Indiana Clean Manufacturing Technology and Safe Materials Institute

2655 Yeager Road, Suite 103, West Lafayette, Indiana 47906-1337


Technical Assistance and Training Program

Wood Furniture and Kitchen Cabinet Manufacturing NESHAP

August 1998


In the fall of 1997, the Jasper Chamber of Commerce received a grant from the state of Indiana, acting by and through the Indiana Department of Commerce, to provide technical assistance and training for twenty-seven Indiana wood furniture and kitchen cabinet manufacturers and involving more than 1,000 finish line personnel. This grant award to the chamber was primarily due to the leadership role of the Jasper Area Environmental Managers Association and their partnership with the Indiana Clean Manufacturing Technology and Safe Materials Institute (CMTI).


The need for a technical assistance and training program became evident with the promulgation of a new environmental regulation. The regulation titled the "National Emissions Standard for Hazardous Air Pollutants" (NESHAP) forced wood furniture and kitchen cabinet manufacturers to change many of their coatings operations. This regulation not only restricts the chemicals that may be used for coating operations, it also requires the implementation of "work practice standards." The work practice standards outlined in the NESHAP include a written work practice plan, solvent accounting system, leak detection and maintenance plan, and an employee training program. The employee training program must include training in chemical storage and handling procedures, coating application equipment setup, and operation and maintenance procedures.

Environmental regulations, such as the NESHAP, can put an increased burden on already stressed company capital and staff. It was clear to the wood product manufacturers and CMTI that by working together, they could combine resources and ease the burden on individual facilities. But the question remained: How to organize this effort? The Jasper Chamber of Commerce and the Indiana Department of Commerce were aware of the wood product manufacturersí importance to the Indiana economy and the impact this regulation could have on the industry. In order to minimize the economic effects of the regulation, government and industry formed a grant-funded technical assistance and training program.


In most wood furniture and kitchen cabinet manufacturing facilities, coatings are applied to enhance the durability and aesthetic qualities of the product. The majority of these coatings are applied using manual spray operations, but the transfer efficiency (the percent of material that is applied to the part) in the average manual spray operation is very poor. In general, less than one-half of the material sprayed through the gun adheres to the targeted substrate. The rest of the sprayed material is lost as overspray. When applying coatings to substrates of complex geometry, such as chairs, the transfer efficiency may drop below 25%. This means that for every gallon sprayed, only about one quart of coatings material will adhere to the targeted surface.

In an attempt to improve the efficiency of the wood furniture coating  process, the United States Environmental Protection Agency (EPA) requires that those companies that fall under the NESHAP use high transfer efficient spray equipment for most production operations. High transfer efficient spray equipment includes HVLP, air assisted airless, airless, and/or electrostatic spray equipment. These types of equipment can greatly improve the efficiency of coating application processes, without requiring major changes in the coating type or mixture. A spray equipment operator well trained in these technologies can achieve a high quality finish using far less material and emitting fewer pollutants into the atmosphere. It is important to remember, however, that using high transfer efficient equipment does not assure efficient coating applications. Improper setup and use of even high transfer efficient spray equipment can actually increase the VOC and toxic emissions released into the atmosphere. An operator untrained in equipment setup and operation may unknowingly apply a greater coating thickness than desired on the substrate, increasing material consumption. Improper use of this equipment may also result in a surface finish with uneven coverage or an undesirable texture known as "orange peel." If the surface finish is not acceptable, recoating may be required, increasing coating costs and emissions. Good spray technique includes proper spray gun settings, spray gun movement, spray distance, spray angle, and "triggering" of the gun at the end of each pass.

Testing performed by Purdue University and the University of Minnesota demonstrated that a three-inch increase in spray distance could result in up to a 13% decrease in transfer efficiency. Testing performed at the University of Northern Iowa indicated that a spray angle that varies as little as five degrees from perpendicular could diminish the transfer efficiency by as much as 4%. These numbers may sound relatively insignificant, but consider this: Spray operators who have not been trained in proper spray techniques usually have poor gun distance, poor gun angle, and poor triggering skills. Operators with poor spray techniques can easily use twice as much coating material as a well-trained sprayer, doubling emissions from the coating operation.

To complicate matters, different coatings and spray equipment types require different spray gun setups and minor changes in spray technique. High transfer equipment can only operate as an efficient tool if used correctly by a skilled operator. Generally, untrained spray operators have poor gun setup skills.

According to a study performed by the Pacific Northwest Pollution Prevention Research Center entitled "Transfer Efficiency and VOC Emissions of Spray Gun and Coating Technologies in Wood Finishing," the emissions released during a surface coating process are directly related to the skill of the spray gun operator. The study concluded that "the difference in transfer efficiency due to painter skill level with a single gun type were often larger than the differences between gun types" (referring to HVLP vs conventional equipment). In other words, the most influential factor in improving transfer efficiency is the operatorís spray technique.

Prior to the NESHAP, only a very few companies provided a comprehensive hands-on training program for their spray equipment operators. In many cases, spray operators received little, if any, training in equipment setup and operation, prior to being placed on the coating line.


Many of the solvents used in coating operations contain chemicals such as methyl ethyl ketone (MEK), toluene, and xylenes--all of which have been categorized by EPA as volatile organic compounds (VOCs) and volatile hazardous air pollutants (VHAPs). The EPA found the wood furniture and kitchen cabinet industry to be among the largest users of solvents in coating operations in the U.S. According to EPA, the wood furniture industry uses almost twice as much solvent in coatings operations as the automotive manufacturing industry.

Spray coating emissions can be decreased significantly by increasing the transfer efficiency of the spray coating operation. In addition, as sprayers' skill increases, so does their constancy. The result is a decrease in rework required. Higher transfer efficiency also translates into decreased material usage, reduced waste, improved productivity, and extended life of potentially hazardous spray booth arrestor banks (particulate filters).


The training program developed by CMTI has two main goals. The first is to provide the necessary training and materials to satisfy the NESHAP requirements. The second is to enhance the operators' skill level (beyond what is required by the rule) in order to improve their efficiency as a sprayer. CMTI exceeded the NESHAP training requirements to give companies an opportunity to improve their spray operatorsí skills and reduce material consumption and emissions in coating operations.

The technical assistance and training program developed by CMTI includes

This training program stresses the importance of proper application, setup, and spray operator technique. It is designed to help spray equipment operators understand their importance in improving transfer efficiency of coating operations.

The camcorder is one of the most influential tools used in the training program. The operators are video taped during a coating operation. This helps them better understand what they can do to enhance their spray techniques. If you have ever taken a golf lesson and the golf pro video taped your swing, you know how beneficial this tape can be. The instructor can tell you what you are doing wrong, but until you see yourself on tape, you will not comprehend what you have been doing wrong. It works the same way with a spray gun operator. Many spray operators have been spraying for years and believe that they know the correct way to spray. They are convinced that they are using the correct spray technique, and no matter how hard you try, you are not going to get them to change--that is, until they see themselves on tape.


So why put such an emphasis on improving transfer efficiency? Letís say that a company uses 20,000 gallons of coatings annually and, on average, each gallon of coating contains six pounds of VOCs. All of the sprayers at the facility were achieving a 40% transfer efficiency. If that company could improve their sprayersí transfer efficiency by 10% (that is achieve an average transfer efficiency of 44%) that company would decrease VOC emissions by over six tons annually. They would also decrease their material usage by 2,000 gallons. If that material cost the company $10 per gallon, a $20,000 yearly savings would result.

To date, CMTI has provided operator training for more than 800 employees at twenty-four plant locations. CMTI estimates that over eleven hundred employees will have gone through the training program by the end of 1998.

It is difficult to compile completely accurate data demonstrating the positive effects of the training program because of the different types of furniture products and their geometry as well as the variety and volume of these products that are manufactured; however, many improvements have been made in operator technique, and reduction in coatings material usage has been accomplished through increases in transfer efficiency. Some companies have reported that individual employees have reduced material consumption by as much as one-half, as a result of the program. Others report a significant decrease in the amount of visual overspray and concentrations of solvent vapor within the facility, as a direct result of employee training programs.

CMTI, using conservative figures, projects an annual state-wide reduction of 250 tons of VOCs and more than 75 tons of VHAPs as a result of the training program. It is estimated that, annually, this training program may reduce material usage by as much as 80,000 gallons, resulting in a saving to Indiana wood manufacturers of nearly $700,000. This amount does not include the savings resulting from reduced rework. If companies continue to monitor operator technique and reinforce the program's training, the VOC/VHAP reduction and the dollar savings could be significantly greater.


Spray operator training continues to be one of the most influential factors in improving transfer efficiency and also the most overlooked. Companies that adopt an operator training program can realize reduced material costs, reduced waste generation, and reduced VOC/VHAP emissions.

This project is an excellent example of companies working together with the state to the benefit of each. CMTI is proud to be a part of this program and hopes that other industrial sectors take note of the successes achieved through this project.