F.R.S – Fire Risk Solutions is passionate about offering the right fire detection systems to meet the correct requirements for our customer; taking into account, the specification, the risk, the competition, the market and the national standards so we offer the correct solution.
The choice of fire alarm system depends on the building structure, the purpose and use of the building and current national regulation. In new or altered buildings the regulatory body is the local building control, and the relevant guidance is explained in the relevant SANS regulations. All installations and maintenance schedules are subject to SANS 10400 and the SANS 10139 standards. The Responsible Person, as defined in the specific standards, has to conduct a fire risk assessment in order to ascertain the class of installation dependent on the risk.
This appropriate regulation contains brief descriptions of the major components which go to make up a fire detection system. The points to be considered are intended to highlight the variables which can exist and need to be considered whilst designing and compiling a specification for component parts.
Types of Wired Fire Alarm Systems
All Fire detection systems essentially operate on the same principle. If a detector detects smoke or heat or someone operates a break glass unit (manual break point), then alarm sounders operate to warn others in the building that there may be a fire and to evacuate. It may also incorporate remote signaling equipment which would alert the fire department via a central station.
Fire Alarm Systems can be broken down into two categories in South-Africa:
- Wired Conventional systems
- Wired Addressable systems
Wired Conventional Fire Alarm System
In a wired Conventional Fire Alarm System, a number of call points and detectors are wired to the Fire Alarm Control Panel in Zones. A Zone is a circuit and typically one would wire a circuit per floor or fire compartment. The Fire Control Panel has a number of Zone. The reason for having Zones is to give a rough idea as to where a fire has occurred. This is important for the fire department and of course for the building management. The accuracy of knowing where a fire has started is controlled by the number of Zones a Control Panel has and the number of circuits that have been wired within the building. The Control Panel is wired to a minimum of two sounder circuits which could contain audible devices. Each circuit has an end of line device which is used for monitoring purposes.
Wired Addressable Systems
The detection principle of an Addressable System is similar to a Conventional System except that the Control Panel can determine exactly which detector or call point has initiated the alarm. The detection circuit is wired as a loop and up to 127 devices may be connected to each loop dependent on the system being installed. The detectors are essentially Conventional Detectors, with an address built in. The address in each detector is set by dil switches and the Control Panel is programmed to display the information required when that particular detector is operated. Additional Field Devices are available which may be wired to the loop for detection only i.e. it is possible to detect a normally open contact closing such as sprinkler flow switch, or a normally closed contact opening. Sounders are wired in a minimum of two sounder circuits exactly as a Conventional System. Loop Isolation Modules are available for fitting on to the detection loop/loops such that the loop is sectioned in order to ensure that a short circuit, or one fault will only cause the loss of a minimal part of the system.