Development of Draft Protocol for Testing of Structural Components and Systems

(a joint initiative of MoHUPA under technology submission of Pradhan Mantri Awas Yojna & IIT, KANPUR)

Galvanised Iron Pipes and Fittings

The GI Pipes are generally used for distribution of treated or raw water in rural or urban areas. These pipes are cheaper, light weight and easy to handle. Details specified below are in reference with IS 1239 Part 1 as given below. .

  1. Supply of Material:
  2. The supply of steel tubes shall conform to IS 1387.

  3. Manufacture:
    1. Chemical composition:
      • Chemical composition of the steel shall comply with Table 1 in Ladle Sample analysis.
      • Table 1: Chemical Composition (Ladle Analysis) Percent, Max as per IS 1239 Part 1



      • Product Analysis:
      • Table 2: Permissible Variation for Product Analysis as per IS 1239 Part 1




    2. The welded tubes shall be manufactured from hot rolled steel strip for welded tubes and pipes conforming to IS 10748 or Cold-rolled low carbon steel sheets and strips conforming to IS 513.

    3. Steel tubes shall be manufactured through one of the following processes:
      • Hot finished seamless (HFS)
      • Cold finished seamless (CDS)
      • Hot finished welded (HFW)
      • Electric resistance welded or high frequency induction welded (ERW or HFIW).

    4. For welded tubes, the height of the internal weld fin shall not be greater than 60 percent of the specified wall thickness.

  4. Dimensions:
  5. Table 3 Dimensions and Nominal Mass of Steel Tubes – Light as per IS 1239 Part 1



    Table 4 Dimensions and Nominal Mass of Steel Tubes — Medium as per IS 1239 Part 1



    Table 5: Dimensions and Nominal Mass of Steel Tubes — Heavy as per IS 1239 Part 1



  6. Tolerances:
    1. Thickness:
      • Welded tubes:
        • Light tubes: + not limited
          – 8 percent
        • Medium and heavy tubes: + not limited
          – 10 percent
      • Seamless tubes: + not limited
        – 12.5 percent
    2. Mass:
      • Single tube (light series): +10 percent
        – 8 percent
      • Single tube (medium and heavy series): ± 10 percent
      • For quantities per load of 15 tonnes, Min (light series): +7.5 percent
        – 5 percent
      • For quantities per load of 15 tonnes, Min (medium and heavy series): ± 7.5 percent
    3. Length:
      • Random length: For orders of over 150 m of any one size of tube, it shall be permissible to supply short random lengths from 2 to 4 m provided that the number of such length does not exceed 5 percent of the total number of lengths for sizes below 65 mm nominal bore and above, 7.5 percent of such short random length shall be permitted. In addition, it shall be permissible for two lengths to be joined together to make a random length, provided that the number of such joint lengths does not exceed 5 percent of the total number of lengths for sizes below 65 mm nominal bore and 7.5 percent of the total number of lengths for sizes 65 mm and above.
      • Exact length: Unless otherwise agreed to between the manufacturer and the purchaser, where exact lengths are specified, either for screwed and socketed tubes or for plain-end tubes each tube shall be within +6−0 mm of the specified length.
      • Approximate length: When approximate lengths are required, either for screwed and socketed tubes or for plain end tubes, each tube shall be within ±150 mm of the specified length.

  7. Joints:
  8. All screwed tubes shall be supplied with pipe threads conforming to IS 554. Gauging in accordance with IS 8999 shall be considered as an adequate test for conformity of threads of IS 554. The minimum length of threads in light tubes shall be 80 percent of that specified in IS 554.

  9. Galvanizing:
    • Where tubes are required to be galvanized, the zinc coating on the tubes shall be in accordance with IS 4736.
    • Tubes, which are to be screwed, shall be galvanized before screwing.

  10. Tests:
    1. Leak Proof Test:
      • Each tube shall be tested for leak tightness as an in-process test at manufacturer’s works either by hydrostatic test or alternatively by Eddy current test, in accordance with Annex B of IS 1239 Part 1.
      • Hydrostatic test shall be carried out at a pressuring of 5 MPa and the same maintained for at least 3 seconds and shall not show any leakage in the pipe.
    2. Tensile Strength:
      • The tensile strength shall be at least 320 MPa (320 N/mm2). The test shall be carried out on full section or strip cut from the selected tubes in accordance with IS 1608 and IS 12278.
      • The elongation percent on a gauge length of 5.65√So where So is the original cross-sectional area of the test specimen, shall be as follows:
      • Table 5: Dimensions and Nominal Mass of Steel Tubes — Heavy



    3. Bend Test for Nominal Bore ≤ 50 mm:
      • When tested in accordance with IS 2329 the tubes shall be capable of withstanding the bend test without showing any signs of fracture or failure. Welded tubes shall be bent with the weld at 90° to the plane of bending.
      • Ungalvanized tubes shall be capable of being bent cold without cracking through 180° round a former having a radius at the bottom of groove in the plane of bending, equal to at least six times the outside diameter of the tube.
      • Galvanized tubes shall be capable of being bent cold, without cracking of the steel, through 90° round a former having a radius at the bottom of the groove equal to at least eight times the outside diameter of the tubes.
    4. Flattening Test for Nominal Bore > 50 mm:
      • Rings not less than 40 mm in length cut from the ends of the selected tubes shall be flattened cold between parallel plates with the weld, if any at 90° (point of maximum bending) in accordance with IS 2328. No opening shall occur by fracture in the weld area until the distance between the plates is less than 75 percent of the original outside diameter of the tube and no cracks or breaks in the metal elsewhere than in the weld shall occur until the distance between the plates is less than 60 percent of the original outside diameter.
    5. Re-test:
      • If test pieces first selected fail to pass any of the tests specified above, two further samples shall be selected for testing in respect of each failure. If passed, the material shall be deemed to comply with the requirements of that particular test. If either of these additional samples fail, the material represented by the test samples shall be deemed as not complying with the standard.

  11. Sampling:
  12. The procedure for sampling of tubes for various tests and criteria shall conform to IS 4711.

  13. Marking:
    • The different classes of tubes shall be distinguished by the following colour bands:
      1. Light tubes: Yellow
      2. Medium tubes: Blue
      3. Heavy tubes: Red
    • Tubes having random length 4 to 7 meters shall have two 75 mm bands one on each end. Tubes having exact length and approximate length as shall have one 75 mm band.

  14. Protection and Packing: in accordance with IS 4740.

  15. For more details, refer to IS 1239 Part 1.

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