Chemical Hygiene Plan - Queensborough Community College ...

9.4 Biological Safety Cabinet Certifications
All biological safety cabinets must be certified to ensure proper operation. Certification is
required:
• Before a cabinet is put into service.
• After a cabinet has been repaired or relocated.
• After a filter has been replaced.
• At least annually.
This certification must be performed by a contractor that is trained to National Sanitation
Foundation Standard No. 49. Please note: your EHSO does not certify biological safety
cabinets.
It is the responsibility of the P.I. or laboratory supervisor to ensure that biological safety
cabinets within laboratories under their supervision are certified annually.
9.5 Types of Biological Safety Cabinets
Biological safety cabinets are divided into 3 classifications. Class I and Class II cabinets, and the
total containment Class III cabinets. Class II cabinets are the most common type of cabinet used
on campus.
• Class I: The Class I biological safety cabinet is designed to provide personnel and
environmental protection only. Unfiltered air is directed through the front opening,
across the work area and out through the HEPA filter on top. This cabinet is
conventionally used with a full width open front, or can be used with an attached armhole
front panel with or without attached rubber gloves. Although Class I cabinets are simple
and economical, and radioisotopes and some toxic chemicals can be used (if the exhaust
is ducted to the outside), filtered air is not provided over the work area. These cabinets do
not protect your materials from contaminants introduced from the environment or the
operator.
• Class II: A Class II cabinet meets the requirements for the protection of product,
personnel, and the environment. The capacity to protect materials within the cabinet is
provided by the flow of HEPA-filtered air over the work surface. There are four subtypes
of Class II cabinets based on the construction, inflow air velocities, and exhaust systems.
These cabinets can be used to manipulate low to moderate risk agents.
o Class IIA1: Air, at a face velocity of 75 lfpm, is drawn into the front grille of the
cabinet away from the work surface. HEPA-filtered air is directed downward
over the work area. As the air approaches the work surface, the blower part of the
air is directed through the front grille and the remainder through the rear grille.
From a common plenum, approximately 70% of the air is recirculated to the work
zone through a HEPA filter and about 30% is exhausted to the room through
another HEPA filter. This cabinet is unsuitable for work that involves radioactive
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