Flanges by standard
AWWA C207 steel flanges for data center water mains
Large data center water mains do not always need ASME process flanges. AWWA C207 waterworks flanges are lighter, flat faced and rated for the pressures that chilled water and condenser water systems run at.
AWWA C207 Class D flat face ring flanges are a common choice for large data center condenser water and chilled water mains: lighter than ASME B16.47, rated 150 to 175 psi, and drilled to match cast iron valves and equipment.
Why waterworks flanges appear in data centers
Hyperscale cooling has pushed water mains into sizes usually seen at water utilities. Much of that large-diameter water piping does not need ASME process flanges. AWWA C207, Steel Pipe Flanges for Waterworks Service, covers sizes from 4 to 144 inches with pressure classes matched to water systems, so it often turns up on condenser water and chilled water mains between the plant and the data halls.
Classes and pressure ratings
| Class | Rated pressure | Sizes |
|---|---|---|
| B | 86 psi (5.9 bar) | 4 to 144 in |
| D | 175 psi (12.1 bar) up to 12 in; 150 psi (10.3 bar) above 12 in | 4 to 144 in |
| E | 275 psi (19.0 bar) | 4 to 144 in |
| F | 300 psi (20.7 bar) | 4 to 48 in |
Ratings apply to water at ambient temperature. Class D suits most data center water mains; Class E covers higher static heads and pump discharge pressures.
Hub, ring and blind flanges
- Ring flanges are flat rings cut from steel plate and slipped over the pipe. They are the usual and most economical form for Class B and Class D.
- Hub flanges have a tapered hub for higher classes and greater stiffness.
- Blind flanges close header ends and future connections, which matters on campuses built in phases.
All C207 flanges are flat faced and used with full-face gaskets. Classes B, D and E are drilled to the ASME B16.1 Class 125 cast iron pattern and Class F to Class 250, so they bolt to waterworks valves, cast iron pumps and strainers.
Send the class, type (ring, hub or blind), nominal size, pipe outside diameter and quantity. We supply AWWA C207 flanges to your specification and drawing, with an EN 10204 3.1 certificate.
Materials
Ring and blind flanges are normally made from carbon steel plate such as ASTM A36 or A516 Grade 70; hub flanges are forged. For stainless water mains, the companion standard is AWWA C228.
AWWA or ASME?
Use AWWA C207 where the piping specification and mating valves are waterworks standard. Use ASME B16.5 or B16.47 where the project is ASME throughout, where raised faces are required, or where the joint sees conditions beyond water service. Compare the two in detail.
Frequently asked questions
Which AWWA C207 class is used for data center water mains?
Class D is the usual choice for chilled water and condenser water mains. It is rated 175 psi up to 12 inches and 150 psi above 12 inches, which covers typical building water pressures.
Are AWWA C207 flanges raised face or flat face?
Flat face. Use full-face gaskets, and bolt them to other flat-faced flanges such as cast iron equipment or AWWA valves.
Will an AWWA C207 flange bolt to an ASME B16.5 Class 150 flange?
Classes B, D and E are drilled to the ASME B16.1 Class 125 pattern, which matches ASME B16.5 Class 150 bolting up to 24 inches. Faces still differ: the B16.5 flange should be flat faced at that joint.