The LWF Blog

Fire Safety for Healthcare Premises – Types of Fire Alarm System – Part 117

March 2, 2020 2:51 pm

In LWF’s blog series for healthcare professionals, our aim is to give information on best practice of fire safety in hospitals and other healthcare premises. In part 116, LWF considered the function of fire alarms in dependent occupant environments. In part 117, we look at the definition of system type given in HTM 05-03.

HTM 05-03 offers a glossary of definitions of terms used within the document, the majority of which are straightforward and require no further explanation. The information given with regards to System Type is based on designations given in BS 5839-1 and are used to describe the function of the system.

Systems described as ‘Type L’ are automatic detection systems which are intended to protect life. All systems used in healthcare environments are ‘Type L’ systems. In some businesses or premises, ‘Type P’ systems may be used and these systems are designed to protect property from damage due to fire. One of the major differences between a Type L and Type P system may be whether the alarm is heard or not. A Type L system is more likely to given a auditory warning, whereas a Type P system may trigger a notification to the Fire Service and the sprinkler system to operate instead.

A Category L1 system is of a type installed throughout a building. It is designed to give the earliest possible warning of fire so that the longest possible time is available for evacuation from the premises, or area of the premises in the case of horizontal evacuation practices.

A Category L2 system may be installed only in defined parts of the building. It should include the coverage necessary to satisfy the recommendations of this standard for a Category L3 system because the objective of an L2 is identical to that of an L3, with the added requirement of affording early warning of fire in specific areas of high fire hazard level or high fire risk. For example, a Category L2 system may be designed to work in areas where high levels of oxygen are present.

A Category L3 system is designed to give warning of fire to enable all occupants (with the possible exception of those in the room of fire origin) to escape safely before escape routes are impassable because of fire, smoke or toxic gases. It would be necessary to install detectors in rooms opening onto an escape route in order for this system to work as described.

In Part 118, LWF will look at Category L4 and Category L5 automatic detection systems. In the meantime, if you have any questions about this blog, or wish to discuss your own project with one of our fire engineers, please contact us.

Lawrence Webster Forrest has been working with their clients for over 25 years to produce innovative and exciting building projects. If you would like further information on how LWF and fire strategies could assist you, please contact LWF on freephone 0800 410 1130.

While care has been taken to ensure that information contained in LWF’s publications is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of this information.

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