When replacing a valve across GB, ASME or European specification systems, the main risk is assuming that matching nominal size and pressure markings prove interchangeability. Check the pipe connection, installation length and service conditions separately before ordering.
Separate four groups of requirements
| Check | Information to provide | Do not assume |
|---|---|---|
| Pipe connection | Flange standard and edition, DN or NPS, rating designation, facing, bolt quantity and bolt circle | Similar standard names do not prove that flanges mate |
| Installation length | Existing face-to-face measurement, measurement datums, drawing and removal space | Matching bolt holes do not prove matching valve length |
| Pressure, temperature and materials | Design pressure and temperature, body and seal materials, fluid composition | A Class number is not a fixed working-pressure conversion |
| Operation and acceptance | Isolation or throttling duty, differential pressure, operating frequency and leakage test requirements | A successful shell test does not establish zero seat leakage in every service |
Specify face-to-face dimensions separately from flange requirements
ASME B16.10 addresses valve face-to-face and end-to-end dimensions. Its applicability depends on the relevant material, valve type, size, rating class and end connection. The project must separately identify the applicable flange requirements and pressure-temperature ratings. A single standard number on a purchase order does not define every dimension or performance requirement.
Build a quotation checklist
- State the existing valve identification, quantity, location and reason for replacement.
- List pipe interfaces, installation length and flange facing separately. Attach drawings or measurements and flag unknown items.
- Describe normal and exceptional conditions, including startup, cleaning, reverse differential pressure and shutdown.
- Ask the supplier to identify scope of supply, deviations, actuator and accessory configuration, and required documents.
- Approve the proposed drawing and record the technical agreement before placing the order.
Use product pages as a starting point, not an interchangeability certificate
For initial discussion, see the chain-operated flanged butterfly valve and JIS 10K gate valve. Suitability for replacement depends on the quoted specification and approved drawing.
For disc clearance and operating space, continue with the butterfly valve replacement checklist. Return to the engineering selection and technical Q&A hub.
Frequently asked questions
Are DN and PN enough to order a replacement valve?
No. Obtain the existing nameplate, connection standard and edition, flange facing and drilling, face-to-face length, fluid and design conditions. Also confirm materials, actuation and acceptance requirements.
Can Class 150 simply be treated as PN16?
No. They are different designation systems. Check the applicable standards, material and allowable pressure at the design temperature, as well as mating flanges and the limits of the complete assembly.
How can I request a quotation without the old drawing?
Provide nameplate and installation photographs, pipe connection details and available measurements, including units and measurement datums. Mark missing information as subject to confirmation; photographs are not a basis for inventing certified dimensions.
References and limits of this guide
This is a purchasing checklist, not a product-specific installation manual or dimensional drawing. The agreed standard editions, project requirements and supplied valve documents govern. Other manufacturers’ manuals illustrate general checks only; their dimensions, ratings and installation details must not be assigned to Tekron products.