NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665

May 27, 1999

Closed System Provides Safe Pesticide Handling

Using good safety practices when handling pesticides is not only personally and environmentally smart, it also makes good economic sense, according to a North Dakota State University agricultural engineer.

"Preventing spills helps reduce operating and production costs, improves your operation's cost effectiveness, and provides a cleaner and more acceptable workplace," says Vern Hofman of the NDSU Extension Service.

In the past, reducing spills meant being extra careful, and reducing human exposure meant wearing protective clothing which was often cumbersome and hot in warm weather. Because of the discomfort, chemical handlers often neglected to use the protective clothing.

Now, a closed handling system can minimize, if not eliminate, both accidental spills and human contact with pesticides, Hofman says. In addition, metering and transferring pesticides with closed systems is usually more accurate than other methods.

In choosing or building a closed system, make sure the system is economical to use, simple to operate, durable, versatile and easy to maintain, Hofman says. The system must be able to withstand the effects of pesticides that may contain solvents. Quality components and construction are a must to assure safety and minimize maintenance.

Closed handling systems using a pump and meter may not be trouble-free. Problems with the meter may arise, including inaccuracy due to different chemical viscosities, a need for air eliminators and regular cleaning to keep them working.

Another key component of a closed handling system is the pump and venturi to provide vacuum to a probe that removes pesticides and rinses the container. Containers should be vented to prevent collapse, and probes should be inserted in such a way that human contact with the chemical is practically nonexistent.

Venturi vacuum systems are mainly trouble-free, can transfer relatively low viscosity pesticides effectively and are low cost, Hofman notes. They should be installed on the discharge side of a pump and made of stainless steel or polypropylene.

Systems of measurement that are accurate whether the amount is a few ounces or several gallons are a necessity, Hofman says. Tall, slim measuring tanks with sight tubes or windows are possibilities. Weigh scales, calibrated probes and calibrated meters with air eliminators are other ideas.

Finally, make sure that all metal parts, seals, gaskets and hoses resist corrosion. High initial costs of materials such as Teflon, stainless steel and cross-linked polyethylene will pay off with low maintenance, high performance and long life, says Hofman.

Personal protection equipment consisting of unlined gloves and an apron must be worn with vacuum closed systems, and goggles are needed with pressure handling systems. This equipment is much easier to put on than the disposable coveralls, rubber boots and head protection that is needed when handling some pesticides without a closed system.

Detailed closed vacuum construction plans are available at no charge from Extension Agricultural Engineering, Box 5626, NDSU, Fargo, ND 58105, (701) 231-7238.

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Source: Vern Hofman (701) 231-7240

Editor: Tom Jirik (701) 231-9629

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