MPS = Manufacturing procedure specification
( For the following information, refer to ISO 15590-2 Petroleum and natural gas industries — Factory bends, fittings and flanges for pipeline transportation systems — Part 2: Fittings )
Fittings shall be manufactured in accordance with a documented MPS. If specified by the purchaser, manufacturing shall not proceed until the MPS has been accepted by the purchaser.
The MPS shall specify the following items (as appropriate):
a) for the starting material:
— name of manufacturer;
— steel-making process;
— steel grade;
— product form and dimensions;
— chemical composition, including that of the weld seam; — welding procedure specification.
b) for fitting manufacture:
— forming procedure;
— welding procedure specification and approval record; — heat treatment procedure including thermal cycles; — machining requirements;
— inspection and test requirements;
c) additional requirements such as end preparation, coating, and marking.
An approval of the MPS might be required at the beginning of production.