ASME B16.10 Face to Face Dimensions

ASME B16.10 is the standard that defines the face-to-face and end-to-end dimensions for flanged, butt-welding, and wafer/lug-type valves. These dimensions, also called “lay lengths,” ensure that any valve from any manufacturer can be installed in an existing piping system without modifying the pipe spools or flange spacing. ASME B16.10 is critical for valve interchangeability in oil and gas, petrochemical, and power plant piping.

When ASME B16.10 Applies

The standard is referenced whenever a valve is specified in a piping system designed to ASME B31.1 (power piping) or ASME B31.3 (process piping). Piping designers use B16.10 dimensions in their 3D models and piping isometric drawings to determine the exact location of each flange face and ensure the pipe spools fit without shimming or cold springing.

Face-to-Face Dimensions: Key Definitions

Term	Definition
Face-to-face (FTF)	Distance between the inlet and outlet flange faces of a flanged valve
End-to-end (ETE)	Distance between the inlet and outlet weld ends of a butt-weld valve
Short pattern	Compact lay length (standard for gate valves, most ball valves)
Long pattern	Extended lay length (standard for globe valves, Y-pattern globe valves)
Wafer thickness	Distance across a wafer or lug butterfly or check valve body

Typical Face-to-Face Dimensions (Flanged Gate Valves, Short Pattern)

NPS	DN	Class 150 (mm)	Class 300 (mm)	Class 600 (mm)	Class 900 (mm)	Class 1500 (mm)
2	50	178	216	292	292	292
3	80	203	241	356	356	356
4	100	229	292	432	432	432
6	150	267	356	559	559	559
8	200	292	394	660	660	660
10	250	330	457	787	787	787
12	300	356	502	838	838	838
16	400	495	572	991	991	991
24	600	610	762	1,346	1,346	1,346

Globe Valves: Long Pattern vs Short Pattern

Globe valves are available in both long and short pattern. The long pattern is the traditional design; the short pattern allows a globe valve to fit in the same space as a gate valve of the same size and class.

NPS	Class 150 Long (mm)	Class 150 Short (mm)	Class 300 Long (mm)	Class 300 Short (mm)
2	203	178	267	216
4	292	229	356	292
6	356	267	444	356
8	419	292	533	394

Butterfly and Check Valve Dimensions

Wafer and lug butterfly valves have significantly shorter face-to-face dimensions than gate or globe valves, which is one of their primary advantages in tight piping layouts.

NPS	Butterfly Wafer (mm)	Dual-Plate Check Wafer (mm)
4	43-56	60-82
6	46-56	70-95
8	46-64	80-105
12	51-76	100-130
24	76-114	150-190

Common Mistake

Assuming that all valve types in the same size and class have the same face-to-face dimension. A Class 150 NPS 6 gate valve (267 mm FTF) and a Class 150 NPS 6 globe valve long pattern (356 mm FTF) have very different lay lengths. Substituting one type for another without checking B16.10 will misalign the piping. Always verify the FTF dimension before any valve change in the field.

For complete face-to-face dimension tables across all valve types and pressure classes, see the full reference.

Read the full guide to valve face-to-face dimensions