NPRO Journal · PROCUREMENT
Seven RFQ Mistakes
That Cost Weeks
Incomplete enquiries create non-comparable quotes and schedule fiction. Fix these seven gaps before you hit send.
Incomplete enquiries create non-comparable quotes and schedule fiction. Fix these seven gaps before you hit send.
An incomplete tube sheet RFQ does not save time — it produces incompatible quotes, late discovery of unmanufacturable ligaments, and rework loops that delay the project more than a thorough first package. Fabricators can only schedule material, CNC, and NDT when the specification is frozen enough to quote. Vague RFQs force assumptions; assumptions become change orders.
This article lists the most common tube sheet RFQ mistakes procurement and OEM teams make, and how to fix them before issuing to vendors. It complements our full checklist in ten questions before ordering and the structured guides on products, materials, and testing.
Writing “stainless” or “316” without ASTM/UNS is the fastest path to non-comparable quotes. SS316L (S31603) and 316 (S31600) differ in carbon limits and weld behaviour. Duplex 2205 is not interchangeable with 2507. State exact grade, product form (plate, forging, clad), and heat treatment condition if required.
Fix: cite UNS and ASTM product spec; link internal datasheets from grades in your RFQ appendix.
Fixed, floating, and U-tube exchangers use different tube sheet roles and tolerances. A quote for a generic disc without knowing whether it is a stationary sheet, floating sheet, or forged backing ring wastes a week when the drawing arrives.
Fix: specify fixed, floating, or U-tube; include fixed vs floating context if the plant is converting type.
Tube count alone is insufficient. Fabricators need tube OD, pitch, layout angle (triangular vs square), start row, and edge margin. Without pitch, ligament checks and CNC time are guesses.
Fix: attach controlled drawing or state OD/pitch/layout; run pitch and tube count tools for consistency before RFQ.
Thickness must reflect current pressure, pitch, and code edition. Value-engineered tube sizes or higher design pressure invalidate legacy thickness.
Fix: provide calculated thickness per engineering and TEMA/ASME; see thickness guidance in our engineering blog content and TEMA classes article.
Omitting joint method implies shop standard, which may not match your fluid hazard or client spec. Joint choice affects hole prep, face groove machining, and NDT.
Fix: state expanded, welded, or hybrid per expanded vs welded comparison; reference TEMA class for severity.
“Clad required” without minimum clad thickness, cladding UNS, and bond UT requirement is unquotable for serious jobs.
Fix: full clad spec per clad tube sheets page; solid vs clad decision documented.
Quotes without PMI, UT, RT, hydro, or EN 10204 certificate type will be low — then rise when inspection pack is clarified.
Fix: mirror project ITP; align with testing pillar and client hold points.
Code baseline changes allowable stress, joint rules, and documentation depth. “ASME design” without class or year is incomplete.
Fix: state TEMA R/C/B, ASME VIII edition, and any API 660 or client supplement.
Export packing, marking, and inspection witness requirements differ by market. A domestic ex-works quote is not comparable to DAP Middle East.
Fix: name port and country using countries pages — e.g. UAE, Saudi Arabia.
Emailing an outdated PDF with a newer revision in the project system causes wrong hole count on the machine floor.
Fix: single revision number, date, and title block on every RFQ attachment.
When critical data is missing, responsible vendors stop and ask questions rather than guess. Each clarification round adds calendar days. Worse, a vendor who fills gaps with optimistic assumptions wins on price and loses on schedule — lead time slips when material and NDT scope are renegotiated after PO.
Minimum comparable package:
Walk the list interactively in ten questions before ordering.
Desalination: brine chemistry and face-by-face alloy — desalination and replacement cycles.
Oil & gas: Class R, welded joints, sour service limits — oil & gas.
Marine: seawater grade justification beyond catalogue labels — marine and marine grade stainless.
Early budgetary RFQs are fine if labelled “indicative” and list assumptions. Firm PO requires frozen pitch and thickness.
Yes, with fluid data — but responsibility stays with the specifier. Send analyses for reviewed recommendation via engineering.
Avoiding tube sheet RFQ mistakes is the cheapest schedule improvement on the project. Use ten questions as your template, then submit a complete package through the NPRO India enquiry form for a comparable, manufacturable quote.
Send your drawing or RFQ — NPRO India reviews code, material and manufacturability before quoting.
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