Equipment and Piping Layout : Steam Systems

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Steam Header

Steam header shall be located generally on the upper tier and at one end of the rack adjacent to columns.

Header Branches

Branch lines from horizontal steam header, except condensate collection points, shall be connected to the top of the pipe header. Isolation valves (if provided) on the branch line shall preferably be provided on the horizontal run and outside the pipe rack. All branch lines shall be drainable.

Drip Legs

Wherever condensate is to be drained, proper condensate draining facility shall be provided. Drip legs & steam traps shall be provided at all low points and dead ends of steam header. Drip legs at low points shall be closer to down stream riser and shall be provided to suit bi-directional flows, if applicable.

Steam Traps

All turbines on automatic control for start up shall be provided with a steam trap in the steam inlet line. All traps shall be provided with strainers if integral strainers are not provided. Steam traps discharging to atmosphere shall be connected to storm water drain/storm sewer or underground condensate collection system.

Steam traps shall be provided at pocketed low points and at dead ends of steam headers. Traps shall also be provided on excessively long runs of steam piping, for sufficient condensate removal to insure dry quality steam at destination. Steam traps located more than 4500 mm above high point of finish surface, except pipeways, shall be accessible from platform.

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Expansion Loops

Expansion loops are to be provided to take care of the expansions within units.

Indian Boiler Regulations (IBR)

Steam lines with conditions listed below fall in the scope of IBR.

  1. Lines having design pressure (max. working pressure) above 3.5 Kg/cm2 (g).
  2. Line sizes above 10″ inside diameter having design pressure 1.0 Kg/cm2(g) &above.
  3. Lines with design pressure less than 1.0 Kg/cm2(g) are excluded.
  4. Users of steam like steam tracing lines, jacket of the steam jacketed lines, steam heating coil within the equipment are excluded from IBR scope.
  5. Boiler feed water lines to steam generator, condensate lines to steam generator and flash drum shall be under purview of IBR.

IBR requirements (in brief)

  1. All materials used on lines falling under IBR must be accompanied with IBR Inspection Certificate in original.
  2. Alternatively, photocopy of the original certificate duly countersigned and attested by local boiler inspector is acceptable.
  3. Leading inspection authority viz. Lloyds, EIL etc are authorised
    inspection authorities for IBR outside India, whereas, for Indian supply only IBR is the inspection authority.
  4. Drawings like ‘General Arrangement Drawings’ and Isometrics of lines falling under IBR must also be approved by IBR authority of State in which the system is being installed.
  5. All welders used for fabrication of IBR system must possess IBR welding qualification certificate.
  6. IBR system shall be designed to comply with IBR regulations as well as ASME B31.3.
  7. Design calculations for the same must be approved by IBR authority.
  8. IBR approval is obtained with requisite fees payable to Indian Boiler Board of the State concerned.
  9. Steam generators (boilers/heat exchangers) shall require exclusive IBR approval alongwith it’s integral piping upto the final isolation valve.
  10. The discretion of IBR authority of state is final and binding for the above cases.
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