Marine-Grade Lighting

Best Practices When Choosing Lighting Fixtures for Marine and Coastal Environments

Marine and coastal environments are harsh on buildings due to airborne salt, wind, and humidity. Salt water becomes aerosolized when ocean waves break, causing premature decay in metal materials. To ensure durability and normal service life for lighting fixtures in these environments, it is recommended to specify marine-grade trims and fixtures.

 

Lighting fixtures in coastal regions should comply with the American Architectural Manufacturers Association’s (AAMA), AAMA 2605 standard for wear and corrosion resistance. AAMA 2605 sets some of the highest standards for protective metal coatings, which are most suitable for marine environments.

 

Specifically, Section 7.8.2, Salt Spray Resistance, is crucial for marine-grade finishes. Test samples are scored to expose aluminum and subjected to a 4,000-hour, 5% salt solution spray test, as defined by ASTM B 117.

 

When evaluating lighting fixtures, choose products with verifiable marine-grade claims based on these tests.

 

Where are Marine-Grade Finishes Required?

While the highest levels of salt spray are closest to shore, accelerated corrosion can occur up to five to 10 miles inland. For installations within 10 miles of the coast, marine grade, IP-rated fixtures should be used for proper protection and longevity. 

 

In regions with extreme weather and environmental conditions, corrosion may occur even further inland than 10 miles. The strongest example would be isthmuses, surrounded by ocean, like the southernmost parts of Florida. Since there isn’t a comprehensive source of corrosion data by geographic region, it’s best to consult local building professionals and examine levels of corrosion in older buildings to identify high-corrosion areas.

Metal Corrosion & Marine-Grade Lighting Finishes

Lighting fixtures use metals like aluminum and steel for housings, trims, and major components. Aluminum is popular for trims and bodies but faces challenges in marine environments. When exposed to air and water, raw aluminum alloys form a protective oxide layer, which is sufficient in most interior or mild climates, but salt and moisture cause galvanic corrosion. This occurs when a more negatively charged metal transfers electrons to a positively charged one via an electrolyte. Marine conditions create this electrolytic solution, making aluminum alloys with elements like copper problematic. Manufacturers must protect metal parts from galvanic corrosion to ensure fixture longevity.

 

For long-lasting light fixtures, marine-grade finished aluminum is an excellent choice. Two main processes achieve marine-grade finishes: epoxy-based powder coating and marine anodizing (hard anodizing). Alternatively, brass or stainless steel, which are naturally corrosion-resistant, can be used, though these are mostly used for landscape lighting.

Epoxy-Based Powder Coating

Powder coating provides a durable, corrosion-resistant finish for aluminum fixtures. This process uses electrostatically charged paint particles that are magnetically attracted to the substrate, ensuring even application. The coated substrate is then cured in an oven, creating a robust finish.

 

Epoxy-based powder coating offers even higher abrasion and corrosion resistance. Epoxies, made of a resin and a hardener, form a rigid, cross-linked structure when mixed, providing excellent durability and flexibility. This makes them suitable for areas with extreme thermal changes as they prevent cracks in the finish due to underlying metal expansion or contraction.

 

The process starts with extensive surface preparation, including mechanical cleaning and chemical treatments for optimal adhesion. An epoxy primer is applied, followed by a super-durable polyester powder coat finish. Once cured, this results in a UV-resistant, corrosion-resistant, and flexible finish that withstands extreme and corrosive conditions.

Anodized Aluminum

Anodizing submerges metal in an acid-electrolyte solution and applies an electrical current through the substrate, creating a controlled oxide later that is relatively durable and corrosion-resistant. Standard anodizing forms a 12-micron thick layer, suitable for indoor or non-marine exterior applications, but can wear quickly and is susceptible to scratching and corrosion.

 

Hard anodizing creates a thicker 25-micron layer using a stronger acid bath and higher electric current density, resulting in greater abrasion resistance and durability. It’s suitable for marine-grade applications and industrial uses requiring high wear resistance.

 

However, both processes involve harsh chemicals, higher costs, skilled labor, and variability in color consistency. Anodized aluminum may also be susceptible to UV damage and color fading, and its metallic appearance may not be ideal for architectural-grade lighting trims.

Non-Aluminum Marine-Grade Fixtures

Some manufacturers use metals other than aluminum for marine-grade durability, with brass being the most common. Brass, an alloy of copper and zinc, forms a protective patina when oxidized, preventing corrosion but changing the fixture’s appearance over time. Raw brass initially has a high shine and yellowish color, but in marine environments, it typically develops a light green patina. This change may be desirable for some installations but bothersome for others due to its unpredictability.

IP65+ Rated Marine-Grade Fixtures

Marine-grade lighting fixtures should be IP rated to protect internal components from humidity, moisture, and salt. They should achieve at least an IP65 rating, meaning they are fully dust-tight and protected against water jets. For more details, refer to DMF’s IP Ratings Technical Bulletin.

DMF’s Marine-Grade Products

DMF Lighting has select products that can be configured with marine-grade trims or finishes, all of which comply with AAMA 2605-05, Section 7.8.2 and achieve a minimum rating of IP65.

  • M Series IP/Marine Grade Trim
    • M Series recessed downlighting family features a wide range of specification options. The newest IP/Marine Grade trim offers superior durability for corrosive, marine environments. Available for the round downlight in both black and white colors, the marine-grade finish utilizes a super durable epoxy-based power coat finish and additionally achieves an IP66 and IK10 rating with its fully sealed and impact resistant front lens. Look for the “IP” part code under the trim selection for the standard round downlight.
  • X & M Series Marine Grade Cylinders
    • X & M Series Cylinders offer a massive array of options for exterior lighting applications, from pendant, surface mount and wall mount cylinders. Utilizing the same light engine modules from their counterpart downlight families, these marine-grade cylinders are finished in the same manner as the Marine Grade/IP trim and achieve an IP65 rating, appropriate for use in fully exposed, uncovered exterior applications. For full information on DMF Lighting’s Marine Grade cylinders, see the X Series & M Series Cylinders Marine Grade specification sheets.

For more information, please review the Marine-Grade Technical Bulletin.