Basic Documentation

Laboratory Ventilation Codes and Standards
Siemens Industry, Inc. 30
Topic Requirement(s) Commentary
Accessories,
Services and
Explosion
Protection
National Fire Protection Association, Standard NFPA 45, 2011
8.2.3 Chemical fume hoods shall not be relied upon to provide explosion (blast)
protection unless specifically designed to do so.
A.8.2.3 Hoods having explosionproof electrical devices are sometimes referred to as
explosionproof hoods. This term does not imply that they will contain an explosion,
only that the electrical equipment will not provide a source of ignition.
American National Standard for Laboratory Ventilation, ANSI/AIHA Z9.5-2003
1.1 This standard does not apply to the following types of laboratories or hoods
except as it may relate to general laboratory ventilation:
• Explosives laboratories;
• Radioisotope laboratories;
• Laminar flow hoods (e.g., a clean bench for product protection, not employee
protection);
• Biological safety cabinets.
Scientific Equipment & Furniture Association
SEFA 1–2006 Recommended Practices for Laboratory Fume Hoods
4.1.9 Many hood manufacturers can equip hoods with a variety of amenities or
services. The more popular services include electrical outlets, sinks, fixtures and
plumbing for gas vacuum, and air. For increased safety, controls for these services
should always be accessible from outside the hood opening.
Service Fixtures All service fixtures shall be installed so that service supply lines
can be connected or disconnected, either by design of the piping assembly or
through an access panel in the hood interior or exterior. All service valves shall be
accessible for maintenance. All service fixture controls (e.g., gas, air, water, vacuum)
should be external to the hood interior, clearly identified and within easy reach. All
internal corrosion fixture outlets shall be corrosion resistant to the application.
Electrical Receptacles All electrical receptacles should be readily accessible.
Provision shall be made so that all electrical wiring will be isolated and physically
separated from vapors handled within the hood interior after the fume hood is
installed. The receptacle shall be installed with the ground outlet above the power
slots.
Although a conventional laboratory fume hood
with a closed sash may provide protection
from an active chemical reaction or even a
‘small’ detonation, they are not typically
designed to provide explosion protection and
should not be used in applications where an
explosion hazard exists.
In order to not have a source of ignition
present at the fume hood, all of the hood’s
internal and external electrical fixtures (lights,
switches, outlets, etc.) have to be explosion-
proof and any equipment placed within the
fume hood interior (heaters, analyzers,
stirrers, etc.) must also be explosion-proof.