Guide to Industrial Lighting
Different types of industrial lighting have specific advantages and disadvantages. Finding the most cost- and energy-efficient lighting that is also the right color and intensity can be a challenge. Check out PE Facts to find out what lighting is the best for your facility!
Lighting is essential to our everyday activities. It is especially important in the work environment because it allows for safety and efficiency. Electrical lighting is necessary in areas that natural light does not reach. The three categories electrical lighting can be broken down into are general, supplemental and emergency lighting. General lighting is the standard lighting that typically lights inside facilities. Supplemental lighting is extra, more intense lighting that concentrates on a specific area such as a workstation. Emergency lighting is the battery- or generator-powered lighting that is used when the usual electrical power is lost or disrupted. Although different, all three categories of lighting use the same basic principles discussed below.
Terminology
Amperes (Amps): A measure of electrical current. The water flow in a water line is a good comparison.
Averaged Rated Life: The point during continuous laboratory testing when half of the test lamps have burned out and half are still burning, or simply the median time it takes a lamp to burn out.
Ballast: A supplementary piece of equipment intended to start and properly control the power flow to gas discharge lights such as fluorescent or high intensity discharge (HID).
Candlepower: A measure of the intensity of light projected by a lamp.
Footcandle: A unit of measurement for the total amount of light reaching a surface. Light that covers one square foot of a surface illuminates one footcandle.
Glare: Intense light or brightness that causes irritation, discomfort, or eye fatigue, that interferes with vision.
Lumen: An international (SI) unit of the amount of light or luminous flux.
Lux: An international (SI) unit of luminance. One lux is equivalent to 1 lumen per square meter.
Voltage: A measure of electrical pressure or electromotive force. It can be compared to the pressure inside of a waterline.
Wattage: A measure of electrical power. In relation to lighting, it represents the amount of power used by the bulb. The multiplying voltage derives it by amperage.
Lamp Types
Incandescent
Incandescent lamps are the most common type of lighting. An electric current passes through a thin filament wire to create white heat which produces light. These lamps can be used for any type of lighting, including general, supplemental or even decorative. Incandescent lamps produce a nice, warm light that lasts about 500-1000 hours. They come in a variety of styles such as, standard bulbs, reflective spot and flood lamps, tubular, decorative bulbs, three way or rough-service bulbs. They are energy efficient (up to 18 lumens per watt) and are easy to install.
Halogen
Halogen lamps create light by using a small filament wire that is enclosed in a quartz tube containing pressurized halogen, iodine or bromine gas. This generates a brighter, whiter light than incandescent bulbs because it burns hotter. Halogen bulbs are typically used as headlights, outdoor flood lamps, accent or display lighting. They come in a variety of styles such as, parabolic aluminized spots, reflective spots and floods, single and double-ended quartz, floods and mini-can bulbs. Halogens produce a more intense, focused light. They have energy efficiency up to 22 lumens per watt and generally last 2000-5000 hours.
Fluorescent
Fluorescent light is created by passing an electric arc through an inert gas. The arc produces heat which vaporizes tiny drops of mercury which emit ultra-violet (UV) light. There is a phosphor coating on the inside of the bulb which glows intensely when interacting with the UV light. Fluorescent lamps are extremely efficient, using up to 105 lumens per watt. They use one-fifth to one third of the energy that incandescent lights do and last up to 20 times longer. They have various styles including u-shaped, circular and straight tubes up to 96" long. They usually last about 12,000-24,000+ hours. Some disadvantages of fluorescent lamps are that they are sensitive to cold temperatures and can only be dimmed by using expensive equipment.
Compact Fluorescent
Compact fluorescent lamps function similar to standard linear fluorescent lamps. These lamps can be used in regular sockets and serve as an energy efficient replacement for incandescent bulbs. They have an energy efficiency of up to 105 lumens per watt and typically last 9,000-10,000 hours. They come in bulb, circular or twin-tube form. Compact fluorescent light is similar in color to incandescent light, so it is a good substitution. They last up to 13 times longer and save 64-82% more energy. For best results, they should be used in places where they will be in use for several hours at a time. One drawback is that they cannot be dimmed.
High Intensity Discharge
High intensity discharge (HID) lamps pass an electrical current through an internal tube filled with a mixture of gases under pressure to create light. There are three types of HID lighting, including high-pressure sodium, mercury and metal halide—all in a screw-base bulb. This powerful light source is typically used for general lighting, landscape lighting or outdoor floodlighting. These are the most energy efficient bright lights, burning from 65-140 lumens per hour. They generally last 10,000-24,000 hours and can endure hot or cold environments. HIDs gradually reach full brightness because it takes a few minutes to warm up.
Cost of Operation
The cost of lighting is not only dependent upon the cost of the bulb itself, but also on the installation and use of electricity. Electricity actually accounts for 80-88% of the total cost. The cost of labor for installation is around 8%, while the cost of the bulb is approximately 4% of the total cost. This is why using the most energy efficient lamps with the longest life will really cut your costs. For instance, purchasing a compact fluorescent bulb rather than an incandescent bulb will have a higher initial cost; however, the savings in labor and especially in electricity will significantly reduce your costs overall. The average national cost of energy is 8-10 cents per kilowatt-hour (kWh). To determine your average energy costs, use the following formula:
Bulb power ( Watts) x Bulb average life x Cost per kWh/1000 = Cost of Electricity
Light Level Recommendations
The type of lighting used in a certain area is extremely affected by what activity goes on in that area. Too much light may cause discomfort or irritation but too little light could decrease accuracy and productivity. Here are some light level recommendations for area, office and industrial lighting.
| Area Lighting | Footcandles Required |
|---|---|
Construction Areas: |
|
| General Construction | 10 |
| Excavation | 2 |
Parking Areas: |
|
| Open (high/medium) activity | 2/1 |
| Covered parking | 5 |
| Entrances (day/night) | 50/5 |
| Storage Yards (active/inactive). | 20/11 |
| Office Lighting | Footcandles Required |
| Corridors, lobbies | 10-20 |
| Easy tasks (large print, typed originals, ink handwriting) | 20-50 |
| Medium tasks (small print, poor copies, pencil handwriting) | 50-100 |
| Difficult Tasks (Very poor copies, pencil handwriting) | 100-200 |
| Industrial Lighting | Footcandles Required |
Service Garages: |
|
| Repair | 50-100 |
| Active traffic areas | 10-20 |
| Loading Platform | 20 |
| Receiving & Shipping | 20-50 |
Warehouse/Storage rooms: |
|
| Inactive | 5 |
| Active: Label-reading, items | 15-30 |
Machine shops and Assembly areas: |
|
| Simple assembly; rough bench and machine work | 20-50 |
| Moderate assembly; medium bench and machine work | 50-100 |
| Difficult assembly; difficult machine work | 100-200 |
| Fine assembly; fine bench and machine work | 200-500 |
*Higher illumination may be achieved through general and supplementary lighting.
Color of Light
The color of light given off by a particular lamp is also important because it changes how people and objects in the area look. The higher the color-rendering index (CRI), the better the objects will appear. A CRI of seventy or more is the best. Another thing to consider is the “warmth” or “coolness” of the bulb. Warm bulbs give off a yellow-white light, while cool bulbs give off a white light on a neutral surface. Incandescent and warm fluorescent bulbs usually strengthen red, orange, and yellow hues, but weaken blue hues. Cool fluorescent bulbs typically strengthen orange, yellow and blue hues, but weaken red hues.
Commonly Asked Questions
Q.What should I consider when choosing lighting for my facility?
A.The amount and type of light required for any space depends greatly on what activity primarily goes on in that area. Providing too little light can reduce productivity and accuracy while too much light may cause irritation, eye fatigue, or discomfort.
Q. What is the conversion between lumen, candlepower, footcandle and lux?
A. Since 1 lumen/sq.ft. = 1 footcandle and 1 lux = 1 lumen/sq. meter; And 1 square foot = 0.0929 square meter; Then, 1 lux = 0.0929 footcandle, and 1 footcandle = 10.76 lux.
EX: 1 Lux/0.0929 = 10.76 Lux
Q. What is color temperature?
A. Color temperature is the balance of wavelengths that make up any “white” light. The higher the color temperature, the cooler or more blue the light source. It is measured in degrees Kelvin, (K). For example, a typical color temperature for an incandescent light is 2800K, while a cool white fluorescent is 4100K.
Q. To measure the lighting at my facility, what type of instrument can I use?
A. A light meter is required to measure light levels in your work areas. The instruments transfer the energy of available light into an electrical current. The meter reads this electrical current and then calculates the appropriate value for footcandles or lux.
Q. Is there a perfect lamp?
A.The perfect lamp is extremely energy efficient, and lasts forever while maintaining its color and light output as it ages. However, this light has yet to be invented. The best lamp is one that suits your specific situation.
Please Note: The information contained in this publication is intended for general information purposes only. This publication is not a substitute for review of the applicable government regulations and standards, and should not be construed as legal advice or opinion. Readers with specific questions should refer to the cited regulation or consult with an attorney.
