MSS SP 75 specifies the dimensional tolerances of WPHY butt-welding pipe fittings sized from 16″(DN400) through 60″(DN1500). For fittings 14″(DN350) and smaller, please refer to ASME B16.9.

Dimension-Tolerances of MSS SP 75 Fittings

The minimum wall thickness shall be 0.01 inch under the nominal thickness. Others are illustrated in the table below,

NPS	Inside Diameter at End	Out of Roundness
		At Ends of Fittings		Throughout body of Elbows
		Elbows	Other
16-24	±0.09	0.19	0.12	2.5%
26-36	±0.09	*A	0.12	2.5%
38-48	±0.12	*A	0.12	2.5%
50-60	±0.25	*A	0.12	2.5%

*A out-of-roundness tolerances at ends shall be 1% of diameter for NPS 26 and larger.

NPS	90°,60°,45°,&30° Elbows & Tees Center-to-End Dimension		Reducers Overall Length	Caps Overall Length
	Long Radius & Tee	3R
16-24	±0.09	±0.12	±0.09	±0.25
26-36	±0.12	±0.25	±0.19	±0.38
38-48	±0.19	±0.38	±0.38	±0.38
50-60	±0.25	±0.38	±0.38	±0.38

NPS	Angularity off Angle Q	Elbows Off Plane P	Eccentric and Concentric Reducers Off Plane *B
16-24	0.09	0.25	2.5%
26-36	0.09	0.50	2.5%
38-48	0.12	0.75	2.5%
50-60	0.19	0.75	2.5%

*B Values that are percent of O.D.

*View more technical details of MSS SP 75 pipe fittings.