Use DN and PN language for EN 1092-1 or DIN-controlled RFQs
BLD Forge Direct
EN/DIN vs ASME Flanges for RFQ Review
EN/DIN and ASME flange RFQs use different designation systems, pressure language and document habits. Before comparing prices, confirm whether the project is controlled by EN 1092-1, a legacy DIN drawing, ASME B16.5, ASME B16.47 or a buyer-specific drawing.
Summary
EN/DIN and ASME flange RFQs use different designation systems, pressure language and document habits. Before comparing prices, confirm whether the project is controlled by EN 1092-1, a legacy DIN drawing, ASME B16.5, ASME B16.47 or a buyer-specific drawing.
Use NPS and Class language for ASME B16.5 or B16.47 RFQs
Treat old DIN references as drawing-controlled unless the project accepts EN replacement
Confirm facing, material equivalency and document scope before comparing offers
Published Standard Scope Check
| Standard route | Designation system | Nominal size coverage | Pressure / rating coverage |
|---|---|---|---|
| EN 1092-1 steel flanges | DN + PN | DN 10 to DN 4000 | PN 2.5 to PN 400 |
| ASME B16.5 pipe flanges | NPS + Class | NPS 1/2 to NPS 24 | Class 150, 300, 400, 600, 900 and 1500; Class 2500 through NPS 12 |
| ASME B16.47 large-diameter steel flanges | NPS + Class | NPS 26 to NPS 60 | Class 75, 150, 300, 400, 600 and 900 |
| DIN legacy drawings | DN + PN or old DIN type | Confirm against the drawing revision | Treat as drawing-controlled unless the project explicitly accepts EN 1092-1 replacement |
EN/DIN vs ASME RFQ Translation Matrix
| RFQ control | EN / DIN habit | ASME habit | Buyer action |
|---|---|---|---|
| Size | DN number and sometimes pipe OD | NPS number and pipe schedule / bore | Do not convert DN to NPS without drawing or line class approval |
| Pressure | PN rating | Class rating | Confirm design temperature and material group before comparing ratings |
| Facing | Form / facing note under EN or drawing | RF, FF or RTJ wording | State gasket face and surface finish requirement in the first RFQ |
| Material | EN material number or project grade | ASTM / ASME material grade | Ask for material-equivalency approval before substituting |
| Documents | EN 10204 3.1, PED or project dossier | MTC 3.1, PMI, NDT or third-party release | List certificate language and inspection hold points early |
| Old DIN reference | DIN 2527, DIN 2633 or project legacy drawing | No direct ASME equivalent | Attach drawing; do not price from product name alone |
Practical Checklist
Use this list before sending drawings or line items for quotation review.
State the governing standard: EN 1092-1, DIN drawing, ASME B16.5, ASME B16.47 or buyer drawing
List the size system exactly as shown in the specification: DN/PN or NPS/Class
Attach the drawing when a DIN legacy number, modified bore, non-standard drilling or special face is mentioned
Confirm facing wording, such as RF, FF, RTJ, EN form note or drawing face
List material grade exactly, including EN material number or ASTM / ASME grade
State MTC 3.1, PMI, NDT, PED, third-party inspection or language requirements at RFQ stage
Confirm whether material or dimensional substitution is allowed by the end user
Common RFQ Mistakes
These points often cause repeated clarification, price revisions or document mismatch.
- Treating PN and ASME Class as direct one-to-one replacements without temperature and material review
- Converting DN to NPS without checking bore, pipe schedule and project line class
- Using a DIN legacy product name without attaching the drawing revision
- Comparing supplier prices when one offer includes inspection documents and another does not
- Assuming an ASTM material is accepted in an EN project without written approval
FAQ
Short answers for buyers preparing this RFQ topic.
Can EN 1092-1 PN flanges be quoted as ASME Class flanges?
Not safely from the product name alone. PN and Class ratings must be reviewed against design temperature, material group, dimensions, drilling and the buyer's specification before a substitution is accepted.
When should a DIN flange RFQ include a drawing?
Attach a drawing whenever the RFQ uses a legacy DIN number, a non-standard bore, modified drilling, special facing or project-specific tolerance. Legacy DIN wording is often treated as drawing-controlled.
Which documents should be listed for EN/DIN vs ASME flange orders?
List MTC 3.1, dimensional report, PMI, NDT, third-party inspection, PED or project dossier requirements before quotation so both price and lead time include the same document scope.
PDF Datasheets for RFQ Review
Use these direct PDF links with the article before sending line items. The PDFs are generated from published product-page RFQ scope tables and do not invent standard dimensions.
EN/DIN Flanges RFQ Datasheet
Use this PDF when the RFQ is controlled by EN 1092-1, DIN legacy wording or a PN-based project specification.
ASME B16.5 Flanges RFQ Datasheet
Use this PDF when the RFQ is controlled by ASME B16.5, NPS, Class, facing, material and inspection requirements.
Send your RFQ or drawing directly to BLD Forge Direct.
Email quote@bldforgedirect.com with standard, drawing, material, quantity and inspection requirements.