ASHCOM Video Smoke Detection
All fire safety professionals constantly seek the benefits of early warning of potential fires. In the perfect
World they imagine being able to place hundreds of smoke detectors millimetres above and around the items or areas
at risk. This would certainly enable a fast response to a potential fire, saving valuable time even in voluminous
areas or where a high airflow may be present. But of course such a dream is not possible from a practical or financial
point of view, OR IS IT?
Principle of Operation:
VSD is based on sophisticated computer analysis of the video image seen by the CCTV camera (sensor). Using advanced
image-processing technology and extensive detection (and known false alarm phenomena) algorithms; the VSD can automatically
identify the distinct characteristics of smoke patterns. The fire detection industry has an abundance of known smoke
signatures and all of these are built into the system to give an accurate decision on whether smoke is present. The VSD
is so accurate in it's analysis that it can even differentiate between steam and smoke.
The VSD system uses standard CCTV equipment linked to a self contained processing system which is capable of recognising
small amounts of smoke within the video image and alerting the system operator both at the processor and by a variety of
The VSD system employs highly complex algorithms to process video information from up to eight cameras simultaneously.
Under normal conditions with all eight cameras connected the system achieves a 5Hz-frame rate for each channel.
The video hardware is designed to allow simultaneous real time digitising of all eight images, which means that the
system does not multiplex images and, therefore, no information is lost or delayed. All alarm condition images are logged,
time & date stamped, and stored within the system's memory.
The VSD system detects smoke rapidly by looking for small areas of change within the image at the digitisation stage
and only passing these pixel changes to the main processor for further filtering. The video information is passed through
a series of filters, which seek particular characteristics that can be associated with smoke behaviour. Further analysis
is then carried out on the relationships between the filtered characteristics to determine whether all the conditions have
been met for the system to confidently predict the presence of smoke.
The system installer has the ability to vary the amount of smoke signal, and the length of time that the smoke exists
before an alarm condition is raised to cater for situations where there may be background smoke present. The installer
may also divide the video image into zones and programme the system to alarm only if smoke is present in 2 or more zones.
The VSD system is now in operation in a variety of applications throughout the world, either installed as a working system
or on trial. Typical applications that can benefit from a VSD smoke detection system include:-
Electrical Power Generating Stations (Nuclear, Fossil and Wood)
Military and Merchant Ship's Engine Rooms
Tunnels (Road and Rail)
Paper and Document Storage Facilities
On Board Aircraft
Chemical and Petrochemical Works
Toxic Waste Plants
Water Treatment Facilities
Historic Buildings and Museums
Storage Facilities (Military and Commercial)
Offshore Oil and Gas Installations