Basic Documentation
Table Of Contents
- About this Application Guide
- Chapter 1–Introduction
- Chapter 2–Goals of the Laboratory Environment
- Chapter 3–Unique Ventilation Needs of a Laboratory Facility
- Chapter 4–Ventilation Systems Classification
- Chapter 5–Laboratory Facility Exhaust Systems
- Chapter 6–Laboratory Containment Units - Ventilation
- Chapter 7–Room Ventilation, Makeup Air, and Pressurization Control Systems
- Chapter 8–Laboratory Temperature and Humidity Control Systems
- Chapter 9–Laboratory Emergencies - Ventilation System Response
- Chapter 10–Laboratory Ventilation System - Validation
- Chapter 11–Laboratory Ventilation System - Commissioning
- Glossary
- Index
Chapter 9–Laboratory Emergencies - Ventilation System Response
Activation of an emergency signaling devices such as a switch or pull station should
normally sound an appropriate facility audible alarm and identify the location and type
of emergency at a constantly attended facility monitoring center. In addition,
appropriate response personnel can be automatically notified by automatic paging
systems. Operation of emergency signaling devices can also provide an input signal
to the ventilation control system to put a room’s ventilation system into the
preplanned operational mode for the specific type of emergency. Following is a more
detailed description of appropriate automatic ventilation system responses for each
different type of emergency situation.
Fire
Outside of laboratories, the most likely fire scenario starts as a slow smoldering
process often of electrical origin. Such fires tend to take considerable time to develop
and can often be detected in their early stages by smoke detectors or alert
personnel. In contrast, laboratory room fires often occur due to accidental ignition of
flammable liquid spills and thus can erupt into a full blown hazard producing dense
smoke and fumes very quickly. Smoke is the most hazardous component of a fire
since it consists of many toxic airborne substances.
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Thus prevention of smoke
spread in response to a fire within a laboratory room is a priority.
The National Fire Protection Association’s Recommended Practice for Smoke
Control Systems (NFPA 92A) calls for preventing the spread of smoke by using the
building’s ventilation system to create a pressure difference between the smoke zone
(area where the fire is located) and adjacent non-fire areas. The smoke zone should
be maintained at a negative static pressure and the surrounding areas at a positive
static pressure.
Laboratory room occupants should be instructed that in event of a fire, their first
priority is to activate the nearest fire alarm station. And, except when a local fire
extinguisher can quickly extinguish a small fire, the occupants should promptly
vacate the room. Aside from activating the building fire alarm system, the operation
of the fire alarm station should automatically initiate the fire emergency mode for the
room ventilation system.
A room ventilation system’s fire emergency mode should consist of maximizing the
exhaust from the laboratory room and fully stopping all supply airflow to the room.
This is intended to attain a very negative static pressure within the laboratory room in
which the fire is located. Simultaneously, the supply air serving the areas adjacent to
the laboratory should be maximized. Operating the ventilation system in this manner
will help prevent toxic smoke from migrating out of the room or fire origin and posing
a hazard throughout the entire facility. This will also assist fire fighting efforts by
allowing the firefighters to efficiency approach the room and not be hindered by
heavy smoke through much of the facility.
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Statistics on the causes of fire deaths generally attribute approximately 80% of fatalities to smoke inhalation.
84 Siemens Building Technologies, Inc.