Conveyor design for food processing: EHEDG, open frame, and cleanability

Three tiers of hygienic design, not one

"Hygienic conveyor" gets used loosely, but in practice conveyor hygiene sits on a spectrum with three practical tiers: basic (IP65-rated, smooth surfaces), EHEDG-compliant (open frame, fully drainable), and aseptic (fully enclosed and CIP-able). Which tier a line needs depends on the product's risk profile and how the conveyor sits relative to open product, not on a blanket "food-grade" label that doesn't map to any single standard.

Basic hygienic design: IP65 and smooth surfaces

An IP65 rating means the equipment's electrical enclosures and drive components are dust-tight and protected against low-pressure water jets from any direction — useful for washdown areas, but it says nothing about the frame geometry or whether soil can accumulate on structural members. Basic hygienic mode, combining IP65-rated drives with smooth surfaces and no exposed catch points, is generally suitable for low-risk food handling areas: packaged product, secondary packaging lines, or product that will be cooked after this stage.

It is not sufficient for direct contact with open, ready-to-eat product or high-risk applications, where the frame construction itself becomes the limiting factor.

EHEDG-compliant: open frame and drainable

EHEDG-compliant conveyor design centers on two structural principles: open frame construction, meaning tubular or profile members without enclosed cavities where product residue and cleaning fluid can collect unseen, and full drainability, meaning every horizontal surface is pitched so no standing water or cleaning solution pools anywhere on the frame or supports.

In practice this rules out square or rectangular hollow-section tubing capped at the ends (a classic hidden-cavity trap) in favor of round tubing, or square tubing left genuinely open and drainable at every low point. Stainless steel is standard — typically 304 for less demanding environments and 316 where wash-down chemical exposure is heavier — and belt material has to be FDA-approved (or the regional equivalent) and chemically compatible with the site's cleaning agents, not just food-safe in a generic sense.

Aseptic: fully enclosed and CIP-able

Aseptic conveyor design is the tier reserved for the highest-risk applications — typically where the conveyor itself is integrated into a validated cleaning-in-place circuit rather than being manually washed down. Here the conveyor is fully enclosed, and the enclosure and belt path are designed to be cleaned in place using the same CIP principles that apply to piping: adequate flow velocity and coverage across every internal surface, not just visual accessibility for a manual wash crew.

This tier is significantly more expensive to specify and maintain than open-frame EHEDG designs, which is why it's reserved for genuinely high-risk product contact rather than applied as a default. Matching the tier to the actual risk, rather than over-specifying, is usually the right call unless regulatory or customer requirements dictate otherwise.

Belt material and drainage in practice

Belt selection interacts directly with the hygiene tier. Modular plastic belting is common in EHEDG-compliant designs because individual belt links can be inspected and replaced, and open-hinge designs allow cleaning fluid straight through the belt rather than pooling on top of it. Solid fabric or PVC belting, more common in basic hygienic mode, needs a smooth, low-friction top surface and enough belt tracking control that debris doesn't collect at the edges where the belt meets the frame.

Drainage isn't only about the belt and frame — it extends to every support leg, guard, and drive housing. A conveyor that is otherwise open-frame and drainable but sits on solid-topped support legs, or has drive guards with a flat, unpitched top, still creates the pooling points that open-frame design is meant to eliminate.

Choosing the right tier

Start from the product risk, not from the equipment catalogue. Packaged or to-be-cooked product generally justifies basic hygienic design. Open, ready-to-eat product handled on the line justifies EHEDG-compliant open-frame construction as the practical minimum. Aseptic, CIP-able conveyors are worth the added cost and complexity only where the product's shelf-life or regulatory classification specifically requires it — otherwise it's cost added without a corresponding food-safety benefit.