Volume-II - GAIL

(iii) Adhesive Layer Thickness
Adhesive layer thickness shall be checked at every one meter spacing at 3,
6, 9 and 12 o’clock positions. The thickness shall comply the specified
thickness requirements.
(iv) Holiday Inspection
Entire pipe shall be subject to holiday inspection and the test voltage shall
be set to exceed 5 v/micron of epoxy thickness specified for the portion
coated only with epoxy layer.
(v) Adhesion Test
(a) Adhesion Test (24 hrs or 48 hrs) shall be carried out on the epoxy
coated pipe. Test method, no. of test specimen and acceptance
criteria shall comply CSA Z.245.20-98, Table 4.
(b) Adhesion of FBE shall also be separately determined at ambient
temperature at two locations by the “St Andrews Cross” method
and the test shall comply with the specified requirements.
(vi) 2.5° Flexibility Test
2.5° Flexibility test shall be carried out on the epoxy coated pipe at test
temperature of 0°C. Test method, no. of test specimen and acceptance
criteria shall comply CSA Z.245.20-98, Table-4.
(vii) Cross-section & Interface Porosity Test
Cross section porosity and interface porosity tests shall be carried out on
the epoxy coated pipe. Test method, no. of test specimen and acceptance
criteria shall comply CSA Z.245,20-98, Table-4.
7.5.2 Tests on pipes coated only with all three layers
(i) Bond Strength
Three test pipes shall be selected for bond strength tests. On each of the
selected pipes, three bond strength test shall be performed for each
specified temperature i.e. one at each end and one in the middle of the
pipe and specified requirements shall be complied with, i.e. bond strength
as well as mode of separation. Length of peel shall be minimum 65mm.
None of these samples shall fail.
(ii) Impact Strength
Three test pipes shall be selected for impact strength test and the test
shall meet the requirement.
GAIL (INDIA) LIMITED
3 – LAYER POLYETHYLENE
COATING OF LINEPIPES
GAIL-TS-COATING-3LPE
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