ANSI / ASME Flanges

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ANSI & ASME B16.5 Pipe Flanges

What’s the difference between ANSI B16.5 and ASME B16.5 standards?

The B16.5 standard was first published by ANSI in 1973.  Prior to that it was an ASA standard.  In 1996 the standard changed to ASME B16.5.  For 10 years prior to the change, the standard included both and was listed as ANSI/ASME B16.5.

So what’s the difference?  The answer is there is no difference.  The ASA, ANSI and ASME have continually refined and broadened the B16.5 standard.  I’m sure there is a committee working on future enhancements right now.

The current and correct standard is ASME B16.5.  ANSI B16.5 is common industry lingo and is still referred to extensively by architects, engineers, manufacturers and suppliers.  And although the ANSI B16.5 standard does not technically exist, it its understood as another way to say ASME B16.5.

 

 

 

The B16.5 Standard defines the following:

1. Dimensions
2. Tolerances
3. Materials
4. Markings
5. Pressure/Temperature Ratings
6. Pressure Testing

ASME B16.5	ASME B16.5	ASME B16.5	ASME B16.5	ASME B16.5	ASME B16.5
Blind	Lap Joint	Slip On	Socket Weld	Threaded	Weld Neck
Flange Dimensions	Flange Dimensions	Flange Dimensions	Flange Dimensions	Flange Dimensions	Flange Dimensions
Class 150	Class 150	Class 150	Class 150	Class 150	Class 150
Class 300	Class 300	Class 300	Class 300	Class 300	Class 300
Class 400	Class 400	Class 400	Class 600	Class 400	Class 400
Class 600	Class 600	Class 600	Class 1500	Class 600	Class 600
Class 900	Class 900	Class 900		Class 900	Class 900
Class 1500	Class 1500	Class 1500		Class 1500	Class 1500
Class 2500	Class 2500	Class 2500		Class 2500	Class 2500

Common produced materials:

ASTM A105 & A105N Forged Carbon Steel

ASTM A182 F304/304L, F316/316L

ASTM A350 LF2