Farm Talk

January 7, 2014

Selecting lighting for farm facilities


CNHI

Parsons, Kansas — Indoor lighting for farm facilities is critical to safe and efficient production. Lighting systems should be designed to meet minimum lighting requirements in the most energy efficient and economical manner.

Farmers have numerous choices regarding types of lighting for facilities.

When selecting the proper lighting for an indoor application, consider not only energy efficiency, but also the initial cost of ballasts and fixtures and the rated life of bulbs. Keep in mind that dirty bulbs and fixtures can reduce light levels, and the environment within farm facilities (moisture, temperature, dust) generally shortens bulb life to less than its estimated “rated life.”

The following is a general description of some of those options.

Incandescent bulbs use electrical resistance to produce light. Most of their energy is given off as heat rather than light, therefore, they are the least efficient type of lighting. Although inexpensive to purchase, over time their inefficiency and short life make them a costly lighting source. These bulbs will be phased out of production during the next few years.

Compact fluorescent lights (CFL) can be direct replacements for incandescent bulbs because they require no wiring changes. They typically use 75 percent less energy than incandescent bulbs and last approximately 10 times longer. CFLs normally will not operate below 0°F and require about one minute to reach full light output. CFLs installed in livestock and poultry facili­ties should be rated for damp environments; however, bulb life may be shortened by placing them in globes or enclosures, due to increased temperatures. CFLs are best suited for facilities where lights stay on for extended periods, since frequent on/ off cycles shorten their life.

Cold cathode fluorescent lights (CCFL) typically last two to three times longer than other CFLs, start at lower temperatures, are compatible with many types of dimmers, and can be turned on and off frequently without significantly shortening bulb life. They are more expensive and slightly less energy efficient than CFLs.

Light emitting diodes (LED) use semi-conductor diodes, electronic devices that permit current flow in only one direction, to produce light. They are up to five times more efficient than incandescent lighting and long-lasting, with ratings up to 100,000 hours. LEDs emit directional lighting rather than the 360-degree illumination provided by other bulbs. They currently have limited application in livestock and poultry housing, due to their susceptibility to moisture, heat, and dust. However, new LED products are being developed and some have been tested successfully in broiler housing.

Tube fluorescent bulbs are available in three diameters. T5 and T8 bulbs are 0.6 inch and one inch in diameter, respectively. The most commonly used is the T12 bulb (1.5 inches in diameter); however, its manufacture is being phased out because it is the least efficient tube fluorescent bulb. T8 systems are four times more efficient than incandescent lights and 30 percent more efficient than T12 tubes. They are best suited for applications where they are mounted less than 12 feet above the floor.

In livestock and poultry housing, standard output tube fluorescent bulbs should be mounted with electromagnetic ballasts in waterproof, gasketed fixtures. T5 bulbs are shorter and more efficient than T8 bulbs. Both T8 and T5 bulbs tend to retain the original light output longer than T12 bulbs. However, T5 bulbs are not recommended for use in vapor-tight fixtures and should be limited to clean-dry environ­ments. High output versions of tube bulbs will start as low as -20°F, but are less efficient than standard output bulbs.

High intensity discharge (HID) lamps include metal halide and high pressure sodium vapor lamps. These typically are easy to install and maintain and are well suited for high bay appli­cations (ceilings higher than 12 feet). However, they require a few minutes to warm up before they reach full light output, so they are not ideal for short-cycle lighting. They should be replaced when light output begins to fade appreciably or when they continually shut off and restrike while power is still on.

Metal halide (MH) bulbs generally have efficiency ratings between 60 and 80 lm/W and are available in a pulse-start or standard version. Pulse-start bulbs typically are more efficient and can have 50 percent more lamp life than the standard version. MH are not instant-on lights, requiring one to three minutes to reach full light output. They must also cool down five minutes before re-starting.

High pressure sodium vapor (HPSV) lighting is more efficient than metal halide lighting. However, these lamps emit a yellow-orange light that may not be desirable for livestock facilities where true color observation is critical to monitoring animal health. They work well at cold temperatures and are typically used outdoors. £