Industrial Lighting Fixtures for Warehouses, Manufacturing Facilities, Hazardous Locations

- Apr 07, 2021-

Industrial lighting products encompass lighting systems designed for application in indoor or covered real estate in the industrial sector. Most industrial luminaires have cross applications in commercial and recreational facilities such as big-box retail stores, gymnasiums, convention centers, exhibit halls, and buildings with expansive, high ceiling spaces. This guide will walk you through information on lighting systems installed in industrial environments. Few things affect an industrial facility more than lighting. From an operations viewpoint, optimum visual conditions can improve productivity or performance, enhance safety and security, and reduce the number of errors and lost-time accidents. For facility management, an ideal industrial lighting solution will provide a good ROI (return on investment) through energy and maintenance savings while having the ability to survive challenging industrial environments. A successful lighting design for a modern industrial facility therefore necessitates the use of lighting systems that excel in efficiency and reliability, and simultaneously deliver high quality light and photometric performance.


Types of Industrial Facilities

There are two major categories of industrial facilities: warehousing facilities and manufacturing facilities.

Warehousing facilities are the largest industrial real estate category. The core differentiating features of warehouses are overall building design (typically rectangular in shape), ceiling height (16 to 80 feet), and loading capabilities. Warehouses can be further divided into regional warehouses, bulk warehouses, heavy distribution facilities, cold storage facilities, and rack supported warehouses. Regional warehouses generally do not exceed 100,000 square feet in size and have an average tenant space exceeding 20,000 square. Their ceiling heights are generally in the range of 16 to 24 feet. Regional warehouses have a varied tenant use. Some are designed to store goods, others are utilized as distribution facilities. Bulk warehouses are used to store large amounts of goods. These facilities have a minimum size of 100,000 square feet and a minimum ceiling height of 20 feet. Heavy distribution buildings resemble those of bulk warehouses but have a larger size (100,000 - 500,000 square feet), and a minimum ceiling height of 24 feet. Typical tenants in these facilities are logistic companies. A cold storage or refrigerated distribution facility which is primarily designed for food processing and distribution usually has a freezer floor section, a cooler, and a dry storage area. Rack supported buildings employ rows of box shelving, or racks, to maximize space utilization. Typically, each rack is several floors high. As such, rack supported buildings may have ceilings as high as 78 feet. The tall narrow aisles established by warehouse shelving can create lighting challenges and inefficiencies.


Manufacturing facilities have physical characteristics that involve the manufacturing processes such as fabrication, assembly, sub-assembly, and finishing, as well as quality control, warehousing and logistics. Manufacturing facilities generally fall into two groups: light manufacturing buildings and heavy manufacturing buildings. Light manufacturing buildings have a size smaller than 100,000 square feet and a ceiling height in the range of 14 to 24 feet. Heavy manufacturing facilities have an average building size of more than 300,000 square feet, a minimum ceiling height of 16 feet, and a maximum height of around 60 feet. Aside from these buildings, airport hangars are also classified as manufacturing facilities. Airport hangars which perform repair and maintenance are similar in size to heavy manufacturing buildings and have ceiling heights usually exceeding those of rack supported buildings.


There're other categories of facilities, which account for a small percentage of the industrial real estate. These categories include flex, multi-tenant, freight, and telecommunications facilities. Flex facilities refer to flexible buildings used by technology and service tenants for product research, development, testing, or display activities. Multi-tenant facilities are designed to accommodate a multiple number of tenants. Freight facilities are classified as truck terminal and air cargo. Telecommunications facilities are generally data/switch centers.


Classified Areas

Industrial environments have a diversity of operating conditions not found within other sectors. Industrial lighting fixtures may be subject to harsh and hazardous environments. These environments are classified and rules are set for the types of luminaires that may be installed in them.


Hazardous locations

Hazardous locations are areas where fire or explosion hazards may exist due to the presence of flammable gases, vapors, liquids, dust, ignitable fibers or flyings. In North America, these areas are defined in the National Electrical Code (NEC) published by the National Fire Protection Association (NFPA) and Canadian Electrical Code (CEC) published by the Canadian Standards Association (CSA). Electrical installations in the European Union are governed by the ATEX Directive 2014/34/EU prepared by European Committee for Electrotechnical Standardization (CENELEC). The IECEx system from International Electrotechnical Commission (IEC) operates globally across many national and regional jurisdictions.


The NEC and CEC define three categories of hazardous locations that have been designated as Class I, Class II, or Class III.


Class I locations are those where flammable gases or liquid-produced vapors may be present. Some typical class I locations are petroleum refineries, oil drilling rigs, gas processing plants, LNG facilities, mining operations, sewage treatment plants, dry-cleaning plants where vapors from cleaning fluids can be present, pipeline pumping stations, and spray-finishing areas. Based on the ignition temperature of the substance, its explosive pressure, and other characteristics of its ignition or explosive potential, the gases and vapors of Class I are broken into four groups: Group A (acetylene), Group B (hydrogen), Group C (ethylene), and Group D (propane).


Class II locations are those made hazardous due to the presence of a combustible or electrically conductive dust in quantities sufficient to ignite or explode. Typical class II locations include grain elevators, flour and feed mills, plants that manufacture or use conductive or metal powders like magnesium, fireworks manufacturers, producers of starch or candies, spice-grinding plants, sugar plants and cocoa plants, chemical and plastic mixing/storage areas, coal preparation plants and other carbon handling or processing areas. Within Class II are another set of groups: Group E (electrically conductive dust), Group F (carbonaceous dust), and Group G (agricultural and polymer dust). The group is determined by nature of the substance (the ignition temperature and conductivity of the dusts).


Class III locations are areas where easily ignitable fibers or flying are present. Typical class III locations include textile mills, woodworking workshops, cotton gins, and cotton seed mills.


Each class of the hazardous locations is further subdivided into two divisions depending on the likelihood of the hazardous material being present in a flammable concentration. Division 1 applies to an area where ignitable concentrations of hazards are present under normal operation conditions. Division 2 refers to abnormal or not normally present condition. The hazardous material is expected to be confined within closed containers or closed systems. Hazards may be present only through accidental rupture or breakdown of such containers or systems, or due to faulty operations.


The IECEx/ATEX system uses Zones to define hazardous locations. Hazardous locations in which flammable vapors or gases may be present are divided into Zone 0, Zone 1, and Zone 2. Zone 0 refers to areas where the flammable vapor or gas is continuously present or present for long periods of time. Zone 1 refers to areas where the flammable vapor or gas is likely to be present in normal operation. Zone 2 refers to areas where the flammable vapor or gas is usually not present in normal operation. The duration of the possible presence is short. Hazardous locations in which a combustible dust may be present are divided into Zone 20, Zone 21, and Zone 22. Zone 20 refers to areas where the combustible dust in sufficient quantities for a fire or explosion hazard to exist is present continuously or for a long period. Zone 21 refers to areas where the combustible dust in sufficient quantities to produce an explosive mixture is likely to be present occasionally during normal operations. Zone 21 refers to areas where a fire or explosion hazard due to the presence of a combustible dust is not likely to occur, and persists for only a short period of time if it does occur.


High humidity or atmospherically corrosive areas

Moisture ingress and corrosion are two major failure factors in industrial lighting systems, particularly LED luminaires. High humidity or corrosive atmospheres are likely to be present in many industrial environments such as chemical plants and warehouses, food processing facilities, pulp and paper mills, dyeing and printing mills, cement plants, and facilities located in coastal regions. Corrosive gases not only rust or wear out exposed metal parts, but can also penetrate through the LED encapsulant which is often silicone-based. Corrosion of the lead frame used in the mid-power LED packages will cause a reduction in light output. Corrosion of electrodes or bonding wires will result in electrical discontinuities or abnormal increases in forward voltage. Long-term exposure to a high humidity environment not just leads to corrosion. The diffusion of moisture within an LED package is the underlying cause of the formation of cracks in silicone encapsulants as well as the delamination between the LED die and the encapsulant, when both temperature and humidity are active stresses. Luminaires installed in high humidity environments have either a damp location rating or a wet location rating. A damp location refers to an environment is normally or periodically subject to condensation of moisture in, on, or adjacent to electrical equipment, and includes partially protected locations. A wet location refers to an environment where water may drip, splash, or flow on or against electrical equipment.


Industrial environments with extreme ambient temperatures

Another challenge inherent to operating LED luminaires is heat. High temperature is one of the primary failure accelerators in LED-based lighting systems. Operations involving high air temperatures or radiant heat sources make it very challenging to thermal management of LED luminaires. The amount of heat that can be dissipated from the LEDs depends on the temperature gradient along the heat flow path from the LED junction to the ambient air circulating around the luminaire. Abnormally high ambient temperatures are often present in industrial applications. Industrial facilities that have a high ambient temperatures include: iron and steel foundries, nonferrous foundries, heat treatment workshops, brick-firing and ceramic plants, glass products facilities, rubber products factories, fossil fuel power stations, boiler rooms, chemical plants, mining sites, and smelters. In these facilities, the luminaires should be designed to survive high ambient temperatures of as high as 65°C.


Unlike fluorescent lamps that require a ballast for low-temperature starting, LED luminaires perform well in low ambient temperatures, with longer lumen maintenance and better color stability. However, the performance of other materials used in the luminaire, such as optical components and gaskets, should be verified at expected temperatures.


Cleanrooms

Clean rooms are sealed, controlled environments designed to eliminate microscopic particles of a specified size, such as dirt, airborne microbes, aerosol particles and chemical vapors. Maintaining the integrity of a clean environment is necessary for many manufacturing processes, such as semiconductor wafer fabrication, pharmaceutical manufacturing, and bio-tech research. Clean rooms are categorized into a series of classifications based on the number of micron particles found in a cubic foot of air inside the room. The International Standards Organization (ISO) cleanroom classifications are rated ISO 1 through ISO 9. The lower the rating, the cleaner the clean room. The classifications of the Institution of Environmental Sciences (IES) cleanroom classifications include start at 100,000 parts per cubic foot (Class 100,000), and proceed through Class 10,000, Class 1,000, Class 100, to Class 10. Cleanroom lights are usually constructed to carry a high degree of ingress protection (IP) and have an outside surface that is smooth, cleanable, and corrosion resistant.


Food processing facilities

Luminaires installed in food processing facilities must hold up to sanitation required to prevent bacteria growth or harborage of other contaminants. Food processing applications usually require such products to be certified to standards such as those established by the National Sanitation Foundation (NSF). The NSF concerns itself with these luminaire construction issues such as the trapping of food particles, encouragement of bacterial growth, suitability for hose-down application. Therefore, the design and construction of the luminaire must take into account these factors: good cleanability, high watertight integrity, free of material toxicity and high corrosion resistance. A watershed design is required to ensure that a flow of water will carry the food or other contaminants off the luminaire housing. The gasketed area of the luminaire must be capable of resisting the daily high-pressure wash downs. The expose materials of the luminaire must endure the corrosive effects of cleaning solutions and will not introduce toxicity into food that would come in contact with the luminaire. However, lighting fixtures often do not come in contact with the food under normal conditions also they can physically located in food preparation and handling areas (the Food Zone). The NSF breaks down the equipment requirements into three zones: Food Zone, Splash Zone, and Non-Food Zone. Lighting fixtures are often located in the Splash Zone and Non-Food Zone.


Challenges

Industrial lighting is a complex task that must balance many different considerations such as upfront cost, quality, reliability, efficiency, maintainability, and controllability. In today's hypercompetitive business environment, maintaining tight control over energy expense without undermining productivity, security and safety can mean the difference between profit and loss. In industrial applications, lighting is a major cost component that is constantly reappraised with regards to its ROI (return on investment) and TCO (total cost of ownership). All industrial lighting must be designed to support a safe, comfortable and productive manufacturing or working environment. To develop lighting solutions that meet quality, quantity and operational criteria, a variety of challenges need to be addressed. High, hard-to-reach ceilings, expansive spaces, high humidity, corrosive or explosive atmosphere, hot or cold temperatures, dirty power, vibration from large machinery, long operating hours and unique building characteristics - these unfavorable conditions can add up in lighting fixtures that have high up-front, installation, operation and maintenance costs.