SWG PIPES



 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

  1. Name or trade mark of the manufacturer
  2. Size ( internal dia)
  3. Class of pipe

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.

  1. Physical Measurements
  1. Internal Diameter

Sl. No

Internal Dia (mm)

 Tolerance    percent (%)

1

100- 350

±3

2

400-800

±2.5

  1. Thickness of Barrel  and socket

Sl. No

Internal Dia (mm)

 Tolerance(mm)

1

100- 350

±3

2

Not exceeding 450

±2

3

500 & 600

±3

4

700 & 800

±5

  1. Internal depth of socket
  2. Excess shoulder measurement
  3. Length   of pipe( Tolerance -1.5  %   & + 4 % mm )
  4. Length of grooving of spigot
  5. Grooving: The  interior of the sockets and exterior of the spigots shall be grooved circumferentially, and such grooving on the spigot shall be for a length equal to one and half times the depth of sockets, and depth of grooves shall be between 1 mm to 2.5mm.

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.

  • Pressure to be applied for pipes – 0.15 MPa
  • Duration of test – 5sec

Water Absorption test:

  • Size of specimen - 50 Sq cm - to 130 Sq cm.
  • Sample required to be dried at Temperature not less than 150° C in oven and bring at room temperature and Weigh it W1.
  • Immersion of sample in water   for an  hour
  • Take the immersed sample and keep it for room temperature and weigh it W2.

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:

  1.  Size of specimen – 5 cm square, not more than 200 g in mass
  2. Liquid needed for immersion 4.9% sulphuric acid and balance distilled water.
  3. Sample required to be dried at temperature not less than 150° C in oven and bring the same at room temperature. Weigh the same as W1
  4. Immerse in above prepared solution (in step ‘b’) for 48 hrs after the process of step ‘c’.
  5. Remove the sample and clean the samples with hot water so that the washed water falls in above prepared solution ( in  step  ‘b’)   .
  6. Filter the solution processed in step   ‘e’ and add 5ml of concentrated sulphuric acid.
  7. Heat the above solution until evaporates and only residue left in crucible.

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:          

  1. Size of specimen: 75 sq cm to 130 sq cm.
  2. Liquid for test solution of Magnesium sulphate and distilled water
  3. Solution should be boiled and sample should be submerged up to 2 hrs in boiling solution.
  4. Remove the sample and keep it in oven for heating not less than 110° C then bring the sample to room temperature.’
  5. Step ‘c ’ and step  ‘d ’ should be repeated 5 cycles
  •  After the completion of 5 cycles there shall be no evidence or pitting softening spalling or cracking.

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

 
6. Load Calculation for SP1 class pipe measuring 0.6 m length:

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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