Flanged Gate Valve Dimensions (AWWA C509/C515)
Before you fabricate a pipe spool or order a replacement, you need the gate valve's face-to-face (lay length) and flange drilling. For resilient-wedge water gate valves these are governed by AWWA standards, so dimensions are consistent across manufacturers within a given standard.
C509 vs. C515 — why lay length differs
AWWA C509 is the original full-body resilient-wedge gate valve. AWWA C515 is the reduced-wall version — lighter and often shorter for the same size. The two can have different lay lengths, so always confirm which standard your valve and your existing spool were built to before swapping one for the other.
Flange drilling
Iron-body flanged gate valves are drilled to ASME B16.1 Class 125, which shares the same bolt pattern as ASME B16.5 Class 150 for matching sizes — so they mate with standard 125/150 companion flanges. For the exact bolt circle, bolt count, and bolt size by line size, see our flange bolt-pattern & dimension chart.
What to verify on the datasheet
- Standard: C509 vs. C515 (affects lay length)
- Face-to-face / lay length for the exact size
- End connection: flanged, mechanical joint (MJ), or push-on
- Stem type: OS&Y (rising) vs. NRS (non-rising) — affects vertical clearance
- Operating nut vs. handwheel and overall height when open
Because lay length varies by standard, we publish the governing standard and exact dimensions on each product page rather than a generic table — that's the number that matters for fit.
Related
See the gate valve selection guide to choose wedge and stem type, then browse gate valves. Need a drop-in match for an existing valve? Send us the old valve's standard and lay length and we'll confirm fit. If the valve itself is misbehaving rather than just needing a dimensional match, see our gate valve troubleshooting guide.
Frequently Asked Questions
What is the difference between AWWA C509 and C515?
Both are AWWA standards for resilient-wedge gate valves, but C509 specifies the original full-body (heavier wall) construction while C515 allows a reduced-wall, lighter-weight body. Because the body dimensions differ, the face-to-face lay length can also differ at the same nominal pipe size. Always confirm which standard an existing valve was built to before ordering a replacement to ensure it drops into the same spool.
What does "lay length" mean for a flanged gate valve?
Lay length (also called face-to-face dimension) is the end-to-end measurement of the valve between its two flange faces. When replacing a valve in an existing pipeline, the lay length must match the spool piece it occupies — even a small mismatch requires cutting and re-welding the pipe. AWWA-standard valves have consistent lay lengths within each standard, which is why confirming C509 vs. C515 matters.
Are AWWA flanged gate valve flanges compatible with ASME B16.5 flanges?
Yes, for the most common pressure class. Iron-body AWWA gate valves are drilled to ASME B16.1 Class 125, which shares the same bolt circle and hole count as ASME B16.5 Class 150 flanges at matching nominal sizes. This means standard Class 150 companion flanges and fittings bolt directly to AWWA-standard iron gate valves without an adapter.
Can I install an OS&Y gate valve in a buried or underground application?
It is not the preferred choice. OS&Y (rising-stem) valves require vertical clearance for the stem to travel upward as the valve opens, which is impractical in a valve box or buried installation. For buried or below-grade service, specify an NRS (Non-Rising Stem) valve, which is operated from the surface using a valve key on the operating nut.