No single document governs a tube sheet. A real specification stacks a material standard, a design code, and a construction standard — and which ones apply changes by destination country and industry.
A complete specification names one standard from each layer. Naming only one — usually the design code — is the most common cause of a quote coming back with clarifying questions.
Defines the chemistry, mechanical properties, and allowable stress of the ordered product form — e.g. ASTM A240 for stainless plate, EN 10028 in Europe. Use the grade designation and product-form reference when translating common UNS, EN and JIS callouts.
Provides the thickness, ligament efficiency, and pressure-boundary calculation — TEMA for the mechanical design of the exchanger, ASME Section VIII for the pressure vessel itself.
Governs fabrication tolerance, welding qualification, and testing/documentation — API 660 for petroleum service, PED for EU market access, classification society rules for marine.
ASME governs pressure vessel and boiler design; ASTM governs material specification. The default pair for US-bound and much of Middle East-bound supply.
European material and pressure equipment standards, required for CE marking and PED compliance on EU-bound equipment.
TEMA is the dedicated mechanical design standard for shell-and-tube exchangers; API standards layer petroleum-industry construction requirements on top.
ASTM and ASME material specifications define chemistry, mechanical properties and product-form requirements. They should be read separately from tube-sheet design standards such as TEMA and from ASME construction / design requirements for the pressure part.
A purchase order that names only a design code is incomplete. Name the material specification and product form as well — for example plate versus forging — then confirm geometry, machining and inspection from the drawing.
ASTM A965/A965M covers austenitic stainless-steel forgings for boilers, pressure vessels, high-temperature parts and associated equipment. ASME SA-965/SA-965M is the corresponding ASME designation where the Code edition adopts it. Grades are listed as F-designations (for example F347), not as plate grades.
Continue to the SS347 / F347 grade page for the flagship entity path, or to forged tube sheets by material specification for the product-form intent.
A965 does not list F316Ti or F310S. Grade pages own entity intent; this hub owns specification education.
Compact navigation only — already verified in Phase 7A. These are not universal tube-sheet standards; each is form-scoped.
Cross-check designations on the grade equivalence resource.
The most common specification error: assuming Class R is simply "better" than Class C. Each class targets a different service, with different design margins.
| Class | Intended Service | Design Margin | Typical Sector |
|---|---|---|---|
| TEMA Class R | Severe petroleum and related process service | Highest — largest corrosion allowance, conservative tube pitch | Oil & gas, refining, petrochemical |
| TEMA Class C | Generally moderate service | Moderate — commercial/general-purpose margins | General industrial, HVAC-adjacent process |
| TEMA Class B | Chemical process service | Tailored to chemical-industry corrosion and cleaning needs | Chemical processing plants |
They work together. ASME Section VIII governs the pressure vessel aspects of the exchanger shell, while TEMA provides the mechanical design standard specific to shell-and-tube construction, including tube sheet thickness formulas. A single exchanger is commonly built to both simultaneously.
Most GCC oil & gas and petrochemical buyers specify ASME/ASTM/TEMA as the base package, often with API 660 layered on for petroleum service, since regional EPC contractors are typically ASME-aligned. Confirm against your specific end-client's purchase specification, as some projects call out additional local requirements.
Yes — in-house specifications are common for large EPC contractors and typically reference a public standard as a baseline with additional clauses. Send the specification document with your enquiry and our engineering team will confirm compliance before quoting.
No — PED (Pressure Equipment Directive) applies specifically to equipment placed on the EU market. Domestic Indian supply is typically governed by IBR (Indian Boiler Regulations) where applicable, or the relevant ASME/TEMA package agreed with the buyer.
Send your destination market and end-client specification — NPRO India will confirm the correct material, design and construction standard before quoting.
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