When the going gets tough, LEDs lighten up

Extreme conditions and high-risk environments in hazardous locations mean that LED luminaires must be designed to meet a unique set of challenging criteria, discovers CAROLINE HAYES.
Imagine a workplace where maintenance and inspection is a constant burden, where the flammable conditions or explosive atmosphere are also subject to vibrations and shock and extreme temperatures. Now imagine that workplace without light. The importance of safe lighting in hazardous environments has led to led street lighting Manufacturer replacing fluorescent and high-intensity discharge (HID) lighting. LEDs offer energy efficiency and better light control and distribution for such applications. Still, it's the rugged design and virtually zero maintenance of solid-state lighting (SSL) that are leading to widespread adoption in this unique application area.
A high risk or hazardous area is where potentially explosive gases and dusts may exist. Low-maintenance design is desirable, as both the luminaire and the location of the facility it is in can be remote or difficult to access. There may also be threats posed by humidity, water ingress, or extremes of temperature.
Typical examples of hazardous environments are refineries, drilling platforms, and chemical and power-generation facilities. In these areas, low maintenance is essential, either due to the inaccessibility of the site or the vast expense of a shutdown.
Oil, gas, and petrochemical refinery processes can create explosive atmospheres and flammable conditions. As well as energy-efficient and fit-for-purpose, lighting also has to be able to withstand constant shock and vibration in extreme temperatures. Lighting used here has to meet OSHA (Occupation Safety and Health Administration — the US federal agency) or EU-OSHA (the European Agency for Safety and Health at work) guidelines.
Changes in lighting design in some hazardous industrial settings has compelled the replacement of fluorescent lighting with energy-saving LED lighting and practical designs of housings, where aesthetics come second to safety, protection, and security. Birthe Tralau, lighting application manager at Zumtobel, explained, "The LED is a directed light source, directed with lenses and optics, whereas fluorescents need reflectors to direct the light, which loses efficiency, hence the reduction in lumens [compared to LEDs]."
Low maintenance
Stuart Head, technical support manager at Dialight, added another reason for LED lighting's adoption. "LED lighting is characterized by low-maintenance design and construction that enables extended periods between maintenance inspections."
He summed up some of the maintenance factors to consider in hazardous areas. "Maintenance in harsh environments can be extremely dangerous. If the units are sealed, it ensures that led street lights price do not require changing and no dust or gas can enter the unit. It also means you do not need access to the lights, because there is no need for bulb replacements — reducing health and safety risk and the cost involved with having to replace bulbs/lamps."
LED lighting in harsh and hazardous environments is used worldwide and on a large scale. Focusing on one small sector, analyst company IHS has calculated the number of offshore oil rigs around the world at 799 in 2014; while not all are working at any one time, they have a geographical spread with offshore rigs in the US, Gulf of Mexico, South America, Northwest Europe, West Africa, Southeast Asia, and the Middle East.
FIG. 1. The Endurance range of sealed luminaires by McGeoch.
FIG. 1. The Endurance range of sealed luminaires by McGeoch.
In offshore rigs, the lighting is also subject to shock and vibration. McGeoch produces the Endurance luminaire (Fig. 1), which is designed as a direct replacement for existing conventional or fluorescent fittings. It is engineered for hazardous areas and particularly for where flammable gases may be present, with ingress protection to IP68 (for indefinite immersion in water) and to IP66 when fitted with a breather drain (for protection against powerful water jets). The sealed luminaire has a constant-current 700-mA driver circuit for use on mains supplies worldwide and an additional, low-level emergency supply. It is maintenance-free, says the company, and is ATEX approved Zone 1 and 21 (directives published by the European Union) for use in potentially explosive atmospheres.
The design offers protection against salt spray and vibration, and has a storage temperature of -20° to +60°C. The Lexan polycarbonate lens is ultraviolet (UV) and impact resistant. The chassis is made of hard anodized marine-grade aluminum, with a stainless-steel bezel. A 17W slimline version has recently been introduced, adding to the 30W and 55W original versions.
Added intelligence
For greater efficiency and longer lifetimes, intelligent lighting control can provide lighting as needed in aisles, rooms, or larger zones in the facility. LED lighting also achieves 100% light output from the instant it is switched on, which is a particular asset in hazardous locations that use independent generators; these are prone to blackout or brownout and so the locations require emergency lighting.
Dialight exploits the instant-on feature of LED lighting, coupling fixtures with occupancy sensors to reduce energy and extend the lighting system's operating lifetime. The company believes it has produced the world’s first hazardous area-rated LED fixture with integrated wireless control to take automated lighting further.

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