Threaded connections
NPT is a tapered pipe thread used in many North American systems. BSP and BSPT vocabulary appears in other markets and can refer to parallel or tapered forms depending on the exact designation. The thread form, nominal size and sealing method should be written together in the RFQ.
Welded connections
Socket weld and butt weld ends affect installation, wall thickness, face-to-face dimensions and maintenance planning. A drawing or line class is useful when the end preparation must match existing pipework.
Flanged connections
Flanged valves require more than “flanged end”. Confirm flange facing, drilling pattern, nominal size, pressure class and the dimensional standard expected by the project.
Testing and records
Testing requirements should be specified as part of the order documents. Ask which pressure test, inspection record, material certificate, drawing and marking information is required. Do not treat a generic standard list as proof that a particular configuration has been tested.
Good RFQ wording
“Stainless steel ball valve, DN25, threaded ends, NPT, body and trim material to be confirmed, service temperature and medium attached, quantity 50 pcs, drawing and pressure-test record required.”