Indiana Clean Manufacturing Technology and Safe Materials Institute,

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


February 1998



The Indiana Clean Manufacturing Technology and Safe Materials Institute (CMTI) and the Coating Applications Research Laboratory (CARL), both located at Purdue University, initiated a project with the Par-Kan Company to investigate coating requirements and gather production-oriented coating data necessary to successfully operate a new, water-based, paint coating line.

NIPSCO, an energy utility company, offered strong support for this project by sponsoring a large portion of the project's cost.


Par-Kan is one of the country's largest producers of industrial solid waste and trash containers. The company purchases flat stock and angle iron steel as its major raw material. It then designs and fabricates the steel into high quality, industrial-grade trash containers. The company employs approximately 100 people.


The company fabricates its industrial trash containers from basic steel sheet. The material is cut to size, shaped, and welded into the final product and then sent to the coating department to be painted. When painted, the container, popularly known as the kan, is placed in a staging/storage area until the paint dries. Kan size varies from 3 x 4 x 5 feet to 6 x 5 x 5 feet. A final inspection step occurs prior to the certification of the kans for shipment.

The company's success and increasing sales volume put a severe strain on its old coating application production system. The old coating line was similar to a "batch"-type process. First, the kans were placed under gas radiant heaters where some initial preheating of the metal surface could be accomplished. The kans were then wheeled into coating booths where a primer and subsequent topcoat layer were applied. The newly painted kans were then moved to a staging area and left to dry, usually overnight. When the coated parts received final inspection approval, they were moved to a finished goods storage area, where they awaited shipment to the company's customers.

The old coating line, which had functioned well for many years, was now the cause of a production bottleneck because it could not adequately handle the increased production rate. The company's solution to this bottleneck issue was to build a new, continuous, painting production line.


Par-Kan realized, far in advance of construction of the new, continuous, coating line, that industrial painting operations were going to be greatly impacted by federal and state government air pollution regulations. Consequently, prior to contacting CARL, the company had already converted approximately one-half of its production to water-based paint coatings. The longer dry-time, typical in water-based systems, put extra pressure on the already stressed, old, batch-type, coating line. Par-Kan wanted to take advantage of the opportunities the new paint line presented to convert all of its production to water-based coatings.

Constructing a new paint line meant the company would have to file for a new air pollution permit, beginning with a new-construction permit. The existing standards limited the amount of volatile organic compound (VOC) solvents (which could be blended into the paint) to 3.5 pounds per gallon. New Clean Air Act Amendment regulations would further control industrial painting operations, and development of a new, nationwide, industrial coating and architectural finish regulation would ensure that future painting process regulations would be even more stringent. Therefore, acknowledging that air pollution regulations will only get tougher, the company committed to a new, continuous coating line employing a 100% water-based painting system.


The company had worked closely with the Indiana Department of Environmental Management (IDEM) on its new air pollution permit and had discovered (through the IDEM inspector) that Purdue University had an industrial coating laboratory, CARL.

CARL is a joint project of three Purdue University entities—the Department of Forestry and Natural Resources, The Institute for Interdisciplinary Engineering Studies, and the Indiana Clean Manufacturing Technology and Safe Materials Institute (CMTI). The laboratory's goal is to assist companies in the modification of their current operations (or in developing new ones) so that new coating systems (i.e., water-base, powder systems, high solids coating systems, etc.) as well as new application and drying/curing systems can be adapted to meet their production quality requirements. The laboratory is designed to duplicate a company's current (or proposed) coating/production requirements and test the "envelope"  limits   in order to define the optimum coating/application/curing process parameters required by the company and by the new coating. (For more information about CARL and how it can be used to benefit a company, call Jim Noonan of CMTI, 765-463-4749.)

Par-Kan contacted CMTI and scheduled investigation time at the laboratory. CMTI then contacted NIPSCO, and they agreed to sponsor one-half of the company's laboratory costs as part of their industrial customer service support program.

Laboratory test procedures were developed which duplicated the production environment characteristics under which the water-based coatings would be required to function. The company requested that CARL define the equipment and parameters necessary to dry their chosen water-based paint candidate in approximately 1.5 hours from the start of primer application to a working dry condition of the topcoat.

The proposed paint line involved two paint stations: a primer application station, followed by flash-off and drying; and a topcoat application station, followed by flash-off and drying. The continuous coating line would employ tubular gas radiant heat; however the number, location, and proximity to the kans, as well as the duration of exposure, was the investigative task of CARL (see paint line diagram, Exhibit I).

Exhibit II illustrates and lists the materials which were required to perform the test. Steel "blanks" (test sample specimens) were primarily 4" x 4" square pieces of 12-guage steel, cut and fabricated for the test (by the company) from the exact steel materials used to construct the kans. Several samples were "angled" in a shape which imitated the final product so that steel surfaces not perpendicular (angled) to the infra-red radiant heat source could be analyzed and compared to flat steel plates with regard to heat uptake and drying.

The steel samples were spray-applied (to the company's thickness specifications) to uncleaned steel plates which contained a thin film of mill oil. The primer coat was allowed to dry for periods ranging from 20 to 30 minutes. Next, the topcoat was applied, allowed to flash-dry for 10 minutes, and then exposed to gas catalytic infra-red (IR) heat at distances of 12" to 72" from the IR source for 50 minutes (see Exhibit II profile of sample/IR exposure layout). Overall, upon completion and analysis of the testing and testing data, the laboratory proved that the water-based paint system could achieve a working dry condition in the required 1.5 hours


Par-Kan committed to use water-based coatings, despite the fact that it already used highly efficient, air-assisted airless spray equipment, and despite the fact that the company could comply with all state and federal regulations by using easier to apply, VOC-based coatings (containing less than 3.5 pounds per gallon of VOC).

Armed with the test results and the drying information gleaned from the laboratory's investigation, Par-Kan was able to refine the construction of the new, water-based paint coating line. The new line achieved its goal¾ a quality coating application, which met (and exceeded) the production rate requirement.

The result of the successful implementation of water-based coatings is an estimated reduction of more than 12 tons of VOC emissions to the environment. The company believes it has achieved not only a high output, quality coating application process, but has also achieved cost savings.

The use of water-based coatings has allowed the company to adopt a synthetic minor air emission permit status. This means that the company, because its VOC emissions are below major source status, will be exempt from new and costly EPA Maximum Achievable Control Technology (MACT) standards. It is estimated that the savings from this exemption, alone, will result in approximately $7,000 per year, primarily due to reduced regulatory liability and fewer regulatory management tasks. Cost savings from avoiding hazardous VOC generation is estimated at approximately $1000, per year. Other savings (which have not, as yet, been quantified) will also accrue—insurance premium savings (stemming from the alternative use of nonflammable, water-based paints) and the increased health and safety of employees. Overall, the company estimates that it will save approximately $10,000, per year, by using water-based paint systems. The management of the firm feels that the annual savings will only increase during the next several years, primarily because using water-based coatings positions the company ahead of the regulatory curve and its competition.


Based upon the findings of the CARL tests and because of Par-Kan's can-do attitude, the company has successfully converted one hundred percent of its coating operations to water-based coating systems.

The project demonstrated that programs offered by the state, universities such as Purdue, and utilities such as NIPSCO, bring value and benefit to companies. In this case, all parties worked together in a common effort to assist in reducing VOC emissions (12 tons reduction) and in saving money ($10,000) annually.