What is a piping specification?

Contents of a specification

• the design conditions: medium, and the range of pressure and temperature;
• the material of pipes and fittings, for example carbon steel or stainless steel;
• per range of nominal sizes: the wall thickness or schedule, the type of connection (butt weld or socket weld), the flange type and the pressure class (PN or Class);
• the gasket type, the bolt material and the valves;
• the corrosion allowance and the requirements for testing.

Naming

A piping class has a short code, for example A1 or CS150. The code appears in the line number, in the line list and on the isometric drawing, so that each line can be traced to its specification.

Why a specification matters

A specification keeps the choice of materials consistent across a project. Purchasing orders the right materials, the workshop knows which welding procedure applies, and inspection checks against one document. A component that does not match the class leads to rejection or to replacement on site.

Specification and bill of materials

Every line of the bill of materials comes from the specification of the line. When a line changes class, its components and the bill of materials change with it.

In FlowCAD3D

Specifications (piping classes) warn or block when a component does not match. Lines get line numbers, and the line list holds the medium, pressure, temperature and insulation per line; a line list is imported from XLSX or CSV.