indian Standard) Draft Indian Standard INSULATING MATS FOR ELECTRIAL PURPOSES SPECIFICATION (First Revision) Last date for receipt of comments is SCOPE. This Indian Standard is applicable to electrical insulating mats made of elastomer for use as a floor covering for the electric protection of workers on electrical installations. Please refer Table for classification and voltage ratings.. It prescribes the requirements for the performance of the product, method of sampling, application, testing, and acceptance..3 While the human safety is the prime concern while developing this standard, it is clear that final safety of the worker is only obtained by considering also work methods, training of personnel and their safety issues which are not in the scope of the standard..3. The spread of the mat to be used for a certain work, the working methods, the care to be taken during use, and periodic checks are some of the elements which will have influence on the final performance of the mat for the intended objective and shall be taken care of by the users. Hence, the Anne A In-service Recommendations is not the mandatory part of the standard and is informative in nature to get the optimum results from the mat procured as per the standard. REFERENCES The standards listed in Anne B contain requirements which, through reference in this tet, constitute provisions of the standard. At the time of publication, the editions indicated were valid. All standards are subject to revision and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards listed in Anne B. 3 TERMINOLOGY For the purpose of this standard, the following definitions shall apply. 3. Elastomer Macromolecular material which returns to its initial dimensions and shape after substantial deformation by a weak stress and release of the stress. NOTES The definition applies under room temperature test conditions.

6 Elastomer is a generic term that includes rubber, late and elastomeric compounds that may be natural or synthetic or a miture or a combination of both. It also includes thermoplastic elastomer (TPE) material. 3. Type Test A test on one or more devices made to a certain design to show that the design meets certain specifications. 3.3 Routine Test A test to which individual device is subjected during or after manufacture to ascertain whether it complies with certain criteria. 3.4 Sampling Test A test performed on a number of devices taken at random from a batch. 3.5 Acceptance Test A contractual test to prove to the customer that the device meets certain conditions of its specification. 3.6 Proof Test Voltage A specified voltage that is applied to a device for the time defined under specified conditions to assure that the electrical strength of the insulation is above a specified value. 3.7 Flashover An arc by-passing an insulating body and occurring between electrodes either over or around, but not through, the insulating body being tested. 3.8 Nominal Voltage A suitable approimate value of voltage used to identify a system. 3.9 Temperature Standard electrical insulating mat should be used in areas having ambient temperatures between 5 C and +55 C and category t (resistant to etremely low temperature) mat in temperatures between 40 C and +55 C. 4 CLASSIFICATION AND DESIGNATION The electrical insulating mats covered by this standard shall be designated as follows: i) by electric class as given in 4. ;and ii) by adding suffices in case of special property mats as given in Three classes of mats, covered under this standard and differing in electrical characteristics for different use voltages are designated as given in Table. Table Classes, Nominal and Maimum Use Voltages (Clause 4.) S.No. Class () i) ii) iii) () A B C Nominal ac (r.m.s.) kv (3) dc (V) (4) 40 * * NOTES a) The maimum use voltage is the voltage rating of protective equipment that designates the maimum nominal voltage of the energized system that may be safely worked. On multiphase circuits, the nominal voltage is equal to phase-to phase voltage. 3

7 b) * Not standardized. However in general it is safe to use up to.4 times the corresponding ac voltage. 4. Mats of all classes shall be resistant to acid, transformer oil and low temperature. Mats with special property of resistance to etreme low temperature shall be identified by a subscript t. Mats, with special property of resistant to alkali shall be identified by a subscript b. Mats, with special property of resistant to HSD shall be identified by a subscript h. 5 COMPOSITION The electrical insulating mat shall be manufactured of elastomer. The side of the electrical insulating mat on which the worker may stand, shall be slip resistant. Any insert shall not affect adversely the dielectric characteristics of the electrical insulating mat. 6 PHYSICAL REQUIREMENTS 6. Shape There is no stipulated requirement for the shape of the electrical insulating mat. Electrical insulating mat may be either of various shapes or in rolls to be cut for individual applications. 6. Dimensions Length and Width Electrical insulating mat shall not have length and width less than 000 mm. Rolls of mat in multiple lengths of mm and in width of 000 mm are preferred in order to minimize the joints. However, the insulating mats of specific shapes in lengths of 000, 000, mm and in width (not less than 000 mm) shall be as agreed between the purchaser and the supplier. The dimensions shall be verified with the mat in flattened condition. 6.. Tolerances Manufacturers shall provide mat length and width as per 6.. Dimensions of each mat shall be within a tolerance of ± % of the stated dimensions. 6.3 Thickness 6.3. Unless otherwise specified, the minimum thickness of the mats of the different classes, when measured as described in C-, shall be as given in Table 3. Table 3 Minimum Thickness of Mats (Ecluding Slip Resistance Design) for Different Classes (Clause 6.3) S.No. Class of Mat i) A Minimum Thickness (mm).0 ii) B.5 iii) C 3.0 4

8 6.3. Wherever, higher clearance is available in front and rear portion of the electrical installation, mats with higher thickness and passing the tests defined in this standard can be used on agreement between the supplier and the purchaser. Manufacturers of such mats shall declare that thickness and the tolerances of ±0 percent shall be applicable on the declared thickness. The slip resistance material shall not be more than 3 mm deep. 6.4 Colour Colour shall be as agreed to between the purchaser and the supplier. However no colour with metallic derivatives shall be used. 7 WORKMANSHIP AND FINISH 7. Mats shall be free on both surfaces from harmful physical irregularities that can be detected by thorough test and inspection. Harmful physical irregularities shall be defined as any feature that disrupts the uniform, smooth surface contour, such as pinholes, cracks, blisters, cuts, conductive embedded foreign matter, creases, pinch marks, voids (entrapped air) and prominent ripples. Non-harmful physical irregularities defined as surface irregularities present on either surface of the mat due to imperfections on forms or moulds or other imperfections inherent to the manufacturing process shall be acceptable. These irregularities appear as mould marks that look like cuts, even though they are actually a raised ridge of elastomer, indentations, or protuberances. 8 PROPERTIES 8. Mechanical Properties 8.. Tensile Strength and Elongation at Break The minimum tensile strength and elongation at break of mats of all classes, measured, as described in C- shall be as given in Table 4. Table 4 Mechanical Properties of Mats (Clause 8..) S.No. () i) Tensile Strength (N/mm) Elongation (%) () 5 (3) Mechanical Puncture resistance This test shall be carried out as described in C Test for Slip Resistance This test shall be carried out as described in C Compression Set Test The compression set shall not eceed 0%, when measured as described in C-5. 5

9 8. Di-Electric Properties 8.. Insulation Resistance with Water Minimum insulation resistance for class A mats shall be G Ω when measured with 500V dc megger and G Ω when measured with V dc megger for all other classes of mats, when measured as described in C Leakage Current The maimum value of the leakage current for all classes of mats shall not be more than 60 ma/ m, when measured as described in C ac Di-electric break down voltage. Minimum di-electric strength of the mats for different classes shall be as given in Table 5, when measured as described in C-6.3 S.N. Table 5 Di-electric Break Down Voltage of Mats for Different Classes (Clause 8..3) Class Di-electric breakdown Strength ac(rms) (kv) () i) ii) iii) 8..4 () A B C (3) ac Proof Voltage Mats of Different classes shall withstand proof voltage as given in Table 6, when using electrodes and applying the voltage as described in C-6.4. The test is deemed successful, if the specified test voltage is reached and maintained for 3 min for the type and sampling test and min for the routine test without becoming appreciably warm at any spot. Table 6 ac Proof Voltages of Mats for Different Classes (Clause 8..4) 8.3 S.No. Class () (i) (ii) (iii) () A B C Proof Voltage ac (rms)kv (3) 0 36 Ageing Properties 6

10 Tensile strength and elongation at break and mechanical puncture test, when measured after subjecting the mat to aging for 68 h at 70 ± C as described in C-7 shall not be less than 75 percent of the corresponding values obtained for un-aged test piece from the same lot. 8.4 Thermal Properties 8.4. Flame Retardation This test shall be carried out as described in C-8.. This test shall be considered as passed if the flame does not reach any point on a 50 mm diameter circle from the center of the test piece, during the observation period Low Temperature Resistance Mats of all classes shall not show any visible break or crack when folded after placing for one hour at a temperature of -0 ± 3 C as described in C-8.. The mats shall subsequently withstand the test for ac proof voltage as per Acid, Alkali, HSD and Transformer Oil Resistance Following the conditioning in acids, transformer oil, alkalis, and, HSD (see Note) as described in C9, the resulting mechanical deterioration and chemical damage on the mats of all classes shall be determined by measuring values as given in mechanical tests. The values obtained for these shall not be less than 75 percent of the corresponding mechanical test values obtained in tests carried out on samples from same batch without conditioning. Notes ) Tests for resistance to acids and transformer oil are applicable to all mats. ) Tests for alkali and HSD resistance is applicable to only those mats with special property of resistant to alkali and HSD respectively (see 4.). Etreme Low Temperature (For Mats With Subscript t Only) 8.6 Mats of all classes with special resistance for etreme low temperature for usage in etreme low ambient conditions shall not show any visible tear, break or crack when folded under force of 00 N for 30 s after conditioning a chamber for 4 ± 0.5 h at a temperature of -40 ± 3 C as described in C0. These shall also pass the proof voltage test as per Note This test shall be applicable to mats with special property of resistant to etreme low temperature only (see 4.). 9 MARKING 9. Every roll/flat shall be marked at every m interval with following: a) b) c) d) e) 9. class and subscripts (wherever applicable); thickness; lot no.; roll No. and; manufacturer s identity BIS Certification Marking The product may also be marked with the Standard Mark. 7

11 9.. The use of the Standard Mark is governed by the provisions of the Bureau of Indian Standards Act, 986 and the Rules and Regulations made there under the details of conditions under which the license for the use of Standard Mark may be granted to manufacturers or producers may be obtained from the Bureau opt Indian standards. 0 PACKING The mats shall be packed either in rolls or flats and shall not be distorted mechanically. In case of rolls material should be rolled smoothly on hollow mandrel made of either hard cardboard or waste plastic, of diameter 50 mm or higher. The material shall be wound tightly and the edges of top most layer should not shift from the edge of st bottom layer by more than 75 mm. The roll should be clamped at places with the help of plastic unidirectional tape and clamps. Gunny/jute material should be used, if material has to be transported over long distances or has to be dispatched through local transportation to avoid any kind of damage to the material. Over the gunny/jute material, proper plastic bag having liming of suitable fabrics should be used. TESTS ON MATS. General.. Unless otherwise specified, the mat shall be pre-conditioned for a period of ± 0.5 h at a temperature of 7 ± deg. C and relative humidity of 50 ± 5 percent... Test methods are described in Anne C...3 The classification of tests-type, routine and sampling to be carried out for different requirements/properties of the mats, the number of mats required for type tests and the allotment of the mats in various testing lots are given in Anne D and Anne E.. Acceptance Testing/Conformity to Standard.. In order to assure the delivery of the mats that meet this standard, the manufacturer shall employ an approved quality assurance plan. This quality assurance plan shall ascertain that the mats meet the requirement contained in the standard. Acceptance testing consisting of routine tests to be carried out on each unit and/or on sampling of units (sampling tests) and the sampling size must be agreed to between the supplier and the purchaser... In the absence of an accepted quality assurance plan, for the purpose of ascertaining the conformity of mats to this standard, the acceptance tests are those (both routine and sampling) specified in the standard and must be carried out as per sampling plans given in Anne E. 8

12 ANNEX A (Clause.3.) A- IN-SERVICE RECOMMENDATIONS The following is for guidance only for the use, maintenance, inspection and retest of insulating mat during service after purchase to ensure highest level of safety: a) Storage Mats should be stored in its container or package. Care should be taken to ensure that the mats are not compressed, folded or stored in proimity to steam pipes, radiators or other sources of artificial heat or eposed to direct sunlight, artificial light or other sources of ozone. It is desirable that the ambient temperature is between 5 C and +55 C. b) Eamination Before Use before use, each mat should be visually: both top and bottom surfaces along with type test report from accredited lab. If, the mat is apparently unsafe, it shall not be used and should be returned for testing. c) Recommendations for Use of mats For obtaining maimum practical safety in adverse working conditions, the mat may be pasted with the help of suitable adhesive/resin, which does not energize in the applied range. All joints and corners shall be filled/covered with insulating material of matching color. Matching color and matching designed tapes should be used to maintain an aesthetic look of the installation over the joints and corners. Wherever the floor is porous in nature and attracts moisture, water proofing compound is recommended to be used to protect insulating and electrical properties. i) Alternatively butt joints may be welded by thermo-fusion method by making a V groove cut at the joint as per IS 800. ii) Mats should be washed with soap and water periodically at temperature not eceeding recommended temperature of use. Contact with petrol/paraffin or white spirit and string acid/alkalis should be avoided. In case of any drop out these be removed immediately for longer life. Dust of any kind, especially coal/cement must be removed regularly. Any paint mark should be removed immediately without ecessive use of thinner. d) Recommended Areas of use All kinds of electric sub-stations, transformers rooms, lift machine rooms, switch rooms, electrical panels, ac plant rooms, X-ray plant rooms, LT/HT Labs, around bus bars, generator rooms, etc. e) Periodic Inspections A yearly visual inspection is recommended. 9

13 ANNEX B (Clause ) LIST OF REFERRED INDIAN STANDARDS IS No. 076 : (Part I) : : (Part I) : (Part X) : : (Part 7): 984 IS 0888 : 984 Title Specification for unsupported fleible polyvinyl chloride sheeting (first revision Sampling procedure for inspection by attributes : Part-I Sampling schemes indeed by acceptance quality limit (AQL) for lot-by-lot inspection Method of test for electric strength of solid insulating materials at power frequencies Methods of test for vulcanized rubbers: Part tensile stress strain properties (second revision) Methods of test for vulcanized rubbers: Part 0 compression set at constant strain Recommended procedure for welding of fleible PVC Methods of test for cables: Part 7 Tensile strength and elongation at break of thermoplastic and elastomeric insulation and sheath. Method for determination of resistance to slipping of gymnastic mats and surfaces for floor eercises 0

14 ANNEX-C (Clauses 6.3, 8.., 8.., 8..3, 8..4, 8.., 8.., 8..3, 8..4, 8.3, 8.4., 8.4., and..4) TEST METHODS C-I THICKNESS Thickness shall be measured with help of venire caliper/screw gauge or alternative instrument, giving substantially same results. Thickness measurements shall be made at five or more points approimately uniformly distributed over the total area of the mat. The instrument should be graduated within 0.0 mm and during measurement sufficient support shall be given to mat so that it will present an unstressed flat surface between the two faces of the measuring instrument. C- TENSILTE STRENGTH AND ELONGATION AT BREAK Five dump-bell test pieces shall be prepared in accordance with IS080 (Part 7). Before the tensile test, the gauge length of 0 mm shall be marked by the two lines centrally on each specimen. The rate of separation of jaws (grips) shall be 50 ± 50 mm/min. The tensile strength and elongation at break shall be determined by measuring the distance between the two marker lines at the instant of the break that is the separation of the gauge marks at break. This distance is used to calculate the percentage elongation at break, based on the original gauge length. The breaking load at which the test piece breaks is also recorded for each piece. C-. Calculation For individual specimen A=w*t Where, w =width of the test piece within gauge length, in mm; and t = thickness of test piece, in mm. NOTE - In case of taper cutting w of both side should be measured and average of it should be taken as w. C-. Tensile Strength (N/mm) = F/A C-.3 Elongation at Break (in Percent) = [(G- G) / G] 00 Where G = original gauge length, in mm; and G = separation of gauge marks at break, in mm. At least five test pieces shall be taken, result shall be processed as per IS 076 or IS 3400 (Part ) or other relevant Indian Standard depending upon the chemical nature of the material of the mat. C-3 MECHANICAL PUNCTURE TEST This test shall be carried out on both sides of the mat.

15 Two circular test pieces 50 mm in diameter shall be cut from the electrical insulating mat and each shall be clamped between two flat 50 mm diameter test plates such that one test piece is perforated from one side and the other test piece is perforated from the other side. The top plate shall have a circular opening 6 mm in diameter and the bottom plate a 5 mm diameter circular opening. The edges of both openings shall be rounded to a radius of 0.8 mm (see Figure ). A needle shall be produced from a 5 mm diameter metallic rod and one end shall be machined to produce a taper with an included angle of and with the tip rounded to a radius of 0.8 mm (see Fig ). The needle shall be clean at time of use. The needle shall be positioned perpendicularly above the test piece (clamped between the plates) and shall be driven into and through the specimen. The rate of traverse shall be 500 mm/min ± 50 mm/min. The force required to perform the puncture shall be measured. The test shall be considered as passed if the puncture resistance is greater than 70 N. Dimensions in millimetres ecept for angles Key Top plate Bottom plate

16 3 Needle Fig. TEST PLATES AND NEEDLE FOR RESISTANCE TO MECHANICAL PUNCTURE C-4 TEST FOR SLIP RESISTANCE C-4. The test shall be performed according to IS 0888 with the following provisions: a) The test shall be carried out on a test piece of insulating electrical mat of 600 mm 600 mm b) The test shall be carried out on the slip resistant side of the test piece c) Before testing, slip resistant surface of the test piece shall be cleaned with isopropanol and allowed to dry completely before continuing the test. C-4. The cylindrical friction piece specified in IS 0888 shall be replaced by a test cube specified as follows: a) Bearing-surface area after rounding the edges: 00 mm 00 mm ± 0.5 mm b) Material of the bearing-surface area: stainless steel for general use (such as martensitic), with a minimum chromium (Cr) content of percent (to avoid oidation) c) Surface teture of the bearing-surface area: roughness average Ra = 0.8 µm d) Roundness of the edges at right angles to tensile direction: r = mm e) Weight of the total test cube: 5 kg ± 5 g. The test shall be considered as passed if the average tensile force F for each side and direction of the test piece is higher than 50 N. C-5 COMPRESSION SET TEST The test shall be performed according to IS 3400 (Part 0) : 977. The cut piece of the mat [specimen of size 30 mm dia] is compressed to 5 % of its original thickness (Ti) measured using a dial thickness gauge having accuracy of 0.0 mm and the assembly of compression set apparatus is conditioned at 70 C for4 h. After taking out from the oven, the compression force is released and the specimen is conditioned at ambient temperature for 30 minutes following which the final thickness (Tf) shall be measured immediately. The percentage compression set shall be determined using the following formula: Compression set ( % )= [(Ti Tf)] / (Ti 0.75 Ti)]*00 Where, Ti = original thickness Tf = final thickness The test shall be passed if percentage compression set eceeds not more than 0 percent. C-6 DI-ELECTRIC MEASUREMENTS C-6. Insulation Resistance with Water Two test pieces measuring 50 mm 50 mm shall be cut out of mat. After 4 hours of immersion in water, the sample shall be taken out, wiped to remove ecess water and shall be sandwiched between 3

17 two electrodes of 5 mm diameter and 75 mm diameter to measure the insulation resistance after min of application of 500 V DC voltage. All dimensions in millimeter Fig. SETUP FOR INSULATION RESISTANCE TEST C-6. Leakage Current Two test pieces in size of 50 mm 50 mm shall be placed in insulating oil and electrodes as prescribed in 5.. of IS 584 shall be used to measure the leakage current by application of maimum use voltage for the mat under testing. C-6.3 ac Breakdown Voltage Five test pieces in size of 50 mm 50 mm shall be immersed in insulating oil at ambient temperature. Di-electric breakdown voltage shall be measured in oil with the help of electrodes as per 5.., 7.. and 8 of IS 584. C-6.4 ac Proof Voltage A 70 mm 70 mm sheet of insulating material 3 mm to 5 mm thick which has a 76 mm 76 mm opening in the center, shall be placed on a grounded metal plate. This mask which has a picture frame appearance shall have the opening filled so as to bring the ground electrode to approimately the same level as the mask in order to maintain direct contact with the mat to be tested. 4

18 The mat or test piece shall be placed over the mask. A rectangular metal plate, 76 mm 76 mm and approimately 5mm thick, having smoothly rounded edges and corners, shall be placed on top of the mat or test piece. This top plate shall then be energized with the test voltage refer Fig. below. All dimensions in millimeters. Fig. TEST ELECTRODE FOR MAT Mat shall be given a voltage test as specified in Table 6 (see 8..4) using electrodes as described above. The ac voltage shall be initially applied at a low value and gradually increased at a constant rate-ofrise of approimately 000 V/s until the specified test voltage level is reached. The test period shall be considered to start at the instant the specified voltage is reached. The test is deemed successful if the specified test voltage is reached and maintained for 3 min for the type and sampling tests and min for the routine test. For type and sampling the mats shall be conditioned for moisture absorption by immersion in water for a period of 6±0.5h at ambient temperature. For routine tests such conditioning is not required. NOTES.. This method will test a 76mm 76 mm area of a 000mm 000mm mat at 40 kv ac r.m.s. as the mask prevents flashover. At the end of the test period the applied voltage should be reduced to approimately half value before opening the test circuit unless an electrical failure has already occurred. C-7 AGEING Subsequent to subjecting the mat to aging as described in 8.3, the tensile strength and elongation at Cbreak shall be measured as described in the C- and mechanical puncture resistance shall be measured as described in C-3. C-8 THERMAL PROPERTIES C-8. Flame Retardance The test shall be carried out in draught-free room or chamber. A test piece of 50 mm 50 mm shall be cut from the mat and mounted horizontally and centrally, 40mm above a gas burner and held by suitable clips. 5

19 The gas supply shall be technical grade methane gas with a suitable regulator and meter to produce a uniform gas flow. The nozzle of a burner shall have a diameter of 9.5 ± 0.5 mm to produce a 0 ± mm high blue flame. The burner is placed remote from the test piece, ignited and adjusted in the vertical position to produce a blue flame 0 ± mm high. The flame is obtained by adjusting the gas supply and air influ of the burner until a 0 ± mm yellow-tipped blue flame is produced and then the air supply is increased until the yellow tip dis-appears. The height of the flame is measured again and corrected, if necessary. The burner shall then be placed centrally below the test piece for 0 s to cause the fire on the mat and then withdrawn. It should be ensured that no air draught interferes with the test. The propagation of the flame on the test piece shall be observed for 55 s after the withdrawal of the testing flame. The test shall be considered as passed if the flame does not reach any point on a 50 mm diameter circle from the center of the test piece, during the observation period. NOTE - If natural gas is used as an alternative to methane/liquefied petroleum, its heat content should be approimately 37 MJ/m3, which has been found to provide similar results. C-8. Low Temperature Resistance (Ecluding the Mats Designated with Subscript t ) For type tests three test pieces 00 mm 500 mm shall be cut from the mat. For sampling tests, the numbers are given in Anne E. Each sample shall be placed in a chamber for h at a temperature of 0 ± 3 C. Two polyethylene plates 00 mm 00 mm 5 mm thick shall be conditioned at the same temperature and for the same time. Within min after removal from the chamber, each piece of mat shall be folded at the mid-point and placed between the two polyethylene plates and subjected to a force of 00 N for 30 s as shown in Fig.3. The test is deemed successful if no tear, break or crack is visible. A mat conditioned simultaneously in the low temperature chamber shall also pass the ac proof voltage test as per 8..4 as given in C-6.4 but without conditioning for moisture absorption. Dimensions in millimetres 6

20 Test piece 3 Centre line of fold Polyethylene plate 4 Force of 00 N Fig.3 Test set-up for low and etremely low temperature folding tests C-9 EFFECTS OF ACID, ALAKLIS, HSD AND OIL The test pieces shall be conditioned by immersion in each of the desired medium, namely 30 percent concentrated sulphuric acid, 30 percent concentrated Na OH LR Grade, HSD (see Note) and Transformer Oil conforming to IS 335, as per product classification in line with 4., for 48 h at room temperature. After conditioning in the given agent, the test pieces shall be dried for 4 h at room temperature before subjecting to test. Tensile strength, elongation at break and mechanical puncture test shall be measured as described in C- and C-3 respectively. Notes ) Tests for resistance to acids and transformer oil are applicable to all mats. ) Tests for alkali and HSD resistance is applicable to only those mats with special property of resistant to alkali and HSD respectively (see 4.). C-0 EXTREME LOW TEMPERATURE (FOR MATS WITH SUBSCRIPT T ) Three test pieces 00mm 500mm shall be cut from the mat each sample shall be placed in chamber for 4 h h at a temperature of -40 ± 3 C. Two polyethylene plates 00mm 00mm 5mm thick shall be conditioned at the same temperature and for the same time. Within min after removal from the chamber, the mat shall be folded at themed-point, placed between the two polyethylene plates and subjected to a force of 00 N for 30 s as shown in Fig. 3. The test is deemed successful if no tear, break or crack is visible. A mat conditioned simultaneously in the low temperature chamber shall also pass the ac proof voltage test as per 8..4, but without conditioning for moisture absorption as given in C

21 ANNEX D (Clause..) LIST AND CLASSIFICAITON OF TESTS Table 7 General Test Procedure Description of Work Subclaus e Classificatio n of Tests Type Tests Routine Tests Lot Lot Lot3 Lot 4 Lot 5 Shape Dimensions Thickness Workmanship and finish Making Packaging Type, Routine 5 6 Tensile Strength and elongation 8. 7 Compression set Test 8..4 Insulation resistance Leakage current Ac dielectric strength ac proof voltage 8.. Type Sampling Ageing 8.3 And Routine Flame retardance test Low temperature Acid and oil resistance Special properties category CEtreme low temperature Size of each lot (unit is the mat) * * ) Tests carried out on test pieces ) Either test or test 8.6 shall be used, according to the special properties of the mat NOTES The number given in the table indicate the order which the tests are to be made The sampling tests are the same as those for type tests 3 The size of each lot for sampling tests is given in Anne 4 Mat which has been subjected to type tests or sampling tests shall not be re-used. 8

22 ANNEX E (Clauses..and..) SAMPLING PLANS ANDPROCEDURES E-GENERAL The sampling procedure does not follow entirely the sampling procedure given in IS 500 (Part ). The characteristics of the product covered by this standard do not lend themselves to the application of the previously mentioned standard Every lot consists of mat of the same class and subscripts. E- CLASSIFICATION OF DEFECTS E-. Major Defect Defect other than critical, that is likely to result in failure, or to materially reduce the usability of the item or product for its intended purpose. E-. Minor Defect Defect that is not likely to materially reduce the usability of the item or product for its intended purpose, or is departure from established standards having little bearing on the effective use or operation of the item. Table 8 gives the nature of defects in function of the tests retained for the sampling procedure. E-3 GENERAL SAMPLING PLANS E-3. Sampling Plan for Minor Defects Samples are drawn and tested following the sampling plan of Table 9 E-3. Sampling Plan for Major Defects Samples are drawn and tested following the sampling plan of Table 0. E-4 SAMPLING PROCEDURE FOR MAT WITH SPECIAL PROPERTIES A first sample of mat with special properties shall be selected in accordance with the sampling plans given in E- and E-3. In addition, a second sample shall be selected in accordance with Table 0 and submitted to test given in 8.6, for each respective special category. 9

23 Table 8 Classification of Defects (Clause E-.) S.No. Type of Test Sub Clause () () (3) i) ii) iii) iv) v) vi) Shape 6. Dimensions 6. Thickness 6.3 Packaging 0 Tensile strength and 8.. Elongation Mechanical Puncture 8.. Resistance Slip Resistance 8..3 Insulation resistance 8.. Leakage current 8.. Ac di-electric strength 8..3 Ac proof voltage 8..4 Ageing 8.3 Thermal Flame retardance 8.4. Low temperature 8.4. Acid /alkali and oil 8.5 resistance Type of Defect Minor Major (4) (5) Table 9 Sampling Plan for Minor Defects (ClauseE-3.) S.No () i) ii) iii) iv) Lot Size () to 90 9 to 50 5 to to Sample Size No. of Defects for Acceptance (4) (3) No. of Defects for Rejection (5) 3 4 6

24 S.No Lot Size (). () i) ii) iii) to 90 9 to to Table 0 Sampling Plan for Major Defects (ClauseE-3.) Sample Size No. of Defects for Acceptance (3) (4) No. of Defects for Rejection (5) 3 NOTES Square meter in case of rolls and number in case of sheet Number of defects for acceptance of defects for rejection is number of defective samples for declaring the specific test deemed to have passed or failed.