Category: Piping Standards

Pipe, Valve & Fitting Standards and Organizations

The two most recognized standards organizations in the piping (PVF) industry are ANSI & ASTM.  ANSI standards are mostly concerned with dimensions and tolerances.  ASTM standards are mostly concerned with materials; their chemistry, construction and mechanical properties.  Dimensions are important if you want the parts to fit and seal, but also for design and engineering.  Materials are important for corrosion resistance, strength and consistency. 

Pipe and fitting standards are also written by ISO, MSS, API and ASME.  These organization’s standards build on the ANSI and ASTM standards.  They have combined the standards, filled a few gaps and further defined more details.  ASME has become the dominate standard for pressure vessels and boilers.  If you compare the ASME classification number with ANSI and ASTM numbers they either are identical or they are nearly identical.

ASME B1.20.1 is the same as ANSI B1.20.1. 
ASTM A105 is the same as ASME SA105.

In the past nearly all pipe, valve and fitting manufacturers built to the ASTM and ANSI standard.  Babcock & Wilcox used to be one of the largest pipe fitting manufacturers in the US.  Sometime in the 1970’s or 80’s they stopped producing fittings.  If you look at theirs and other manufacturer’s catalogs up to the early 2000’s you will see they produced pipe, valves and fittings to the ANSI & ASTM standards.  Today you will find that many manufacturers are producing to the ASME, API, MSS and ISO standard, yet most product specifications still list the ANSI and ASTM standard. 

It is important to note that these standards organizations don’t just dictate what the standards should be; they collaborate with independent engineers, manufacturers, governments and other standards organizations. 

ANSI – American National Standards Institute  http://www.ansi.org/

ASTM International –American Society of the Association for Testing and Materials

http://www.astm.org/

ISO – International Organization for Standards http://www.iso.org/iso/home.htm

MSS – Manufacturers Standardization Society - http://msshq.org/Store/index.cfm

ASME – The American Society of Mechanical Engineers - https://www.asme.org/

API – American Petroleum Institute http://www.api.org/

Below is a list of common ANSI and ASTM standards for pipe and fittings.  For the ASME equivalent of ASTM change the A to SA and B to SB.  ANSI and ASME use the same number designations.