Disclosure to Promote the Right To Information

Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

इंटरनेट मानक

“!ान $ एक न' भारत का +नम-ण”Satyanarayan Gangaram Pitroda

“Invent a New India Using Knowledge”

“प0रा1 को छोड न' 5 तरफ”Jawaharlal Nehru

“Step Out From the Old to the New”

“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan

“The Right to Information, The Right to Live”

“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता है”Bhartṛhari—Nītiśatakam

“Knowledge is such a treasure which cannot be stolen”

“Invent a New India Using Knowledge”

है”ह”ह

IS 10753 (1983): Code of practice for preservation ofwooden sleepers for railway track by pressure treatment[CED 9: Timber and Timber Stores]

1s : 10753 - 1983

Indian Standard

CODE OF PRACTICE FOR PRESERVATION OF WOODEN SLEEPERS FOR

RAILWAY TRACK BY PRESSURE TREATMENT

Timber Sectional Committee, BDC 9

Chairman Representing

INSPECTORGENERAL OFFORESTS Ministry of Agriculture

Members

ADDITIONAL INSPECTOR GENERAL Ministry of Agriculture OF FORESTS

SARI S. K. BANJWEE National Test House, Calcutta SHRI D. K. KANUNGO ( Alternate )

CHIEF CONSERVATOR OF FORESTS Forest Department, Government of Himacha] Pradesh, Simla

CONSERVATOR OF FORWTS ( Alternate ) SHRI V. N. DESHPANDE Engineer-in-Chief’s Branch, Army Headquarters,

New Delhi SHRI D. S. SAXENA ( Alternate )

DIRECTOR Indian Plywood Industries Research Institute, Bangalore

SHRI V. SIVANANDA ( Alternate ) DIRECTOR, FOREST RESEARCH Forest Department ( Government of Kamataka),

AND UTILIZATION Bangalore DIRECTOR ( TRACK ) Railway Board ( Ministry of Railways )

JOIN DIRECTOR, CE ( TM ) ( Alternate ) CMDE V. P. GARQ Mini%st&;f Defence ( Naval Headquarters ), New

AWSTANT INDUSTRIAL MANAGER ( AIternate )

SHRI D. P. GriosH Ministry of Defence ( DGI ) SHRI S. K. KAPOOR ( Alternate )

SHRI U. B. KANCHAN Ministry of Defence ( R & D ) SHRI B. B. MBHTA ( Alternate )

SHRI K. S. LAULY Federation of Indian Plywood and Panel Industry, New Delhi

EXECUTIVE DIRECTOR ( Akernate )

@c, Copyright 1984

( Continued on page 2 )

INDIAN STANDARDS INSTITUTION This publication is protected under the Indian Copyright Act ( XIV of 1957 ) and reproduction in whole or in part by any means except with written permission of the publisher shall be deemed to be an infringement of copyright under the said Act.

IS:10753-1983

( Continued from page 1 )

Members Representing

SHRI D. N. LOHANI Forest Department ( Government of Uttar

SHRI J. S. MATHARU Pradesh ), Lucknow

Dir.xtorate General of Technical Development, New Delhi

Soar P. V. MEHTA ( Alternate ) DR A. N. NAYER In personal capacity ( C-59, Inderpuri, New

Delhi-110012 ) SHRI R. C. PRA~AD Bihar State Forests Development Corporation

Ltd ( Government of Bihar ), Patna SHRI B. M. PRASAD ( Afternate >

PRB~IDENT Indian Academy of Wood Science, Dehra Dun GENERALSECRETARY( Alternate)

DR A. PURUSHOT~~AM Indian Plywood Manufacturing Co Ltd, Bombay SHRI S. S. RAJPUT Forest Research Institute & Colleges (Timber

Mechanics Branch ), Dehra Dun DR RAME_SH DAYAL Forest Research Institute & Colleges (Wood

Anatomy Branch ) , Dehra Dun DR V. RANGANATIUN In personal capacity (28-C, N. Block, Malviya

Nagar Extn, Saket, New Delhi-1IOO11) DR R. S. RATRA National Buildings Organization, New Delhi SHRI A. C. SEKHAR In personal capacity ( 17-I-391/54, Subraman.va

Nagar, Saidabad Colony, Hyderabad 500659 ) SHRI SEXNUN SINCW Directorate General of Supplies and Disposals,

New Delhi SHRI F. C. SHARMA Directorate General of Civil A&ation, New Delhi DR M. C. TEWARI Forest Research Institute & Colleges (Forest

Products Research ), Dehra Dun DR A. CHANDRA ( &er?%xte )

SHRI G. RAMAN, Director ( Civ Engg )

Director General, IS1 ( .&officio Member )

Secretary Smu VIJAY RAJ

Assistant Director ( Civ Engg ), IS1

Timber Seasoning and Treatment Subcommittee, BDC 9 : 3

Convener

DR M. C. TaWARI Forest Research Institute & Colleges (Forest Product Research ), Dehra Dun

Members

SIWI S. R. BHATNAOAR Castro1 Limited, Bombay SHRI R. A. SAVOOR ( Alternate )

C.&IEF CONSERVATOR OF FOREST Fores\s;yrtment ( Government of Assam ),

Fom’r OFFICER ( TIMBER TREAT- MENT PLANT ) ( Alternate )

-BP CONSERVATOROF FORESTS Forest Department ( Government of Kamataka ), ( DEVIXOPMENT ) Bangalore

DIRECTOR, FOREST RBSEAPCH AND UTILIZATION (Alternate)

( Continued on page 14 )

2

IS : 10753 - 1983

Indian Standard CODE OF PRACTICE FOR

PRESERVATION OF WOODEN SLEEPERS FOR

RAILWAY TARCK BY PRESSURE TREATMENT

0. FOREWORD

0.1 This Indian Standard was adopted by the Indian Standards Institution on 13 December 1983, after the draft finalized by the Timber Sectional Committee had been approved by the Civil Engineering Division Council.

0.2 preservation of timber is covered in IS : 401-1982*. The Sectional Committee while revising IS : 401 felt that in view of its specialized usage the subject of preservation of wooden sleepers for railways should be dealt with in a separate standard. Thus, while IS : 401-1982* covers the preser- vation of timber for other service conditions, this standard has been formulated to cover the preservation of wooden sleeper for railway track.

0.3 In the formulation of this standard due weightage has been given to international co-ordination among the standards and practices prevailing in different countries in addition to relating it to the practices in the field in this country.

0.4 For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, express- ing the result of a test or analysis, shall be rounded off in accordance with IS : 2-196Op. 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 covers perservation of railway wooden sleepers with &&r&t pt’dk\t&tives using pressufe processes. ”

2. PRE~ER+‘ATIVES . .

:’

2.0 Any of the preservatives given in 2.1 to 2.4 shall be usek for treatment.

*C&k? of practice for presdrvation Of timber ( third revi@?8]), tRules for rounding off tlumerical v&es ( ‘revised ),

3

IS : 10753 - 1983

2.1 Creosote - Coal tar creosote conforming to IS : 21%1983*.

It may be used alone, or with admixture of petroleum, coal tar, fuel oil ( Grade LV ) conforming to IS : 1593-1971 I’ or other suitable oils having high boiling range. The creosote shall be diluted to the extent of not more than 50: 50.

2.2 Copper-Chrome-Arsenic Composition - shall conform to IS : 10013 ( Part 2 )-1981$.

2.3 Acid-Cupric-Chromate Composition - shall conform to IS : 10013 ( Part 1 )-1981s.

2.4 Creosote Fuel Oil ( 25:75 )+2 Percent Peotachloropbenol

NOTE - Treatment with water borne preservatives ( given in 2.2 and 2.3 ) shall be followed by treatment with 10 percent asphalt solution in crude oil to prevent split- tihg and checking of sleepers in service.

3. PREPARATION OF THE MATERIAL FOR TREATMENT

3.1 Moisture Content Requirement - The moisture content of sleepers shall be within 25 percent, to a depth of 20 mm from the surface, taken 30 cm away from the ends and may be estimated by a suitable moisture meter or by means of conventional oven drying method by taking increment borings. A rough method of estimating moisture content is by taking ~a boring with an increment borer, to split it and to score the fresh surface with a copying pencil.

3.2 Contra1 of End Checking - Since wood dries more rapidly from the ends rather than from the side surfaces of the sleepers, end checking is a problem in the seasoning of particularly certain species of hardwoods. ‘Iherefore, antichecking iron clamps or wire straps, shall be used before the checks develop The detail of end checking by means of end clamps, end coating, etc, are given in Appendix A.

*Specification for creosote and anthracene oil for use as wood preservatives ( second revision ) .

ispecification for fuel oils ( first revision ). ’ $Specification for water sdiuble type w’&d preservatives: Part 2 Copper-chrotne-

arxnic ( CCA ) wood preservative. &e&cation for water soluble type wood preservatives: Part 1 Acid-copper-chrome

( ACC ) wood preservative.

4

IS : 10753 - m3

3.3 Mechanical Preparation

3.3.1 The surface of the timber to be treated shall be free from water, mud or dirt as well as from all inner and outer bark. Adzing, boring, inci- sing, marking, etc, shall be carried out before treatment of sleepers as any of these operations after treatment may expose untreated wood. In case it becomes absolutely necessary to cut or bore a treated timber, the’ surface exposed shall be thoroughly brushed with the preservative used. In case of freshly bored hole, retreating may be done by means of Greenless bolt hole treating apparatus or by means of a brass syringe given in IS : 401-1982*.

3.3.2 Adzing - Adzing shall be on top of sleeper, that is, the heart side of the sleeper across its full width to a depth not greater than that which is necessary for a full, smooth and true bearing under the bearing plates, except in the case of a bowed, checked or split sleeper whiih shall be used with the heart side down and consequently adzed on sap side.

3.3.3 Boring - Spike holes may be bored in sleepers, according to the specified design. A tolerance of f2 mm shall be permitted on the distance between the holes. The spike holes shall be centred across the width of the sleeper in such a way that the bearing plates will centre on the sleeper, when the spikes are driven into the prebored holes. A tolerance of f3 mm in centring across the width of the sleeper is permissible.

3.3.4 Marking - Identification “code letters” for species as given in Appendix B and the month and year of treatment at plant shall be etched on the top surface before incision and treatment.

3.3.5 Incising - Species given in B-l of Appendix B are resistant to penetration even with the pressure treatment and the distribution of the preservative and its penetration may be uneven and inadequate. Incision improves the penetration and absorption. Where it is specified that the timber shall be incised, the incision shall be made parallel to the general direction of the grain to a depth of 20 mm and shall be spaced 22 to L5 cm apart in rows extending across all four faces of the sleeper except the end surfaces. The distance between the rows shall be 57 to 60 mm and the incision in adjacent rows shall not be in direct line longitudinally, but staggered by 5 to 7 mm, that is, the incision in every fourth row will be in direct line ( see Fig. 1 1.

*Code of practice for preservation of timkr ( third revision ).

GRAIN .I. w--L. ER

I

LB--j----B 4 I

SIZE UNIT (mm)

iTi 228-238 57-60

D" 22-25 19 E 5-7 P 3

Frc. 1 PATTERN OF INCISIONS IN PLAN SHOWING LIMITS OF DIMENSIONS

I§ : 10753 - 1983

4. PENETRATION

4.1 The penetration shall be through and through in the sapwood and non- durable heartwood portions, but a minimum penetration of 35 to 40 mm is essential in species given in B-2. Where the heartwood of non-durable timbers is refractory to treatment or partially treatable, incisions of all the surfaces of species given in B-l excepting the ends to a depth of 12 to19 mm is recommended to obtain a penetrated shell of minimum 12 mm thickness all around.

5. TREATMENT PROCESS

5.1 Sleepers shall be given preservative treatment by the pressure process in accordance with 5.2.

5.2 Pressure Process - may be done either with oil type or with water soluble type preservative. In the former case, a temperature of 80-90°C should be maintained during the pressure period. The treatment shall be carried out by either full-process or empty cell-process.

5.2.1 Bethel or Full Cell Process - For full cell process, the timber is subjected to a vacuum of at least 74 KPa and maintained for 30 minutes to remove as much of air as possible from the wood cells. At the end of the vacuum period, the prestrvative is introduced into the cylinder with the vacuum pump working. When the cylinder is completely filled with the preservative solution, the vacuum pump is stopped and the cylinder is subjected to antiseptic pressure of 0’35 to 1’25 mPa depending on the species, refractory nature of the timber, etc. The pressure is -held until the desired absorption is obtained or until refusal, after which the preservative is withdrawn from the cylinder and finally a vacuum of 50 to 74 kPa for about 15 minutes is once again applied to free the timber from dripping preservative.

5.2.2 Empty Cell Process

5.2.2.1 Lowry process - In this process the cylinder is loaded with tim- ber and closed. It is then filled with the preservative. An antiseptic pressure of 0’35 to 1’25 mPa depending on the timber species, refractoriness, etc, is aplpied until the required absorption is obtained. The cylinder is drained off and finally a vaccum is applied as described in full cell prccess. This process is recommended for easy treatment of species or sleepers consisting of mixed wood species.

7

1;s : 10753 - 19Q

5.2.2.2 Rueping process - In this process the timber is subjected to an initial air pressure between 0’175 to 0’5 mPa for specified period depen- ding on the sapwood content of the timber and maintained during the subsequent stage of filling the cylinder with the preservative. When the cylinder is filled, an antiseptic pressure of 0’5 to 1’25 mPa depending on the species is applied till the desired absorption of the preservative is obtained. This is followed by vacuum as described in full cell process.

5.2.3 With the empty cell process, gross absorption of two or three times the net retention may be necessary in order to comply with the penetration requirement. Thisprocess is specially recommended for treating timbers of mixed species and also timber containing sapwood and heartwood.

6. CHOICE OF TREATMENT

6.1 The chaise of lreatment is governed by the timber species and its sap- wood content. Treatment of railway sleepers is necessary in the case of:

a) Sleepers containing sapwood even though the species may be durable in the heartwood; and

b) Sleepers of non-durable species, even though these may be completely from heartwcod. NOTE - Empty cell process is espcially recommended for~treating timbers of

mixed species and also timbers containing sapwood and heartwood. In case of refractory species of timber, treatment shall be done to refusal using full cell process.

7. TESTING

7.1 The purchaser or his agent shall have an access to all parts of the plant used in the preparation and treatment of sleepers. The testing shall be carried out in accordance with IS : 4x)1-1982*.

APPENDIX A ( Clause 3.2 )

A-l.

CONTROL OF END CHECKING BY MEANS OF END CLAMPS AND END COATING

END CLAMPS

A-l.1 ‘c’ and ‘S’ clamps conforming to IS : 10394-1982t may be used for driving into the ends of sleepers to control the development of splits and cracks. Sleepers should be end clamped soon after these are made to prevent the development of cracks and splits during the course of air seaso- ning and uneven drying.

*Code of practice for preservation of timber ( third revision ). tSpecifiaation for wooden sleepers for railway track.

8

IS: X0753- 1983

A-2. END COATING

A-2.1 End coating for treatable sleepers should not harm the fittings of the creosoting plant by plugging up tubes, piping, etc. The coating should also not clog up the pores of the wood and prevent penetration of preservative. Coal tar and crude earth oil mixture are most suitable for treatable sleepers. For refractory to treatment sleepers, that is, for treatability class C to E, white lead, aluminium paint, pitch resin, hardened glass oil, etc,mare suitable for use in end coating.

APPENDIX B ( Clauses 3.3.4, 3.3.5 and 4.1 )

B-l. SPECIES REQUIRING INCISION BEFORE TREATMENT

B-1.1 The following species of sleepers are recommended to be treated after incising by full cell process to give an absorption of minimum 80 kg/m3 and side penetration minimum of 12-19 mm on all faces.

Botanical Name -

Standard Code* Durabi- Heart CSI Trade Letters lity Wood- Name Class Treat-

ability Class

(1) (2) (3) (4) (5) (6)

Abies spp. ( other than Abies Densa )

Acrocarpus fraxinifolius Albizia lebbeck

Albizia odoratissima

Albizia procera

Altingia excelsa

Anogeissus Iatifolia

Artocarpu$ ihaplasha

Artocarpus hirsutus

Mundani Kokko Kala-siris

Safed-siris

Jutili Axlewood (Bakli)

Chaplash Aini

CP II D 65 AN I C 79

*These are different from thost given in IS : 1150-1976 ‘Trade names and abbreviated symbols for’tittiber &p&es ( &wwzd revision )‘.

(Continued)

Fir F

MD KK

KS

KR JT AW

III

III I I

I

II I

D -

C 87

C 78

E 111

C 80

E 104 E 103

c

9

IS:10753-1983

Botanical Name

Standard Code* Durabi- Heart CSI Trade Letters Name

lity Wood- Class Treat

abiIity Class

(1) (2) (3) (4) (5) (6)

Artocarpus lakoocha

Bridelia spp.

Cedrus deodara

Calophyllum spp.

Chukrasia velutina ( Syn. C. tabularis )

Diospyros spp. ( other than Diospyros marmorata )

Dipterocarpus bourdilloni

Grewia tiliifolia Hardwickia binata Hopea andamanica’

Hopea glabra Hopea parviflora

Hopea utilis ( Balanocarpus utillis )

Kingiodendron pinnaturn (Syn. Hardwickia pinnata >

Lagerstroemia lanceolata Lagerstroemia hypoleuca

Lagerstroemia parviflora

Lagerstroemia speciosa ( Syn. L. flosreginae )

ManiIkara spp.

Mesua ferrea

Palaquium eIlipticurn

Lakooch LK

Kasi KI

Deodar D

Poon PN

Chickrassy cs

Ebony EN

Gurjan Dhaman Anjan

(~zg?l, Hopea

-do- -do-

-

DM A HP

KG KW KA

Piney (Kolava) Benteak Pyinma Lendi

Jaurul

KV

BT PJ LD

JR

Bulletwood M-esua

Pali ,

PW

,NL Pr

I

I

I II II

III

-

II I II

I I II

II

I I III

II

I I

II

C E C E

C

C

C

D E E

E E E

E

E E E E

C E

E

62

65 63

75

74

-

-

108 103 -

103 - -

68

79 63 -

80 73

131 157

74

*These are different from those given in IS : 1150-1976 ‘Trade &ii& ‘abbt;ev’iated symbols’for timber species ( second revison )‘.

(Continued)

10

Botanical Name

(1)

IS : 10755 - lPS3

Standard Code* Durabi- Heart CSI Trade Let tcrs lity Wood- Name c14ss Treat-

ability Class

(2) (3) (4) (5) (6)

Pinus wallichiana ( Syn. P. Excelsa )

Poeciloneuron indicum

Pterocarpus dalbergioides

Pterocarpus marsupium

Schima wallichii Shorea assamica

Shorea robusta

Syzygium spp. Tactona grandis Terminalia bialata ( Sapwood )

Terminalia chebula Terminalia paniculata

Vateria indica

Vitex spp.

Xylia xylocarpa

Ballagi

Padauk

Bijasal

Chilauni

Makai

Sal

Jaman

Teak

White chuglam

Myrobalau

Kind al Mellapine

Milla

II%1

SY I

PAD I

VG I

SW III

MK III

S I

JN II

RT I

WC III

E 162

C -

E 84

D 65 C 57 E 110

E 93 E -

E 79

KD

PM

VP

ML

I

II

I

III

I

I

C 117 C 88

E -

E 125 E 120

_vOTES -

CSI Durability

Composite sleeper index.

Based on grave yard test at Forest Research Institute and Colleges’ Dehradun. I Average life 120 months and more.

II Average life 60 to 119 months. 111 Average life below 59 months.

Treaatability A Heartwood easily treatable. B Heartwood treatable but complete penetration not always

obtained.

Kail X II C -

C Heartwood only partially treatable. D Heartwood refractory to treatment. E Heartwood very refractory to treatment, penetration of

preservative extremely difficult.

*These are different from those given in IT : 1150-1976 ‘Trade names abbreviated symbols for timber species ( second revision )‘. I_ ._.

11

B-2. SPECIES FOR TREATMENT WITHOUT INCISION

B-2.1 The following species of sleepers are recommended to be treated by empty cell process to give absorption of preservatives minimum 80 kg/m3 penetration minimum of 35 to 40 mm on lateral faces:

Botanical Name

Standard Code* Durabi- Heart- CSI Trade Letters lity Wood Name Class Treat-

ability Class

(1) (2) (3) (4) (5) (6)

Amoora wallichii Amari LL (Lali)

Castanopsis hystrix Indian HG chestnut

Maniltoa polyandru ( Syn. Cynometra polyandra >

Ping PG

Cullenia rosayroana ( Syn. C. excelsa )

Dipterocarpus spp. ( other than D. macrocarpus )

Dipterocarpus macrocarpus

Dillenia spp. Pinus roxburghii

( Syn. P. Iongijblia )

Planchonia valida ( Syn. P. andamanica )

Stereospermum spp. Schlekhera oleosa ( Syn. S. trijuga )

Terminalia arjuna

Terminalia bellirica

Karani PL

Gurjan G

Hollong HL Dillenia DT Chir C

Red-bombwe BL

Padri PA Kusum PD

Arjun AR Bahera TN

II A

III B

III B

III B

B

III A III A III B

III A

III B III A

II B III B

66

70

116

74

73

80 69

48

108

82 -

114

84

77

*These are different from those given in IS : 1150-1976 ‘Trade names and abbreviated symbols for timber species ( second revision )‘.

(Continued)

12

IS : 10753 - 1983

Botanical Name

Standard Code+ Durabi- Heart CSI Trade Letters Iiiy Wood- Name Class Treat

ability Class

(1) (2) (3) (4) (5) (6)

Terminalia manii

Terminalia myriocarpa

Black- chuglam Hollock

BG II A 101

HK III A 63 Terminalia procera

Terminalia alata

White- BM 111 bombwe Laurel - II

B 68

B 103

NOTES -

CSI

Durability Composite sleeper index. Based on grave yeard test at Forest Research Institute and Colleges, Dehradun.

I Average life 120 months and more. II Average life CO to 119 months.

III Average life below 59 months.

Treatability A Heartwood easily treatable. B Heartwood treatable but complete. Penetration not always

obtained. C Heartwood only partially treatable. D Heartwood refractory to treatment. E Heartwood very refractory to treatment, penetration of

preservative extremely dilllcult.

*These are different from those given in IS : 1150-1976 ‘Trade names and abbreviated symbols for timber species ( second revision )‘.

13

@:107$3 - 1983

( Continued from page 2 )

Members

DIRECTOR

Representing

Indian Plywood Industries Research Institute, Bangalore

DR S. ANANTHANARAYAN ( Alternate ) DIRECTOR ( TRACK ) Railway Board ( Ministry of Railways )

JOINT DIRECTOR, CE ( T.M. ) ( Alternate ) DISTRICT FVREST OFFICER Forest Department ( Government of Andhra

Pradesh ), Rajahmundry DIVISIONAL FOREST OFFICER Forest Department ( Government of

‘I INIEGRATED UNIT 1 Maharashtra ‘1. Ballatshah Dk R. GNANAHARA~ ’ SHRI J. C. JAIN

SHRI Y. K. LAIJLY

Kerala Forest Research Institute, Peechi Forest Research Institute & Colleges (Forest

Research Laboratory ), Bangalore The Gurdit Institute ( P > Ltd. Dharwar

DR BIDHI SINGH BAINS ( Ahernate ) ., ,

SHRI J. S. MATHARU Directorate General of Technical Development, New Delhi

SHRI P. V. MEHTA ( Alternate ) OFFICER-IN-CHARGE Forest Research Institute & Colleges ( Wood

Preservation Branch ), Dehra Dun OFFICER-IN-CHARGE Forest Research Institute & Colleges ( Wood

DR A. PURUSI-XO~HAM Seasoning Branch ), Dehra Dun

DR R. S. RA~RA Indian Plywood Manufacturing Co Ltd. Bombay

SHRI SHIROMANI SHARMA National Buildings Organization, New Delhi Development Commissioner, Handicraft

SHRI V. C. SHLJKLA ( AIternate ) ( Ministry of Commerce )

SHRI J. K. SINHA SHRI GULAM ALAM ( Alternate )

Ministry of Defence ( DGt )

SHRI V. R. SON11 Ascu Hickson Ltd, Calcutta DEPUTY CHIEF ExE~uT~~~ ( Alternate )

14