Deluge and Water
Spray Systems

 

Deluge systems are installations with a discharge pipe array fitted with open sprinkler heads or water spray nozzles with the water to the discharge pipe array being controlled by a quick opening (deluge) valve.

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The operation of the deluge valve is controlled by an independent detection system, usually either electric (e.g. heat detectors, smoke detectors, or other detectors suited to the specific risk being protected) or a further system of small diameter piping with closed sprinkler heads charged with gas or water for control purposes.

 

On operation of the detection system the deluge valve is opened, water is admitted into the discharge pipe array and is discharged through the open sprinklers or water spray nozzles to provide complete coverage of the entire protected area. Deluge systems are designed primarily for the protection of high hazard risks where intensive fires with a rapid rate of propagation are expected and it is desirable to discharge water simultaneously over the entire zone in which the fire may occur.

 

Water spray systems are utilised for more challenging fires where it is necessary to direct the water onto the hazard or surface being protected using directional nozzles. Water spray systems are most commonly used for exposure protection of bulk storage flammable and combustible liquid tanks to cool the shell, prevent explosion or collapse of the tank and extension of the fire. In addition, water spray systems can be utilised for extinguishment and control of some flammable liquids fires, some combustible liquid fires, class A combustibles, and electrical transformer.

 

 

Water Spray Nozzles

Foam
Systems

 

Foam deluge and foam sprinkler systems are utilised to protect specialist risks involving the storage and handling of flammable and combustible liquids.

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Examples of occupancies where foam systems may be used include:

  • Storage tank protection
  • Warehouse storage of flammable and combustible liquids
  • Aircraft hangars
  • Heliports
  • Truck loading areas

 

How does fire fighting foam work? Fire fighting foams suppress fire by forming a blanket across the surface of the liquid fuel and separating it from the air (oxygen) that it needs to burn. In addition to smothering the fire the foam blanket also cools the fuel and suppresses the release of flammable vapours.

 

Types of Fire Fighting Foam There are several different types of foam to suit a wide range of applications and fuel types. Argus’s engineering and design team would be happy to discuss your needs with you to ensure that the best solution is offered to meet your specific requirements.

 

Dry
Systems

 

A dry pipe installation is a sprinkler installation in which the installation pipe work is permanently charged with gas under pressure above the alarm (dry pipe) valve and with water under pressure below the valve.

Preaction
Sprinkler Systems

 

Argus Fire Protection has considerable experience with the design, on-going service, maintenance, testing and compliance management of specialist fire sprinkler systems such as preaction sprinkler systems. We are able to offer a full range of specialist systems of this type and the backup service to support your installation.

What is a Preaction Sprinkler System?

Preaction sprinkler systems are utilised in situations where a greater level of security against false discharge of water is required. A preaction sprinkler system is a form of dry pipe sprinkler system incorporating water discharge pipework fitted with closed sprinkler heads, but charged with low pressure gas for supervision purposes. Water entry to this piping system is controlled by an independent detection system, usually either electric (e.g. heat detectors, smoke detectors, or other detectors suited to the specific risk being protected) or a further system of small diameter piping with closed sprinkler heads charged with gas for control purposes.

Before water may be discharged it is necessary that both the detection system and the sprinkler heads on the discharge pipework operate.

Preaction sprinkler systems are categorised by their style of operation (generally either single interlock or double interlock) and their type of detection (generally electric or pneumatic) as described below.

Types of Preaction Sprinkler Systems

The basic types of preaction sprinkler systems and their typical uses are described below.

Single Interlocked

With a single interlocked preaction sprinkler system the preaction control valve opens and charges the discharge pipework with water on operation of the detection system. Water is not discharged from the discharge pipework until one of the closed head sprinklers on the discharge pipework operates. The discharge pipework is normally charged with gas at low pressure for supervision purposes to ensure that the pipe remains closed. If a sprinkler on the discharge pipework is operated without the detection system operating then the preaction system will provide indication of a defect state, so that the service agent can be brought to site to repair the system.

Single interlock preaction systems are typically installed to protect sensitive equipment such as computer server suites which require a higher level of protection against accidental water discharge.

 

Double Interlocked

With a double interlocked preaction sprinkler system the preaction control valve does not open until both the detection system and one of the closed head sprinklers on the discharge pipework operates.

Double interlocked preaction sprinkler systems are more complex than single interlocked sprinkler systems and are therefore considered to be less reliable. In addition, because the preaction control valve does not open until both the detection system and a closed head sprinkler on the discharge pipework operate, there is a longer delay before water is discharged onto the fire.

The New Zealand automatic fire sprinkler standard (NZS4541) only permits the use of double interlocked preaction sprinkler systems in freezers and other similar environments where it is undesirable to permit water to enter the discharge pipework until the after the sprinklers have been activated, due to the risk of and damage associated with freezing water in the pipework

Pneumatic Detection

The most common type of detection for a preaction sprinkler system is pneumatic detection where a system of small diameter piping with closed sprinkler heads charged with gas (normally dry air) is distributed throughout the enclosure for detection and control purposes. When a sprinkler on the detection network operates, the gas pressure is lost and the preaction control valve operates.

 

The New Zealand automatic fire sprinkler standard (NZS4541) favours the use of pneumatic detection over other means of detection.

Electric Detection

The New Zealand automatic fire sprinkler standard (NZS4541) only permits the use of electric detection in limited circumstances such as freezers and then only with the specific approval of the Sprinkler System Certifier.

Gaseous Fire
Suppression Systems

 

Gaseous fire suppression systems (also referred to as clean agent systems) are utilised to protect high value assets such as computer server rooms, PLC control rooms, storage of irreplaceable artefacts where a high level of fire protection is required and the use of water or other suppressant agents would be damaging to the protected equipment.

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Gaseous fire suppression systems extinguish fires using a gaseous agent that is able to permeate into cabinets and obstructed areas to ensure complete extinguishment. The gaseous agents are non-conductive and non-corrosive making them safe to use around live electrical equipment. The gaseous agents leave no residue so there is no clean up following a discharge and business is able to be quickly resumed.

 

Argus Fire Protection offers a range of gaseous fire suppression agents to meet a variety of challenges. These gaseous agents are described here.