Choosing Commercial Lighting for Different Installation Environments

Here is a common problem with selecting the lighting for commercial projects: You found the foot candles requirement; you picked the right brightness luminaires to meet them; everything is NRTL certified and meets building codes; but you just discovered the lights are not meant for the low temperatures of the space. Oops! As frequently happens with contractors, you overlooked the environmental suitability. 

The basic rule is straightforward, but there is no single universal environmental standard or governing body that determines every requirement for every commercial lighting installation. In practice, suitability is often evaluated on a project-by-project basis using applicable codes, fixture listings, project specifications, manufacturer documentation, and the requirements of the local authority having jurisdiction. That can make the requirements unclear or difficult to interpret, especially in environments that fall between common categories. This guide provides a practical starting point by outlining the most important conditions to check when determining whether a luminaire is suitable for its intended environment. Contractors should then verify the final requirements for the specific project and installation.

Start With Dry, Damp, or Wet Location Ratings

For most commercial projects, the first distinction is whether the fixture will be installed in a dry, damp, or wet location. These are more than merely general durability descriptions. They reflect requirements that may be legally enforceable when adopted through applicable electrical codes, OSHA regulations, or project requirements.

Dry locations include typical conditioned interiors such as offices, classrooms, retail spaces, and many interior corridors. Damp locations are areas that may regularly or periodically experience moisture or condensation, including some partially protected exterior spaces. Wet locations are those where water can drip, splash, or flow onto electrical equipment. 

Check for Dust and Water Ingress Requirements

Some installations require a more specific level of protection from dust or water. Warehouses, garages, manufacturing facilities, exterior applications, and washdown areas are common examples.

This is where an IP, or Ingress Protection, rating may become important. The two digits in an IP rating describe protection against solid-object ingress and water ingress. For example, an IP-rated high bay may provide significantly greater protection from airborne dust and moisture than a fixture designed for a typical conditioned interior.

However, contractors should not assume that an IP rating replaces a NEMA enclosure rating or another required location marking. IP and NEMA ratings are parallel systems that describe different aspects of enclosure performance, so they are not interchangeable (NEMA ratings are generally North American (NEMA/UL) while IP ratings are international and goverened by the IEC). An IP rating primarily identifies protection against solid-object and water ingress, while a NEMA rating may address additional characteristics such as corrosion resistance, construction, and protection against specific environmental conditions. In many commercial and industrial installations, both ratings may be necessary. The fixture’s listing, location rating, project specifications, and applicable code requirements still need to be checked for the installation.

Verify the Fixture’s Ambient Temperature Range

Temperature is another environmental condition that can affect fixture selection, and it is not limited to obviously extreme environments.

An office ceiling may stay close to the building’s conditioned temperature, while a high bay installed near the roof of an unconditioned warehouse can experience substantially higher temperatures. Cold-storage facilities create the opposite problem. Mechanical rooms and industrial spaces can also expose luminaires to conditions well outside those of ordinary commercial interiors.

Before installation, compare the expected temperature around the fixture with the manufacturer’s specified operating-temperature range. OSHA specifically includes excessive temperatures among the environmental conditions for which electrical equipment must be identified as suitable.

Account for Corrosion, Chemicals, and Washdown Conditions

Certain projects introduce additional environmental concerns. Parking structures may expose fixtures to moisture, pollutants, and temperature swings. Coastal installations can introduce salt and corrosion. Food-processing or industrial facilities may involve washdown, chemicals, oils, or other deteriorating agents.

In these environments, project specifications may call for particular enclosure types, corrosion resistance, materials, or other performance characteristics. OSHA requires equipment exposed to gases, fumes, vapors, liquids, and other deteriorating agents to be suitable for that operating environment.

Know When a Location Requires Specialized Equipment

Combustible dust, flammable gases, vapors, or similar hazards require a different level of evaluation. An ordinary wet-location or dust-resistant fixture is not automatically suitable for a hazardous classified location.

Equipment used in these locations must be suitable for the particular hazards present, and lighting fixtures can require specific hazardous-location markings and approvals.

For these projects, contractors should follow the applicable classified-location requirements rather than treating a high IP rating as sufficient protection.

Match the Fixture to the Project, Not Just the Application

Two buildings described as “warehouses” can expose lighting equipment to very different conditions. One may be clean, conditioned, and dry, while another contains airborne dust, high ceiling temperatures, moisture, or corrosive materials.

Before comparing fixture performance, identify the actual installation environment. Confirm dry, damp, or wet-location suitability first, then check for any additional dust, water, temperature, corrosion, washdown, or hazardous-location requirements. Finally, verify the fixture against its listing and manufacturer documentation, the project specifications, and the requirements of the local authority having jurisdiction.