How do I improve booth energy efficiency?
- Start by upgrading the fan motor. Replace it with one meeting the newer, premium energy efficient electric motor standards. These motors are constructed using heavier wire, better grades of steel, thinner and longer laminations and better bearings. The efficiency increase is particularly significant in the lower horsepower range. For example, a typical filter booth is equipped with a 5 hp, 3-phase motor. The standard efficiency motor supplied with the booth has a power conversion efficiency of 84%; while its premium efficiency cousin will have a power conversion efficiency of 89.6%. According to U.S. Department of Energy (DOE) the cost of the electrical power consumed by an industrial motor over its useful life is 30 times its initial purchase price. The cost premium for an energy efficient motor is frequently recovered in less than a year
- Resist the temptation to oversize the fan motor. Over-sizing the motor adds cost in two ways. The initial purchase cost will be higher and the actual operating energy efficiency will be lower, needlessly inflating its power consumption. Consult NEMA (the National Association of Electrical Manufacturers) or the motor manufacturer’s guidelines when sizing a replacement motor for your booth. Usual practice is to operate motors in their most efficient range – 75% to 100% of their full load rating.
- Replace inefficient, power consuming, mechanical control devices, such as variable speed pulleys, dampers and bypass vents with a variable frequency drive (VFD) designed to drive your new energy efficiency motor. The DOE estimates industrial motor energy consumption could be reduced by up to 18% if companies replaced their motors with high efficiency ones and powered them with energy efficient electronic variable frequency drives.
- Consider upgrading the spray booth to include energy efficient, closed-loop constant airflow control technology. This new control package includes both an energy efficient motor and a variable frequency drive. The closed-loop system automatically maintains the preset exhaust airflow as your booth’s arresting filters load with overspray by monitoring the actual exhaust airflow and adjusting the motor rotational speed to maintain it at the preset level. The system consumes only as much power as is needed to maintain the preset exhaust airflow at any given moment in time. An added benefit of upgrading the booth airflow control system is gaining a stable environment for the spray finishing operation the booth houses. Practitioners of six sigma and other popular continuous improvement disciplines find constant booth airflow enables them to fine tune the entire spray application operation, further reducing the line’s operating cost.
What codes will my booth be required to meet?
Most municipalities/cities require that paint booths, including installations, meet National Fire Protection Association (NFPA) Chapter 33, OSHA 1910, NEC, and more recently IFC. These are national and international code guidelines; however, local authority prevails in most cases and will have the final say on code requirements.
What types of requirements or permits would we need to put in a vented paint booth?
You might not need a permit from your state air pollution control agency if you are using “very little” paint, but the fire department will probably want you to vent the booth. Your insurance company will also definitely want you to vent it to prevent a fire or, worse, an explosion.
You will need to read your state’s air pollution permit rules to determine what the “de minimum1” amount of paint is below which a permit is not required. The size of the booth and the design is also a factor.
It’s possible retrofitting your booth with a fan that will pull at least 100 ft./min. of air could possibly help. As another suggestion, download bulletin NFPA-33 from the National Fire Protection Association website (www.nfpa.org/catalog/product.asp?catalog%5Fname=NFPA+Catalog&pid=3395&query=nFPA+33&link%5Ftype=search&src=nfpa).
Cleaning procedures for polycabonate booth walls
- Wash the booth walls with a mild soap or detergent (such as Joy Dishwashing Liquid) and lukewarm water, using a clean sponge or soft cloth. DO NOT SCRUB OR USE BRUSHES!!!
- Rinse well with clear water.
- Dry thoroughly with a chamois or cellulose sponge to prevent water spots
- Fresh paint splashes, grease and smeared glazing compounds can be removed easily before drying by rubbing lightly with a grade of VM&P naphtha or isopropyl alcohol. This should be followed by warm wash using a mild detergent and ending with a thorough rinsing with clean water.
The following are the only solutions recommended for use by the manufacturer of the polycarbonate material:
Compatible Cleaning Agents
- Windex with Ammonia D
- Mr. Clean
- Top Job
- Formula 409
- Naphtha (VM&P Grade)*
- Kerosene* (DO NOT USE GASOLINE)
* Following immediately with a thorough soap and water cleaning.
If scratching should occure, minor abrasions can be removed or minimized by using a mild automobile polish. Examples of such polishes include (1) Johnson Paste Wax, (2) Mirror Glaze Plastic Polish (M.G.M10-Mirror Bright Polish co., Pasadena, CA), (3) Plexus (B.T.I. Chemical, Aguora, CA), and Novus Plastic Polish #1 and #2 (Novus Inc., Minneapolis, MN).
NOTE: A test should be made on a sample area with the selected product before all over use
- Use abrasive or highly akaline products
- Scrape walls with squeeges, razor blades or other sharp instruments
- Use Bensene gasoline, acetone or carbon tetrachloride
- Clean while booth temperature is elevated or when a high percentage of humidity exists
What is the typical annual schedule for dry filter spray booth maintenance?
Preventative maintenance on a spray booth will help reduce the likelihood of fires and explosions.
- Regular maintenance of the booth system and maintaining its systems in good order contribute to the fire prevention effort by removing flammable accumulations and dust, as well as make a clean finish possible.
- Use of the booth requires a regular schedule of filter replacement. Codes require that filters be inspected after each period of use and that clogged filters be discarded and replaced immediately, another practice that contributes to fire prevention as well as a clean finish.
- Clean/wipe down air hoses
- Vacuum interior of spray booth
- Wipe interior of spray booth walls
- Clean light fixture glass
- Vacuum pit and tunnel
- Clean and remove overspray from floor
- Check motor belts
- Pressure wash floor grates
- Inspect door seals (replace when required)
- Check and tighten all electrical connections
- Service airflow switches
- Lubricate door hinges
- Pressure wash spray booths
- Lubricate blower shaft bearings
- Calibrate booth pressure balancing gauge
- Fire suppression system
- Clean light tubes
- Check light fixture glass seals
- Clean inside of all light fixtures and glass
- Clean exhaust stack, dampers and stack head
- Clean main exhaust blower/fan
- Burner system tune-up (start-up procedure)
- Clean upper plenum
- Lubricate motors
- Door seal/gasket replacement
- Door hinge brass bushing replacement
Replace light tubes and ballasts
Do I need an Air Make Up unit with my spray booth?
The proper air flowing into a spray booth meets the following conditions:
The air volume in the plant (cubic feet) should be 20 times the air exhausted in one minute by the spray booth. Put another way, you want no more than three plant air changes in one hour. The following gives an example of using plant air. To calculate booth exhaust air multiply booth face square feet by velocity required.
||Air Exhausted @100 FPM
|1 Spray Booth 8′ x 12′
|2 Spray Booths 8′ x 10′
|2 Spray Booths 8′ x 8′
|Total Air Exhausted
||38,400 Cubic Feet
Multiplying the air exhausted by 20 yields a plant volume requirement of 768,000 cubit feed, or a building size of 200′ x 256′ with 15′ ceilings.