Problem:
- how to adapt production spaces to the requirements of fire protection law
- how to protect waste storage locations against fire
- how to protect wood processing machines against fire
- how to design a fire alarm system for warehouses, which will be technologically optimal and cost-effective
Solution:
- preparation of an engineering design for a fire alarm system in accordance with the applicable laws and regulations
- application of different types of fire detectors, optimal for the operating conditions
Check the details for equipment and services in the field of fire protection installations:
- preparation of an engineering design for a fire alarm system
- optical-acoustic alarm devices
- fire alarm central unit
- backup power supply with batteries
- linear, addressable smoke detector
- thermal detector
- photo-thermal detector
- optical smoke detector
- manual call points
The task was to design a fire alarm system for production spaces as well as technical, social and storage rooms in a wooden doors production plant. In order to carry out the task, we have assumed total protection of all rooms. In the event of a fire, the alarm system has the following tasks:
- activate an acoustic and optical fire alarm in the emergency evacuation zone,
- activate an acoustic fire alarm in the security room (24-hour surveillance),
- transmit a 2nd level alarm for the opening of doors secured by an access control system,
- transmit the 2nd level alarm for the opening of the fire doors,
- transmit the 2nd level alarm and information about the correct opening of fire doors to the alarm monitoring station and the State Fire Service.
Which fire detectors to use – optimisation of technology and costs
Due to the design of the protected spaces and staff facilities, but also to the cost-effectiveness of the project, four types of detectors were used in the fire alarm system:
- smart, addressable linear detector,
- photo-thermal detector,
- thermal detector,
- optical smoke detector.
The selection of the detectors listed above took into account the working conditions in individual rooms. This guarantees that the system generates alarm signals with a high degree of certainty, which eliminates the risk of false fire alarms. In all areas, MCP buttons are provided for immediate triggering of a 2nd level alarm.
Locations of fire detectors
Linear smoke detectors based on a sensor cable with addressable detectors were implemented to protect production spaces. This solution not only enables quick fire detection, but also pin-pointing the fire location. Optical smoke detectors are used to protect small technical, social and storage rooms. On the other hand, thermal and photo-thermal detectors were used to monitor smaller workshop and waste storage areas, respectively.
Fire protection of production waste storage areas
Photo-thermal detectors were used to protect production waste storage areas, mainly for wood scraps. Their main advantage in this case was multi-functionality, which allows to detect both quick fires and smouldering. Another important requirement was that the photo-thermal detectors could be programmed to act as thermal detectors at certain times of the day.
Fire protection of production machines
For the protection of production machines, IR flame detectors in intrinsically safe enclosures were proposed. Production machines, particularly working in the wood processing environment, pose a high fire risk. The detector reacts to low frequencies (from 1 to 15 Hz) of infrared flickering emitted from the flames during combustion. Infrared flame flickering allows the detector to operate efficiently through a layer of oil, dust, water and steam or ice.
Most IR flame detectors respond to 4.3 μm light emitted by hydrocarbon fires. The proposed flame detector responding to light emissions from 1.0 to 2.7 μm can detect not only flame fires, but also those invisible to the naked eye.
Fire development and the design of protected spaces – engineering assumptions
The project envisages a slow development of fire in wood-based materials and insulation materials. These phenomena will be accompanied by the production of a significant amount of smoke with a weak thermal column.
In addition, the protected spaces are provided with roofing made of sandwich panels, which affects the conditions in the ceiling area. This creates an airbag in this area, which limits the flow of smoke to the ceiling. This phenomenon required the application of linear detectors at a certain distance from the ceiling, thus improving detection efficiency.
The fire alarm system is equipped with a back-up power supply together with a set of batteries. This solution will ensure correct operation of the fire alarm system, even if there is no permanent power supply.
Individual elements of the fire alarm system were connected to the fire alarm central unit.
