COMMERCIAL LIGHTING SUPPLY / TECHNICAL LIBRARY
IP Ratings, Wet-Location Listings & Washdown: What Each Actually Covers
Technical guidance for commercial lighting specification, product selection, and project planning.
IP Ratings, Wet-Location Listings & Washdown: What Each Actually Covers
An IP rating, a wet-location statement and a cleaning procedure are three different pieces of information. A product may carry more than one of them, but one label should not silently stand in for the others. The selection must address the actual exposure and the exact installation.
Use three separate checks: what ingress protection is documented; what location suitability and installation conditions apply; and what cleaning agents and methods the manufacturer permits. Keep all three attached to the proposed ordering configuration.
Understand IP Ratings Before Specifying Washdown Lighting
Intertek's IEC 60529 testing overview explains the two numerals in an IP code. The first concerns solid-object ingress and the second concerns water ingress. Its table distinguishes dust-tight protection, water jets, powerful water jets and immersion categories. These are defined test categories, not unrestricted descriptions of every factory cleaning process.
| Notation | Meaning described in the Intertek overview | Question it does not settle alone |
|---|---|---|
| IP6x | Dust-tight enclosure category. | Suitability for a classified combustible-dust location. |
| IPx5 | Protection against water jets. | Every pressure, temperature or chemical used in a site's cleaning process. |
| IPx6 | Protection against powerful water jets. | Unrestricted immersion or chemical compatibility. |
| IPx7 / IPx8 | Temporary / continuous immersion categories. | The complete permitted application without the relevant conditions. |
The x in these examples isolates one part of the notation; it is not a claim that an unspecified part has been tested. Read the complete reported designation and its supporting document for the proposed product.
Do not treat a higher-looking number as an all-purpose upgrade across unrelated exposures. Request the applicable test basis and product conditions when the project depends on a particular exposure. For applications requiring a particular test method, confirm the applicable standard and supporting product documentation.
Verify Wet-Location Certification and Installation Conditions
UL Solutions' outdoor-lighting guidance describes wet-location considerations within luminaire safety evaluation and separately discusses additional IP evaluation. That distinction is the reason to retain both forms of evidence where relevant.
For the selected luminaire, identify the applicable listing or certification information, the location statement and the installation instructions. Have qualified personnel determine whether they support the actual project. An IP entry copied into a purchasing spreadsheet does not answer every electrical-safety or installation question.
Inspect the complete proposed arrangement. Accessories, cable entries, covers, mounting interfaces and optional components need their applicable documentation. Do not assume an enclosure designation proves that an improvised assembly or an open cover retains the same suitability.
Keep hazardous-location review separate
Dust-tight and vapor-tight descriptions should not be used as substitutes for a qualified hazardous-area assessment and matching equipment review. If process materials introduce that question, retain the classification basis and involve the appropriate professionals.
Vapor-tight terminology describes a product category, not hazardous-location approval. Evaluate the actual equipment markings and site classification independently.
Confirm Chemical Compatibility With the Cleaning Process
The RAB SEAL family specification reports IP66 and wet-location suitability. In the same document, it warns that certain cleaning-agent chemistries affect its polycarbonate. The warning remains relevant even though the product is described as a washdown luminaire.
That is a useful counterexample to “water protected means chemical compatible.” Keep the site's actual agent, concentration, temperature, exposure duration and application method available for review. Ask for confirmation where the manufacturer documentation does not establish the proposed use.
Do not improvise a universal approved-detergent list from the material name alone. A product includes more than its main housing: lens, seals, finish and other components may be relevant. Use the exact manufacturer's instructions and clarification for the complete configuration.
| Site information | Compare against | If unresolved |
|---|---|---|
| Cleaning agent and concentration | Product-specific material warnings and permitted cleaning instructions. | Request written clarification for the named agent and conditions. |
| Application method | Permitted process and relevant ingress evidence. | Retain a hold on suitability for that process. |
| Temperature and exposure | Applicable operating and cleaning limits. | Identify the missing condition rather than selecting a generic default. |
| Access and servicing | Manufacturer maintenance instructions and qualified facility procedures. | Resolve a practical maintenance method before accepting the equipment. |
The facility’s cleaning procedure and the manufacturer’s permitted-use conditions must agree before the product is specified.
Check High-Pressure Washdown Claims Against Product Instructions
RAB's H22 product page reports an IP69K designation for high-pressure and high-temperature cleaning. Its H22 instructions, H22-IN-0325, still give specific maintenance limitations, including use of a non-abrasive cleaning solution and restrictions on cleaning materials. The product claim does not remove the instructions.
Keep the reported designation as written. Do not silently translate IP69K into another standard's designation or infer exact test pressures and temperatures without the relevant supporting documentation. If a procurement requirement names a specific standard or test, request evidence for that requirement.
These product examples illustrate why an ingress designation should always be read alongside the installation and maintenance instructions for the exact model and options.
Food-Processing Requirements Need Separate Verification
Food-facility certification has its own product and application scope. Verify the exact model and relevant zone through the applicable listing and project review. It should not be treated as a blanket approval for any chemical or washdown method.
For refrigerated or cold-processing areas, also verify operating-temperature limits and the ratings of optional sensors, batteries and controls. Food-area certification, washdown suitability and cold-temperature operation require separate evidence.
Select Washdown Fixtures Using All Three Requirements
Suppose a fictional project requires a new cleaning agent, but the candidate's documentation establishes only its IP designation and wet-location suitability. Two checks have supporting information; chemical compatibility remains unresolved. It is inaccurate to describe the entire selection as approved simply because two boxes are complete.
The next step is to identify the agent and conditions and obtain the missing product-specific response. If a different candidate is proposed, compare it against the same process rather than weakening the requirement to make the paperwork pass.
When reviewing washdown high bay candidates, retain the exact model, options and source documents with the cleaning procedure. For vapor-tight lighting candidates, do the same rather than assuming the category name supplies the evidence.
The right washdown fixture is the one whose documented protection, location suitability and material compatibility match the facility’s actual conditions. Record the selected model and cleaning requirements together so changes in chemicals, equipment or procedures trigger a timely review—not an avoidable failure after installation.