Procurement guide
How to Compare PN, Class and JIS Pressure Designations
Direct answer: PN, Class and JIS are pressure designation systems tied to their referenced standards. Do not convert or substitute them by number alone. Compare the exact design standard, material, temperature, size, end connection, flange interface and project specification before quotation.
Information to Compare
| Comparison field | What to state | Why it matters to the RFQ |
|---|---|---|
| Designation | Record the exact PN, Class, or JIS designation written in the project requirement. | The label and number must remain attached to the specified system. |
| Referenced standard | Record the design, valve, flange, or piping standard supplied by the project. | The referenced standard defines the basis for comparison. |
| Material and temperature | State the required materials and design or working temperature. | Pressure-related limits cannot be reviewed independently of material and temperature. |
| Size and connection | Provide DN or NPS, end connection, flange facing, drilling and dimensional requirements. | The adjoining interface must be checked with the pressure designation. |
| Project specification | Attach the relevant line list, datasheet, drawing, or specification when available. | Project documents resolve fields that a short designation cannot describe. |
| Confirmation record | Keep any proposed comparison or substitution visibly marked for buyer confirmation. | An assumed conversion must not enter the quotation as a confirmed requirement. |
Buyer Questions
Can PN16 be converted directly to Class 150 by the label alone?
No. Compare the referenced standards, material, temperature, size, connection and project requirements before confirming any relationship or substitution.
What JIS information should be included in an RFQ?
Include the exact JIS designation and referenced standard, plus size, material, temperature, connection, flange details and project documents.
How should a proposed pressure-system substitution be handled?
Record it as a proposal for technical and buyer confirmation. Do not present it as an exact or approved conversion without supporting project evidence.
Prepare the Inquiry
Use the checklist to organize known requirements and mark missing fields for confirmation.
Send Your RFQ or BOM