GAS CYLINDER THREADING.

It is rather tempting to get back to the customer and clarify the thread required.

Note that on gas cylinders themselves, a fueL has a Left-hand thread, so as not to mix up the regulators.

Either BSP or NPT threads depending on the customers preferred spec. See http://www.colder.com/Downloads/NPT.pdf.

The following ANSI/ASME standards cover threading in piping and vessel design :

ASME B1.1-2003 Unified Inch Screw Threads (UN and UNR Thread Form)

ANSI B18.2.1 Square and Hex Bolts and Screws Inch Series

ASME B18.2.2-R1999 Square and Hex Nuts Inch Series

ANSI/ASME B1.20.1-R2001 Pipe Threads, General Purpose (Inch)

ANSI = American National Standards Institute

ASME = American Society of Mechanical Engineers