Understanding Piping Specification.

Piping specification also known/referred as piping material specification, PMS, PMC, pipe spec, line class etc., however all the names represent this one engineering document which is very crucial during the design phase of a project.

Piping specification in perspective of plant design/3D software’s like S3D, E3D, Auto Plant 3D etc., is to assist the piping designer in the selection of piping commodities by limiting the selection as a piping system is being designed/modelled and has a lot of other things like specification rules, specification notes, piping commodity filter, connection commodity filter, piping commodity material control data etc., which can be discussed later in detail.

Pipeline class contains/specifies the components/commodities such as pipe, schedule, material, flange ratings, valve types, valve trim material, branch types, gaskets, bolts and all other specific components required to be used with different fluid services under different operating conditions within a piping system. Pipe class development mainly considers the service category, design & operating pressure, temperature, corrosion conditions, toxicity of fluid, flammability of fluid etc.,

Piping material engineers prepare the piping material specification based on the client requirements and inputs from process engineers by following all the relevant codes and standards whatever/wherever applicable along with the above said considerations like design & operating pressure, temperature, corrosion allowance, types of fluid service etc.,

A typical piping material specification document contains the following information.

The order of the information may be shuffled from project to project, client to client, company to company but the details mostly remain the same.

Cover page which specifies document number along with the name of PMS and other info like revision details etc.,

Header page which specifies details such as design code, piping base material, fluid service, corrosion allowance, flange rating, gasket material, bolting material, valve material, valve trim etc.,

Followed by other details such as detailed allowable services, pressure – temperature limits, default schedule/thickness (NPS, OD, Schedule, Wall thickness) data, general notes and any specific notes based on requirement.

Followed by the commodity items allowed to be used with a short description consisting of size range, material type, end conditions, schedule/thickness/rating, commodity codes categorized as pipe, fittings, flanges, gaskets, bolts, valves, specialty items (if required) etc.,

Fittings would generally consist of 45-degree elbow, 90-degree elbow, equal tees, reducing tees, caps, swages, concentric/eccentric reducers etc.,

Valves would generally consist of ball valves, butterfly valves, check valves, gate valves, globe valves etc.,

Ending with a branch table usually a 90-degree branch table and a 45-degree branch table if required with any specific branch notes.

You can find a sample pipe class, credits of this document to internet.

Thanks for the read and hopefully it might be helpful for any beginners who are seeking to understand about the piping specifications.