Piping Material Specification for Steam Traps


Steam traps are normally specified in main Piping Material Specification for the project. Variety of information must be specified accurately so that correct type of steam trap is procured for the given steam service.

Piping Material Specification for Steam Traps

Piping Material Specification for Steam Traps

Sample Steam Trap Specifications

Piping material specification for steam traps depends on base piping specification for concerned steam piping network. Piping material engineer has to specify following information for procurement of steam traps.

Material Short Code

It depends on company or project specification. Used for tracking of MTO in material management systems.

Example short code : STT

Nominal Size

This is decided by process department and indicated in P&ID, and depends on calculated condensate load. Normally used sizes are 1/2″ and 3/4″.

Commodity Code

This too depends on project as well as company standard for specifying commodity code.

Example commodity code : KFKJAFKJKLFJ


Its just a name of fitting. Its “Steam Trap” in this case.

Type of Steam Trap

Selection of type of steam trap is made by process department based on operating temperature, pressure, condensate load, nature of condensate, condensate removal strategy (Open drain or closed drain system) etc. It is specified in steam trap data sheet by process department.

E.g. Bimetallic

End Conditions

Steam traps comes in all three end conditions i.e. Flanged, Socket welded and threaded. Their selection depends on end conditions of other fittings for that size in concerned piping material specification.

E.g. Flanged Ends


This specifies if strainer should be integral to trap or not. Most of the time, integral strainers are used to reduce number of fittings.

E.g. Integral Strainer

Body Material

Strainers are mostly forged fittings. So same material that is used for other forged fittings like socket weld fittings or flanges etc. is used to specify body material for strainers. It depends on Piping Material Specification for concerned steam piping system.

E.g. ASTM A105

Internal Trim

Internal trim specifies material of construction for internal parts like integrated strainer, screws, discs, valves etc. It is always stainless steel for trouble free operation without any corrosion.

E.g. 316 SS

Flange Facing

If flanged steam trap is specified, flange facing type need to be specified. Most of the time, it will be raised face. It depends on base piping material class for concerned steam piping system.

E.g. Raised Face

Dimensional Standards

Steam traps are fabricated as per Manufacturers own standard. There is no common international standard for the same.

E.g. Manufacturer’s own.


Process data sheet for the steam trap should be specified which is tagged with Commodity Code.

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