AWWA C207 steel pipe flanges are designed for waterworks service, including municipal water transmission, industrial water systems, water-treatment plants, cooling-water systems and large-diameter steel pipelines.

AWWA C207 covers steel ring-type slip-on flanges and blind flanges in sizes from 4 in. through 144 in. (100 mm through 3,600 mm).

Among the available pressure classes, AWWA C207 Class D is widely used for water pipelines, pump stations and large-diameter steel piping systems.

Available products include carbon steel ring flanges, blind flanges, forged flanges, plate flanges and custom large-diameter flanges with optional FBE coating, hot-dip galvanizing and project-specific protective coatings.

AWWA C207 Flange Overview

Item	Specification
Standard	AWWA C207
Service	Waterworks
Size Range	4″–144″
Common Classes	Class B, D, E, F
Flange Types	Ring-Type Slip-On, Blind
Typical Facing	Flat Face
Material	Carbon Steel / Stainless Steel
Coating	FBE, HDG or Project-Specified
Applications	Water Transmission, Treatment Plants, Pump Stations

AWWA C207 Class D Flanges

Class D is one of the most commonly specified AWWA flange classes for medium-pressure waterworks piping.

Typical working pressure ratings are:

Nominal Size	Working Pressure
4″–12″	175 psi
Over 12″	150 psi

Pressure selection should consider normal operating pressure, surge pressure, hydrostatic testing, flange assembly and system design conditions.

AWWA Class D pressure ratings should not be treated as equivalent to ASME Class 150 pressure-temperature ratings.

AWWA Class D Ring Flange

AWWA C207 Class D steel Ring Flange

A Class D ring flange is a steel ring fitted over the outside diameter of the pipe and welded to the pipe.

It is commonly used for:

• Water transmission pipelines
• Pump stations
• Water-treatment facilities
• Cooling-water systems
• Fire-water systems
• Industrial water piping
• Large-diameter steel pipe

Ring flanges are particularly suitable for large-diameter water piping where economical and practical flange connections are required.

AWWA C207 Blind Flange

AWWA C207 blind flanges are used to close:

• Pipeline ends
• Valve connections
• Equipment nozzles
• Temporary system openings
• Future branch connections

Blind flange thickness and dimensions depend on nominal size and pressure class.

AWWA C207 Class D Dimensions

AWWA C207 defines important flange dimensions including:

• Outside diameter
• Inside diameter
• Flange thickness
• Bolt-circle diameter
• Number of bolt holes
• Bolt-hole diameter

For large-diameter pipe, the flange inside diameter should be confirmed against the actual pipe outside diameter, wall thickness and internal lining.

This is especially important for cement-mortar-lined water pipe and fabricated steel pipelines.

AWWA C207 and ASME Flange Drilling

AWWA Class D flanges use established waterworks drilling patterns.

Class D flange drilling is compatible with ASME B16.1 Class 125 cast-iron flange drilling.

For sizes through 24 in., the drilling pattern also corresponds with ASME B16.5 Class 150 steel flange drilling.

This dimensional compatibility does not make the pressure ratings equivalent.

The flange pressure rating remains governed by the applicable AWWA C207 class.

Flange Facing

AWWA C207 flanges are generally supplied with flat-face gasket seating surfaces.

Typical gasket options include:

• Full-Face Rubber Gasket
• Ring Gasket
• Compressed Fiber Gasket
• EPDM Gasket
• NBR Gasket
• PTFE-Based Gasket

Gasket material and thickness should be selected according to fluid, temperature, flange size and project requirements.

AWWA C207 Flange Materials

AWWA C207 flanges can be manufactured from forged steel, steel plate or fabricated steel rings depending on size and project specification.

Carbon Steel

Common material options include:

• ASTM A105
• ASTM A36
• ASTM A516 Grade 60
• ASTM A516 Grade 65
• ASTM A516 Grade 70
• Project-Specified Carbon Steel

Large-diameter ring flanges are commonly manufactured from plate or fabricated steel rings.

Stainless Steel

For corrosive water and special industrial service, stainless steel flanges can also be manufactured in materials such as:

• 304
• 304L
• 316
• 316L

Material requirements should be clearly stated in the purchase specification.

ASTM A105 AWWA C207 Flanges

ASTM A105 may be used when a forged carbon steel flange is required.

Typical applications include smaller-size forged AWWA flanges or projects specifically requiring forged construction.

For large-diameter flanges, plate construction is often more practical.

A complete specification should identify both the flange standard and material.

Example:

AWWA C207 Class D Ring Flange, 12″, ASTM A105 Forged Carbon Steel

or

AWWA C207 Class D Ring Flange, 48″, Carbon Steel Plate, FBE Coated

FBE Coated AWWA Flanges

Fusion Bonded Epoxy coating can be applied to AWWA C207 flanges for enhanced corrosion protection.

FBE-coated flanges are commonly used in:

• Potable-water pipelines
• Buried water mains
• Water-treatment facilities
• Industrial water systems
• Coastal environments
• Desalination facilities

Coating requirements can include:

• Surface preparation
• Specified dry film thickness
• Holiday testing
• Adhesion requirements
• Repair procedures
• Potable-water approval when required

Hot-Dip Galvanized AWWA Flanges

Hot-dip galvanizing is available for selected carbon steel AWWA flanges.

Typical applications include:

• Above-ground water piping
• Utility systems
• Outdoor installations
• Fire-water systems
• Corrosive atmospheric environments

Bolt-hole dimensions and mating surfaces should be considered when specifying heavy galvanized coatings.

AWWA C207 vs ASME B16.5

Item	AWWA C207	ASME B16.5
Main Application	Waterworks	Process Piping
Size Range	4″–144″	1/2″–24″
Common Flange Types	Ring, Blind	WN, SO, Blind, SW, Threaded
Pressure Designation	Class B/D/E/F	Class 150–2500
Typical Facing	Flat Face	RF, RTJ, FF
Large-Diameter Water Pipe	Common	Limited

AWWA C207 is particularly suitable for large-diameter water pipelines where lighter and more economical steel flange construction is required.

Typical Applications

AWWA C207 Class D flanges are commonly used in:

• Municipal water transmission
• Potable-water systems
• Water-treatment plants
• Wastewater facilities
• Pump stations
• Cooling-water systems
• Fire-water systems
• Industrial water pipelines
• Irrigation systems
• Desalination plants
• Large-diameter steel pipelines

Inspection and Certification

AWWA C207 flanges can be supplied with:

• Material Test Certificate
• EN 10204 Type 3.1 Certification
• Chemical Analysis
• Mechanical Test Reports
• Dimensional Inspection
• Bolt-Hole Inspection
• Visual Inspection
• Coating Inspection
• FBE Holiday Testing
• Third-Party Inspection
• Material Traceability

How to Order AWWA C207 Flanges

A complete inquiry should include:

• AWWA flange class
• Flange type
• Nominal size
• Pipe outside diameter
• Flange inside diameter
• Material
• Quantity
• Coating
• Gasket requirement
• Inspection requirement

Example 1

AWWA C207 Class D Ring-Type Slip-On Flange, 32″, Flat Face, Carbon Steel, 150 psi, FBE Coated

Example 2

AWWA C207 Class D Ring Flange, 28″, Flat Face, ASTM A105, 150 psi

Example 3

AWWA C207 Class D Blind Flange, 24″, Flat Face, Carbon Steel, FBE Coated

Frequently Asked Questions

What is AWWA C207?

AWWA C207 is a steel pipe flange standard primarily used for waterworks service.

What sizes are available?

AWWA C207 flanges are available from 4 in. through 144 in.

What is the pressure rating of a Class D flange?

Class D flanges are typically rated for 175 psi working pressure in sizes 4–12 in. and 150 psi in sizes above 12 in.

Is AWWA Class D the same as ASME Class 150?

No. Some drilling dimensions are compatible, but their pressure-rating systems and design basis are different.

Are AWWA C207 flanges flat face?

AWWA waterworks flanges are generally supplied with flat-face gasket seating surfaces.

Can AWWA flanges be FBE coated?

Yes. FBE coating is commonly supplied for water, buried pipeline and corrosion-protection applications.

Can AWWA C207 flanges be made from ASTM A105?

Yes. ASTM A105 can be used for forged construction where specified. Plate and fabricated steel construction are also commonly used.

AWWA C207 Class D Flange Supplier

We manufacture and supply AWWA C207 steel flanges for municipal, industrial and large-diameter water piping systems.

Available products include:

• AWWA C207 Class D Ring Flanges
• AWWA C207 Class D Blind Flanges
• Class B, D, E and F Flanges
• Large-Diameter Steel Ring Flanges
• ASTM A105 Forged Flanges
• Carbon Steel Plate Flanges
• FBE-Coated AWWA Flanges
• Hot-Dip Galvanized Flanges

For quotation, please provide the flange class, size, pipe OD, flange ID, material, coating, quantity and inspection requirements.