Fire Suppression System - Water Based

Fire Suppression System - Water Based

Water is the most natural of all fire extinguishing agents, usually available in sufficient quantities and affordable. It is environmentally-friendly and prevents smoke and pollutants. The extinguishing effect of water is based on its heat retention capacity - it extinguishes fires by cooling.

Water extinguishing systems, such as Fire Hydrant System & Automatic Fire Sprinkler System discharge water onto the flames normally through a fixed piping system.

Fire Hydrant System

The fire hydrant system is the backbone of the fire fighting systems in a building or premises. The system is a water distribution system consisting of water tank, suction piping, fire pumps and a distributed piping system. The distributed piping system establishes connectivity throughout the building through fire hydrants, hoses and nozzles. The purpose of the fire hydrant system is to provide a readily available source of water to any point throughout the building. This helps in controlling fire during an emergency.

Through the fire main system, the fire-fighter is provided with a reliable and versatile system capable of providing a number of different methods for controlling the fire. Water can be supplied through the fire hydrant system as a straight stream for combating deep seated fires and as a spray for combating combustible liquid fires.

Automatic Fire Sprinkler System

An automatic fire sprinkler system is an active fire protection measure, consisting of a water supply system, providing adequate pressure and flow rate to a water distribution piping system, onto which fire sprinklers are connected.

Although historically only used in factories, large commercial buildings, systems for home and small building are now available at a cost-effective price.

Sprinklers may be required to be installed by building codes, or may be recommended by insurance companies to reduce potential property losses or business interruption.

Types & Operation of Fire Sprinkler System

There are 4 types classified based on the operational procedure of water based fire sprinkler system. The hazard / risk to be protected will determine the most suitable type of system you need.

Wet Pipe Fire Sprinkler System

Wet pipe systems are the most common fire sprinkler system.

  • A wet pipe system is one in which water is constantly maintained within the sprinkler piping.
  • When a sprinkler activates this water is immediately discharged onto the fire.
  • Advantages to using a wet pipe fire sprinkler system include:

  • System simplicity and reliability - Wet pipe sprinkler systems have the least number of components and therefore, the lowest number of items to malfunction. This produces unexcelled reliability which is important since sprinklers may be asked to sit in waiting for many years before they are needed. This simplicity aspect also becomes important in facilities where system maintenance may not be performed with the desired frequency.
  • Relative low installation and maintenance expense - Due to their overall simplicity, wet pipe sprinklers require the least amount of installation time and capital. Maintenance cost savings are also realized since less service time is generally required compared to other system types. These savings become important when maintenance budgets are shrinking.
  • Ease of modification - Wet pipe fire sprinkler systems are advantageous since modifications involve shutting down the water supply, draining pipes and making alterations. Following the work, the system is pressure tested and restored. Additional work for detection and special control equipment is avoided which again saves time and expense.
  • Short term down time following a fire - Wet pipe sprinkler systems require the least amount of effort to restore. In most instances, sprinkler protection is reinstated by replacing the fused sprinklers and turning the water supply back on. Pre-action and dry-pipe systems may require additional effort to reset control equipment.
  • Disadvantages to using a wet pipe fire sprinkler system include:

  • Wet pipe systems are not suited for sub-freezing environments.
  • There may also be a concern where piping is subject to severe impact damage and could consequently leak.

  • Dry Pipe Fire Sprinkler System

    A dry pipe sprinkler system is advanced one

  • In which pipes are filled with pressurized air or nitrogen, rather than water.
  • This air holds a remote valve, known as a dry pipe valve, in a closed position.
  • Located in a heated space, the dry-pipe valve prevents water from entering the pipe until a fire causes one or more sprinklers to operate.
  • Once this happens, the air escapes and the dry pipe valve releases.
  • Water then enters the pipe, flowing through open sprinklers onto the fire.
  • Advantages of using dry pipe fire sprinkler systems include:

  • Dry pipe sprinkler systems provide automatic protection in spaces where freezing is possible. Typical dry pipe installations include unheated warehouses and attics, outside exposed loading docks and within commercial freezers.

  • Many people view dry pipe sprinklers as advantageous for protection of collections and other water sensitive areas. This perceived benefit is due to a fear that a physically damaged wet pipe system will leak while dry pipe systems will not. In these situations, however, dry pipe systems will generally not offer any advantage over wet pipe systems. Should impact damage happen, there will only be a mild discharge delay, i.e. 1 minute, while air in the piping is released before water flow.

    Disadvantages of using dry pipe fire sprinkler systems include:

  • Increased complexity - Dry pipe systems require additional control equipment and air pressure supply components which increases system complexity. Without proper maintenance this equipment may be less reliable than a comparable wet pipe system.
  • Higher installation and maintenance costs - The added complexity impacts the overall dry-pipe installation cost. This complexity also increases maintenance expenditure, primarily due to added service labor costs.
  • Lower design flexibility - There are strict requirements regarding the maximum permitted size (typically 750 gallons) of individual dry-pipe systems. These limitations may impact the ability of an owner to make system additions.
  • Increased fire response time - Up to 60 seconds may pass from the time a sprinkler opens until water is discharged onto the fire. This will delay fire extinguishing actions, which may produce increased content damage.
  • Increased corrosion potential - Following operation, dry-pipe sprinkler systems must be completely drained and dried. Otherwise remaining water may cause pipe corrosion and premature failure. This is not a problem with wet pipe systems where water is constantly maintained in piping.

  • With the exception of unheated building spaces and freezer rooms, dry pipe systems do not offer any significant advantages over wet pipe systems.

    Pre Action Fire Sprinkler System

    Pre-action fire sprinkler systems employ the basic concept of a dry pipe system in that water is not normally contained within the pipes. The difference, however, is that water is held from piping by an electrically operated valve, known as a pre-action valve. Valve operation is controlled by independent flame, heat, or smoke detection.

    Two separate events must happen to initiate sprinkler discharge. First, the detection system must identify a developing fire and then open the pre-action valve. This allows water to flow into system piping, which effectively creates a wet pipe sprinkler system. Second, individual sprinkler heads must release to permit water flow onto the fire.

    In some instances, the pre-action system may be set up with a double interlock in which pressurized air or nitrogen is added to system piping. The purpose of this feature is two-fold: first to monitor piping for leaks and second to hold water from system piping in the event of inadvertent detector operation. The most common application for this system type is in freezer warehouses.

    Advantages of using pre-action fire sprinkler systems include:

  • The dual action required for water release -The pre-action valve must operate and sprinkler heads must fuse. This feature provides an added level of protection against inadvertent discharge. For this reason, pre-action systems are frequently employed in water sensitive environments such as archival vaults, fine art storage rooms, rare book libraries and computer centers.
  • Disadvantages of using pre-action fire sprinkler systems include:

  • Higher installation and maintenance costs - Pre-action systems are more complex with several additional components, notably a fire detection system. This adds to the overall system cost.
  • Modification difficulties - As with dry-pipe systems, pre-action sprinkler systems have specific size limitations which may impact future system modifications. In addition, system modifications must incorporate changes to the fire detection and control system to ensure proper operation.
  • Potential decreased reliability - The higher level of complexity associated with pre-action systems creates an increased chance that something may not work when needed. Regular maintenance is essential to ensure reliability.

  • Deluge Fire Sprinkler System

    A deluge system is similar to a pre-action system except the sprinkler heads are open and the pipe is not pressurized with air. Deluge systems are connected to a water supply through a deluge valve that is opened by the operation of a smoke or heat detection system. The detection system is installed in the same area as the sprinklers. When the detection system is activated water discharges through all of the sprinkler heads in the system. Deluge systems are used in places that are considered high hazard areas such as power plants, aircraft hangars and chemical storage or processing facilities. Deluge systems are needed where high velocity suppression is necessary to prevent fire spread.

    Deluge Fire Sprinkler Systems differ from conventional Fire Sprinkler Systems in the sense that all sprinkles or nozzles employed in the system are open and when water is released into the system it flows from all discharge devices. As such, this special type of system is generally found within industrial type hazards that require the application of water over a large hazard or area. The control of water is accomplished by the use of a Deluge Valve which is a device that prevents water from entering the system piping until required. A detection system which may incorporate the use of heat, smoke, or flame detectors is used to open the Deluge Valve when a fire or its products of combustion are detected. All system piping is filled with water which discharges from the open sprinklers and nozzles used in the system. In addition to the application of water some deluge systems will incorporate the use of a foam concentrate to mix with water and form a foam solution which can then provide a protective blanket of foam to help control the development of a fire.

    Deluge Fire Sprinkler systems protect extra hazard occupancies that require significant amounts of water to cool and control the growth or development of a fire. Typically they are employed on hazards that contain low flash point flammable liquids or hazards with large amounts of combustible liquids. These types of hazards may include, oil extraction processes, transformers, tank or vessel protection, distillation processes. Water or Foam Deluge systems are used in the protection of large Aircraft Hangers as one primary means of fire protection.