Understanding Valve End-to-End Face-to-Face Dimensions

Why Standardized Dimensions Matter

Face-to-face (F-F) and end-to-end (E-E) dimensions define the overall length of a valve along the pipe axis. Standardization ensures valves from different manufacturers are interchangeable during maintenance without modifying the piping.

Key Standards

• ASME B16.10: face-to-face and end-to-end dimensions for ferrous valves (US standard)

• ISO 5752: face-to-face dimensions for flanged valves (international)

• EN 558: face-to-face for industrial valves (European projects)

• API 6D: pipeline ball and gate valves—longer face-to-face than B16.10 in some classes

Short vs. Long Pattern

Many valve types come in short pattern (compact) and long pattern dimensions. Globe valves in long pattern allow for in-line maintenance without disturbing the pipeline. Butterfly valves come in wafer (shortest), lug, and flanged configurations with increasing face-to-face.

Specifying F-F Correctly

Procurement specifications must explicitly state the applicable F-F standard and whether short or long pattern is required. Receiving a different standard or pattern will require spool piece modifications—costly and disruptive on tight piping schedules.

Impact on Piping Design

Piping designers use F-F dimensions from valve data sheets to set spool piece lengths in the pipe stress model. Incorrect F-F data causes interferences or unintended gaps in the fabricated piping system, leading to field rework.