GUIDELINES FOR FACTORY INSPECTION OF SWG pipes (IS 651 - 2007)
1. Marking
Every pipe and fitting shall have legibly impressed upon it before firing the following
2. Sampling
a) Scale of sampling for Physical dimensions:
Sl.No |
Lot Size |
Sample |
Sample Size |
Cumulative sample size |
General quality and Dimensions ( Sections A & B) |
|
ac |
rc |
|||||
1 |
Up to 150 |
First |
20 |
20 |
1 |
4 |
|
|
Second |
20 |
40 |
4 |
5 |
2 |
151 to 280 |
First |
32 |
32 |
2 |
5 |
|
|
Second |
32 |
64 |
6 |
7 |
3 |
500 to 1200 |
First |
80 |
80 |
5 |
9 |
|
|
Second |
80 |
160 |
12 |
13 |
4 |
1201 to 3200 |
First |
125 |
125 |
7 |
11 |
|
|
Second |
125 |
250 |
18 |
19 |
5 |
3201 to 10,000 |
First |
200 |
200 |
11 |
16 |
|
|
Second |
200 |
400 |
16 |
27 |
b) Sampling for Chemical & Mechanical Tests (Water absorption, Acid resistance test, Alkali resistance test and Crushing Strength)
Lot Size |
No of pipes to be tested |
Up to 150 |
3 |
151 to1 200 |
5 |
1201 to 10, 000 |
8 |
c) Hydraulic test: The no of pipes or fittings to be tested for Hydraulic test shall be 5 % of the lot.
Sl. No |
Internal Dia (mm) |
Tolerance percent (%) |
1 |
100- 350 |
±3 |
2 |
400-800 |
±2.5 |
Sl. No |
Internal Dia (mm) |
Tolerance(mm) |
1 |
100- 350 |
±3 |
2 |
Not exceeding 450 |
±2 |
3 |
500 & 600 |
±3 |
4 |
700 & 800 |
±5 |
Dimensions of Barrels and Sockets:
Sl.No |
Internal Diameter |
Class |
Mean thickness of Barrel & socket( Min) |
Internal depth of socket (min) |
Excess shoulder measure ment(Min) |
Length of grooving of spigot (Min) |
1 |
100 |
Sp1 |
12 |
50 |
10 |
75 |
|
|
Sp2 |
14 |
55 |
11 |
82.5 |
|
|
Sp3 |
18 |
60 |
14 |
90 |
2 |
150 |
Sp1 |
15 |
57 |
11 |
85.5 |
|
|
Sp2 |
16 |
60 |
12 |
90 |
|
|
Sp3 |
20 |
62 |
12 |
93 |
3 |
200 |
Sp1 |
16 |
63 |
12 |
94.5 |
|
|
Sp2 |
18 |
65 |
13 |
97.5 |
|
|
Sp3 |
22 |
68 |
15 |
102 |
4 |
230 |
Sp1 |
19 |
63 |
12 |
94.5 |
|
|
Sp2 |
21 |
65 |
14 |
97.5 |
|
|
Sp3 |
24 |
68 |
16 |
102 |
5 |
250 |
Sp1 |
20 |
70 |
16 |
105 |
|
|
Sp2 |
22 |
66 |
17 |
99 |
|
|
Sp3 |
26 |
69 |
18 |
103.5 |
6 |
300 |
Sp1 |
25 |
70 |
16 |
105 |
|
|
Sp2 |
24 |
72 |
18 |
108 |
|
|
Sp3 |
28 |
74 |
19 |
111 |
7 |
350 |
Sp1 |
30 |
75 |
16 |
112.5 |
|
|
Sp2 |
32 |
76 |
20 |
114 |
|
|
Sp3 |
34 |
76 |
20 |
114 |
8 |
400 |
Sp1 |
35 |
75 |
16 |
112.5 |
|
|
Sp2 |
36 |
77 |
20 |
115.5 |
|
|
Sp3 |
38 |
77 |
20 |
115.5 |
9 |
450 |
Sp1 |
37 |
76 |
16 |
114 |
|
|
Sp2 |
40 |
78 |
20 |
117 |
|
|
Sp3 |
45 |
79 |
20 |
118.5 |
10 |
500 |
Sp1 |
40 |
80 |
19 |
120 |
|
|
Sp2 |
45 |
85 |
20 |
127.5 |
|
|
Sp3 |
50 |
90 |
20 |
135 |
11 |
600 |
Sp1 |
43 |
90 |
19 |
135 |
|
|
Sp2 |
50 |
95 |
22 |
142.5 |
|
|
Sp3 |
55 |
100 |
22 |
150 |
12 |
700 |
Sp1 |
50 |
95 |
20 |
142.5 |
|
|
Sp2 |
55 |
100 |
23 |
150 |
|
|
Sp3 |
60 |
110 |
23 |
165 |
13 |
800 |
Sp1 |
55 |
100 |
24 |
150 |
|
|
Sp2 |
65 |
110 |
26 |
165 |
|
|
Sp3 |
75 |
120 |
27 |
180 |
Tests at Factory:
Hydraulic test :
When subjected to the hydraulic test, straight pipes shall withstand an internal hydraulic test pressure of 0.15 MPa on the barrels and without showing signs of injury or leakage.
The pressure shall be applied on pipes shall be maintained for at least 5 s. Care shall be taken to ensure that all air is expelled before the test commenced.
Water Absorption test:
Increase in mass, percent = W3 / W1 * 100
Where, W1 – Mass of dry specimen, (in grams)
W2 - Mass of specimen after immersion (in grams)
W3= W2 – W1
The percentage increase in mass of each test piece by absorption of water shall not exceed the following values.
Sl.No |
Thickness of pipes or fitting (mm) |
Increase in mass percent |
1 |
Up to and including 20 |
6 |
2 |
Over 20 and up to 25 |
7 |
3 |
Over 25 and up to 32 |
8 |
4 |
Over 32 and up to 38 |
9 |
5 |
Over 38 |
10 |
.Acid Resistance test:
Loss in mass, percent = W4/ W1 * 100
Where, W1 – Initial weight of sample, (in grams)
W2 – weight of crucible (in grams)
W3 – weight of crucible + residue (in grams)
W4 - W3 – W2
The loss in mass shall not exceed 2.5%.
4. Alkali Resistance test:
5. Crushing strength test:
When tested along the full length of the pipe barrel from shoulder to spigot, the crushing strength of each class of pipes or pipe sections shall be not less than the values given below:
Sl.No |
Internal diameter (mm) |
Class |
||
SP1 (Kn/m) |
SP2 (Kn/m) |
SP3 (Kn/m) |
||
1 |
Up to 150 |
16 |
18 |
21 |
2 |
200 to 300 |
16 |
21 |
24 |
3 |
350 to 450 |
16 |
26 |
32 |
4 |
500 to 800 |
16 |
32 |
60 |
RAM Diameter = 7.5 cm ; Area of Ram = (3.14/4)*(7.5*7.5) = 44.18 sqcm
As per crushing strength table, load to be applied for SP1 class pipe = 16 kN/m
= 16 x 1000/100 = 160 N/cm
Hence for 60 cm pipe load to be applied = 160x60 = 9600 KN
Now 1 Kg = 9.8 N
Converting Load applied into Kg = 9600/9.8 = 979.59 kg
Hence Crushing load to be applied (in Kg/sqcm) = Load/ Area of RAM = 979.59/ 44.18
= 22.17 kg/sq cm.
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