|
System Requirements
- A high performance aspirating smoke detection system shall be
supplied, installed and commissioned by the specialist contractor
in accordance with the requirements detailed in the BFPSA Code
of Practice for Category 1 Aspirating Detection Systems.
- The protected area(s) shall be:
- The system shall be designed to provide Primary/Secondary
Sampling to the protected area.
- The system sensitivity shall be: normal/enhanced/very high.
- The system shall incorporate a high performance laser based
particle detection system based on the principal of forward light
scatter, a high efficiency aspirator and a sampling pipe system
designed to sample air from within the protected area(s).
- The system shall incorporate a facility to desensitise detector
alarm thresholds by a pre-programmed percentage to accommodate
planned occurrences that may cause unwanted alarms.
- The system shall interface with the main building Fire Alarm
system for remote monitoring of multiple alarm levels and faults.
Performance Requirements
- HSSD (High Sensitivity Smoke Detection) detectors shall be capable
of achieving the sensitivity required to meet or exceed the sensitivity
and pass all fire tests described in EN54 part 9 with a sampling
hole dilution ratio of 99:1. Evidence of this shall be provided
at time of offer, in the form of an LPCB Test Report or equal
and approved.
- Resistance to unwanted alarms is of paramount importance. The
system shall incorporate advanced statistically based signal processing
techniques proven to reduce unwanted alarms. Each detector shall
utilise a system of Artificial Intelligence to ensure a consistent
level of protection by constantly varying its operating parameters
to match environmental changes within the protected area.
- The detector shall continuously monitor all internal and external
components, and signal warning in the event of any malfunctions
including; filter contamination, detection chamber operation,
air flow in sampling pipes outside normal limits, microprocessor
functioning correctly, power supply, etc.
- The detector shall incorporate a dual technology system for
the automatic discrimination of signals from non-fire related
sources such as dust. The system shall automatically adjust itself
to eliminate any deterioration in performance caused by a build
up of contamination.
Detector Construction
- The aspirating system shall be manufactured in Europe within
an ISO 9001 quality environment. These ISO 9001procedures shall
be independently audited by the LPCB.
- The laser detector chamber, aspirator, and control electronics
shall be housed in a single purpose designed metallic cabinet
finished in a neutral colour.
- Multi-channel detectors shall incorporate individual laser detector
chambers for each channel housed in a single enclosure. These
chambers shall be electronically monitored to constantly maintain
protection to all areas irrespective of whether the system is
in quiescent or alarm condition. Each channel shall have the facility
to be programmed with different operating parameters.
- Where detectors are connected to each other in a network configuration
each detector should have facilities for the provision of electrical
isolation from both open and short circuit loop faults. Network
communications should be serial RS485 incorporating full error
checking.
Connection to other systems
- The detection system shall incorporate a minimum of two (2)
alarm levels. A minimum of one of these alarms and fault shall
be connected to the main building Fire Alarm system. Other
alarm levels shall be used either for pre-warning signals to the
Fire Alarm system or to initiate local warning, first stage alarm
on a coincidence release activated gaseous extinguishing system,
equipment shut down, or connection to a Building Management System.
- The detector shall have an input(s) programmable for the following:
remote sensitivity override
remote isolate
remote reset
remote day/night mode switching
reference detector
- The detector shall incorporate an RS232 serial interface. This
shall be used to facilitate remote diagnostics/fault finding to
component level and provide access to the detectors internal chart
recorder and memory. The serial interface shall also enable upload/download
of programming software and connection of a printer for hardcopy
records of system events etc.
- System facilities should be available to facilitate connection
to other systems such as BMS via an RS232 interface that may be
configured to the ANSI/ASHRAE 135-1995 BACnet communications protocol.
Sampling Pipe Installation
- The Sampling Pipe system shall be installed and identified in
accordance with the British Fire Protection Systems (BFPSA) code
of practice for category 1 Aspirating Detection Systems.
- The sampling pipe selected shall be purpose designed for aspirating
smoke detection systems and be marked 'Aspirating smoke detection
system pipe - do not paint or obstruct sampling holes'. All sampling
point holes shall be similarly marked.
Performance and Acceptance Testing
- The installed system shall be proven capable of satisfactorily
responding to an appropriate system performance test. Appropriate
performance tests may be selected from those detailed in the following
documents:-
BS 5839 1988
BS 6266 1992
BFPSA Code of Practice for category 1 Aspirating
Detection Systems
- The installer shall provide evidence of flow/pressure calculations
for the 'as installed' system to ensure optimum sampling performance.
These calculations shall be done by computer aided design software
depicting 3D isometric drawings of the pipe network.
- It shall be verified that all alarm and fault interconnections
are fully operative by means of activation of the signals. In
sensitive areas, such as food storage, the detector system shall
be capable of generating test alarms automatically without the
need for generation of smoke.
|
