Labconco Protector Work Stations 3930021 - Manual (Page 55)

Chapter 6: Maintaining Your Enclosure
Product Service 1-800-522-7658 51
Determination of When to Replace
Carbon Filters and How to Replace
Both carbon filters MUST be replaced when any one of the following two
conditions are met:
1. The filtered enclosure outlet (exhaust) concentration approaches the inlet
concentration, indicating filter saturation.
2. The odor in the work area becomes intolerable or the concentration of the
chemical in the work area is greater than the TWA.
There are four means of determining when its time to change the carbon filters (not
shown in the order of preference).
Odor - A person’s sensitivity to odor, tolerance of odor and their comfort level
under odoriferous conditions vary with the individual. While odor is an indicator
that chemicals are passing through the carbon filter, several points need to be
understood:

Odor within the room is not necessarily an indication of saturation or
hazardous exposure concentrations.

Odor can be used as a prompt to sample the chemical concentration on the exit
side of the carbon filter.

Organic chemicals approved for use in the filtered enclosure have odors that
are detectable before reaching the time weighted exposure limits.
Detection Tubes - Color change indicators can be used to measure the
concentration of the chemical at the exit side of the carbon filter or in the outlet
exhaust. A kit including syringe pump and flexible tubing can be purchased as an
accessory from Labconco (Catalog # 6924900). Labconco Customer Service
Representatives are supplied with detector tube catalog numbers, as well as
telephone numbers to direct you to where to purchase these items.
For Organic, Formaldehyde and Ammonia, chemical specific detector tubes should
be purchased when installing fresh filters. Each kit contains instructions on how
many strokes of the syringe are required to obtain the stated sensitivity. The
sampling syringe is connected to the filtered enclosure exhaust. Connect the
syringe to the detector tube while the system is running and pull the air through the
tube with the syringe. Each stroke of the syringe represents a 100-ml sample and
corresponds to the number of strokes necessary to give the indicated color changes.
Due to the wide variety of organics and varying TWA’s, it is recommended that
specific detector tubes be purchased directly from Sensidyne, Draeger or your
laboratory supply dealer. Alternate detector pumps can also be purchased from
your laboratory supply dealers. The vast majority of detector tubes available start
measuring at the TWA. When a user observes a color change in the tube, they
should replace the filter immediately. If no detector tube for your specific
chemical is available, other means of detection must be used.