The LWF Blog

Fire Safety for Facilities Management Personnel – Fire Detection & Fire Alarms – Part 194

March 27, 2023 11:54 am

Lawrence Webster Forrest (LWF) is a specialist fire engineering and fire risk management consultancy whose aim is to give information on best practice in fire safety for facilities management personnel through this blog series. In part 193, LWF began to discuss alarm devices. In part 194, we continue looking at the sound pressure levels of alarm sounders.

One of the challenges of achieving the required 65 dB(A) in all areas is that the sound pressure level is unlikely to be achieved in an area with more than one door between that area and the nearest sounder. In a hotel (or other relevant establishment with sleeping quarters) the required sound pressure level of 75 dB(A) at the bedhead is only likely to be achieved if there is a fire alarm sounder within the room. It is generally considered normal practice to install a fire alarm sounder in each bedroom within sleeping accommodation. Commonly, the sounders are contained within the bases of the fire detectors.

It is essential that sleeping persons in a hotel or other establishment are woken from their sleep in order to evacuate the building ‘under their own steam’. In a residential care facility, however, it may be that the fire alarm is not intended to rouse sleeping occupants so that they may evacuate themselves. Where that is the case and residents will be expected to evacuate independently, the sound pressure level of 75 db(A) at the bedhead applies. However, when residents will need to be assisted with their evacuation to a place of safety, BS 5839-1 Fire detection and fire alarm systems for buildings – Code of practice for design, installation, commissioning and maintenance of systems in non-domestic premises would consider the premises should be treated as a non-sleeping occupancy and the standard 60-65 dB(A) level would apply throughout.

It should be noted that HTM 84 and equivalent Scottish guidance conflicts with the recommendation contained in BS 5839-1, in that they recommend the much lower sound pressure levels which are applied in hospitals. However, alarms pitched at this level may be difficult for staff to hear in rooms in which televisions or radios are operated at a relatively high volume, as may be the case when care home occupants have hearing impairments.

In part 195 of this series, LWF will continue to look at the necessary sound pressure levels required in different environments. In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please contact LWF on freephone 0800 410 1130.

 

Lawrence Webster Forrest is a fire engineering consultancy based in Surrey with over 35 years’ experience, which provides a wide range of consultancy services to professionals involved in the design, development and construction and operation of buildings.

 

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.