Spray Booth Lights: Which Type for Best Results?|
Most paint spray booths utilize one of two types of lighting fixtures in their design, either fluorescent tubes, or high intensity discharge lamps. Incandescent lamps are poor choices for spray booth applications because they are highly inefficient, have very short life-spans, and produce copious amounts of heat during their operation. It would require a large number of incandescent lamps to produce the same amount of light as either fluorescents or HID’s although incandescent bulbs do have good color rendering characteristics. Their heat and energy consumption simply make them impractical and so they have little value in commercial spray booth applications.
Fluorescent tubes are by far the favorite lights for spray booths and are the most common type of lighting used in spray booths today. Fluorescent tubes are preferred because of their ability to produce good color rendering and high levels of illumination while also producing much less heat than traditional incandescent bulbs. Fluorescent tubes also have long services lives, and can last over 20,000 hours as compared to an incandescent bulb’s paltry 700-2000 hours. Rounding out their desirability is their high efficiency, reducing the electrical costs associated with operating a commercial spray booth.
HID lighting is also popular and is considered a particularly efficient form of lighting. They require a high initial voltage for warm-up and ignition, but once lit require a small amount of electrical energy to keep them burning. HIDs are particularly effective in producing large amounts of light, allowing the number of lights used within a booth to be reduced as compared to fluorescents. They have good longevity and can last anywhere from 5,000 to 24,000 hours. They have good color rendering although not on par with high quality fluorescent lamps. One of the drawbacks of HIDs however is their tendency to create a spotlight effect and glare, making them somewhat uncomfortable and difficult to work under in spray booth applications.
For overall lighting quality and ease of operation, fluorescent bulbs are preferred over HIDs. Fluorescent lamps have gained this popularity due to their ability to provide sufficient lighting in the spray booth at an affordable cost with few unwanted lighting effects like glare. Aside from their basic traits, other factors also affect the choices available for spray booth lighting. Because spray booth operations involve volatile chemicals and paints that produce combustible gases and vapors when applied, they are regulated under various federal and state codes. These regulations specify explosion proof lighting for spray booths, and this lighting must adhere to a Class1- Division1 rating for lights mounted in ceilings or walls, while lights near openings must be vapor proof and adhere to a Class1 Division2 rating. These lights must be able to operate in an atmosphere that constantly presents volatile gases or vapors without being able to cause inadvertent ignitions of these compounds.
Because of these regulations, the lighting to be used within spray booths is higher in cost compared to normal lighting equipment. This increased cost is an added consideration for anyone deciding on the type of light to be used in the booth. Fluorescents are cost effective and present a good choice because of how well they diffuse light over a large area without producing glare than can make controlling the quality and uniformity of paint applications in the booth difficult. A good spread of the light produced by a lamp means a more even and uniform light pattern and less dark spots. This is helpful because the basic tendency in illuminating spray booths is to add as many lights as possible to produce an even saturation of light, and more lights means higher costs. Better light saturation means fewer lights will be necessary, which means lower costs.
Another consideration is the quality of the light produced. The quality of the lighting in the spray booth will have a direct effect on the ability of operators to produce high quality spray applications. Particularly in applications where paint is being applied, lamps with a high CRI or Color Rendering Index are preferable. The higher the CRI of a lamp, the better it renders the true colors of objects it illuminates. Fluorescent lamps can be had in a variety of CRI ratings and a general rule of thumb to keep in mind when making a selection is that as the CRI goes up, power requirements also rise and efficiency then tends to drop somewhat. Because of this association between power and efficiency, choosing the right lamps is something of a compromise although even the highest CRI rated fluorescents are still far more efficient than a typical incandescent lamp.
Further consideration must be given to maintenance of the lighting fixtures. In spray booth applications where lights must be explosion proof and properly rated, cleaning and re-lamping becomes a significant issue. Fluorescent lamps hold an advantage here as well because of their longevity. Explosion proof fixtures require careful handling and more effort when changing out expired bulbs. The differences are obvious when considering Larson Electronics’s Explosion Proof Fluorescent Lights for Paint Booths. Spray booth lights like these are not simply fluorescent tubes in a fixture. All of the electrical connections are designed to reduce the chances of errant sparks. The fluorescent tubes themselves are contained within sealed glass tubes, and the ends of the sealed tubes lock down to provide a secure seal. The entire housing is constructed of aluminum, which reduces the chances of sparks being created by impacts or contact with other metallic objects.
All of these features create a rugged fixture that typifies explosion proof lighting and requires extra effort and care when replacing tubes. End caps must be properly removed and reinstalled, connections must be maintained and checked for flaws, and the sealed glass tubes must be periodically cleaned to allow maximum radiation of light. Fluorescent tubes reduce the amount of time and effort required for maintenance by reducing the frequency with which bulbs must be replaced. Rather than looking at replacement intervals of 700- 1000 hours for incandescent bulbs, or 5000, to 24,000 hours for HIDs, fluorescents can extend that period to 40,000 hours. Of extra benefit are the reduced costs for replacement bulbs, adding to the economical aspects of fluorescent tubes.
Overall consideration of the features and compromises necessary when choosing spray both lighting spells out the need for an effective explosion proof fixture that will satisfy demanding illumination requirements as was as economical concerns. With explosion proof fluorescents, these requirements can be fulfilled without all the drawbacks of incandescent and HID lighting options.