Commercial Pit Lighting Recommendations, Layouts and Best Practices|
Article - January 19, 2016 By LarsonElectronics.com
Commercial Pit Lighting Recommendations, Layouts and Best Practices
According to an article archived by Commercial Motor (published on May 25, 1973), inspection pits typically found in commercial repair garages are filled with dangerous hazards that could cause fatal accidents. The publication was one of the first organizations to acknowledge explosive hazards associated with handling ignitable liquids during car repair projects.
Today, inspection pits are still being used by leading auto repair shops and garages. But unlike 40 years ago, there are now numerous guidelines in place that are designed to prevent deadly explosions and accidents in inspection pits. These recommendations involve proper selection, placement and installation of explosion proof luminaries, as well as safety practices that protect employees from falling objects and forceful contact.
Notable Hazards in Commercial Pits
Before getting into the types of fixtures used in inspection pits, one must first understand the long list of hazards associated with such locations. As mentioned earlier, pits are found in commercial garages that conduct repair on vehicles, such as diesel-fueled trucks or other large vehicles that may not be suitable for a lift. Other types of vehicles, such as private cars, may also be repaired using an inspection pit.
Traditionally, glass is used to house the lamp or bulb. Its transparent and sturdy properties are highly favored by operators in the marine sector. It is important to consider that corrosion resistant boat lights should also actively prevent the entry of saltwater. Gaskets and rubber or plastic cord rings may be installed around the luminary’s housing or cord ends to ensure corrosive agents and moisture does not affect the internal components (wirings, ballast or driver- just to name a few) and performance of the unit.
• Falling or slipping into the pit
• Fire or asphyxiation from highly concentrated, potentially deadly gases or vapors
• Bodily injuries from objects falling into the pit
• Head injuries from forceful, accidental contact with the vehicle and nearby equipment
There are several ways to address such hazards, which can help improve safety in the workplace. Since this article focuses on lighting requirements, we will only go into solutions related to improving visibility and preventing explosions related to fixtures being used in and around the pit. Boosting visibility is an effective way to reduce risks in commercial garages. For inspection pits, a lighting level of 550 lux is recommended. Furthermore, the walls of the location should be painted with a bright, reflective color (white) to increase the efficiency of the lighting system.
Explosion Proof Lighting in “Major Repair Garages”
Professionals working in car pits perform a myriad of tasks that involve explosive and corrosive liquids. This may include (but is not limited to) the following: brake fluids, detergents, cleaning agents, volatile chemicals, gas and oil. Moreover, the semi-enclosed and confined nature of the pit promotes the accumulation of ignitable substances. To prevent accidental ignition of explosive compounds in the location, explosion proof luminaries must be installed in the commercial pit and garage. Specifically, for pit areas classified under “Major Repair Garage” in Article 511 and 514 (for handling fuel dispensing tasks) of the National Electric Code (NEC), Class I Division 1 explosion proof fixtures must be installed up to floor level, if the pit is unventilated. For ventilated pits with a minimum of six air changes per hour, Class I Division 2 luminaries are recommended.
The garage ceiling must also be equipped with explosion proof lights to accommodate volatile gases or vapors that escape the pit. For such locations, the ceiling area must use Class I Division 2 explosion proof fixtures. If ventilation is provided (not exceeding 18 inches from the highest point in the ceiling, which exhausts the location at a rate of 1 cfm per square feet [minimum] when the area is occupied or when cars that utilize “lighter than-air gaseous fuels” are in the garage), explosion proof lights in the ceiling are not necessary, because the ceiling area would be considered unclassified (Article 511). It is important to consider that the lights on the floor area (18 inches above the floor) must use lights with Class I Division 2 ratings. This requirement does not cover garages that conduct fuel-dispensing works involving gasoline or other gaseous fuels.
Explosion Proof Lighting in “Minor Repair Garages”
For commercial pits classified under “Minor Repair Garage,” explosion proof lighting is not needed, if the area is ventilated with four air changes per hour (minimum). In such configurations, exhaust air components must be installed within 12 inches from the floor of the pit with a ventilation rate of 1 cfm per square-foot of the floor area. Without ventilation, Class 1 Division 2 luminaries must be used, up to floor level (18 inches above the floor). Floor areas three feet outside of this zone may use unclassified luminaries. If the adjacent room or area next to the classified location is adequately separated via walls, dividers or partitions, unclassified luminaries may be used outside of the classified location.
Fixed lighting should be installed 12 feet or higher from the floor to prevent sparks or other hot particles from reaching the floor or reacting with volatile compounds. If the fixture is completely enclosed, the unit may be installed below 12 feet (Article 511.7[B][b]).
Other Ratings to Consider
In addition to explosive hazards, fixtures in commercial pits may be exposed to dust, water and other corrosive agents that could cause the light to malfunction or fail. To prevent dust and water from damaging the luminaries an Ingress Protection rating of IP65 or higher is recommended. For the housing, cast aluminum is preferred over polycarbonate. Shock resistance (IK-10 rating is recommended) is a feature that may also help keep the light working properly under demanding conditions.
It is crucial to note that using low voltage lights, such as 12-volt units, does not offer protection against explosive hazards in commercial pits. Because of this, portable lights, including hand lamps, pen lights, flash lights, drop lights and other portable luminaries must also support explosion proof ratings that is relevant to the classified location.