Fire safety and property protection systems for buildings requires knowledge and understanding of hazards to decrease the potential fire occurrence and its risk to life and property during fire.
Importance of Fire Safety and Property Protection Systems for Buildings
When fire is occurred, injury and death might be due to asphyxiation from poisons fume and smoke, burns from direction exposure to the fire, heart attacks because of stress and exertion, impact resulted from structural collapse, explosions, and falls.
Not only does the life safety and property protection influenced by the design of the structure and its fire protection measure but also, they affected by construction material quality, maintenance and building content.
Balanced design depends on three complementary systems to decrease the danger of death and risk to property as a consequent of fire.
The three systems are a detection system to warn occupants of fire, a contaminant system to limit or restrict the extent of fire, and an automatic suppression system to control the fire until it can be extinguished.
These systems of balanced design complement each other by adding fire resistance feature which is not offered by other components. Moreover, some balanced design component features are redundant which mean if a certain part is failed the other part will offer fire safety.
In addition to apply an excellent physical balanced design for fire safety, a perfect education and training program need to be integrated with fire safety plan.
Fire Safety and Property Protection Systems for Buildings
- Automatic detection
- Automatic suppression
- Property protection
- State of the art in designing for fire safety
Automatic Detection of Fire
The first and most important measure against fire, which is slow with smoke but without fire and low heat that does not activate sprinkler head, is an exact early warning.
From life safety point of view, detectors are substantially significant because they warn occupants close to the source of the fire to run away.
To alert fire department, alarm systems could be installed to decline reaction time of firefighters, increase the speed of rescue operation, and restricting the spread of fire and structural damages.
If detectors are fixed at corridors and connected to central alarm, the evacuation of the whole occupant will be easy and potential injury and death will be reduced. Smoke sensing fire detector is the most usual detector that employed for early warning.
Generally, detectors need to be connected to continuous power supply and should have a battery as a backup for the case where power is failed.
Location of Automatic Fire Detector
Automatic detector location is specified based on general building code requirements. In residential building, detectors should be provided in all sleeping rooms, areas adjacent to sleeping rooms, and on all level of the building including the basement.
The selection of suitable detectors is based on number of storeys, obstruction rooms, amount of air movement, and other factors.
The installed detectors are vulnerable to various unanticipated malfunctions for example lack of maintenance because of human neglect, faulty of power supply, and act of sabotage.
Fig.1: Automatic Fire Detection System in Buildings
Fig.2: Installed Automatic Fire Detection System
Automatic suppression of Fire in Buildings
The purpose of automatic sprinkler system is to control fire at its origin. Despite that fact that residential sprinkler is not produced to extinguish fire, but it is dependable and influential in limiting the fire source in the room until it can be stopped completely.
Automatic sprinkler can reduce the possibility of flashover that can be dangerous event. Not only does the fire suppression permits access to building to help occupants out of dangerous area but also allows the continuation of fire suppression.
The National Fire Protection Association (NFPA) recommends minimum standard for sprinkler system design and installation. Standard for the installation of sprinkler systems (NFPA-13) involves sprinkler system for general utilization while standard for the installation of sprinkler systems in residential occupancies up to and including four stories in height (NFPA 13R) covers residential applications.
If large amount of combustible content is present in building, then the NFPA 13 should be followed without storey height consideration so as to guarantee the protection of storage rooms, closets, and other concealed closed areas constructed with combustible materials.
The design, installation, testing, and maintenance of sprinkler systems are dealt with by NFPA standards. Clearly, effective and influential sprinkler head needs sufficient water supply and piping system to supply adequate water to the sprinkler head.
The standard determines areas or rooms which are not needed to be sprinkled. After the completion of sprinkler installation, based on standards, inspection and acceptance of piping valves, pumps, and tanks of the system.
Insufficient maintenance and improper water supply lead to poor performance of the sprinkler.
Fig.3: Fire Suppression System in Buildings
Fig.4: Automatic Fire Suppression System in Kitchen
Fig.5: Installed Fire Suppression System in Residential Building
Compartmentation of Buildings
Compartmentation restricts the spread of fire by dividing the building into compartment areas surrounded by fire walls and by fire rating floors and ceilings. Added to that, the spread of smokes and poisons fumes to adjacent areas of the building is limited by compartments.
Large and destructive fire beyond compartments is avoided by restricting total fuel load increasing the fire.
Not only do compartments provide a safe place for occupants for whom unable to escape such as elderly and handicapped but also safe refuge areas for long time when the fire are blocked or filled with smokes.
Until the fire is controlled, compartments work to contain the fire. Each concrete or masonry walls that construct compartments walls need to have adequate fire resistant rating and need to have the capability of protecting structural integrity of the building during fire. In multifamily housing, it is recommended that each room constructed in such a way that works as a separate compartment.
Added to that, storage rooms, electrical rooms, mechanical rooms, and interior exist ways must work as separate compartments. It is required to fire rat exterior walls because not only does it prevent the exterior fire penetration but also control interior fire.
If joints between floors and walls, exterior curtain wall, or between ceilings and walls are not adequately fire protected, the Compartmentation effect is decreased.
These weakness points in the compartment boundary need to be dealt with properly to avoid fire movement. It is substantially significant to seal and repair damages occurred because of equipments, abuse, or utility installation to eliminate smoke and gas passage.
Fig.6: Compartmentation of Fire to Protect Building Content and other Property
Fig.7: Compartmentation of Building to Prevent the Spread of Fire
Property Protection Systems for Buildings
The initial cost of installing fire safety can be quite large but it can be offset by advantage which obtained by applying balanced design. The possible loss thus fire can be decreased by providing high protection level for structures and its contents. Fire and smoke damages to the contents of the building is restricted by balanced design.
The compartment boundary which is not combustible limit structural damages and substantially decrease the repair time after the fire. Generally, the repair is nonstructural and possibly it involves the replacement of doors, windows, switches, electrical outlet, wiring, heating ducts, and covers of floors, walls, and ceilings.
State of the Art in Designing for Fire Safety
Fire protection is more like an art than a science, and number of unknowns and fire propagation possibilities are substantially large. So, fire protection mainly depends on risk assessment rather than exact computation. Designers use both Building Code criteria and understanding science of fire as guidance to deal with fire safety.
Table-1 provides number of important fire safety problems which are needed to be taken into consideration and their relative ranking and effectiveness of each component in contributing to the balanced design. It can be observed from the table that, it is possible that several components are effective while a specific hazard is mitigated.
There no any component that is totally safe and not subjected to failure by itself, therefore overlapping of functions are needed to achieve level of safety. Nonetheless, there are number of function in the table that is being dealt with by merely one component of balanced design.
There is a consensus among fire safety and regulatory communities that computer modeling contributes to improve fire safety in the built environment. Complex analytical models and computing equipment provide fire safety engineers contemporary and ever evolving tool to improve and enhance fire safety requirements in buildings.
Table-1: Fire Safety Functions of Balanced Design