User Manual

17
Siemens Switzerland Ltd
Building Technologies Division
Silent/coded alarm Broadcasting of a “silent” alarm in the form of a coded message transmitted via the
hotel PA system e.g. “Will Mr. Black please report to the manager’s office.”
3.2.3. Alerting hotel guests
Hotel guests can be warned of the impending danger in several ways depending on where the guests are
currently located (bedrooms, restaurants, bars, discos, parking garages, etc.).
Acoustic alarms Electronic sounders are regarded as the normal means of raising an alarm and
are suitable for most hotel applications.
The minimum sound pressure level regarded as being suitable to rouse a sleeping
person is 75 dBA at the bed head. This will generally require an electronic
sounder in the bedroom itself as there will be too great an attenuation of the
sound level through the guest room door.
In larger and noisier areas such as discos, parking garages or technical plant
rooms more powerful horns or fire bells may be required.
Visual alarms Strobes or rotating beacons may be regarded as supplementary alarms which
enhance the effectiveness of sounders, with sounder beacons combining the
advantages of both device types. Beacons are of particular importance for
hearing-impaired persons or in noisy environments where people may be
wearing ear protection.
Where several beacons may be visible within a single area it is important that
they are synchronized to avoid the risk for persons with photosensitive epilepsy
to suffer a seizure.
Voice alarms A voice alarm system consists of prerecorded voice messages (and acoustic
signals) which can be activated manually or automatically, for example, by an
alarm from the fire detection system. The preprogrammed evacuation process
can then be initiated. Typically the system delivers an alarm signal (specified by
local standards), followed by a stored voice message.
Research has clearly shown that many people do not react quickly to a
conventional acoustic fire alarm. The success of the voice alarm system relies on
its ability to convince people of the seriousness of the event very quickly. For the
majority of able-bodied hotel guests a successful self-rescue is then just a matter
of course. Voice alarms are therefore becoming increasingly popular and can also
incorporate a public address facility.
An added advantage of a voice alarm signal over the normal acoustic sounder is
that different messages may be conveyed to different areas within the premises.
This flexibility can also be considerably improved by the live voice message
feature, which gives a fire chief the ability to address people in specific areas of
the building directly.
Alternative alarms
Vibration alarms for people with hearing difficulties
Neither acoustic nor visual alarms may be sufficient to rouse a person from sleep
if they are deaf or have severe hearing difficulties. In such cases the use of some
form of vibrating device, may be employed. These however have inherent
limitations: for example a pager can only alert a person if he is wearing it and for
a vibrating pillow or mattress to be effective the person must be lying on the
bed. This would suggest that there is no one solution to the problem of alerting a
hearing impaired person and a combination of alternative solutions should be
considered.