Volume-II of IV - GAIL

MECON LIMITED
REGD. OFF : RANCHI (BIHAR)
PROCESS & PIPING
DESIGN SECTION
NEW DELHI
STANDARD SPECIFICATION
TITLE WELDING OF ONSHORE GAS
SPECIFICATION NO. PAGE 16 OF 48
PIPELINES
MEC/S/05/62/02 REVISION
i. Any length of inadequate penetration of the root bead as defined by API-
1104 is not acceptable except that root concavity is allowed as per API
1104.
ii. Any amount of incomplete fusion at the root of the joint as detailed in para
6.3.4 of API 1104 sixteenth edition May, 1983 (Ref. Fig. 13) is considered
unacceptable.
iii. Unrepaired burn through areas are unacceptable.
All requirements mentioned in the specification shall be arranged and executed
by the CONTRACTOR through his own resources. In addition, for pipes with wall
thickness 9.5mm and above, ultrasonic inspection is required in the following
cases as per clause 15.0 of this specification.
a) On the first 100 welded joints corresponding to each automatic (GTAW/
GMAW) welding procedure used.
b) When 20mm or more are cut from the pipe end as supplied, the ends shall
be ultrasonically inspected for an additional length of 20mm to assure no
lamination exist.
c) When welds are repaired.
d) When in the opinion of COMPANY, ultrasonic inspection is required to
confirm or clarify defects indicated by radiography.
e) When automatic procedure is used at least 10 cm on each weld shall be
ultrasonically inspected at COMPANY's discretion.
In addition, ultrasonic inspection may be required for certain critical weldings of
the pipeline (i.e. tie-ins, welding of valves, flanges) randomly selected at
COMPANY's discretion. All fillet and groove welds other than those radiographed
shall by subjected to dye penetrant/ MP inspection. The non-destructive test
system used for inspecting welds must be approved by the COMPANY.
Weld quality is judged on the basis of the acceptability criteria mentioned below:
\\Akjha\work contrac\standard TS for Pipe Line WC (Vol-II) MASTER FOLDER\02A welding onshore gas pipeline\Welding of Onshore Gas Pipelines with addendum - I 02A.doc