IS 15932 (Part 1) : 2012

Hkkjrh; ekud

fofHkUu izdkj ds fyXukslSY;qyksfld iSuy ds p;u vkSj iz;ksx -- jhfr lafgrk
Hkkx
1

e/;e /kuRo ds ikfVZdy cksMZl

Indian Standard SELECTION AND USE OF VARIOUS TYPES OF LIGNOCELLULOSIC PANEL PRODUCTS -- CODE OF PRACTICE
PART 1 MEDIUM DENSITY PARTICLE BOARDS

ICS 79.060.20

© BIS 2012

BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002

August 2012

Price Group 4

Wood and Other Lignocellulosic Products Sectional Committee, CED 20

FOREWORD This Indian Standard (Part 1) was adopted by the Bureau of Indian Standards, after the draft finalized by the Wood and Other Lignocellulosic Products Sectional Committee had been approved by the Civil Engineering Division Council. Particle boards are classified into three types based on their density as low density, medium density and high density particle boards. All the three types of particle boards have specific application and usage. While low density particle boards are used as ceiling tiles and display boards, high density particle boards are used for specialized tools, in aircraft, automobile and general engineering industries; their usage however is only to a limited extent. The most common type of particle boards being used is the medium density boards which find extensive use in partitioning, in manufacture of doors, in manufacture of furniture, etc. Over the past few years medium density particle boards have become one of the major products of growing importance to furniture industry. In view of its construction and properties being different from that of wood, especially with regard to carpentry work, the need to formulate a comprehensive Code for proper guidance to industry and consumer in the selection and use of medium density particle board was felt. This Code of practice is a guideline for use of medium density particle boards only. The Code may be read in conjunction with IS 3087 : 2005 `Specification for particle boards of wood and other lignocellulosic materials (medium density) for general purposes (second revision)'; IS 3097 : 2006 `Specification for veneered particle boards (second revision)' and IS 12823 : 1990 `Specification for prelaminated particle boards'. This standard is published in three parts. The other parts in the series are: Part 2 Part 3 Hardboards (under preparation) Fibreboards (under preparation)

In the formulation of this standard, due weightage has been given to standards and practices prevailing in the country. The composition of the Committee responsible for the formulation of this standard is given in Annex A.

IS 15932 (Part 1) : 2012

Indian Standard SELECTION AND USE OF VARIOUS TYPES OF LIGNOCELLULOSIC PANEL PRODUCTS -- CODE OF PRACTICE
PART 1 MEDIUM DENSITY PARTICLE BOARDS
1 SCOPE This standard (Part 1) covers guidelines for use and application of medium density particle boards widely used in building interiors, cabinets, joinery, mass produced furniture/wardrobes, kitchen cabinets, shelving and storage units, partitions, door infill, work stations, floor decking, temporary constructions and mock ups. Particle boards are amenable to be used in combination with wood, aluminium and steel external frame work. 2 REFERENCES The following standards contain provisions which through reference in this text constitute provisions of this 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
Sl No. i) Type of Board Medium density particle board for general purposes

of applying the most recent editions of the standards indicated below: IS No. 3087 : 2005 Title

Particle boards of wood and other lignocellulosic materials (medium density) for general purposes -- Specification (second revision) 3097 : 2006 Veneered particle boards -- Specification (second revision) 12823 : 1990 Prelaminated particle boards from wood and other lignocellulosic material -- Specification 3 GRADE AND GRADE SELECTION 3.1 Grades The medium density particle boards shall be selected from the following grades/types:
Designation FPS XPS XPT FPT 1 FPT 2 PLB 11 PLB 12 PLB 13 PLB 14 PLB 21 PLB 22 PLB 23 PLB 24 SOGP-I SOD-I TUGP-I TUD-I SOGP-II SOD-II TUGP-II TUD-II IS No.

Grade/Type Flat pressed, single layer Extrusion pressed, solid Extrusion pressed, tubular Flat pressed, multilayer: a) Grade I b) Grade II Grade I: a) Type I b) Type II c) Type III d) Type IV Grade II: a) Type I b) Type II c) Type III d) Type IV Grade I: a) Type 1 b) Type 2 c) Type 3 d) Type 4 Grade II: a) Type 1 b) Type 2 c) Type 3 d) Type 4

IS 3087

ii)

Prelaminated particle boards

IS 12823

iii)

Veneered particle boards

IS 3097

1

IS 15932 (Part 1) : 2012 3.2 Grade Selection All the above grades of particle boards with the exception of tubular veneered particle boards, are suitable for use in interior dry locations or in air conditioned environments. For hazard Class 1 environments only Grade I prelaminated or Grade I veneered particle boards shall be used (phenolic resin bonded). Particle boards of different grades presently manufactured in the country are not suitable for exposed/out door conditions or for interiors with high moisture and wet conditions.
NOTE -- Hazard Class 1 environment have relative humidity less than or equal to 70 percent.

E

= modulus of elasticity, in N/mm2.

The deflection in shelves may be restricted to between span/200 to span/240. Due to creeping behaviour of particle boards under varying humidity condition and sustained load effect, the load bearing capacity may be reduced by 20 percent. For continuously supported conditions (supported on two or more supports), the load bearing capacity of the boards may be increased by twice the value arrived at by the above formula. 5 JOINTING/FASTENING TECHNIQUES 5.1 The principal use of medium density particle board is in the manufacture of factory produced cabinets and furniture. Besides, medium density particle board is also used as infill panels where plain or prelaminated/ veneered particle boards are inserted in wood or metal frames. Medium density particle board is also used as a cladding material in building interiors where boards are directly screwed to wood or metal framework. 5.2 In cabinet construction/panel furniture/storage units, particle boards have to be joined at right angles forming `L' or `T' joints. The joints have to be suitably detailed depending on the appearance. Common corner joints (`L' joints) suitable for particle board are butt, mitre, lap and bare faced housing as shown in Fig. 1. These joints have to be further strengthened with the help of connectors, dowels or loose tongue in combination with adhesives. Special knock downs are also available for making butt joints especially in mass productions and do-it-yourself furniture and cabinets. T-joints are also detailed on similar lines as shown in Fig. 2. 5.3 Specially made screws, dowels, loose tongue and special hardware and adhesives are additionally used to strengthen joints. Manufacturer's instructions should be followed in use of these hardwares. 5.4 Joints usually used in wood work such as mortise and tenon, dovetail and box, are not suitable for working with particle board and other panel materials due to splitting tendency and low tensile strength of these material. These types of joints should be avoided. 5.5 End to end joints in particle boards can be used to increase the width or length. Tongue and groove, loose tongue and dowels are suitable for making end joints as shown in Fig. 3.

4 STRUCTURAL CONSIDERATIONS 4.1 Particle board like other board has relatively low bending strength (modulus of rupture, MOR) and low stiffness (modulus of elasticity, MOE) as compared to wood or plywood. It also possesses high inplane rigidity which makes it ideal for box like constructions (cabinets). Combining particle board with wood or metal framework can overcome the limitations in bending strength and stiffness of the material. 4.2 Fastener like wood screws and nails are generally not suitable for making joints in particle boards as they have a tendency to split the board when screwed or nailed edgewise. A wide variety of fasteners like particle board screws and connectors to improve the jointing efficiency in particle boards are available (see also 6). 4.3 Where stiffness is the main consideration as in shelving, storage units and floor decking, the load bearing capacity for a given thickness of particle board for uniformily distributed loading condition depends upon the MOE of the material and is given by:
W= 32 bt 3 d E 5 L3

where W b t d L = = = = = total load (uniformly distributed), in kg; width of shelf, in mm; thickness of board, in mm; deflection at the centre, in mm; distance between two supports (span), in mm; and

2

IS 15932 (Part 1) : 2012

Butt Joint (Edge Exposed)

Mitre Joint (Concealed Edge)

Lap Joint (Partially Concealed Edge)

Bare Faced Housing Joint (Exposed)

F IG. 1 L-J OINTS

Butt Joint

Housing Joint

Bare Faced Housing Joint

Mechanical Support

FIG. 2 T-JOINTS

splitting the board. These types of screws can be used in strengthening `T' and `L' joints.
Tongue and Groove Joint Loose Tongue Joint

6.3 As a general rule suitable shank diameter (size) of the screw equivalent to one-fifth of the thickness of the board to be joined can be selected. Length of the screws can be two and a half to three times the thickness of the board in `L' and `T' joints. 6.4 Pilot holes are required for any type of screws, through the face into the edge of the board. As a rule pilot hole diameter could be 80 percent of the shank diameter of the screw. Normally screw heads can either be countersunk or concealed with specially made decorative covers. 6.5 Strong joints can be achieved by inserting threaded nylon plugs/inserts into pre-drilled holes in the edge of the board and ordinary wood screws can be driven to make straight strong corner or `T' joints as shown in Fig. 4. 6.6 Specially made screw connectors, coarse threaded are also used in the manufacture of do-it-yourself furniture. These type of screws are driven into pilot holes with ordinary screwdrivers as shown in Fig. 5. 6.7 Hard wood dowels, 6 to10 mm in diameter also provide good means of making `L' and `T' joints. Generally grooved hardwood dowels are used for this 3

Dowel Joint

F IG. 3 E ND J OINTS 6 FASTENERS FOR PARTICLE BOARD 6.1 Particle boards have different structure as compared to wood. Layered or graded construction used in the manufacture of boards make them vulnerable to splitting when screwed or nailed. It is always safe to screw through the face of the board and specially made hardwares are designed to follow this rule. 6.2 Wood screws do not provide required withdrawal strength for making strong joints in particle boards. As an alternative, fully threaded self tapping or twin threaded screws provide better holding in joints. These types of screws facilitate easy screwing without

IS 15932 (Part 1) : 2012 b) The frame planks and wooden beams in pallet should be of uniform thickness. c) A pallet should be used between each metre height of stack. d) When loose wooden beams are used instead of pallet, then the beams should be laid at equal distance and the position of each beam should fall in one vertical line. e) A stack of particle boards shall be covered with a weight on the top board. The weight on top should not warp or bend the boards. f) Boards should not be stored near open windows or near open door during monsoon or the windows should be kept closed. g) Boards should be stored in a clear, covered and dry place with proper ventilation. 9 WORKING OF MEDIUM DENSITY PARTICLE BOARDS 9.1 Medium density particle boards have no definite directional characteristics. Therefore, unlike wood, particle boards can neither be ripped nor be cross cut when sawed, regardless of direction. Particle boards must be sawed by a combination of the two cutting methods. 9.2 The conventional hand saw does not work well in particle boards because of thermosetting resin used and silica content in the raw material. Thermosetting resins are somewhat abrasive and dull the steel saws rapidly. It is therefore recommended to use tungsten tipped carbide saw blades. Chip load in the range of 0.08 to 0.13 mm per tooth is recommended. Low chip loads result in a fine cut edge. Chip load is the amount of material removed per tooth and is related to the number of teeth on the blade, the running speed and the material feed rate. In order to get a side finish suitable for edge-bonding, use of a scoring saw is a must. Such equipment is otherwise required to avoid chip-offs. 9.3 The following guidelines shall be followed while cutting: Cutting speed should be a minimum of 4 500 rpm. b) Use of a strudy machine with scoring blade facility gives an edge surface suitable for edge bonding and edges without any chip-offs. c) Use of fine tungsten carbide tipped blade is recommended. d) The height of blade above the board surface shall be maintained between 12 mm to 25 mm. e) Support to the work shall be extended up to 4 a)

Nylon Insert and Wood Screw Joint

F IG. 4 NYLON INSERT AND WOOD SCREW JOINT

Screw Connection

F IG. 5 SCREW CONNECTOR purpose. As a general rule the diameter of the dowels may be half the thickness of the board to be joined and length of the dowel may be five times thickness of the board. 6.8 Nails shall only be used for nailing particle board through the face into the wooden framework for temporary use. Nails shall never be used for making `L' and `T' joints in particle boards. 7 ADHESIVES Woodworking adhesives based on polyvinyl acetate (PVA) are suitable for use in strengthening the joints, in lipping and in laminating with high pressure laminates. The use of new generation adhesives for use with particle boards may also be considered. 8 STACKING AND HANDLING Particle boards are hygroscopic in nature and will thus respond to variations in atmospheric temperature and relative humidity. A change in moisture content affects the dimensions and likely loss in the flatness. Improper handling causes physical damages to the boards. Many of the problems can be avoided by taking precautions in handling and storage of particle boards. The following precautions are needed in handling and storing of particle boards: a) Particle boards should be kept off the floor. A pallet shall be placed on ground as base on the floor.

IS 15932 (Part 1) : 2012 the position of the blade in order to obtain a vibration free cut and to avoid chip-offs. f) Boards shall be cut using sharp blades only. g) When using hand saws, the following shall be ensured: 1) Use of a thinner saw, 2) Use of fine tooth cross cut saw having a tooth angle towards the operator, and 3) Material should not be cut at a right angle position. The blade shall be at a minimum angle position or should have a cutting angle of less than 40°.
NOTE -- A sharp saw tooth is to be maintained.

11.4 The manufacturer's instructions should be followed for preparation of the surface (with proper use of abrasive paper) and sealing the surface with sealers and primers. 12 FITTINGS FOR JOINERY 12.1 Numerous types of hardware are now available for use with panel materials. Surface mounted hinges are recommended for fixing particle board shutters in manufactured items like cabinets, storage units and wardrobes. 12.2 Slides, drawer glides and shelve supports are specially available for panel materials to facilitate easy fixing and avoid damage during fabrication. 12.3 Fittings like ex-centre wheel, corner blocks, mini fix are ideal for making corner joints in knock down and assembled furniture. 12.4 Fabricators should follow instructions given by the manufacturers of the special hardware. They should check the strength and wear and tear of such hardware under prolong use. 13 APPLICATIONS 13.1 Particle board plain, veneered or prelaminated, are ideal for making cabinets, furniture units, partitions, door panel inserts and wardrobes. Veneered particle board with phenolic resin bonded core can be used for semi-structural applications like floor decking in airconditioned rooms. Perforated particle boards are suitable to be used in suspended type false ceilings. 13.2 Generally, particle boards in thickness 20 to 25 mm are suitable for cabinets, built-in furniture, partitions and floorings. Boards in the range of 9 to 12 mm are used as panel inserts, in ceiling, wall panelling and for backing of cabinets. The relevant Indian Standards on various types of door shutters should be referred for use of particle board as panel inserts. 13.3 Particle boards, plain, prelaminated and veneered; are also suitable for making partitions, cabins and workstations. Boards of 12 to 15 mm thickness, supported by wood or metal framework should be adequate for this purpose. 13.4 Particle boards are also useful for making mock ups, settings, exhibition structures and other temporary applications.

10 EDGE PROFILING AND FINISHING 10.1 Edges of particle boards can be profiled using tungsten carbide tipped cutters fitted to spindle moulding machine. 10.2 PVC edge bands specially made for particle boards are widely used for factory produced items. These are in wide range of colours and profiles that match with the lamination. Special edge bending machines are used to fix the bands using hot melt adhesives. Veneer bands are also available for finishing the edge of particle board. 10.3 For wood lipping, plastic laminates can also be used to finish the edges using PVA and rubber based adhesives. In plain particle board the edges can be painted or lacquered, after sealing the edges with sealants. 11 FINISHING 11.1 Plain particle board being absorbent in nature should be sealed with a proprietary sealants and fillers. The surface may be finished with pigmented finishes based on alkydes, melamine and polyurethanes. They can also be finished after sealing, staining with lacquers based on nitrocellulose, polyurethanes and melamines. 11.2 Plain particle board cabinets and table tops can also be finished with high pressure laminates using PVA or rubber based adhesives. 11.3 Veneered particle board may be finished using the same methods used for finishing wood. Clear/ pigmented finishes, lacquers, varnishes or paints are suitable for finishing veneered particle board.

5

IS 15932 (Part 1) : 2012

ANNEX A (Foreword)
COMMITTEE COMPOSITION Wood and Other Lignocellulosic Products Sectional Committee, CED 20
Organization Indian Plywood Industries Research & Training Institute, Bangalore Bamboo Society of India, Bangalore Building Materials & Technology Promotion Council, New Delhi Central Building Research Institute, Roorkee Central Public Works Department, New Delhi Century Plyboard India Ltd, Kolkata Coir Board, Bangalore Directorate General of Supplies & Disposals, Hyderabad Directorate of Standardization, New Delhi Engineer-in-Chief's Branch, New Delhi Federation of Indian Plywood & Panel Industry, New Delhi Forest Research Institute, Dehradun Housing and Urban Development Corporation, New Delhi Indian Academy of Wood Science, Dehradun Indian Plywood Industries Research & Training Institute, Bangalore Institute of Wood Science & Technology, Bangalore Jolly Board Limited, Mumbai Kerala State Bamboo Corporation Ltd, Ernakulam Kutty Flush Door & Furniture Co Pvt Limited, Chennai Mangalam Timber Products Limited, Bangalore Ministry of Defence (DGQA), Kanpur Ministry of Defence (R&D), New Delhi Ministry of Railways, Lucknow National Mission on Bamboo Application, New Delhi National Test House, Kolkata Northern India Plywood Manufacturer Association, Jalandhar Nuchem Limited, New Delhi Permalli Wallace Limited, Bhopal Representative(s) DR C. N. PANDEY (Chairman) SHRI N. S. ADKOLI SHRI A. S. SADASHIVAIAH (Alternate) SHRI J. K. PRASAD SHRI A. K. TIWARI (Alternate) DR S. P. AGARWAL DR B. S. RAWAT (Alternate) SHRI SURINDER KUMAR SHRI S. K. VERMA (Alternate) SHRI AJAY BALDAWA SHRI NIKHILESH ROY CHOWDHURY (Alternate) SHRI M. SUDHAKARAN PILLAI SHRI R. VASUDEV (Alternate) SHRI M. GANGARAJU DR (SHRIMATI) INDU GUPTA SHRI G. K. SHARMA (Alternate) SHRI N. B. SHELAR SHRI SANJAY MITTAL (Alternate) SHRI JAYADEEP CHITLANGIA DIRECTOR SHRIMATI MANJU SAFAYA SECRETARY JOINT SECRETARY (Alternate) SHRI K. SHYAMASUNDAR SHRI M. VENUGOPAL NAIDU (Alternate) DIRECTOR SHRI ARVIND JOLLY SHRI P. K. DAS GUPTA (Alternate) SHRI M. R. ANIL KUMAR COL. G. KRISHNAN SHRI K. SHANKARKRISHNAN (Alternate) SHRI G. S. GUPTA SHRI R. KRISHNAN (Alternate) SHRI NUSRAT ULLAH SHRI K. C. GUPTA (Alternate) SHRI RAVINDER KUMAR DIRECTOR ASSISTANT DIRECTOR (Alternate) SHRI SUNIL PANDEY SHRI ALOK DE SHRI S. THIRUMALAI KOLUNDU (Alternate) SHRI N. K. TIWARI SHRI ANIL GOEL (Alternate) SHRI SUDEV BARAR SHRI JITESH NICHANI (Alternate) SHRI S. K. KADESIA SHRI B. S. PARMAR (Alternate)

6

IS 15932 (Part 1) : 2012
Organization Rajiv Gandhi Rural Housing Corporation Ltd, Bangalore The South Indian Plywood Manufactures Association, Chennai The Western India Plywood Limited, Kannur Timber Development Association of India, Dehradun Timpack Pvt Limited, Byrnihat BIS Directorate General Representative(s) SHRI MAHADEVA PRASAD SHRI K. SANKARAKRISHNAN SHRI P. K. MOHAMED SHRI K. RAGHUNATHAN (Alternate) REPRESENTATIVE DIRECTOR SHRI A. K. SAINI, Scientist `F' & Head (CED) [Representing Director General (Ex-officio)] Member Secretary SHRI J. ROY CHOWDHURY Scientist `E' (CED), BIS

Wood, Other Lignocellulosic Based Building Boards and Speciality Wood Products Subcommittee, CED 20 : 6
In personal capacity (573, 23rd Cross, 13th Main, Banashankari 2nd Stage, Bangalore 560070) Arunachal Plywood Industries Limited, Kolkata Bharat Heavy Electricals Limited, Piplani Central Building Research Institute, Roorkee Central Institute of Coir Technology, Kalavooor Coir Industrial Products Co-operative Society Limited, Bangalore Central Public Works Department, New Delhi DGS&D, New Delhi ECO Board Industries Limited, Pune Engineer-in-Chief's Branch, New Delhi Federation of Indian Plywood & Panel Industry,New Delhi Indian Plywood Industries Research and Training Institute, Bangalore Forest Research Institute (Forest Products Division), Dehradun Godrej & Boyce Manufacturing Company Limited, Mumbai Indian Plywood Industries Research & Training Institute, Bangalore Institute of Wood Science and Technology, Bangalore Integral Coach Factory, Chennai Jolly Board Limited, Mumbai DR H. N. JAGADEESH (Convener) SHRI M. M. JALAN SHRI J. PRASHAD (Alternate) SHRI M. V. PRABHAKAR SHRI S. K. GUPTA (Alternate) SHRI B. SINGH SHRIMATI MANORAMA GUPTA (Alternate) SHRI M. SUDHAKARAN PILLAI SHRI JOHN SUDHIR SHRI VIJAY GHORPADE (Alternate) SUPERINTENDING ENGINEER EXECUTIVE ENGINEER (Alternate) SHRI N. K. UPADHYAY SHRI V. S. RAJU SHRI S. P. SETHI (Alternate) SHRIMATI P. MEENAKSHI COL N. A. KUMAR (Alternate) SHRI ARVIND JOLLY SHRI MOIZ S. VAGH (Alternate) SHRI M. VENUGOPAL NAIDU SHRIMATI. D. SUJATHA (Alternate) HEAD OF DEPARTMENT DR S. P. KHALI (Alternate) SHRI GIRISH V. NALAVADE SHRI MANUBHAI M. SHAH (Alternate) DR S.K. NATH SHRI M. VENUGOPAL NAIDU (Alternate) DR R. V. RAO DR AJAY KARMAKAR (Alternate) REPRESENTATIVE SHRI ARVIND JOLLY SHRI P. K. DAS GUPTA (Alternate)

7

IS 15932 (Part 1) : 2012
Organization Kerala State Bamboo Corporation, Cochin Kutty Flush Doors & Furniture Co Pvt Limited, Chennai Mangalam Timber Products Limited, Kolkata Ministry of Defence (DGQA), Kanpur Ministry of Defence (R&D), Kanpur Ministry of Railways, Lucknow Natura Fibretech Pvt Limited, Bangalore NCL Industries Limited, Hyderabad North India Plywood Manufacturing Association, Jalandhar Novopan India Limited, Hyderabad Nuchem Limited, Faridabad Permali Wallace Limited, Bhopal The Gurdit Institute Pvt Limited, Dharwad The Mysore Chipboards Limited, Mysore The South Indian Plywood Manufacturers' Association, Kottayam The Western India Plywood Limited, Kannur In personal capacity (5/6, 1st Floor, 13th Main, HAL, 2nd Stage, Indira Nagar, Bangalore 560 008) Representative(s) SHRI M. R. ANIL KUMAR SHRI K. SANKARAKRISHNAN COL Y. G. KRISHNAN (Alternate) SHRI G. S. GUPTA SHRI R. KRISHNAN (Alternate) SHRI NUSRAT ULLAH SHRI K. C. GUPTA (Alternate) SHRI P. S. SRIVASTAVA SHRI RAVINDRA KUMAR (Alternate) DEPUTY DIRECTOR STANDARDS ASSISTANT DIRECTOR (Alternate) SHRI TOMMY MATHEW SHRI SUNIL VARGEESE (Alternate) SHRI M. KRISHNA PRASAD SHRI PRAKASH RAJU (Alternate) SHRI SURINDER ARORA SHRI NARESH TIWARI (Alternate) SHRI S. A. NAQUI SHRI SUDEV BARAR SHRI JITESH NICHANI (Alternate) SHRI S. K. KODESIA SHRI B. S. PARMAR (Alternate) SHRI YASKARAN SINGH LAULY SHRI P. HOSMAI (Alternate) SHRI A. ANANTHACHAR SHRI K. SANKARAKRISHNAN SECRETARY (Alternate) SHRI K. P. KAMALUDDIN SHRI C. A. GAFOOR (Alternate) SHRI P. K. BAGCHI

8

Bureau of Indian Standards BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promote harmonious development of the activities of standardization, marking and quality certification of goods and attending to connected matters in the country. Copyright BIS has the copyright of all its publications. No part of these publications may be reproduced in any form without the prior permission in writing of BIS. This does not preclude the free use, in the course of implementing the standard, of necessary details, such as symbols and sizes, type or grade designations. Enquiries relating to copyright be addressed to the Director (Publications), BIS. Review of Indian Standards Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewed periodically; a standard along with amendments is reaffirmed when such review indicates that no changes are needed; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standards should ascertain that they are in possession of the latest amendments or edition by referring to the latest issue of `BIS Catalogue' and `Standards : Monthly Additions'. This Indian Standard has been developed from Doc No.: CED 20 (7608).

Amendments Issued Since Publication Amend No. Date of Issue Text Affected

BUREAU OF INDIAN STANDARDS Headquarters: Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi 110002 Telephones : 2323 0131, 2323 3375, 2323 9402 Website: www.bis.org.in Regional Offices: Central Eastern : Manak Bhavan, 9 Bahadur Shah Zafar Marg NEW DELHI 110002 : 1/14 C.I.T. Scheme VII M, V. I. P. Road, Kankurgachi KOLKATA 700054 Telephones

{ { {

{

2323 7617 2323 3841

2337 8499, 2337 8561 2337 8626, 2337 9120

Northern : SCO 335-336, Sector 34-A, CHANDIGARH 160022 Southern : C.I.T. Campus, IV Cross Road, CHENNAI 600113 Western Branches: : Manakalaya, E9 MIDC, Marol, Andheri (East) MUMBAI 400093

{

60 3843 60 9285

2254 1216, 2254 1442 2254 2519, 2254 2315 2832 9295, 2832 7858 2832 7891, 2832 7892

AHMEDABAD. BANGALORE. BHOPAL. BHUBANESHWAR. COIMBATORE. DEHRADUN. FARIDABAD. GHAZIABAD. GUWAHATI. HYDERABAD. JAIPUR. KANPUR. LUCKNOW. NAGPUR. PARWANOO. PATNA. PUNE. RAJKOT. THIRUVANANTHAPURAM. VISAKHAPATNAM.
Published by BIS, New Delhi