IS 10987: Code of practice for design, fabrication, testing and installation of underground/above ground horizontal cylindrical storage tanks for petroleum products

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IS 10987 : 1992

( Reaffirmed 2003 )

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Indian Standard

CODE OF PRACTICE FOR DESIGN,
FABRICATION, TESTING AND INSTALLATION

OF UNDER-GROUND/ABOVE-GROUND

HORIZONTAL CYLINDRICAL STEEL STORAGE

TANKS FOR PETROLEUM PRODUCTS

(First Revision)

UDC 621-642-37/-39-005 : 665-6/-7 : 006-76

© BIS 1992

BUREAU OF INDIAN STANDARDS

MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002

March 1992 Price Group 5

Structural Engineering Sectional Committee, CED 7

FOREWORD

This Indian Standard ( First Revision ) was adopted by the Bureau of Indian Standards, after
the draft finalized by the Structural Engineering Sectional Committee had been approved by the
Civil Engineering Division Council.

This code has been prepared to provide the petroleum industry with tanks of adequate safety
and reasonable economy which can be built in any size required to meet the needs of the indus-
try subject to the limitations given in this code and to establish uniformity in designing,
fabricating, testing and installing the horizontal storage tanks.

This code is not intended to establish a fixed series of allowable tank sizes but to assist the
purchaser in the selection of the size of the tank that may be required to meet his particular
need.

This code was first published in 1984. In the first revision, based on the experience gained in the
use of this code, following major modifications have been elfected:

a) Minimum shell plate thickness both for underground and above-ground tanks has been
modified as 5-00 mm for tanks up to 20 kilolitre capacity.

b) A clause relating to earthing connection to safeguard the tanks from the accumulation of
static charge has been included.

In this code numerical values are given in SI units only.

In the preparation of this standard assistance has been derived from BS 2594 : 1975
'Specification for carbon steel welded horizontal cylindrical storage tanks' issued by the British
Standards Institution.

For the purpose of deciding whether a particular requirement of this standard is complied with,
the final value, observed or calculated, expressing the result of a test or analysis, shall be
rounded off in accordance with IS 2 : 1960 '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.

IS 10987 : 1992

Indian Standard

CODE OF PRACTICE FOR DESIGN,
FABRICATION, TESTING AND INSTALLATION

OF UNDER-GROUND/ABOVE-GROUND
HORIZONTAL CYLINDRICAL STEEL STORAGE

TANKS FOR PETROLEUM PRODUCTS

(First Revision)

1 SCOPE

1.1 This code is intended to provide purchasers
and manufacturers with guidelines in design,
fabrication, testing and installation of under-
ground as well as above-ground horizontal
cylindrical steel tanks with flat ends for storage
of petroleum products.

1.1.1 Provisions of this code may also be applied
to design and construct tanks for storage of
various chemicals having specific gravity less
than one. In such cases, special considerations
regarding lining and corrosion allowance shall
be made while designing the tanks for intended
use.

1.1.2 Provisions of this code are applicable for
storage of products under ambient temperature
and atmospheric pressure conditions.

1.2 This standard is complementary to IS 800 :
1984 and IS 816 : 1969.

1.2.1 Provisions regarding permissible stresses,
design, fabrication and erection as included in
IS 800 : 1984 shall apply unless specified other-
wise in this code.

1.2.2 For provisions regarding analysis for
saddle support and associated local loads,
reference shall be made to IS 2825 : 1969.

1.3 The above-ground storage tanks covered in
this standard are not intended for mobile
application.

1.4 Unless otherwise stated specifically, provi-
sions, covered in this standard apply to both
above-ground and underground tanks.

2 REFERENCES

The Indian Standards listed in Annex A are
necessary adjuncts to this standard.

3 STATUTORY PROVISIONS

Compliance with this code does not absolve
anyone from the responsibility of observing
any statutory provisions as may have been
promulgated by the statutory bodies, such as
Department of Explosives, Nagpur.

4 DEFINITION AND SYMBOLS

4.1 Underground Tank

A tank placed in earth, masonry or concrete
pit and packed around with sand, earth or clay
leaving no air space between the tank and the
pit. No part of the tank is visible.

4.2 Welding Terms and Symbols

4.2.1 Welding Terms

Shall be according to IS 812 : 1957.

4.2.2 Symbols for Welding Used on Plans and
Drawings

Shall be in accordance with IS 813 : 1986.

5 NOTATIONS

For the purpose of this standard, the following
notations shall have the meaning indicated
against each ( see Fig. 1 ).

B = Steel saddle width

Bj = Width of wear plate of saddle support
( Bi > B + 10 t„ )

C = Steel saddle breadth

D = Shell outside diameter

E =: Spacing between saddle supports

H = Height of the stifi'ener

L = Overall length

b = Width of saddle support

rs 10987 : 1992

LIFTING
LUGS

r VENT
VCONNECTION

FILLING r LIFTING
p, ..,-c POINT-, i LUG

5TIFFENERS.

WELD
LINE

150 mm mm.

NORAW-OFF I i

PfMNT

-I

Fig. 1 Typical Arrangement of Above-Ground Horizontal Tank

t„, =• End plate thickness

ta — Shell plate thickness, Min

1^ = Wear plate thickness

6 GENERAL

6.1 The tank may be manufactured from
able size plates covered in IS 1730 : 1989.

suit-

6.2 Table 1 covers recommended sizes, plate
thickness for tanks of various nominal capaci-
ties up to 90 kl. The shell and end plate thick-
nesses include a corrosion allowance of 1'5 mm.

6.3 General arrangements for above-ground
and underground tanks are shown in Fig. 1
and 2, respectively.

6.4 Enquiries or Order Form

With a view to facilitating the manufacturing
and supply of welded oil storage tanks, certain
detailed information is to be supplied to the
manufacturer. The information so required is
listed in Annex B.

7 MATERIALS

7.0 General

Unless agreed otherwise, the material for the
construction of oil storage tanks shall conform
to Indian Standards, where applicable.

7.1 Structural Steels

7.1.1 Steel plates and sections used in the
tank construction shall conform to any one of
the following specifications:

IS 226 : 1975, IS 961 : 1975, IS 2002 : 1982,
IS 2041 : 1982, IS 2062 : 1984 or IS 8500 : 1977.

NOTE— The plate material specified in 7.1.1 may
be used without impact testing for tank shells and
its reinforcements for design metal temperature up
to-10°C.

7.1.2 The dimension of structural steel sections
and plates used in tank construction shall
conform to IS 808 : 1989 and IS 1730 : 1989,
respectively.

7.2 Cast Steel Mountings

The mountings shall be suitable for welding and
shall conform to Grade 3 of IS 1030 : 1982.

. 7.3 Electrodes

The electrodes for metal arc welding shall con-
form to IS 814 : 1991.

7.4 Piping

Unless specified otherwise the pipe and pipe
couplings shall conform to IS 1978 : 1982. If so
specified in the contract or order, couplings for
threaded connections may be supplied without
recesses; when so supplied the coupling in all
other respects shall conform to IS 1978 : 1982.
Pipes used for structural purposes shall conform
to IS 1978 : 1982 or IS 1979 : 1985 with respect
to physical properties of the material. Pipes of
heavy class conforming to IS 1239 ( Part 1 ) :
1990 may be used for nozzles on tank and
internal piping, if so specified in the contract
or order.

7.5 Flanges

Plate ring flanges shall be made from any of the
plate material listed in 7.1.1. Requirements of
slip on welding and welding neck flanges are
covered in IS 6392 : 1971.

IS 10987 : 1992

LIFTING
LUGt

DIP
CONNECTION

VENT
CONNECTION

n

FILLING

FLANGE

DRAW-OFF
POINT

POINT; ff-w*"'

IFTING
PLUG

FALL

i.

T

STIFFENERS

00mm

WELD
LINE

Fig. 2 Typical Arrangement of Under-Ground Horizontal Tank

7.6 Bolts and Nuts

Bolts shall conform to property class 4.6 or
4.8 and other requirements specified in IS 1367
( Part 3 ) : 1979. Nuts shall conform to pro-
perty class 4 of IS 1367 ( Part 6) : 1980.

7.7 Other materials used in association with
steel work shall, where appropriate Indian
Standard specifications for materials exist,
conform to such specifications.

8 PERMISSIBLE STRESSES

8.1 Maximum permissible stresses in shell and
other structural members shall not exceed
values stipulated in 8.1.1, 8.1.2 and 8.1.3.

8.1.1 In the design of tank shells, the maximum
permissible tensile stress before applying the
factor of joint eflSciency of 0*7 shall not exceed
165 MPa in case of steels conforming to
IS 226 : 1975 and IS 2062 : 1984. For other steels
this shall be taken as 0-70 of the minimum
yield stress or 0-4 of the minimum tensile stress
specified, whichever is less.

8.1.2 The permissible stresses in compression,
buckling, shear, bearing, etc ( not covered
in 8.1.1 ), shall not exceed those specified in
IS 800 : 1984. For this purpose steel conforming
to IS 2002 : 1982 and IS 2041 : 1982 shall be
treated as equivalent to IS 226 : 1975 or IS
2062 : 1984 whereas Type 2 steel conforming
to IS 2041 : 1982 shall be treated as equivalent
to IS 961 : 1975.

8.1.3 The stresses specified in 8.1.1 and 8.1.2
are applicable for design temperatures of— 10°C
to + 200°C.

8.2 The permissible stresses for welds and
welded connections shall conform to the values
given IS 816 : 1969.

9 DESIGN

9.1 Tanks manufactured to provisions of this
code, shall be designed for a pressure of 0-05
MPa when full of water. Thicknesses chosen
shall not be less than the thicknesses given in
Table 1.

9=2 Tanks to be installed underground shall
also be designed for external earth pressure
acting on the tank when it is empty.

9.3 Corrosion Allowance

Minimum corrosion allowance of 1-5 mm shall
be considerd in design of tanks. To safeguard
against corrosion caused by the environment
and the product stored 1.1.1 and 10 should be
followed.

9.4 Design Temperature

The design temperature shall be the lowest one
day mean temperature where the tank is to be
installed, as available from relevant IS codes,
metreological department or local authorities.

9.5 Foundation

9.5.1 Tanks shall be built on good foundations.
Above-ground tanks shall be provided with
steel wear plates for installing them on con-
crete pedestals or steel cradles as specified by
the purchaser.

9.5.2 Typical arrangement for above-ground
tank is given in Fig. 1. Concrete pedestals shall
be designed to support the tank full with water.

9.5.3 As tank diameter or shell thickness ratio
increases, the shell shall be analysed for buck-
ling resistance to reaction loads at the concrete
pedestals and associated local loads as per
IS 2825 : 1969.

IS 10987 : 1992

Table 1 Dimensions and Capacities of Horizontal Underground and Above-Ground Storage

Tanks With Flat Ends

( Clauses 6.2, 9.1, 13.4 and 14.3)

Nominal
Capacity

Shell
Out-
side
Dia-
meter

D

Overall
Length

L

Spacing

Between

Saddle

Supports

E

Thickness

Size of Mi

_ SltiiTnnrs \

nimum Minimum
Vidth Breadth
of of
(addle Saddle
ipport Support
B C

Approximate
Ullage

Wear
Plate

Shell Plate
, ^^ ,

Under- Above-
ground ground
tank tank

ts t.

End Plate ( angle

with Sections) S
Stiflfners Si

( Above
Nominal

Capacity

(1)

(2)

(3)

(4)

(5)

(6) (7)

(8)

(9)

(10)

(11)

(12)

KI

mm

mm

mm

mm

mm mm

mm

mm

mm

mm

percent

5

1 600

2 750

2 110

6-0

5-0 5-0

6-0

65x65x6

150

1385

7-8

7-5

] 600

4 000

3 610

60

5-0 50

6-0

65x65x6

150

1 385

4-9

10

1 800

4 250

3 530

60

50 50

8-0

65x65x8

250

1 560

5-9

15

1 950

5 503

4 720

6-0

50 50

8-0

70x70x8

250

1 690

7-5

20

2 250

5 500

4 600

8

60 50

8

90x90x8

250

1 950

7-5

25

2 500

5 500

4 500

8

60 60

100

90x90x10

250

2 295

6-3

30

2 650

6 000

4 910

8

60 80

100

100x100x10

250

2 340

8-3

35

2 700

6 750

5 670

8'0

60 80

100

100x100x10

250

2 330

8-4

40

2 750

7 500

6 400

80

60 80

100

100x100x10

250

2 380

9-5

45

2 750

8 250

7 100

8-0

60 8-0

100

100x100x10

250

2 380

7-2

50

2 750

9 000

7 900

8-0

60 8-0

10-0

100x100x10

250

2 380

5-2

55 ■

2 750

10 000

8 900

80

60 80

10-0

100x100x10

550

2 380

6-4

60

2 750

11000

9 900

8

60 80

100

100x100x10

250

2 380

7-3

70

2 750

13 000

11 900

80

6 8

10-0

100x100x10

250

2 380

8-7

80

2 750

14 750

13 650

80

6-0 100

100

100x100x10

250

2 380

7-7

90

2 750

16 500

15 400

8'0

60 100

100

100x100x10

250

2 380

7-1

NOTES

1 The thickness specified above are the minimum requirement only (including internal and external corrosion
allowance ), pertaining to yield value of steel as 250 MPa.

2 The actual thickness required shall be checked taking into the consideration soil pressure, fluid pressure
and external loading.

3 End plates in col 8 of the flat ends shall bz provided with stiffners given in col 9 and agreed as per Fig. 3E.

4 End plates of the flat ends shall preferably be without joints. Where the end plate is made by welding of
two or more plates, the weld joint shall be made horizontal. Full width of plate( s ) should be utilized at
the bottom.

10 CORROSION PROTECTION

Tanks to be installed underground shall be
suitably protected against corrosion caused by
the soil strata and/or sub-soil water. The
purchaser shall specify type of such protection
that he considers desirable. Suggested good
practices for asphalt doping are given in
Annex C.

11 TANK ANCHORAGE

11.1 Tank to be installed underground shall be
anchored to resist the buoyancy force induced
by high water tables that may occur seasonally.
The anchorage could be either provided by
means of steel flat of round bars having ade-
quate cross Section to resist the uplift at a
stress level of 140 MPa maximum.

11.2 The anchors should be embedded in RCC
draft having necessary dead weight, bonding
and shear strength to resist the uphft force.

12 APPURTENANCES AND MOUNTINGS
12.1 General

12.1.1 Appurtenances or mountings installed
on tanks shall conform to this code. Alternative
designs of appurtenances which provide equiva-
lent strength, tightness and utihty are permis-
sible, if so agreed to by the purchaser.

12.1.2 Manhole necks, nozzle necks, reinforcing
plates and shell-plate openings which have
either sheared or oxygen-cut surfaces, shall
have such surface made uniform and smooth,
with the corners rounded, except where such
surfaces are fully covered by attachment welds.

IS 10987 : 1992

12.1.3 The opening in tank larger than 65 mm
in diameter shall be reinforced. The minimum
thickness of the reinforcing pad shall be the
same as the shell thickness and diameter shall
be twice the diameter of the hole cut subject
to maximum diameter of the opening plus
200 mm.

12.2 Manhole

12.2.1 Each tank shall have a minimum of one
manhole of not less than 500 mm size
( diameter ).

12.2.2 The manhole cover may be hinged with
single or multiple bolt fixing, as required by the
purchaser.

12.3 Nozzles

The nozzle sizes shall be selected to meet
individual operating conditions of filling and
emptying rates.

12.4 Lifting Lugs

The lifting lugs shall be provided in the tank
at appropriate position to lift the empty tanks
only. Typical details of lugs and positions are
shown in Fig. 1 to 3.

12.5 Accessories

The tank shall be provided with a fill connec-
tion, a draw-off connection, a dip-connection
a vent connection and a drain connection.

12.5.1 Fill Connection

When the tank is filled from the top, an internal
fill pipe running down to within 100 mm of the
tank bottom shall be provided to avoid splash-
ing of product and generation of static
electricity. End of the fill pipe shall be
chamfered at 45°.

12.5.2 Dip Connection

The dip connection shall be provided with a
galvanized iron, aluminium or brass screwed
cover and be fitted with an internal perforated
pipe running down to within 100 mm of the
tank bottom. Appropriate perforation shall be
provided for various products. Alternatively,
in case of above-ground tank a float arrange-
ment for continuous gauging of liquid level
inside the tank may be used.

12.5.2.1 The calibrated dip rod shall be of non-
sparking material ( 12 mm square brass rod is
recommended ).

12.5.3 Vent Connection

The vent pipe shall be securely supported and
shall not be less than 4 m in height and at 4 m
distance from any adjoining land or property
or any other source of fire. Vent pipe of any
tank shall not be interconnected with that of
another. The open end of every vent pipe shall
be covered with two layers of non-corrodible
metal wire gauge having not less than 11 meshes
per linear centimetre and shall be further
protected from rain by a hood or by suitably
bending it downward.

12.5.4 Earthing Connection

The horizontal storage tank, whether above-
ground or underground, shall invariably be
provided with earthing connection to elimi-
nate the possibility of accumulation of static
charge on the surface of the tank either due to
atmospheric electricity or due to flow of product
into the tank.

For this purpose, two earthing bosses of appro-
priate sizes shall be welded to the saddle
support in case of above-ground tanks and to
the end plate in case of underground tanks.
Guidelines for making earthing connection for
tanks are also given in Annex D.

13 FABRICATION AND SHOP PAINTING

13.1 The workmanship and finish shall be first
class in every respect subject to closest inspec-
tion by the manufacturer's inspector, whether
or not the purchaser, waives any part of the
inspection.

13.1,1 The tanks shall be fabricated by welding.
Welding procedure in general and the qualifi-
cation of welders shall be as specified in
IS 9595 : 1980 and IS 817 : 1966.

13.2 The cylindrical shell shall be of full
penetration double butt-welded construction.

13.2.1 The end plates and penetration shall be
attached to the cylindrical shell by means of
double fillet welds.

13.3 Shell Plate Arrangement

13.3.1 When the shell length is produced from
more than one single plate the longitudinal
seams shall break joint at intermediate circum-
ferential seams. It is recommended that whenver
possible a longitudinal seam should be situated
in the upper third of a tank or on the top
centre line.

13.4 The end plates shall be adequately stiflened.
The recommended size of angle stiffeners as

IS 10987 : 1992

given in
Fig. 3 C.

Table 1 shall be arranged as per 14.3 Tolerance on Overall Length

13.5 Typical weld joint details are shown in
Fig. 3.

13.6 Shop Painting

All the external surfaces of the tank shall be
thoroughly cleaned and freed from rust and
scale and painted with one coat of an approved
primer paint. All the interior surfaces of the
tank shall be cleaned to remove all rust and
foreign matters like grease, dirt, etc, before
despatch.

14 TOLERANCES

14.1 Tolerance on Shell Diameter

The tolerance on diameter at any point on the
length of the tank shell shall be within ± 0*35
percent of the specified diameter ( Max ) when
calculated from an external circumferential

measurement.

14.2 Tolerance on Circularity

The tolerance on circularity at any point on
the length of the shell that is the difference
between maximum and minimum internal shell
diameter, shall not exceed one percent of the
nominal internal diameter.

The overall length of the tank shall not differ
by more than 0-5 percent of the overall length
given in Table 1.

15 INSPECTION AND TESTING

15.1 Examination of welds shall be done by
visual means. However, non-destructive testing
such as spot radiography may be carried out at
the option of the purchaser.

15.2 All gauges and templates necessary for
inspection, to the satisfaction of the inspector
shall be supplied by the manufacturer.

15.3 All tanks shall be subjected to hydraulic
test at a pressure of 0-05 MPa and checked for
leaks.

16 CALIBRATION

16.1 Tanks may be calibrated mathematically
unless otherwise specified by the purchaser.
Where physical calibrations are specified by the
purchaser, tanks shall be calibrated in accor-
dance with IS 2009 : 1975 using a certified
water. Calibration tables shall show volume of
product for every 0-5 cm of filling height of the
tank.

16.2 Calibration may be
independent authority, if so
purchaser.

certified by
required by

an
the

ts^S&emm (8mm OPTIONAL)

ZmmJ -*j |«— 3mm

ts= 8mm AND 10 mm
(b)

3A TYPICAL LONGITUDINAL AND CIRCUMFERENTIAL
JOINTS OF SHELL

CONTINUOUS i
FILLET WELD

CONTINUOUS
FILLET WELD

SHELL

3B TYPICAL SHELL TO COUPLING
JOINT DETAILS

Fig. 3 Typical Weld Joint Details — ( continued )

IS 10987 : 1992

2I^§

CONTINUOUS f:
FILLET WELD

SEALING
WELD'

■~ ^/A \ m

l/1 I L

I

CONTINUOUS
FILLET WELD;

^ ■

r WELD/

(a) (b)

3C TYPICAL JOINT FOR MANHOLE AND NOZZLE NECK TO SHELL

LIFTING LUG 12mm
THICK

^ 150 mm

■^•^4-20 mm I

HOLE^iOmm

FILLET

WELD

ALL AROUND

CONTINUOUS
FILLET WELD

3D WELD JOINT FOR FLAT ENDS AND LIFTING LVG

H/2

it;

SECTION YY

SECTION XX

3E STIFFENING DETAILS OF END PLATE
Fig. 3 Typical Weld Joint Details

IS 10987 : 1992

ANNEX A
( Clause 1 )

LIST OF REFERRED INDIAN STANDARDS

IS No.

226:

1975

800 :

1984

808 :

1989

812 :

; 1957

813 :

: 1986

814 :

: 1991

816 : 1969

817 : 1966

961 : 1975

Title

Structural steel ( standard qua-
lity ) ( fifth revision )

Code of practice for general
construction in steel ( second
revision )

Dimensions for hot rolled steel
beam, column channel and
angle sections ( revised )

Glossary of terms relating to
welding and cutting of metals

Scheme of symbols for welding

Covered electrodes for manual
metal arc welding of carbon
and carbon manganese steel
( fifth revision )

Code of practice for use of
metal arc welding for general
construction in mild steel ( first
revision )

Code of practice for training
and testing of metal arc welders
( revised )

Structural steel ( high tensile )
( second revision )

IS No. Title

studs with full
( second revision )

loadability

1030 •. 1982 Carbon steel castings for

general engineering purposes
( second revision )

1239 Mild steel tubes, tubulars and

( Part 1 ) : 1990 other wrought steel fittings:

Part 1 Mild steel tubes {fifth

revision )

1367 Technical supply conditions for

( Part 3 ) : 1979 threaded steel fastners: Part 3

Mechanical properties and test

methods for bolts, screws and

1367 Technical supply conditions

(Part 6 ): 1980 for threaded steel fastners:
Part 6 Mechanical properties
and test methods for nuts with
specified proof loads ( second
revision )

1730 : 1989 Dimensions for steel plate,

sheet, strip and flats for general
engineering purposes ( second
revision )

1978 : 1982 Line pipe ( second revision )

1979 : 1985 High test line pipe (first

revision )

2002 : 1982 Steel plates for pressure vessels

for intermediate and high tem-
perature services including
boilers ( first revision )

2009 : 1975 Method for calibration of

horizontal and tilted oil storage
tanks ( first revision )

2041 : 1982 Steel plates for pressure vessels

used at moderate and low
temperature {first revision )

2062 : 1984 Weldable structural steel {third

revision )

2825 : 1969 Code for unfired pressure

vessels

6392 : 1971 Steel pipe flanges

8500 : 1977 Weldable structural steel

( medium and high strength
qualities )

9595 : 1980 Recommendations for metal

arc welding for carbon and
carbon manganese steels

IS 10987 : 1992

ANNEX B
( Clause 6.4 ) .
INFORMATION TO BE FURNISHED BY THE PURCHASER

B-1 The following information shall be supplied
by the purchaser in his enquiry:

a) Location of tank;

b) Nominal capacity of tank;

c) Tank diameter and/or length restrictions;

d) Internal tank pressure and/or vacuum;

e) Rate of filling and emptying tank;

f ) Product to be stored and its design and
specific gravity;

g) Minimum ambient temperature where
tank is located or design metal tempera-
ture;

h) Corrosion allowance for shell, end plates
and other parts both — internal and
external;
j ) Maximum wind speeds;
k) Earthquake factor;

m) Any additional loads to be considered
for tank design;

n) Type of foundation and bearing capacity

of the soil;
p) List of mountings required and their

location on the tank;

q) Type of construction, lap or butt-welded;

r) Extent of painting required and surface
preparation; and

s) Scope of supply of tank manufactured.

ANNEX C
( Clause 10.1 )

ASPHALT DOPING

C-1 ASPHALT DOPING

Asphalt doping should be adopted to provide
satisfactory protection to steel against soil
attack.

C-1.2 Doping of tank should not be taken in
hand until the tank is finally tested inside the
pit and all water emptied out. However, on the
portion of the outside surface of tank which
come in contact with cement concrete or
foundation, doping can be carried out ( as per
the laid down procedure/specifications ) before
testing, excluding the welding joints portions
which shall be completed after testing.

C-1.3 Recommended practices for carrying out
asphalt doping are as follows:

a) Surface Preparation — The outside surface
of the tank, turn buckle, anchor bolts,
hurried portion of manholes, nozzles,
saddles, etc, should be thoroughly
cleaned by scraping with wire brushes
and sand papers to bare metal. All mill
scales dirt should be completely removed
before starting the doping work.

b) Primer Coat — The surface thus prepared
should be treated with two coats of
'Tankmastic' or equivalent primer. Each
coat is applied uniformly after the
previous is completely dried. The approxi-
mate coating capacity of 'Tankmastic'
or equivalent is about 11 to 13 m-/l
coat.

c) Doping — After the application of primer
coats, two coats of hot 30/40 Grade
bitumen shall be applied as per manufac-
turer's recommendations, resulting in an
overall coating thickness of 3-2 mm.

The 30/40 Grade bitumen shall be heated
to the required temperature as recom-
mended by the manufacturer for easy
and uniform application of bitumen.

The application of bitumen shall be done
in such a way as to give the appearance
of a rough cast plaster and this can be
obtained by dabbing only and not
painting.

IS 10987 : 1992

ANNEX D
( Clause 12.5.4 )

EARTHING CONNECTION

D-1 GUIDELINES FOR MAKING EARTHING connections and contacts shall have as few

CONNECTIONS joints as possible. All joints shall be riveted,

welded or bolted and also soldered to ensure

D-1.1 Every tank shall be electrically connected both mechanical and electrical soundness. The

with the earth in an efficient manner by not less resistance to earth shall not exceed 70 and the

than 2 separate and distinct connections placed resistance to earth plate or to any part of

at the opposite extremities of such tank. The fitting shall not exceed 20.

10

Standard Mark

The use of the Standard Mark is governed by the provisions of the Bureau of Indian
Standards Act, 1986 and the Rules and Regulations made thereunder. The Standard Mark
on products covered by an Indian Standard conveys the assurance that they have been
produced to comply with the requirements of that standard under a well defined system
of inspection, testing and quality control which is devised and supervised by BIS and
operated by the producer. Standard marked products are also continuously checked by
BIS for conformity to that standard as a further safeguard. Details of conditions under
which a licence for the use of the Standard Mark may be granted to manufacturers or
producers may be obtained from the Bureau of Indian Standards.

Bureau of Indian Standard

BIS is a statutorA^ institution established under the Bureau of Indian Standards Act, J986 to
promote harmonTOUs 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.

Revision of Indian Standards

Indian Standards are reviewed periodically and revised, when necessary and amendments, if
any, are issued from time to time. Users of Indian Standards should ascertain that they are in
possession of the latest amendments or edition. Comments on this Indian Standard may be
sent to BIS giving the following reference:

Doc : No. CED 1 ( 4728 )

Amendments Issaed Since Poblication

Amend No.

Date of Issue

Text AflFected

BUREAU OF INDIAN STANDARDS

Headquarters :

Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi 1 10002
Telephones | 331 01 31, 331 13 75

Regional Offices i

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

Eastern : 1/14 C. I. T. Scheme VII M, V. I. P. Road, Maniktola
CALCUTTA 700054

Northern : SCO 445-446, Sector 35-C, CHANDIGARH 160036

Southern : C. I. T. Campus, IV Cross Road, MADRAS 600113

Western : Manakalaya, E9 MIDC, Marol, Andheri ( East )
BOMBAY 400093

Branches : AHMADABAD, BANGALORE, BHOPAL, BHUBANESHWAR, COIMBATORE,
FARIDABAD, GHAZIABAD, GUWAHATI, HYDERABAD, JAIPUR, KANPUR,
LUCKNOW, PATNA, THIRUVANANTHAPURAM.

Telegrams t Manaksanstha
( Common to all Offices )

Telephone

(331 01 31
(331 13 75

37 86 62

53 38 43

235 02 16

6 32 92 95

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