Basic Documentation

Table Of Contents
Laboratory Ventilation Codes and Standards
Siemens Industry, Inc. 54
Topic Requirement(s) Commentary
Shutdown
Procedures
U.S. OSHA, 29 CFR, Part 1910, Occupational Safety and Health Standards,
Subpart Z, Toxic and Hazardous Substances,1910.1450,E1(n):
Leave the hood "on" when it is not in active use if toxic substances are stored in it or
if it is uncertain whether adequate general laboratory ventilation will be maintained
when it is "off".
California OSHA Division of Occupational Health & Safety (DOSH) Subchapter
7. General Industry Safety Orders, Group 16. Control of Hazardous Substances,
Article 107. Dusts, Fumes, Mists, Vapors and Gases
5154.1. Ventilation Requirements for Laboratory-Type Hood Operations:
(d) Operation. Mechanical ventilation shall remain in operation at all times when
hoods are in use and for a sufficient time thereafter to clear hoods of airborne
hazardous substances. When mechanical ventilation is not in operation, hazardous
substances in the hood shall be covered or capped off.
American National Standard for Laboratory Ventilation, ANSI/AIHA Z9.5-2003
7.6 Hoods shall be in operation whenever hazardous volatile materials are being
used or stored inside.
5.3.2.4 If the hood is completely turned off, the hood shall be emptied and
decontaminated and provisions shall be implemented to prevent the hood from back
drafting.
8.1 Operations served by equipment being shutdown for inspection shall be safely
discontinued and secured during such maintenance. Lock-out/tag-out procedures
shall be implemented. Laboratory workers shall be notified in advance of inspection
and maintenance operations.
“Turing off” or shutting down a fume hood
generally means stopping the fume hood’s
exhaust and is permissible only if the following
requirements are fulfilled:
No chemicals remain in the hood either
in use or in storage.
The hood interior is cleaned to remove all
chemical residues.
The hood sash is kept fully closed.
The cessation of the hood’s exhaust
airflow does not reduce the laboratory
room’s ventilation rate to less than the
allowable minimum. (Unless all chemicals
are also removed from the room, the
room still remains a ‘laboratory’ even
though no one is present an/or no hoods
are in use.)
The laboratory room’s negative static
pressurization can be maintained.
Adequate and prominent signs on the
fume hood warn that it cannot be used
until the fume hood is returned to safe
operational status. (Safe operational
status requires ensuring that proper fume
hood exhaust and the required face
velocity is again present and any
associated fume hood controls and
monitoring provisions are in proper
operation.)
It may be beneficial from an energy savings
standpoint to shut downa fume hood if the
above conditions can be met. In general,
educational facilities normally can derive the
greatest benefit from this practice if a lab class
will not be in session for a semester or for an
extended holiday period.