Chapter Four: Considerations before buying LED warehouse lighting
Industrial facilities need high quality warehouse lighting to keep workers safe and factories productive. Lighting solutions not only need to be durable enough to withstand harsh environmental conditions, including high temperatures, humidity, corrosive atmosphere, dirty power, and vibration, but also must comply with
applicable fire, safety, and material codes. In addition to these requirements, the luminaires should require only minimal maintenance and be energy efficient.
Because of recent advances in LED technology, industrial facility managers now have other options than just the traditional high intensity discharge (HID)
lamps of yesterday, and can achieve substantial savings in energy and lighting maintenance LED. Today’s LED systems use 2–3 times less energy and
require up to 90% less maintenance compared with traditional Metal Halide and High Pressure Sodium High-intensity discharge lamps—bringing lighting
to the forefront of sustainability and cost reduction initiatives. Factories and plants are upgrading mission critical lighting applications to achieve rapid payback on investment with significantly better light quality and control. This white paper describes the major lighting applications within the Industrial sectors and key points to consider when upgrading to LED lighting.
1)Maintained Illumination: Illumination, measured in lux or foot candles, is the measure of the amount of light that falls onto a surface. The level of illumination required depends on the task being performed. Organizations like OSHA and IESNA recommend minimum lighting levels for performing specific tasks based on the frequency of activity and the inherent danger present. ‘Maintained’ refers to light level from a luminaire not at the beginning of its life,
but rather at the end of its life; therefore light decay must be factored into the equation when calculating minimum illumination. It has been proven time
and again that accidents and productivity can be directly linked to adequate lighting, and therefore, it is imperative to provide a minimum level of maintained lumens. Since LED warehouse luminaires do not have replaceable ‘lamps’, the maintained lumens are calculated at the end of its life.
2) Control Systems: The instant dimming and turn on-off capabilities of modern day LED systems allow for a more efficient utilization of electricity, not possible with HID lamps. In addition to standard analog dimming, lighting can be made adaptive to the environment based on foot or vehicle traffic via occupancy sensors, daylight using photocells or timers, and peak electricity costs utilizing advanced lighting controls. These controls use wireless or power line communication, and can also provide facilities managers with real time usage and maintenance data. Resilient luminaires are compatible with wired and wireless control methods depending on the specific need of the facility.
3) Vertical and Horizontal Illumination: Illuminance levels play a vital role in worker and food safety. There are two types of illumination, horizontal and
vertical. Horizontal illumination is the light that shines on horizontal surfaces, such as work benches or conveyor belts, while vertical illumination is the light
that shines on vertical surfaces such as signs on a wall or labels on vertical storage rows. The USDA specifies minimum horizontal illumination in meat and
poultry plants, while IESNA (Illumination Engineering Society of North America) recommends the illuminance levels for other food and beverage plants sites.
Typically, vertical illumination should be 25-50% of the horizontal illumination and free of shadows in critical areas to create a safe working environment
4) Color Rendering: Color rendering is the ability of a light source to represent the true colors of an object, and the Color Rendering Index (CRI) is a scale that measures this ability. A CRI of a 100 indicates that a light represents color perfectly (sunlight represents a CRI of 100). In food and beverage processing facilities, a high CRI light sources allows workers to see colors accurately and perform their jobs safely and correctly. Most importantly, high CRI light sources allow workers to discern the quality of food products in processing and inspection areas, impacting the safety of the food. In general food processing areas, a CRI of 70 is desired, whereas in inspection areas, a CRI of at least 85 is required
5) Dirty Power: Voltage and current fluctuations in the power line are a known problem in heavy industrial settings. Large temporary surges in power can
be caused by lightning storms, but more often the facilities are impacted by smaller, dirtier surges from load switching, and the use of low power factor
devices. Constant dirty power use over time will lead to premature lighting failures. Resilient’s power solutions counteract and guard against this at the individual luminaire level by utilizing proprietary protective circuits to defend against various types of dirty power.
6) Light Penetration: Luminaires in heavy industrial sites are often hung at near ceilings exceeding 30 meters high and require at least 750 to 1000 lux in
moulding, smelting and plating areas. In addition, the particulates in the air can accumulate on the luminaire lens exacerbating the need for powerful light output to penetrate to the facility work areas. Light fixtures in such areas should utilize long throw optics to reach the work floor, and a luminaire dirt depreciation factor of 0.65 should be used to calculate the level of light output and the number of luminaires needed to illuminate the workspace.
7) Extreme Temperatures: Heavy industrial plants produce extremely hot environments often exceeding average temperatures of 50°C (122 F). LED chips and driver electronics are extremely sensitive to high temperatures, which accelerate lumen decay and increase premature failure rates. Standard
luminaires designed for outdoor area or commercial use will not survive in such conditions. Resilient luminaires utilize advance vapor chamber based cooling
to ensure luminaires will operate continuously at a 55°C ambient temperature for over 100,000 hours
8) Lighting control and technology
Using the lighting intelligent controls will bring lots of benefits to warehouse lighting application. These benefits include improved energy efficiency and responsible power use, increased security and safety, and responsive controls.
The control requirements and devices are:
- Occupancy sensors are mounted in the ceiling or on a wall switch, available in passive infrared (PIR) or “dual-technology,” which incorporates PIR plus either a microphonics or ultrasonic sensor. PIR is limited to line-of-sight movement only, so it is not a good choice in areas with lots of obstructions like tall cubicle walls, large equipment, or restroom stall doors. Microphonics uses a tiny microphone to detect sound, while ultrasonic sensors emit high-frequency sound waves to detect motion. The sensors operate by turning on the lights in the space upon occupancy to a level determined in ASHRAE 90.1 and turning them off automatically after 20 to 30 minutes when unoccupied. Most space types in a commercial application, aside from mechanical/electrical rooms, require occupancy sensors.
- Daylight sensors are mounted in the ceiling, ideally with lights between the sensor and a window. They operate by taking a reading of total available light in the space. Throughout the day, sensors dim the artificial lights to where the artificial light level plus the sunlight level in the space meets the programmed foot-candle either at the work surface (generally 30 in. above the floor) or on the floor, depending on space usage. Per the 2016 version of ASHRAE 90.1, any space with windows or skylights and total lighting wattage in the sunlit area greater or equal than 150 W requires daylight-sensor control.
- Automatic receptacle control was introduced in ASHRAE 90.1-2010 and consists of a relay pack that controls 50% of the electrical receptacles in the space. Let’s consider two different ways how a private office with four duplex receptacles is controlled:
- Two full duplex receptacles will be controlled.
- The bottom (or top) receptacle on each of four duplex receptacles is controlled.
- Controlled receptacles shall be marked with the International Power Symbol per NFPA 70: National Electric Code (NEC), Article 406.3 (E). The receptacles can be tied to the operation of the occupancy sensor in the space or they can be incorporated into a scheduled time-of-day shutdown. In the case of occupancy sensor-controlled receptacles, they turn on upon occupancy and turn off after 20 to 30 minutes of being unoccupied. These receptacles are a good choice to plug in noncritical loads, such as a desk lamp that may inadvertently be left on. (per ASHRAE 90.1-2016). A best practice is to bring this up early in the design process so clients are not blindsided.
- Bilevel lighting control is a method of having at least two separate lighting-output levels for a space, one of which may be automatic upon entry while the second is manual. A smart switch with full dimming capabilities also meets this requirement, provided the automatic operation is no higher than 50%. When an occupant enters the space, the lights come on to 50% output automatically. If the occupant wants full light output, they manually hit the second-level button (or dimmer buttons) on the wall switch. This requirement is in place to prevent wasted energy on someone stopping in briefly and leaving immediately. For example, a janitor closet, where the janitor would open the door, grab a broom and leave, triggering the occupancy sensor. This requirement can be programmed into the system or be a pre-installed option on a relay pack.