In most production or process facilities, good visibility is crucial for safety in the workplace. This is particularly true in hazardous areas. Operators in refineries, on oil rigs or in clean rooms depend on electrical lighting for a good view of day-to-day activities. However, conventional industrial luminaires do not meet the strict standards for hazardous areas. Such environments call for explosion-protected lighting systems. Only a few specialised manufacturers can provide a versatile range of state-of-the-art solutions for diverse needs in these conditions. Users not only expect a broad portfolio of suitable lights to choose from, but also appreciate suppliers with extensive expertise in both explosion protection and lighting system planning.
A range of different lights are required in hazardous areas, e.g. individual luminaires, floodlights, compact luminaires, or even full-scale emergency light solutions complete with a central battery system. One major trend in recent years is the increasing popularity of LED technology for more and more of these and other types of lamps – with substantial benefits for end users.
LED: Long-lived, efficient, dynamic
The reasons for the rise of LEDs are economical as well as technological. The price of light emitting diodes has come down considerably in recent years as improved manufacturing methods have taken hold and production quantities have multiplied. At the same time, high-performance diodes have been constantly enhanced and now offer an excellent light yield as well. In addition, several LED characteristics are particularly well suited to harsh industrial environments. For one, LEDs are hardly susceptible to vibrations at all. Moreover, in hard-to-access locations, they enable compact lighting solutions including intelligent systems that automatically adjust for changing ambient light sources. LEDs also achieve several times the life span of incandescent and fluorescent lamps. Notably, the energy efficiency of LED luminaires – and the service life along with it – even increases at low temperatures. That makes LED lights ideally suited to applications in very cold environments, e.g. oil and gas industry facilities in arctic regions. Of course, this is a segment that is also notorious for the prevalence of hazardous areas.
Versatile range of LED luminaires
LEDs became popular early on for hand lamps and torches. These devices used to be fitted with incandescent lamps with a relatively short life span that only achieved a moderate light yield. In LED versions, the internal resistance of the batteries is now usually sufficient to ensure a consistent supply current. The fact that LEDs are typically limited to a narrow beam is largely irrelevant for these types of luminaires. In signal lamps, LEDs are becoming a technology of choice as well. These types of lamps benefit from the instant start functionality of LEDs as well as from their tolerance for frequent switching without negative repercussions on their service life. The low energy intake and therefore low intrinsic heat is also a vital aspect that enables highly effective, yet at the same time extremely efficient signal light solutions. A somewhat more recent development is the foray of LED technology into the field of general-purpose light fittings. These luminaires used to be the strongest domain of classical illuminants until a few years ago. LED-based models such as the EXLUX 6002 and 6402 
lines from R. STAHL, for example, now serve as very energy-efficient general lighting solutions in Ex zones 1/21 and 2/22: one 52 W model of these new LED devices can replace two standard 36 W fluorescent lamps while ensuring a much better life span of 100,000 operating hours. Given a high luminous flux of 5,800 lm, it also achieves an excellent light yield that surpasses 100 lm/W.
Life cycle cost reduction
Accessories are compatible as well – existing facilities can therefore be easily modified or retrofitted with LED technology. The new units also weigh at least a third less than comparable competing standard products, which further facilitates handling. R. STAHL also offers compact LED-based tubular light fittings for use in Ex zones 1/21 and 2/22 that provide users with an alternative to typical linear luminaires. With a diameter of merely 55 mm, the new lights take up less than half the space required by conventional linear luminaires, and also weigh some 50% less. The tubular design makes the new 6036 series extraordinarily light-efficient: 30 such LED-based fittings with a length of four foot (1240 mm), for instance, ensure an illuminance of approximately 500 lx. That would usually require 35 linear luminaires with two 36 W fluorescent tubes each, or even 48 conventional box-type units retrofitted with LEDs. However, R. STAHL’s new lights consume only about half as much power and the specific power consumption per 100 lx amounts to a mere 1.5 W/m². Operating expenses are therefore greatly reduced – realistic cost savings range from some 20% to more than 50%, depending on the relevant time frame and specific solutions that are compared. They can also be fitted with a light sensor to ensure automatic switch-off as long as sufficient ambient light is available. In this case, operating costs can come down even further in some applications.
Non-LED luminaires for hazardous areas
Of course, LEDs are not the only lighting option for hazardous areas. There are also novel developments for luminaires using conventional illuminants. For example, R. STAHL recently introduced a new generation of robust, hazardous area light fittings with regular illuminants in the EXLUX 6001 line. These achieve a higher energy efficiency and provide approximately 10% more luminous flux than otherwise comparable products. Current EXLUX 6001 luminaires for use in Ex zones 1/2 and 2/22 also feature a design that is considerably more compact, stable, and torsion-resistant than the preceding generation. Depending on their performance class, new 6001 series luminaires are a quarter to a third lighter than their predecessor models and other products of this category. Other notable developments for R. STAHL are extra-tough signalling devices for use in Ex zones 1/2 and 2/22. FX 15 series beacons are designed to withstand extreme environmental conditions, e.g. a wide ambient temperature range of 55 °C to +70 °C. A GRP enclosure combined with a stainless steel 
guard and fixings provide a corrosion-resistant product. The light source is a xenon tube providing a high light output. A polycarbonate Fresnel lens helps to direct and enhance the impression from the 5 Joule xenon flash. FX15 series beacons with a clear lens produce an excellent luminous intensity of 49 effective candela.
Spotlight on luminaire development for hazardous areas
Comprehensive expertise in all three crucial fields – light planning, luminaire technology and explosion protection for hazardous areas – is a rare combination among manufacturers worldwide. R. STAHL has been a driving force of late: „We are continually growing in the market segment for luminaires in hazardous areas. Today we already rank third among the manufacturers in that segment and we aim to further boost our success e.g. with new products based on LED technology“, said Martin Schomaker, CEO of R. STAHL. The German company offers to engineer, manufacture and commission customised illumination solutions, e.g. comprehensive lighting installations or complex emergency lighting systems. R. STAHL’s dedicated production facilities can also manufacture application-specific luminaires. What was already considerable in-house expertise for lighting systems has been significantly enhanced by the acquisition and integration of Clifford & Snell, the British optical and acoustic signal device specialist, a number of years ago. In recent years, R. STAHL has also expanded the main lighting products plant in Weimar. Originally established in 1991 and now employing more than 100 staff, this location serves as the R. STAHL competence centre for luminaires. Only recently a 622 sqm laboratory and administration building, constituting an infrastructure investment of some €1.5 mn, was inaugurated at the Weimar plant. As experts for hazardous area luminaires as well as for lighting system planning, R. STAHL can provide machine engineers and plant operators with very flexible solutions based on a wide range of suitable products with conventional illuminants or LEDs. Users can therefore rest assured they will always get a bright solution to shine a light on what is going on in hazardous areas.
