IE
S.I. No. 157/1949 - Standard Specification (Galvanised Cisterns and Cylinders For Domestic Water Supply) Order, 1949.
Table of Provisions (16)
Statutory Text (16 Articles)
1. For the purpose of this specification the following definitions shall apply
(
a
)
Cistern.
A rectangular cold water vessel open to atmospheric pressure. Note : The vessel here termed
cistern
is frequently called
tank
or
open tank.
(
b
)
Cylinder.
A vessel, shaped as a right cylinder and closed by dished ends, adapted to the circulation or storage of water.
(
c
)
Screwed Connection.
Any threaded connection such as a boss, flange or socket to which a pipe can be fitted.
MATERIAL.
2. Standard galvanised mild steel cisterns and cylinders shall be made from mild-steel plates or sheets, free from defects (see Clause 7).
MANUFACTURE.
3. Cisterns and cylinders shall be soundly constructed and may be riveted, welded, or partly riveted and partly welded.
Should the purchaser specifically require one or other of these methods of manufacture, this shall be stated in the enquiry and order.
Cisterns shall be made with double turnover flanged tops. Cisterns larger than 15 gallons nominal capacity shall be fitted with corner plates.
Cylinders of all capacities shall be fitted with a handhole not less than 6 in. in diameter. The handhole shall be adequately reinforced and shall be provided with a cover of a thickness not less than that of the wall of the cylinder.
GALVANISING.
4. Cisterns and cylinders shall be galvanised, after manufacture' in the following manner
After proper preparation by pickling in acid, the article shall be dipped in a bath of molten virgin spelter (containing not more than 2½ per cent. of impurities) at a temperature suitable to produce a complete and uniformly adhesive coating of zinc, which shall be such that when samples of the articles, after galvanising, are stored for at least one week under cover, but with all the surfaces, as far as possible, exposed to the free movement of air, the zinc coating as examined by a visual inspection at the end of the period shall be clean, smooth and continuous, and free from acid spots.
The weight of the coating when applied in the above manner shall be not less than 1
1
/
8
oz. per superficial foot on each side and the coating shall be evenly applied.
STANDARD SIZES.
5. The standard sizes of cisterns and cylinders, when measured in the manner described in Clause 6, shall conform to the dimensions given in Tables 1 and 2 respectively. The actual capacity shall not vary by more than 5 per cent. up or down from the figures specified in these tables.
METHOD OF MEASURING SIZES.
6. The dimensions of cisterns shall be measured externally over the rivets, if any.
The diameter of cylinders shall be measured internally and the height externally from base to top of dome.
TABLE 1.—DIMENSIONS OF CISTERNS.
Standard size number*
Dimensions
Capacity
Water line from top
Overflow or warning pipe details
Inlet details
Outlet details
Minimum thickness of sheet before galvanising
Length†
Width
Height
Nominal
Actual to water line
Size of hole
C/L from top
Size of hole
C/L from top
Size of holes††
C/L from bottom
ft.
in
ft.
in.
ft.
in.
gall.
gall.
in.
in.
in.
in.
in.
in.
in.
B.G.
1.3
2
0
1
0
1
3
15
10
4
3
/
8
1
3
/
32
3
7
/
8
1½
1
3
/
8
2½
18
1.4
2
0
1
6
1
7
30
20
4½
1
3
/
8
3
7
/
8
1½
1
3
/
8
2½
18
1.5
2
0
1
8
1
8
35
25
4½
1
3
/
8
3
7
/
8
1½
1
3
/
8
2½
18
1.6
2
3
1
8
1
8
40
30
4½
1
3
/
8
3
7
/
8
1½
1
3
/
8
2½
18
1.7
2
5
1
10
1
10
50
40
4½
1
3
/
8
3
7
/
8
1½
1
3
/
8
2½
16
1.8
2
6
2
0
2
0
62
50
4½
1
3
/
8
3
7
/
8
1½
1
3
/
8
2½
16
1 9
3
0
2
0
1
9
65
50
4½
1
3
/
8
3
7
/
8
1½
1
3
/
8
2½
16
1.10
3
0
2
0
2
0
75
60
4½
1
3
/
8
3
7
/
8
1½
1
3
/
8
2½
16
1.11
3
0
2
6
2
2
100
80
4½
1
3
/
8
3
7
/
8
1½
1
3
/
8
2½
16
1.12
3
2
2
3
2
3
100
80
4½
1
3
/
8
3
7
/
8
1½
1
3
/
8
2½
16
1.13
3
2
2
6
2
7
125
100
5½
2
3¼
1
3
/
8
1¾
2
3
14
1.14
5
0
3
0
2
8
250
200
5½
2
3¼
3
/
8
1¾
2
3
14
*It is strongly recommended that cisterns should be ordered by the size number given in Column 1 so as to avoid confusion between nominal and actual capacities.
†In the case of welded cisterns the length may be increased up to 1 in. (see Fig. 3).
††See Clause 11 in regard to 1¾ in. outlet holes for sizes 1.7 to 1.12.
In the case of size 1.3 the water line has been fixed at 1 in. below the invert or lip of the overflow pipe. For all other sizes the distance of the water line below the invert or lip of the overflow pipe has been made equal to the diameter of the overflow pipe
TABLE 2.—DIMENSIONS OF CYLINDERS.
Dimensions
Capacity
Grade A.
Grade B.
Grade C.
Standard size number†
Diameter inside††
Height over dome
Nominal
Actual (see Clause 5).
Test pressure 70 lb. per sq. in. Max. working head of water 100 ft.*
Test pressure 40 lb. per sq. in Max. working head of water 60 ft.*
Test pressure 20 lb. per sq. in. Max. working head of water 30 ft.*
Thickness of plate before galvanising
Thickness of plate before galvanising
Thickness of plate before galvanising
For barrels in all cases and ends dished outwards
For ends dished inwards
For barrels in all cases and ends dished outwards
For ends dished inwards
For barrels in all cases and ends dished outwards
For ends dished inwards
in.
in.
gall.
gall.
3.1
15
36
23
21
}
1
/
8
in.
3
/
16
in.
12 B.G.
1
/
8
14 B.G.
12 B.G.
3.2
18
30
28
25
3.3
18
36
33
30
3.4
18
42
39
36
3.5
20
51
58
55
}
3.6
24
48
78
73
3.7
24
63
103
98
*The permissible working head shall be measured from the bottom of the cylinder.
†It is strongly recommended that cylinders should be ordered by the size number given in Column 1 so as to avoid confusion between nominal and actual capacities.
†† ½ in. to be added to give external diameter in the case of welded seams, or 1 in. in the case of riveted seams.
The actual capacities given above are the figures for cold water and do not indicate the quantity of hot water actually available.
THICKNESS.
7. The thickness, measured before galvanising, of the steel plates or sheets used in the manufacture of cisterns or cylinders shall in no case be more than 5 per cent. under the thickness specified in Tables 1 and 2 for the respective capacities and/or working heads.
The grade of cylinder shall be specified when ordering and shall, together with the thickness of the barrel and of each end, be clearly marked on the finished article (see Clause 15).
RADIUS OF CURVATURE OF CYLINDER ENDS.
8. Both ends of cylinders shall have a radius of curvature not exceeding 1
1
/
3
times the diameter of the cylinders (see Fig. 1).
TESTS.
9. Finished cisterns, after galvanising, shall be filled with water for a period of at least 5 minutes and shall not show a leak or any permanent distortion as a result of the test. They shall be marked to show that they have passed this test.
Finished cylinders, after galvanising, shall be filled with water and shall withstand for a period of at least 5 minutes the test pressures given in Table 2. They shall not show a leak or any permanent distortion as a result of the test. They shall be marked to show that they have passed this test.
SCREWED CONNECTIONS FOR PIPES.
10. Cylinders, unless otherwise specified, shall be fitted with five screwed connections suitable for 1 in. pipe in the case of sizes 3.1, 3.2 and 3.3 ; for 1¼ in. pipe in the case of sizes 3.4 and 3.5 and for 1½ in. pipe in the case of sizes 3.6 and 3.7.
The screwed connections shall be threaded in accordance with B.S. 84 : 1940 Pipe (Parallel) thread, medium fit, Tables 15 and 19.
The position of the screwed connections, unless otherwise specified, shall be as shown in Fig. 2.
HOLES IN CISTERNS.
11. Unless otherwise specified, all cisterns shall be provided with three plain holes, one each for overflow, inlet and outlet. If required by the purchaser, there shall be two plain holes for outlets. The holes shall be cut before galvanising and placed in the positions determined by reference to Table 1 and Fig. 4.
The sizes of the holes shall be as given in Table 1 but, if required by the purchaser, the outlet holes for the standard size numbers 1.7 to 1.12 shall be 1 ¾ in.
Screwed connections shall not be supplied unless ordered specially.
TOLERANCES.
12. The maximum permissible variation from the specified positions of screwed connections shall be ±
1
/
8
in.
INSPECTION.
13. The purchaser, or his representative, shall, if required, be given access to the works of the manufacturer at all reasonable times for the purpose of carrying out inspection during manufacture and testing.
REJECTION.
14. The purchaser shall have the option of rejecting any cistern or cylinder supplied to this specification which fails to comply with the requirements laid down herein.
MARKING.
15. The cisterns and cylinders shall be clearly marked to show that they have passed the test described in Clause 9, and shall also have the following marks
(
a
) The reference of this specification, size number, and, in the case of cylinders, the Grade.
(
b
) The nominal capacity in gallons.
(
c
) The thickness of the plate or sheet. In the case of cylinders; the thickness of plate or sheet used for the barrels and ends shall be separately stated.
(
d
) In the case of cylinders, the permissible working head in feet of water.
(
e
) The manufacturer's name or mark.
APPENDIX.
Equivalents of Birmingham Gauges (B.G.) in parts of an inch.
B.G. No.
In.
12
0·0991
14
0·0785
16
0·0625
18
0·0495
Fig. 1. — Radius of curvature of cylinder ends.
Fig. 2.—Positions of screwed connections on cylinders.
* This dimension, to the nearest inch above, is as follows
23 in. for cylinders 30 in. high.
27 in. ,, ,, 36 in. ,,
32 in. ,, ,, 42 in. ,,
36 in. ,, ,, 48 in. ,,
39 in. ,, ,, 51 in. ,,
47 in. ,, ,, 63 in. ,,
Fig. 3.—View of welded tank, showing sides projecting at each end.
(See note to Table 1). This drawing is typical only and does not purport to indicate a standard method of construction.
Fig. 4. Positions of holes in tanks (see Clause 11 and Table 1).
GIVEN under my Official Seal this 23rd day of December, 1949.
DANIEL MORRISSEY,
Minister for Industry and Commerce.
S.I. No. 157 of 1949.
STANDARD SPECIFICATION (GALVANISED CISTERNS AND CYLINDERS FOR DOMESTIC WATER SUPPLY) ORDER, 1949.
I, DANIEL MORRISSEY, Minister for Industry and Commerce, in exercise of the power conferred on me by subsection (3) of
section 20
of the
Industrial Research and Standards Act, 1946
(No. 25 of 1946), hereby order as follows