CTA Report, Draft 1, ISP Review - US Chemical Safety and Hazard ...

4.1.2 Mat-former and Baghouse
In the mat-former, air-suction dispersed the phenolic resin powder throughout the web to create a resin-
impregnated fiberglass mat. The suction air—along with excess resin powder and smaller fiberglass
fibers—traveled from the mat-former via four vertical air ducts to a baghouse, which was located on the
plant’s roof. Fire dampers and manually actuated water sprinklers were located in the vertical ducts.
The pulse-jet baghouse, designed with a capacity of 40,000 cubic feet per minute, was a large rectangular
metal box with a series of long cloth bags hung inside. This baghouse was fitted with an explosion vent.
In addition to providing suction for the mat-former, it also served as a pollution control device. The
baghouse was designed to remove small fiberglass fibers and phenolic resin powder with 99 percent
efficiency. Particulate-laden air entered on one side of the baghouse and passed through the bags, which
acted like filters to remove fibers and resin dust. During this process, a dust cake formed on the exterior
of the bags.
The difference in pressure between the dirty and clean sides of the baghouse determined the amount of
suction generated in the mat-former. A gauge mounted in the blend room measured the pressure in inches
of water. 7 Written procedures required that the line be shut down and the baghouse cleaned if the
pressure gauge reading was above 6 inches, an amount recommended by the manufacturer. The pressure
drop across the baghouse was recorded in a log twice a day to meet a requirement of the plant’s air quality
permit.
Operators reported that when the bags clogged, an excessive amount of dust blew out of the base of the
mat-former and into the plant. To keep the baghouse functioning efficiently, CTA used two methods to
periodically clean the bags.
7 An “inch of water” is a unit of pressure equal to the pressure exerted by a column of liquid water 1 inch high at a
standard temperature. One inch of water equals 0.0361 pound per square inch (psi).
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