Advantages of Corrosion Resistant Lighting in Offshore Helidecks|
Article - January 13, 2016 By LarsonElectronics.com
Advantages of Corrosion Resistant Lighting in Offshore Helidecks
Corrosion resistant lighting must be installed in offshore helidecks due to the extreme nature of the hazardous location. The use of such luminaries can extend the lifespan of the location’s lighting system and provide safety for aircraft pilots and workers on the site.
Read on to understand the benefits of corrosion resistant lighting, and specific requirements for offshore helideck fixtures.
Corrosion Resistant Lighting Properties
Exposure to corrosive agents, such as salt, acid and cleaning solutions, is a leading cause of light failure or malfunction in hazardous locations. Sectors that rely on corrosion resistant units include (but is not limited to) the following: marine, oil and gas, military, chemical processing plants and mining. In marine environments, the application of such products are often combined with best practices in reducing salt-based corrosion, such as washing down exposed gear with freshwater.
The type of materials used to create corrosion resistant fixtures are brass, stainless steel and glass. Brass offers non-corroding and stabile features that are resistant to rough environments, such as wind, rain, sunshine and ice. Stainless steel is commonly used for marine deck lights, flood lights and search lights. The metal is treated or cured with powder coat paint for extra protection, which allows it to withstand high temperatures. It is important to consider that stainless steel expands at half the rate of aluminum. Paint on stainless steel surfaces do not shed as fast, compared to aluminum, making it ideal for corrosion resistant fixtures. In addition to stable metals, corrosion resistant products are finished with baked on glazes, specialty paints, coatings and/or non-corrosive materials.
Traditionally, durable glass has a reputation for standing up against marine-related corrosion. The material is used to house the fixture due to its transparent and stable properties. Plastic is usually avoided for the construction of corrosion resistant luminaries, because the surface warps under unstable conditions. When it comes to the exterior components, manufacturers typically install gaskets or plastic cord rings around the light’s housing and cord ends. The main function of the components is to prevent moisture from entering the fixture.
Offshore Helideck Fixture Requirements and Compliance
CAP 437 (Standards for Offshore Helicopter Landing Areas) is the leading authority for the proper configuration and implementation of lights on helidecks. Below are the requirements set forth by the institution and other aviation organizations on helideck lighting systems:
• Final Approach and Takeoff Area (FATO) perimeter lights: FATO is a critical location on the helideck, where the aircraft approaching for a landing is at its final phase (hovering). This is also where takeoff is initiated. According to the Federal Aviation Administration (FAA), a minimum of 16 perimeter lights must the utilized, with a maximum spacing of 25 feet. The International Civil Aviation Organization (ICAO) recommends the application of white lights, with a maximum spacing of five meters. It is common for small helipads to use eight lights for this purpose. The type of lights used for FATO are the following: semi-flush inset, or low surface mounted (less than six inches in height).
• Touchdown and Lift-off Area (TLOF) lights: TLOF refers to a paved area on the helideck where the helicopter lands and takes off, usually located at the center of the FATO. Like FATO, TLOF lights may be semi-flush fixtures, with symmetrical and closely spaced configurations.
• Landing Direction lights: Landing Direction lights provide guidance for the pilot, when engaging the helideck. Five green lights for each angle of approach with a minimum of 15 feet of spacing are recommended for this section of the helideck (set forth by the FAA). The lights may also be semi-flush inset or raised on FAA frangible couplings.
• Helideck Beacons: Beacons are used to help aircrafts find the helideck. It is common practice for the beacons to be mounted at the highest point of the location, while emitting light with a 360-degree radius.
• Floodlights: Floodlights on helidecks provide general lighting in the location. They must not be excessively bright, which could blind the pilot and nearby workers. According to a letter from March 2006, sent by UK CAA to the offshore industry, “four xenon floodlights have to be installed on the deck at an angle of 90 degrees equally spaced around the platform for optimal illumination of the deck.”
• Wind Cones with Lights: Lighted aviation wind cones are used for illumination after sunset. A red obstruction light is installed on top of the cone. The primary function of lighted wind cones is to indicate the free stream wind conditions of the target location.
• Status/Obstruction Lights: Based on CAP 437 guidelines, fixtures should be installed on the helideck if there are any hazardous conditions that exist, such as gas leaks, or the presence of a crane on the pad. “Omnidirectional steady red lights of at least 10 cd intensity should be fitted at suitable locations to provide the helicopter pilot with visual information on the proximity and height of objects which are higher than the landing area and which are close to it or to the LOS boundary.”
ATEX and IP Ratings
ATEX (derived from the French title of the 94/9/EC directive: Appareils destinés à être utilisés en ATmosphères EXplosibles) zone ratings are essential for fixtures that are used for work environments with explosive atmospheres, including offshore helidecks. The most common zones that are applicable for such marine environments are Zone 1 and Zone 2 (for dangerous gases, vapors and liquids present in the air). Zone 1 consists of equipment categorized under “very high levels of safety” with two independent components that provide protection. This classification is commonly applied in locations where explosive compounds are always present for long periods of time. Zone 2 refers to luminaries with “high levels of safety,” supporting a robust design that actively contains sparks in an explosion proof enclosure. Gases may enter the device, but the explosions are suppressed inside the unit. During application, fixtures with Zone 2 ratings are used in locations where combustions are likely to occur.
Offshore helidecks are constantly exposed to water and corrosion. Because of this, fixtures installed on the site must support various IP (International Protection or Ingress Protection) ratings. IP53 ratings are considered to be the lowest form of protection against water, vapors, moisture, dust and corrosion. IP65 and IP66 are optimal ratings for corrosion resistant lights due to protection against water jets (water projected by a nozzle [12.5 mm] from any direction) and heavy seas (immersion up to one meter). IP67 is the most efficient rating for marine helideck luminaries, because they can withstand high pressure hosing during wash down and cleaning, which is regularly practiced to prevent the build-up of salts and other corrosive agents.