6
Chapter 2: Prerequisites
At a minimum, the supporting structure usually consists of a base
cabinet and chemically-resistant work surface.
• A stand or mobile bench is not recommended if the enclosure
will be used for precise weighing of powders.
Location and Air Current Requirements The Purifier Filtered Enclosures have been designed to contain
hazards by negating typical cross drafts and turbulence within the
opening. However, as a precautionary safety measure and a higher
level of quality management, it is recommended that the enclosure
be placed in an area to avoid:
• High traffic areas where walking might cause an air
disturbance or be a nuisance.
• Overhead or wall HVAC diffusers, fans, radiators or other lab
equipment producing air currents.
• Next to doorways or windows that may be opened.
Exhaust and Blower Requirements The Purifier Class I Enclosure and Purifier Filtered Enclosure use
an integral motorized impeller to draw room air past the operator
and through the enclosure. This contaminated air is then pushed
through the HEPA filter. The HEPA-filtered exhaust air is then
forced out the top of the enclosure. An optional carbon filter may
be installed on the downstream side of the HEPA filter to protect
against nuisance odors.
The HEPA-filtered exhaust air can be recirculated into the
laboratory or exhausted outside with the addition of the exhaust
connection kit and remote blower listed in Chapter 7. Data for the
exhaust volume and enclosure static pressure loss are listed for
each filtered enclosure model at face velocities of 60, 75, 80, 90,
100, and 105 fpm.