How to Prepare a Technical RFQ for Industrial Flanges

A technical RFQ, or Request for Quotation, should include enough information for the supplier to identify the required flange and check its compatibility with the piping system.

An incomplete RFQ may lead to repeated questions, incorrect selection or delays in quotation and production.

1. Specify the Flange Type

First, identify the required flange type:

• Weld Neck Flange
• Slip-On Flange
• Blind Flange
• Lap Joint Flange
• Socket Weld Flange
• Threaded Flange

The flange type should match the pipe connection method, operating conditions and maintenance requirements.

2. Provide the Size and Dimensions

State the nominal pipe size using NPS or DN.

For replacement projects or non-standard requirements, also provide:

• Outside diameter
• Bore or inside diameter
• Flange thickness
• Bolt circle diameter
• Number and size of bolt holes
• Pipe wall thickness

A technical drawing, dimensional table or existing sample can help the supplier confirm the required dimensions.

3. Confirm the Standard and Pressure Rating

The RFQ should specify the applicable standard, such as:

• ASME B16.5
• ASME B16.47
• EN 1092-1
• JIS B2220

The pressure rating should also be clearly stated, for example:

• ASME Class 150, Class 300 or Class 600
• PN10, PN16 or PN40

Different standards may use different dimensions, drilling patterns and pressure designations. The standard should therefore be confirmed before quotation.

4. State the Material and Grade

Common flange materials include:

• Carbon steel
• Stainless steel
• Alloy steel

Typical material grades include:

• ASTM A105
• ASTM A350 LF2
• ASTM A182 F304
• ASTM A182 F316

Material selection should be based on the process medium, operating temperature, working pressure and corrosion conditions.

5. Specify the Facing and Connection

The RFQ should include the required flange facing:

• RF — Raised Face
• FF — Flat Face
• RTJ — Ring Type Joint

It should also specify the connection method, pipe outside diameter and any special requirements related to welding, threading or machining.

The flange, gasket, bolts and connected equipment should be checked as one complete connection system.

6. Confirm Inspection and Documentation

For industrial projects, the buyer may need to request:

• EN 10204 3.1 Material Test Certificate
• Chemical Composition Report
• Mechanical Properties Report
• Dimensional Inspection Report
• Pressure or Leakage Test Report
• Certificate of Conformity

Documentation requirements should be stated before production to avoid delays.

7. Add Quantity and Delivery Information

The RFQ should also include:

• Required quantity
• Delivery destination
• Required delivery date
• Packaging requirements
• Marking or customer logo requirements
• Special inspection requirements

RFQ Checklist

Before sending the inquiry, confirm that the following information is included:

Flange type, size, standard, pressure rating, material grade, facing, connection details, quantity and documentation requirements.

A complete technical RFQ helps the supplier check compatibility and prepare a more accurate quotation.