Guide
What Do 3-A, EHEDG and ASME BPE Each Mean for a Machined Stainless Part?
3-A, EHEDG and ASME BPE are three separate hygiene frameworks: 3-A is a US organization whose standards and symbol program cover hygienic food equipment, EHEDG is a European group that publishes hygienic design guidelines and tests equipment, and ASME BPE is a standard for equipment in bioprocessing, pharmaceutical and personal-care plants. They overlap in subject but not in scope, and none of them is a stamp that a machinist can apply to a stainless part. This guide is for the OEM engineer or buyer who has been handed one of the names on a drawing or purchase order and needs to know what it asks of a machined fitting, valve body or pump housing.
By Saola Manufacturing engineering team · Published · Updated
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What does each of the three actually cover?
They cover different things: 3-A is a US food-equipment program, EHEDG is a European hygienic design and testing group, and ASME BPE is a bioprocessing equipment standard that fixes materials, dimensions and finishes for fittings.
3-A Sanitary Standards, Inc. presents itself as the gold standard of hygienic food equipment design. Its standards are developed by volunteer working groups and sold, and its program covers a 3-A Symbol, a certificate database and accredited conformance evaluators who assess equipment (3-A SSI).
EHEDG says its specialists have spent about 30 years in working groups producing more than 50 documents on food processing buildings, production environments and equipment, with members getting free access and others buying individual guidelines (EHEDG guidelines). Its certification scheme covers different equipment types and classes, supported by authorized evaluation officers and testing laboratories (EHEDG).
ASME describes BPE as the requirements applicable to the design of equipment used in the bioprocessing, pharmaceutical and personal-care products industries, covering materials, design, fabrication, inspections, testing and certification (ASME BPE). A distributor summary contrasts it with 3-A fittings: BPE fittings are held to tighter tolerances and cleaner interior finishes, require material traceability and specific markings, and are dimensionally consistent regardless of manufacturer (Ferguson, 2023).
| Framework | Published by | What it covers | What it means for a machined part |
|---|---|---|---|
| 3-A | 3-A Sanitary Standards, Inc. (US) | Hygienic design standards for food equipment, with a symbol program, a certificate database and accredited conformance evaluators | Applies to the finished equipment or component; a distributor summarizes it as food, beverage and dairy fittings and tubing, with no material traceability requirement |
| EHEDG | European Hygienic Engineering & Design Group | More than 50 guideline documents on equipment, buildings and environments, plus test methods and an equipment certification scheme with types and classes | Guidelines for valves, pumps, couplings, sensors, seals and welding set design rules; the test applies to the equipment as designed |
| ASME BPE | ASME | Requirements for design of equipment used in bioprocessing, pharmaceutical and personal-care industries; covers materials, design, fabrication, inspections, testing and certification | Tighter tolerances, material traceability and defined interior finish designations on fittings, which are dimensionally consistent whatever the maker |
Can a machined part itself be 3-A or EHEDG approved?
Usually the approval belongs to the finished equipment or component as designed, built and assessed by the scheme, so the OEM holds it and the machinist's job is to make the part to the drawing.
The 3-A program works through a certificate database and accredited conformance evaluators, and EHEDG works through types and classes of equipment assessed by authorized evaluation officers and testing laboratories. Both describe assessments of equipment, not of an unfinished blank turned from bar. A machined stainless body that goes into a valve is assessed as part of that valve.
That has a practical consequence for sourcing. A supplier that machines a part to your drawing cannot pass on an approval that sits with your product, and a supplier that claims a symbol it was never granted creates a problem for you. The right questions are which document your product is assessed against, which features of the drawing that document constrains, and what evidence the machinist has to supply so your assessment holds. The rules differ between schemes and change, so confirm the details with the scheme and your own quality team; nothing here is legal or compliance advice.
Which drawing features does a machinist actually control?
Material and traceability, the surface finish and lay on wetted surfaces, edge breaks and radii, burr-free internal features, the threads and crevices in the product zone, cleanliness and packaging.
Most of what these frameworks ask of a part is a drawing feature, and these are the ones a CNC machinist controls or can screw up:
- Material and traceability. The grade, the mill test report and the heat number carried through to the part. The distributor summary notes traceability is required for BPE fittings and not required for 3-A fittings, and that markings on BPE fittings include heat number, material type, maker, country of origin, finish and the BPE mark (Ferguson, 2023).
- Surface roughness and lay on wetted surfaces. The value comes from the customer's specification, not from a general rule. This guide does not give a 3-A roughness figure because the number sits in the standard text; if your document sets one, copy it onto the drawing with the measurement method. The ASME BPE finish designations separate mechanical polish from electropolish. The guides on Ra on machined parts and electropolishing and passivation explain how those are written.
- Edges, radii and crevices. No sharp internal corners, no burrs, no undercuts that trap product. EHEDG's hygienic design principles document is free to download, and its guideline list includes separate documents on materials of construction, valves, pumps, sensors and welding (EHEDG guidelines).
- Threads and joints in the product zone. Where the design allows, keep threads out of contact with product; if a thread is unavoidable, say how it is sealed.
- Cleanliness and packaging. BPE fittings are shipped capped, bagged and color-coded according to the distributor summary, so the packaging requirement belongs in the RFQ.
Finishing steps that affect the hygienic surface, such as electropolishing and passivation, are separate steps from machining, so the finish and the verification method must be on the drawing. Neither is among the finishes Saola currently lists on its surface finishing page, so confirm at drawing review who will apply them.
Which standard should the RFQ name?
Name the document your customer or end market cites, with its number and edition, rather than the framework by name alone.
"Sanitary" or "3-A" on a drawing is ambiguous. If the end user is a dairy or food processor in the US, the equipment is often specified to 3-A. If the system is a European food line, EHEDG guidelines and its equipment certification scheme often come up. If the product is a bioprocess skid, a pharmaceutical line or a personal-care plant, the specification is more often ASME BPE. The distributor summary draws the same line, placing 3-A fittings in food, beverage and dairy use and BPE fittings in pharmaceutical and personal-care facilities (Ferguson, 2023).
Whatever the framework, ask the customer for the document number, the edition and the table or clause that the part drawing relies on. Meeting one framework does not automatically meet another, and editions change: ASME shows a 2026 listing for BPE, so confirm which edition a given drawing cites. Put the clause references in the RFQ so every quoting supplier prices the same requirement.
What can a build-to-print supplier honestly say about these standards?
Saola does not hold a 3-A, EHEDG or ASME BPE credential and does not claim one; it machines to your drawing and tells you at quote stage which documents the production plant can supply.
The honest position is narrow. Saola quotes CNC turning and CNC milling at the lead plant in Vietnam; stainless bar is not among the materials it currently lists as running, so stainless scope is confirmed at drawing review rather than assumed. It will not mark a part with a 3-A symbol or a BPE mark, and it will not imply that a part is assessed to any of these frameworks. What it can do is review the dimensions, material and roughness on your drawing, say plainly what it can and cannot make, and tell you which inspection and material documents are available for the order.
Send the drawing together with the framework your customer cites, the clauses that apply to the part, and the list of documents you need with each shipment. The quote will say what can be supplied, and anything missing is better learned before the order than at your customer's audit. Start with the CNC turning page for the machining capability.
Frequently asked
Is EHEDG a standard?
EHEDG publishes guidelines and runs a testing and certification scheme for equipment, and its documents are listed as guidelines (EHEDG guidelines). Ask your customer which document number the part relies on.
Is 316L required for all three?
The grade comes from the customer's specification. A distributor summary lists 304 and 316 as common for 3-A fittings and 316L among the alloys for pharmaceutical use (Ferguson, 2023), but do not infer a grade from the framework name.
If a part meets the BPE finish, does it meet 3-A too?
Not automatically. They are separate documents with separate schemes, and a finish value that satisfies one does not substitute for the clause in the other. Confirm the clause that applies to each drawing.
Do I need to buy the standards to quote this work?
The party that specifies the standard should supply the relevant clauses with the RFQ. The standards are sold by their publishers, and EHEDG offers some guidelines, such as its hygienic design principles, free of charge.
Sources
- EHEDG guidelines list, European Hygienic Engineering & Design Group, accessed 2026
- EHEDG home page and certification overview, European Hygienic Engineering & Design Group, accessed 2026
- 3-A Sanitary Standards, Inc., accessed 2026
- BPE: Bioprocessing Equipment, ASME, 2026 listing
- The difference between sanitary 3-A and BPE, Ferguson Enterprises, 2023