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Key facts
- What it is EHEDG Guideline 8, Hygienic Design Principles
- Radius a radius on internal angles of less than 135 degrees, with the value left to GL 10 and GL 13
- Drainability a design principle in its own right, with no slope angle given in the fourth edition
- Dead legs no L over D figure in Guideline 8. That limit comes from other documents
- Grades the 2004 edition is commonly cited for the 304 and 316 envelope
- Editions the fourth edition of December 2025 renumbered the lot, so cite the one you hold
Learn to cite the right document, every time
Hygienic Design Essentials teaches the ten rules with the real numbers and the document behind each one, so you can hold a supplier to a figure without being caught out on the source. Five hours, online, self paced.
What Guideline 8 does cover
Guideline 8 sets out the principles that make equipment cleanable, and it is the reference most South African specifications lean on, usually second hand. The parts you will use most:
- Internal angles. A radius on any internal angle of less than 135 degrees. The fourth edition no longer gives the value, leaving it to GL 10 for closed equipment and GL 13 for open equipment, and 3 mm remains the working minimum in most specifications. Below that, no brush, cloth or spray reaches the bottom of the angle.
- Drainability. Product contact surfaces slope to one side so that they drain. The fourth edition makes drainability a principle and gives no angle at all, so 3 degrees is a figure from practice rather than from the guideline, and horizontal surfaces avoided.
- Dead spaces. Areas that cannot be cleaned in place must be avoided. Note the wording: it states the principle without giving the ratio.
- Surface finish. Product contact surfaces finished so they can be cleaned, with Ra 0.8 micrometres the figure most often specified.
- Joints, seals and fasteners. Continuous welds, seals flush with the product surface, no exposed threads in the product zone.
- Materials. Non toxic, corrosion resistant, non absorbent and stable in the cleaning chemistry and at the temperatures actually used.
What it does not say, and what gets wrongly credited to it
Dead legs. Guideline 8 gives no length to diameter figure. EHEDG closed equipment guidance is where an L over D of 1 comes from, and 3-A practice is commonly cited as 2 and never longer than 127 mm. Quoting Guideline 8 for this is the most common citation error in the field, and it is the one a competent supplier will catch.
The 5 degree external slope. Widely used for external horizontal surfaces, and it is commonly cited supplier and industry guidance rather than Guideline 8.
The 30 degree cabinet roof. Same position. It is sound practice, and it is not from Guideline 8.
Clearances under equipment. The 200 mm figure for clearance, and the 300 mm figure for a cabinet base, are supplier guidance in common use.
None of these figures is wrong. The error is attribution, and attribution is what makes a specification enforceable.
How it sits beside South African law
Guideline 8 is guidance. R638 of 2018, regulation 6(1), is law, and it already requires food contact surfaces to be smooth, rust proof, non toxic and non absorbent, and free of open joints or seams. The guidance tells you how to achieve what the regulation requires, and it gives you numbers the regulation does not.
In practice, write the legal requirement and the guidance figure side by side in a specification. The first gives you standing, the second gives the fabricator something to build to.
How to cite it so your specification holds
- Name the document, the edition and the year. Editions renumber sections.
- Quote the figure, not a paraphrase of it.
- Where a figure is industry practice rather than the guideline, say so in the specification. Commonly cited industry guidance is a perfectly professional phrase and it protects you.
- Keep the document. A specification that quotes a guideline nobody in the building has read is a specification that gets negotiated away in the first meeting.
Frequently asked questions
Does EHEDG Guideline 8 give a dead leg limit?
No. It sets out the principle that dead spaces must be avoided, without giving a length to diameter figure. The L over D of 1 comes from EHEDG closed equipment guidance, and 3-A practice is commonly cited as 2 and never longer than 127 mm.
What internal radius does Guideline 8 require?
The fourth edition of December 2025 gives no value. It says an internal angle of less than 135 degrees needs a radius, and leaves the figure to GL 10 for closed equipment and GL 13 for open equipment. Three millimetres is the working minimum most specifications use, 6 mm is often preferred, and 10 mm is specified in chutes and hoppers where product is dropped.
Is EHEDG certification the same as complying with Guideline 8?
No. Certification tests particular equipment types against particular protocols. Guideline 8 sets design principles. A machine can be certified and still be installed in a way that makes it impossible to clean, which is why installation belongs in your own specification.
Which edition should I be quoting?
The one you actually hold and have read. Section numbers move between editions, so a citation to a section number without an edition is not checkable. If a supplier quotes a section you cannot find, ask which edition they are using before assuming either of you is wrong.
Is Guideline 8 free?
EHEDG guidelines are published by EHEDG and are generally purchased, with member access arrangements. Buy the one your specifications rely on. It is the cheapest document in the whole capital process.
Learn to cite the right document, every time
Hygienic Design Essentials teaches the ten rules with the real numbers and the document behind each one, so you can hold a supplier to a figure without being caught out on the source. Five hours, online, self paced.