The following recommendations are applicable.
a) In the absence of any relevant British, European or International Standard,
components of a radio-linked system should comply with the Loss Prevention
Certificate Board test standard, LPS 1257.
b) Radio-linked systems should comply with all recommendations of this standard
except that:
1) all radio-linked components should be supplied from at least two
independent power supplies. These can be either:
i) the normal mains supply plus a reserve battery (primary or
continuously charged secondary); or
ii) a primary battery plus a second primary battery; or
iii) a primary battery plus a secondary battery.
NOTE Where primary batteries are specified, capacitors with an appropriate
specification may be used as an alternative.
2) components, other than control and indicating equipment, may utilise
batteries to provide the normal power supply;
3) Power supplies incorporating one or more primary batteries should give
at least 30 days warning of impending failure of each battery. This should be
indicated as a low battery warning condition at the control and indicating
equipment;
4) At the point at which the power supply(ies) to any radio-linked
component can maintain the component in normal operation for no more than 7
days, and, in addition, in the case of the fire alarm devices, 30 min in the
alarm condition, a fault warning should be given at the control and indicating
equipment;
5) Power supplies should have a minimum, normal operational life of three
years over the temperature range of +15ºC to + 35ºC before the low power
condition is signalled;
6) Any fault giving rise to loss of communication with a radio-linked
component should be indicated at the control and indicating equipment within two
hours of occurrence of the fault.
c) Cable of antennae that are external to components of a radio-linked system
should be monitored for open and short circuits. A fault condition should be
given at the control and indicating equipment within 100s of the occurrence of
such a condition.
d) Cables of antennae that are external to components that form part of the
critical signal path should satisfy the recommendations of 26.2. However, cables
that do not comply with 26.2b) may be used provided they are routed through
areas of low fire risk, or are protected against exposure to fire by burial in
at least 12mm of plaster or by separation from any fire risk by materials that
would afford a fire resistance of at least 30 in if tested in accordance with
the relevant part of BS 476.
e) Antennae should be so arranged that special tools are required for
disconnection or removal of the outer housing.
f) Facilities for automatic silencing of radio-linked fire alarm sounders should
comply with the recommendations of 16.2.1h).
g) Unless the visual indication at the detector of initiation of a fire alarm
signal is manually reset at the control panel, it should remain illuminated for
not less than 20 min after initiation. The illumination may then automatically
extinguish.
h) A fault indications should be given within 100 s at the CIE if no valid radio
transmissions are received from any of the radio fire devices for two hours.
i) After 30 s of continuous interference to the transmitted signal that can
compromise the performance of the fire detection and alarm system, a fault
indication should be given at the CIE within a further 100 s.
j) Installation of a radio-linked system should only take place after a
comprehensive radio survey has been undertaken to ascertain the following:
1) there are no other sources of radio transmission that could interfere
with, or block radio communication between the control and indicating equipment
and other components of the system;
2) there is adequate signal strength for communication both to and from
components as appropriate in all areas of the building(s) in which radio-linked
components are to be located. This should take into account the minimum
acceptable signal level defined by the manufacturer in respect of the level of
background radio ‘noise’ at the time of the survey;
3) where the system is networked it should be established that the communication
conditions described in item 2) are achieved throughout the network;
4) records of signal strength readings for each radio device taken at the time
of the survey, and of the background noise level, should be kept for future
reference.
k) Only radio survey test equipment that has been approved by the manufacturer
and regularly calibrated should be used to carry out the survey. A record of the
date of calibration and the date when the next calibration is due should be
marked on the survey equipment.
l) At the time of commissioning and after the installation of all equipment
including remote antenna(e), the following records relating to the radio data
should be recorded:
1) the system coding (i.e. system address) which should where possible be unique
to avoid the possibility of interference from similar systems on the same
frequency;
2) details of the signal level being received at each of the receiver units.
This data should include the received signal levels of all the radio devices and
the background noise level. In the case of a networked system (i.e. multiple
panel system), this should also include the signal levels for the radio-links
between panels. In addition to other servicing recommendations in other parts of
this standard, this should be undertaken at each routine service visit.
m) The signal levels recorded should be within the specifications set by the
manufacturer of the radio system. If not within the specification, appropriate
remedial action should be undertaken;
n) A copy of the signal levels should be kept on site with the system log book.
o) Where a network of CIEs is used, the system specification should define
whether there is to be:
1) on master CIE at which all controls and indications where available, with
other panels not having controls or indications; or
2) a supervisory CIE at which essential indications are available and possibly
some controls are also available, with other CIEs also having some controls and
indications.
Dependent on the choice of system configuration, CIEs with an appropriate
specification should be selected.
