Most commonly found in factories and large commercial buildings, a sprinkler system, similarly to a fire suppression system, is designed to extinguish a fire to minimise smoke and fire damage to a building, but most importantly to prolong the time any occupants have to escape the building when the fire alarm is activated. The automatic sprinkler system is designed to provide an immediate response when fire is detected to protect lives and to minimise material losses. A significant benefit is that sprinklers remove the risk of harm by removing then need for human intervention in attempting to extinguish a fire. Rather than gas however, a sprinkler system uses water to suppress the fire using temperature sensitive elements in the sprinkler head that are only activated when they exceed safe temperature levels.
Generally installed in ceilings, or side walls where appropriate, a sprinkler system will consist of a water supply, piping system and a number of sprinkler heads (determined by the size of the room / building, and its contents). When a fire is detected, the sprinkler heads will discharge water automatically. One common myth is that when one sprinkler head activates, the whole system will be activated, but this is not true. Sprinkler heads are not triggered by smoke, they instead feature a temperature sensitive element which will only activate the water flow when a high enough temperature is detected (usually between 60 and 70°C). This means that only the heads that detect the high temperature will activate, thus minimising unnecessary water damage and financial cost.
The volume of water used by a properly designed, installed, and maintained automatic fire sprinkler system is considerably less than the amount of water discharged by a traditional fire hose. Another common myth surrounding sprinkler systems is that they cause more damage than the fire, however this is almost always not the case. A fire that is allowed to spread unchecked will cause considerably more damage, both in smoke damage and structural damage. Sprinkler heads used in quick response sprinkler systems typically discharge between 36 to 72 litres of water per minute, compared to a firefighting hose which can discharge over 600 litres per minute.
There are many different types of sprinkler system, with each offering their own benefits for different applications. A few different types are listed below:
A wet pipe sprinkler system features a pipe network that is constantly filled with water. When the sprinkler head detects a high enough temperature, the glass bulb or sensitive element / fusible link in the sprinkler will break. As the water is already present in the pipe network, water can flow out of the activated sprinkler head immediately.
Similar to wet pipe, the main difference for a dry pipe system is that the pipe network is not permanently filled with water. Instead, the water is kept behind a dry pipe valve. This means that there is a delay between the glass bulb of the sprinkler head breaking and the water being released, so there are size limitations with this type of system. They use the same trigger (glass bulb / fusible link in the sprinkler head), and once a sprinkler head is activated, air is released from the sprinkler which creates a drop in system pressure. This pressure drop causes the dry pipe valve to open, filling the system with water, and allowing water to flow out of the open sprinkler head.
A pre-action system is more complex that a wet / dry pipe system. It combines the benefits of a both wet and dry pipe sprinkler systems, with additional benefits against accidental water damage. A pre-action system requires more than one stimulus for water to release from the sprinkler heads. Most pre-action systems are linked to an independent fire detection system, which upon detecting a fire, release the pre-action valve and allows the pipe network to fill with water. From this point, a pre-action system turns a dry pipe system into a wet pipe system, and will release water immediately when a sprinkler head bulb breaks.
Deluge systems are similar to pre-action systems in that they also use another type of detection in order for water to release from the sprinkler heads. The main difference is that a deluge system uses open sprinkler heads. Instead of water releasing from only those sprinkler heads that have been triggered, once a deluge system fills with water, water is released from every sprinkler head. Water will enter the pipe network when the connected fire detection system (such as smoke detection) is activated.
There are certain elements that should be included in all servicing and maintenance packages for fire sprinkler systems. These elements are in place to fulfil your legal requirement and give you the confidence that your system has been serviced properly, by someone who is qualified & competent, and that it has been completed to a recognised industry standard.
During the site visit, a trained engineer will carry out a thorough check of the system to ensure correct operation of the heads and the system itself, as well as the automatic triggering mechanisms. These regular checks are also critical to the longevity of the system, ensuring that all components are free from wear and damage. You can expect the following to take place during a site visit:
Reviewed: 22/12/2022 (doc:760 V1.0). Our articles are reviewed regularly. However, any changes made to standards or legislation following the review date will not have been considered. Please note that we provide abridged, easy-to-understand guidance. To make detailed decisions about your fire safety provisions, you might require further advice or need to consult the full standards and legislation.