US What washdown means
A washdown area is a part of a plant that is cleaned regularly with water, detergents and sanitizers, often hot and at high pressure, to keep it hygienic. “Washdown” describes both the cleaning process and the conditions that equipment in those areas must survive. Equipment built for it is often described as washdown duty.
Washdown areas are common in food, beverage, dairy, meat, poultry, seafood and pharmaceutical production, where residue left on a surface can harbour bacteria such as Listeria or Salmonella. The term is also used on boats and in vehicle depots, where decks and machines are hosed down, but the toughest regimes are found in food processing.
Wash-down schedules vary from a rinse between batches to a full clean at the end of every shift. Equipment that is not designed for it fails in predictable ways: water and chemicals get past seals, plastic and paint degrade, and food residue builds up in gaps where bacteria can grow.
What happens during a washdown
A typical sanitation cycle in a food plant follows the same broad steps, although the chemicals and temperatures depend on the product and the soil being removed.
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Dry clean. Loose product and debris are scraped or brushed away before water is used, so it is not spread around the room.
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Pre-rinse. Warm water at low or medium pressure removes most of the remaining soil.
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Foam or detergent. Alkaline or caustic foam is applied to break down fats and proteins, with acid cleaners used periodically to remove mineral scale.
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Rinse. Water, often hot and at high pressure, removes the detergent and loosened soil from every surface.
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Sanitize. A sanitizer such as chlorine, a quaternary ammonium compound or peracetic acid is applied to kill remaining bacteria.
Washdown conditions and the ratings they need
The cleaning regime decides how well equipment must be sealed and what it should be made of. The table is a practical guide for computers, displays and other electronics.
| Cleaning regime | Typical conditions | Ingress rating to look for | Materials |
|---|---|---|---|
| Wipe-down only | Damp cloth, mild detergent | IP65 front | Painted steel or aluminum, sealed front |
| Low-pressure hose | Water jets, mild chemicals | IP65 or IP66 all round | 304 stainless steel |
| High-pressure hot wash | Close-range hot jets, daily | IP69K all round, often with IP66 or IP67 | 304 or 316 stainless steel |
| Aggressive chemicals | Caustic, acid or chlorinated cleaners | IP69K plus chemical-resistant seals | 316 stainless steel |
| Clean in place | Closed process lines cleaned internally | Not applicable to external electronics | Product-contact stainless steel |
Ratings are only part of it. A sealed enclosure can still trap residue in seams, behind brackets or around cable entries, so hygienic shape matters as much as the IP code. Our hygienic design guide explains how washdown computers are built.
What equipment in a washdown area needs
Every piece of equipment in the area has to survive the cleaning and must not become a place for bacteria to hide.
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High ingress protection. IP66 and IP69K sealing against jets, ideally across the whole enclosure.
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Corrosion-resistant materials. Stainless steel, with 316 grade where chlorides and acids are used. Our 304 vs 316 stainless steel guide compares the two.
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Hygienic shapes. Flat, crevice-free fronts and curved edges that drain.
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Sealed connectors. M12 connections instead of open ports and cable glands.
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Food-safe gaskets. Seals in materials that tolerate hot water and chemicals without cracking, swelling or harbouring residue.
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No fans. A fanless design has no vents to draw in moisture and no filter to clean, which is why washdown computers are almost always fanless.
Washdown zones in a food plant
Many plants divide the floor by risk. Areas where open food is handled, often called high-care or high-risk zones, get the most frequent and aggressive cleaning. Areas nearby where packaged product moves, and splash zones next to the line, are cleaned less intensively. Offices, control rooms and plant rooms sit outside the washdown regime altogether.
Equipment placement should follow the zones. A computer or HMI on the line itself needs full washdown protection, while one in a packing area may only need a sealed front. Closed process equipment such as pipework and tanks is usually cleaned internally by clean in place (CIP) systems rather than by hosing, which changes what the surrounding area sees.
Cleaning crews also treat everything within reach of the hose as part of the washdown, whatever the zone drawing says. Cable runs, mounting arms, keyboards and barcode scanners next to a line all get sprayed, so the whole installation needs the same protection as the computer it serves.
Quick answers on washdown
Washdown: common questions
What does washdown duty mean?
Built to survive routine washdown. Washdown duty equipment, such as motors, scales and computers, is sealed and made from corrosion-resistant materials so it can be hosed and sanitized every shift.
What IP rating is needed for washdown?
IP69K for high-pressure hot washing. IP66 covers powerful jets, but IP69K proves resistance to the close-range, hot, high-pressure jets used in food plants.
Why is stainless steel used in washdown areas?
It resists corrosion and is easy to clean. Stainless steel tolerates water, detergents and sanitizers, and its smooth surface gives bacteria few places to hide. 316 grade adds resistance to chlorides.
How often is a washdown done?
Often daily, sometimes more. Many food plants wash down at the end of every shift and rinse between batches or product changes.
Can a normal computer be used in a washdown area?
No. Vents, fans, open ports and painted cases let in water and trap residue. Use a sealed, fanless, stainless steel design.
Our stainless steel panel PCs and IP69K panel PCs are built for washdown areas, and we have supplied them across food and beverage sites. We integrate and validate each system as standard, matched to the plant’s cleaning regime.