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Maintenance of ventilation systems: a case study at a furniture stripping facility.

Watkins D; Estill C
American Industrial Hygiene Conference and Exposition, May 20-25, 2000, Orlando, Florida. Fairfax, VA: American Industrial Hygiene Association, 2000 May; :72
Little attention has been focused on routine preventive maintenance and designing ventilation systems for preventive maintenance. This study examined the preventive maintenance of a ventilation system installed on a furniture-stripping dip tank to reduce employee exposures to methylene chloride. In 1991, a new ventilation system was installed on the dip tank. The system consisted of two slots (one on the front and one on the back of the tank) and a gasoline-powered centrifugal fan. The exhaust rate was 3200 fpm and 2900 cfm. Wood furniture was also sanded nearby in this facility. No maintenance was performed on this system during the subsequent years, but the fan was replaced with a similar electric fan and a rain cap was added. In 1997, the exhaust system was re-evaluated. The slot velocity had dropped to 780 fpm and the exhaust volume was 1060 cfm using an electric, centrifugal fan. The slots on the dip tank were clogged with stripping solution. A T-duct had a hole due to rust. Inside the plenums were nine inches of paint chips and sawdust. It was apparent that access for cleaning was now a problem. These improvements were made to the ventilation system: hinges were added to the slots so they could be opened for cleaning; access holes were made in each plenum for cleaning; a new stack head was installed for rain protection; and the rusted T-duct was replaced by a 90 degree duct. After these renovations, the slot velocity increased to 1700 fpm and exhaust volume increased to 2080 cfm. Preventive maintenance should be performed at least annually, including cleaning slots and plenums and checking ducts for rust. It is apparent that exhaust ventilation systems that are ventilating over thick solutions and dust need to be designed for cleaning. Small initial design changes can improve the ease of maintenance and thereby increase the exhaust volumes.
Ventilation; Ventilation-equipment; Ventilation-systems; Exhaust-systems; Exhaust-ventilation; Furniture-industry; Furniture-workers; Equipment-reliability; Equipment-design; Industrial-equipment; Industrial-ventilation; Employee-exposure; Methyl-compounds; Chlorides; Dip-coating; Centrifugal-force; Woodworkers; Woodworking; Woodworking-industry; Paint-removers; Machine-operation; Environmental-engineering; Environmental-technology
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American Industrial Hygiene Conference and Exposition, May 20-25, 2000, Orlando, Florida
Page last reviewed: March 25, 2022
Content source: National Institute for Occupational Safety and Health Education and Information Division