Active fire protection (AFP) is an integral part of
fire protection
Fire protection is the study and practice of mitigating the unwanted effects of potentially destructive fires. It involves the study of the behaviour, compartmentalisation, suppression and investigation of fire and its related emergencies, as we ...
. AFP is characterized by items and/or
system
A system is a group of Interaction, interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment (systems), environment, is described by its boundaries, ...
s, which require a certain amount of motion and response in order to work, contrary to
passive fire protection
Passive fire protection (PFP) is components or systems of a building or structure that slows or impedes the spread of the effects of fire or smoke without system activation, and usually without movement. Examples of passive systems include floo ...
.
Categories of active fire protection
Manual fire suppression
Manual fire suppression includes the use of a
fire blanket
A fire blanket is a safety device designed to extinguish incipient (starting) fires. It consists of a sheet of a fire retardant material that is placed over a fire in order to smother it.
Small fire blankets, such as for use in kitchens and aro ...
,
fire extinguisher
A fire extinguisher is a handheld active fire protection device usually filled with a dry or wet chemical used to extinguish or control small fires, often in emergencies. It is not intended for use on an out-of-control fire, such as one which ha ...
, or a
standpipe system.
Fire blanket
A fire blanket is a sheet of fire retardant material that is designed to be placed over a fire to smother it out. Small fire blankets are meant for inception stage fires. They are normally made of
fiberglass
Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cloth ...
or
Kevlar
Kevlar (para-aramid) is a strong, heat-resistant synthetic fiber, related to other aramids such as Nomex and Technora. Developed by Stephanie Kwolek at DuPont in 1965, the high-strength material was first used commercially in the early 1970s a ...
. Larger ones can be found in laboratories and factories, and are designed to be wrapped around a person whose clothes have caught fire.
Fire extinguisher
Fire extinguishers are devices that contain and discharge a substance that extinguishes or puts out a fire. These handheld devices come in a huge range of sizes, but the most common are portable fire extinguishers, typically weighing up to 15kg in total. These can be easily handled and operated by one person and placement can either be wall-mounted, on a fire extinguisher trolley or housed inside a cabinet. Fire extinguishers are one of the most common manual fire suppression devices and are required in all commercial buildings and vehicles. Fire extinguishers can be used with little to no training and are meant for small incipient stage fires. The most common extinguisher is the ABC extinguisher and are found in most offices and homes. It can be used on normal fires, liquid fires, and electrical fires. There are also special extinguishers for kitchen fires and for use on burning metals.
Standpipe
Standpipes are installed in most large, multistory buildings. There are two types of standpipes: dry and wet. Most standpipes are dry systems and cannot be used by the public. Dry systems require a fire engine to pump water into the system. Most dry systems don't have pre-connected hoses and require firefighters to bring in the hose. In wet systems, there is always water in the pipes and they can be used by anyone. Wet systems will have hoses so building occupants can try and extinguish fires. Wet systems are becoming less common with the increase in number of sprinkler systems being installed.
Automatic fire suppression
Automatic control means are any form of suppression that requires no human intervention these can include a
fire sprinkler system, a
gaseous clean agent, or
Automatic foam suppression system. Most automatic suppression systems would be found in large commercial kitchens or other high-risk areas.
Sprinkler systems
Fire sprinkler systems are installed in all types of buildings, commercial and residential. They are usually located at ceiling level and are connected to a reliable water source, most commonly municipal water supply. A typical automatic sprinkler system operates when heat at the site of a fire causes a fusible link or glass component in the sprinkler head to fail, thereby releasing the water from the sprinkler head. This means that only the sprinkler heads at the fire location actuate – not all the sprinklers on a floor or in a building. However, certain systems, such as deluge systems, do spray water from all heads in the same zone upon actuation. Sprinkler systems help to reduce the growth of a fire, thereby increasing life safety and limiting structural damage.
Gaseous clean agent
Gaseous clean agents are installed to result in less fire and water damage than sprinklers, such as in computer rooms. The system works by flooding an area with a gas which interferes with the
fire tetrahedron
The fire triangle or combustion triangle is a simple model for understanding the necessary ingredients for most fires.
The triangle illustrates the three elements a fire needs to ignite: heat, fuel, and an oxidizing agent (usually oxygen). A fi ...
.
Foam suppression system
Automatic foam suppression systems come in three main forms low expansion, medium expansion, and high expansion.
= Low expansion
=
Low expansion foam expands less than 20 times its original size. These systems can be installed in a variety of places but are commonly found in places where hydrocarbons are stored. Low expansion foam systems when using film forming work by making a blanket of foam over the burning liquid to both cool it down and suppress the vapors.
= Medium expansion
=
Medium expansion foam expands between 20 and 200 times its original size. These can be installed in outdoor settings like transfer stations or for use in open pits. Medium foam is used outdoors because it is denser than high expansion and won't blow away as easily. It works by covering what is on fire in a thick blanket of foam to smother it and suppress vapors.
= High expansion
=
High expansion foam expands between 200 and 1000 times its original size. These systems are commonly installed in large volume areas like airplane hangars, mine shafts, and ship holds. These systems are normally installed inside and make a very light foam. They extinguish the fire by rapid smothering and cooling.
Its rapid rate of expansion enables it to fill large areas with foam rapidly. When used on LNG tanks they provide an added insulation layer that helps reduce the vapor rate.
= Electronically controlled
=
Nozzles that are powered by electrical energy that is generated and supplied by fire detection and control devices and are typically closed.
Fire detection
Fire detection works using
smoke
Smoke is a suspension of airborne particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-produc ...
or
heat
In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is al ...
sensors. These systems are very effective tool at alerting people in the immediate vicinity of where the fire is detected but
building regulations require an integrated fire detection system. These system not only alerts people throughout the building by triggering the
fire alarm
A fire alarm system warns people when smoke, fire, carbon monoxide or other fire-related or general notification emergency, emergencies are detected. These alarms may be activated automatically from smoke detectors and heat detectors or may also ...
but it can also summon emergency services. There are two types of systems available – addressable and conventional.
Addressable systems Addressability is the ability of a digital device to individually respond to a message sent to many similar devices. Examples include pagers, mobile phones and set-top boxes for pay TV. Computer networks are also addressable, such as via the MAC ...
monitor the specific location of each device (eg smoke detector, call point or sounder). It means in the event of a fire or other emergency you know exactly where the problem is. This saves precious time and helps the emergency services prevent the loss of life and serious damage. Conventional systems can only determine the problem is in a general area and thus are more suited for small sites.
When the fire detection system is activated it can also send an alert to the local
fire department, broadcast a prerecorded warning message and unlock the buildings
access control system.
Hypoxic air fire prevention
Fire can be prevented by hypoxic air.
Hypoxic air fire prevention system
Hypoxic air technology for fire prevention, also known as oxygen reduction system (ORS), is an active fire protection technique based on a permanent reduction of the oxygen concentration in the protected rooms. Unlike traditional fire suppression ...
s, also known as oxygen reduction systems are new automatic fire prevention systems that permanently reduce the oxygen concentration inside the protected volumes so that ignition or fire spreading cannot occur. Unlike traditional fire suppression systems that usually extinguish fire after it is detected, hypoxic air is able to prevent fires. At lower altitudes hypoxic air is safe to breathe for healthy individuals.
Construction and maintenance
All AFP systems are required to be installed and maintained in accordance with strict guidelines in order to maintain compliance with the local
building code
A building code (also building control or building regulations) is a set of rules that specify the standards for constructed objects such as buildings and non-building structures. Buildings must conform to the code to obtain planning permiss ...
and the fire code.
AFP works alongside
modern architectural designs and construction materials and fire safety education to prevent, retard, and suppress structural fires.
See also
*
Fire damper
Fire dampers are passive fire protection products used in heating, ventilation, and air conditioning (HVAC) ducts to prevent the spread of fire inside the ductwork through fire-resistance rating, fire-resistance rated walls and floors. Fire/smoke ...
*
Fire hydrant
A fire hydrant, waterplug, or firecock (archaic) is a connection point by which firefighters can tap into a water supply. It is a component of active fire protection. Underground fire hydrants have been used in Europe and Asia since at least t ...
*
Fire protection engineering
Fire protection engineering is the application of science and engineering principles to protect people, property, and their environments from the harmful and destructive effects of fire and smoke. It encompasses engineering which focuses on fire ...
References
External links
Treatise on Active and Passive Fire Protection from UK GovernmentWhen Fire Strikes, Stop, Drop and... Sing?– Article about acoustic fire suppression, ''Scientific American'', January 24, 2008
Karlsruhe Institute of Technology (KIT) - Forschungsstelle für Brandschutztechnik
{{DEFAULTSORT:Active Fire Protection
Fire protection