User Manual

24
4 Alarming, smoke control
and evacuation
4.1 Introduction
Once a fire has been detected by an automatic detector,
by sprinkler flow monitoring or by a person activating a
manual call point, the fire detection system will generate
the appropriate pre-programmed control and alarm
signals.
A major factor that can affect the success of building
evacuation is that many people do not take the sounding
of a fire alarm sufficiently seriously or do not understand
the meaning of the acoustic signal. Such doubts lead to
unnecessary delays in people’s reaction to the warning
and may mean the difference between life and death.
The more clearly the information can be conveyed to the
public, the better the situation will be understood and
the more quickly the necessary actions will be taken.
A fast and efficient evacuation procedure is essential.
This not only saves lives, but once the evacuation of the
building has been completed, the fire services can
concentrate on minimizing the damage to property.
4.2 Alarming
4.2.1 Objectives
The purpose of a fire alarm is to warn people about the
presence of a fire within the premises. In the context of
colleges and universities these people may be divided into
3 target groups:
 Members of staff
 Students
 The municipal fire service
For each of these target groups various technical
solutions are available, which can alert the people
concerned in the most appropriate and efficient manner.
4.2.2 Alerting members of staff
Alarms intended for staff are always generated without
delay to allow the cause of the alarm to be investigated.
Time is of the essence: investigation must begin
immediately. It is still possible that the fire is small
enough to be dealt with by local means. The aim is
to prevent any unnecessary disruption; however, a safety-
first policy in education premises will generally mean that
the building will be evacuated immediately.
Without activating the main alarm, members of staff may
be alerted in one (or more) of the ways listed below.
The appropriate choice will largely depend on the size
of the establishment and, more particularly, on the
number of staff involved.
Pager
Alarm activation via an in-house pager system, causing
the pagers carried by all members of staff to vibrate.
Mobile/Cell phone (SMS)
Transmission of a pre-programmed text message.
Smart phone (mobile app)
Modern technology permits a more user-oriented
presentation of the alarm message and a reminder of the
next steps of the emergency procedure.
Local (discreet) acoustic
Activation of buzzers or speakers in staff rooms only.
Local visual alarm
Activation of a strobe (e.g. VID - Visual Indication Device).
Silent/coded alarm
Broadcasting of a “silent” alarm in the form of a coded
message transmitted via the PA system (which may be
present in some larger colleges and universities) e.g.
“Will Mr. Black please report to the principal’s office.”
4.2.3 Alerting students
Students can be warned of the impending danger in
several ways.
Acoustic alarms
Electronic sounders are regarded as the normal means
of raising an alarm and are suitable for most applications.
The recommended sound level of such devices (according
to EN54-3) should be no less than 65 dB(A) or 5 dB(A)
above the ambient noise level.
Visual alarms
VID (Visual Indication Devices) are strobes or rotating
beacons which may be regarded as supplementary alarms
that enhance the effectiveness of sounders.
VAD (Visual Alarming Devices) are beacons that act as
primary alarming devices where occupants cannot be
alerted by acoustic means (e.g. hearing-impaired
persons). Note that these devices need to provide
sufficient light output to effectively attract attention
throughout the protected area.
It is also important that, in cases where several beacons
may be visible within a single area, they are synchronized
to avoid the risk of persons with photosensitive epilepsy
suffering a seizure.
Voice alarms
A voice alarm system consists of a network of speakers
distributed throughout the building, which permits pre-
recorded voice messages to be transmitted (either by
manual activation or triggered automatically by an alarm
from the fire detection system). Such systems may be
appropriate in university environments, as different
messages may be conveyed to different areas within the
same premises. The effectiveness of such a system can be
considerably improved by the live voice message feature.
This allows the person responsible for orderly evacuation
to address people in specific areas of the building directly
and consequently get their full attention. The better
people are informed, the less likely panic situations can
develop and the more efficient the evacuation will be.