Pre-Action Fire Sprinkler Systems

Torvac have now completed the installation of a new 150 mm Pre-Action Fire Sprinklers Systems at the Australian Museum. The system installed to protect the Pacific store collection area, which is a collection of material culture, ethnography, history, and archaeology of the Indigenous peoples of the Pacific region. The collection consists of over 60,000 ethnographic objects and is a major asset and great symbol of Australia’s close connection to the Pacific Islands and its people.

Pre-Action Sprinkler Systems
2 types of Pre-action systems: single interlock and double interlock.

Pre-Action Fire Sprinklers Systems are suitable for use in areas requiring that water be kept out of the sprinkler piping until an electric detecting device and a sprinkler have both been activated. The piping is filled with low pressure supervisory air to guard against accidental discharge due to sprinkler or pipe damage. Typical applications include Museums, Libraries, Archives, Computer rooms and cable/ transformer rooms.

There are two main subtypes of pre-action systems: single interlock, and double interlock.

Single Interlock Pre-Action Fire Sprinklers Systems

The operation of single interlock systems is similar to dry systems, except that these systems require a “preceding” fire detection even. Typically, the activation of a heat or smoke detector, takes place prior to the “action” of water introduction into the system’s piping by opening the pre-action valve, which is a mechanically latched valve (i. similar to a deluge valve).

In this way, the system is converted from a dry system into a wet system. The intent is to reduce the undesirable time delay of water delivery to sprinklers that is inherent in dry systems. Prior to fire detection, if the sprinkler operates, or the piping system develops a leak, loss of air pressure in the piping will activate a trouble alarm. In this case, the pre-action valve will not open due to loss of supervisory pressure, and water will not enter the piping.

Double Interlock Pre-Action Fire Sprinklers Systems

The operation of double interlock systems are similar to deluge systems, except that automatic sprinklers are used. These systems require that both a “preceding” fire detection event, typically the activation of a heat or smoke detector, and an automatic sprinkler operation take place prior to the “action” of water introduction into the system’s piping. Activation of either the fire detectors alone, or sprinklers alone, without the concurrent operation of the other, will not allow water to enter the piping. Because water does not enter the piping until a sprinkler operates, double interlock systems are considered as dry systems in terms of water delivery times, and similarly require a larger design area.

If your property contains precious, irreplaceable items or documents, Torvac can assess your property’s needs and design, install and maintain your system to comply with all current Australian standards.

Case Study

Pre-Action Fire Sprinkler Systems  Installation – Australian Museum

The Australian Museum, established in 1827 houses valuable collections of great cultural and historical significance to Australians. Torvac Solutions have recently installed two new Pre-Action Fire Sprinkler Systems at the Australian Museum in Sydney. Both systems protect  the Anthropology collection of the Museum. Our team worked closely with Facilities and Collection Managers as well as the Security Department to ensure a seamless installation.

Why a Pre-Action Fire Sprinkler System

Pre-action sprinkler systems used in locations where accidental activation is undesired, such as in museums with rare art works, manuscripts, or books; and Data Centres, for protection of computer equipment from accidental water discharge.

Pre-action Fire Sprinkler Systems are hybrids of wet, dry, and deluge systems, depending on the exact system goal. There are two main subtypes of pre-action systems: single interlock, and double interlock.

Single Interlock Systems

The operation of single interlock systems are similar to dry systems. The exception is  that these systems require  a “preceding” fire detection event. Typically, the activation of a heat or smoke detector, takes place prior to the “action” of water introduction into the system’s piping by opening the pre-action valve, which is a mechanically latched valve (i.e., similar to a deluge valve). In this way, the system is converted from a dry system into a wet system. The intent is to reduce the undesirable time delay of water delivery to sprinklers that is inherent in dry systems. Prior to fire detection, if the sprinkler operates, or the piping system develops a leak, loss of air pressure in the piping will activate a trouble alarm. In this case, the pre-action valve will not open due to loss of supervisory pressure, and water will not enter the piping.

Double Interlock Systems

The operation of double interlock systems are similar to deluge systems, except that automatic sprinklers are used. These systems require that both a “preceding” fire detection event, typically the activation of a heat or smoke detector, and an automatic sprinkler operation take place prior to the “action” of water introduction into the system’s piping. Activation of either the fire detectors alone, or sprinklers alone, without the concurrent operation of the other, will not allow water to enter the piping. Because water does not enter the piping until a sprinkler operates, double interlock systems are considered as dry systems in terms of water delivery times, and similarly require a larger design area.