Paint Spray Booth Lighting Fundamentals|
Article- September 2011 By Larson Electronics.com
Larson Electronics Explosion Proof Paint Spray Booth Light
In many industries, lighting plays a unique and critical role in production rates and the quality of the finished products. Intensity, how light interacts with the environment, and the specific color properties of light all play a large role in how an object appears and can have a significant effect on how an object is perceived by the human eye. In paint spray booth applications, the effects of lighting on the finished product are pronounced and demonstrate how important applying the correct lighting according to application can be. In the spray booth, the ability to easily view surface imperfections and apply uniform coatings is critical. Additionally, effective color matching and correctness depends greatly on having lighting that will not interfere with the trueness of color.
With paint spray booth lighting, the lamps of choice are generally four to eight foot long fluorescent fixtures depending upon the size of the booth. Fluorescent lamps are the popular choice for several reasons. They provide uniform light coverage, have relatively high output, can be configured over a range of color spectrums and temperatures, and produce only moderate amounts of heat. The choice of lamp types for the spray booth is for the most part dictated by how well the lamp reproduces colors, but is to a lesser extent also influenced by operator preferences.
Generally speaking, fluorescent lamps within the higher end of the color rendering index scale are preferable because they produce less color variance and reproduce colors more accurately. The color rendering index, or “CRI” of lamps is a scale which basically denotes how closely the lamp mimics the full spectrum of natural light. Ranging from 0 to 100, the CRI of a typical cool white fluorescent lamp is around 65. For critical applications like paint booths, a CRI of 80 or better is preferable because it more closely mimics the natural lighting that the finish will be viewed under in normal conditions.
As well as CRI, the output of a lamp and uniformity of that output has a lot to do with how well the lamps cover the work area with light and thus how effectively a finish is applied. Fluorescent tubes emit their light energy over their entire surface, thus emitting light in all directions. In order to get as much of the light as possible onto the desired surfaces, fluorescent paint booth fixtures are equipped with reflector assemblies which direct output over a specific angle of radiation. A narrower angle means the light is more concentrated over a smaller area resulting in more intense illumination, while a wider angle means the light is spread over a larger area but is more diffused. For paint booths, reflector angle is usually a decent compromise between angle and intensity, which is fortunate because there aren’t many options for manipulating the angle of reflection.
When considering overall coverage of the entire work area within a paint spray booth, the size of the booth and how much area a single fixture can cover practically will decide how many fixtures are needed and at what wattage level. For paint booths, 100 foot-candles at 3-feet is a generally accepted figure. A larger paint booth may be effective with only a few more powerful lamps in order to achieve that level, while a smaller booth can make do with several smaller, less powerful units. The largest factor here is to ensure uniform light distribution in order to avoid dark spots and shadowing that may hinder your ability to make uniform coating applications.
Of huge importance to paint spray booth applications is the safety regulation compliance of the lighting equipment and its suitability for use in a hazardous environment. Due to the flammable nature of the chemicals and compounds used within the booth, removing potential sources of ignition is critical. Since any electrical equipment used is a potential source of heat, sparks or flame, it must be properly designed and certified for use in hazardous locations. Paint spry booth lighting that is mounted within the booth is required to be certified Class 1 Division 1 for use in locations where hazardous materials are present continuously or during normal work operations.
Lighting that is mounted outside the booth or in sealed panels is generally Class 1 Division 2 and certified for areas where contact with flammable atmospheres and materials is not normally expected. Also important for spray booths are group certifications and temperature ratings which spell out how suitable a fixture is for use around certain chemicals and materials. For lighting that will be inside paint booths, the lights will usually be classed for material Groups C and D, with a T6 temperature rating. This ensures that the lamps are safe for use with the common flammable vapors and liquids used in paint spraying operations and that the surface temperature of the fixtures does not exceed the ignition point of those compounds.
Explosion proof paint spray booth lights from manufacturers like Larson Electronics are specially designed to meet the safety requirements for hazardous locations such as paint spray booths while still providing the necessary illumination levels as well. Usually constructed of non sparking aluminum and designed to contain or prohibit ignition, such explosion proof lights are mandatory for any type of paint booth operations. If there is one area where compromise or alternatives are not reasonable, it is making compliance. It’s not worth the increased threat to employee safety or the potential financial losses to accept low grade or poorly matched equipment in an effort to save a few dollars.
On a final note, potential buyers of spray paint booth lighting should take note of the recent changes in efficiency regulations that are now going into effect. As a result of new federal energy policies, some fluorescent lamps such as eight foot long T12s will no longer be available, and solid state ballasts will be replacing older magnetic units. It will be necessary to make sure that any fixtures purchased will be able to use alternatives such as T5HO or T8 lamps, and that magnetic ballasts are used.