4 General Technical Specification of Bhilai Steel Plant, SAIL ...

© 2007 MECON Limited
All rights reserved
General Technical Specification
05. Bends for pipes for oxygen service shall have a radius of not less than three times the
nominal pipe dia unless otherwise specified.
06. In general pipes having size 50mm and above, shall be joined by butt welding and 40mm
& below by socket welding / screwed connection. Threaded joints shall have to be seal
welded except for galvanized pipes where teflon sealing tapes shall be used. For
galvanized pipeline, pipe joints which are to be made before galvanising shall be of
welding type. Those joints which are to be made after galvanising shall be either flanged
or screwed type. As far as practicable, whole fabricated piping assemblies shall be
galvanized at a time in order to minimize the number of joints to be made after
galvanising.
07. All pipelines shall be provided with drain connections, generally at the lowest point for
removing accumulated condensate or water and line draining. The drain piping shall
have drain pockets and isolation valves. Trap stations shall be provided where
necessary. Lines shall be given proper slope towards the drain points.
08 Piping coming under the purview of Indian Boiler Regulations (IBR) shall be designed in
accordance with such regulations. The design criteria of piping coming under the purview
of IBR shall have to be approved by "Chief Inspector of Boilers" of the respective State
prior to manufacture. All welding procedures, stress relieving procedures, inspection /
testing / certificates and all other records shall have to be approved by Chief Inspector of
Boilers in approved form.
09 Pipes having nominal bore less than 15 mm, shall not be used. Design pressure of steam
and all other service pipelines shall be considered as 1.2 times the maximum expected
pressure. However it shall not be less than 4.0 kg/cm 2 gauge for steam services and 3.5
kg/cm 2 gauge for other services. Design temperature for steam services shall be as pr
IBR and for other pipelines shall be 5 deg. above the maximum sustained service
temperature expected.
10 All the piping coming under the purview of IBR, shall be designed with the allowable
design stresses as per IBR. For all other piping, the allowable design stress shall not be
more than that specified in ANSI B 31.1 or BS:806 latest revision. Pipe thickness of all
pipeline shall be taken as per the pipe thickness schedules. The design and stress
analysis shall take into account the effect of internal/external pressures, thermal
expansion, self weight of piping, support reactions, shock due to relieving devices, surge
and water hammer, earth quake and wind effect, noise and vibrations, corrosion and
erosion etc. and any other effects dictated by recommended engineering practices.
11 Adequate flexibility shall be provided in the pipelines to keep stress and reactions in the
system arising due to thermal expansion or other effects within limits. Where the piping
terminates at an equipment or at the terminal point of a system, the reactions and
thermal movement imposed by piping on the equipment or the system concerned shall
be well within the limits specified.
12 The flexibility analysis of steam, condensate and hot service media pipelines shall be
furnished.
02.15 PIPE SUPPORTS, ANCHORS, RESTRAINTS
- In general pipe supports, restraints, braces or anchors shall be located at those
points in the building or outdoor where provision has been made for the loads
imposed. Loads at the supporting points or restraints shall be determined
sufficiently early and provisions shall be made in the building or outdoor structures
for pipe supports. The Tenderer shall locate, design, supply and erect all the
Gases & Liquid Fluids
Page 18 of 51
GS-02