Eliminating Production Contaminated
Air
Written By:
Henry P. Shotwell, CIH
Senior Vice-President
Atlantic Environmental, Inc.
Unlike the typical office environment, the air inside
a manufacturing facility may
contain particulates, some so small as to be respirable
(capable of entering the
region of the lung where gas exchange takes place). It
may also contain gases and
vapors or a combination of these contaminants. What makes
the atmosphere in
a production shop different from the air in an office
is that the particulates (like
silica) and the gases and vapors (like benzene or cyanide)
may be hazardous and
even lethal.
Here, the goal of the ventilation system is to capture
and remove the contaminant
as close to the point of generation as possible, while
at the same time limiting
the loss of expensively cooled or heated air. (See:http://www.lni.wa.gov/Safety/Topics/AtoZ/Ventilation/default.asp,
and http://www.ohiobwc.com/downloads/blankpdf/OAC4123-1-5-99.2.pdf).
For a complete treatise on the design and testing of Local
Exhaust
Ventilation (LEV) systems, see the ACGIH Industrial Ventilation
Manual
(acgih.org/resources).
Local Exhaust Ventilation (LEV) systems consist minimally
of a “hood” or entry
way into the system, ductwork, a fan for pulling contaminated
air through the
system, and an exhaust stack. In addition, the system
may need an air cleaner
(such as a bag house, an electrostatic precipitator or
a scrubber) through which the
air is passed prior to being released into the atmosphere.
The LEV system causes contaminated air to move in a specific
direction: into
the system. The exhaust fan causes a drop in the air pressure
within the hood
and ductwork. In other words, suction or “negative
pressure.” In order to move
anything, even air, energy has to be expended to overcome
resistance, or inertia.
So the exhaust fan has to produce enough suction or negative
pressure to overcome the resistances offered by the hood,
the ductwork, any air cleaners or other in-line devices,
the fan itself and by the exhaust leg of the system. These
considerations are taken into account when designing the
system. Ultimately, an exhaust fan has to have the capacity
not only to move contaminated air, keep it from settling
in theductwork, draw it through filters and overcome all
the resistances that are built into the system. Not a
simple task to say the least. Knowledge of the contaminants,
theplant conditions, potential for employee exposure and
emission regulations must beconsidered. Mechanical Engineers,
Chemical Engineers and Industrial Hygienists must be involved
for proper design and construction.
Atlantic Environmental Inc
2 East Blackwell Street
Dover, NJ 07801
(800) 344-4414
(973) 366-4660
(973) 366-3116 Fax
info@atlenv.com
Indoor Air Quality
| Mold Testing and Remediation
Indoor Air Quality
in Highrise Buildings |
Industrial Hygiene
Environmental Site Assessments/Phase I, II & III
Industrial Safety
Construction Safety | Environmental
Articles | Asbestos|
Environmental
Expert Witness and Litigation Support | Environmental
Test Chamber |Pricing |
Professional
Staff | History
| Home Page
| Links
|
