The LWF Blog

Fire Safety for Healthcare Premises – Audible and visual alarms – Part 138

July 27, 2020 1:54 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 137, LWF began discussing audible and visual alarms in healthcare environments. In part 138, we finish discussing visual alarms and look at radio-linked systems.

When visual alarms are used in healthcare premises, the alarm devices should comprise flashing lights, commonly and preferably red, but other colours may be used where necessary. They should also normally include a sounder of low sound output which should be similar in output to that of the main alarm devices.

The use of flashing lights as a visual fire alarm should be given careful consideration, as people suffering from photo-sensitive conditions may suffer adverse reactions. The flash rate should not exceed 130 flashes per minute in any environment.

Radio-linked Systems

Radio-linked smoke and heat alarms are networked by radio signal and are considered to be easy to install. BS 5839-1 has more detail on design installation.

The main disadvantage to such a system is the replacement of batteries, which can prove to be both expensive and inconvenient. It is possible to find mains-powered radio-linked systems, although some of the simplicity of installation is then lost.

In the environment proposed for a radio-linked system, sufficient surveys must take place to ensure radio communication is reliable. The potential cumulative effects of such a system must also be considered.

In particular:
the potential for radio frequency interference to other systems derived from the radio-linked system emissions;
the potential for radio frequency interference from other systems derived from the radio-linked system susceptibility;
the potential for data packet collisions with other existing data systems or those proposed.

Subject to compliance with BS 5839-1 and HTM 05-03 – Part B, radio-linked systems may be used in providing temporary protection in healthcare premises.

Where contractors are working on refurbishments or expansion, such systems can provide cover where the normal system is not operational. It must be noted that where contractors are working in close proximity, particularly with the likes of scaffolding, these works can affect signal strength on radio systems.

It is suggested that permanent use of such systems in healthcare premises should only be considered where the system is well proven and preferably independently certified against a suitable product standard.

It is essential that any fire alarm system should comply fully with the recommendations of BS 5839-1.

In Part 139, LWF will discuss electromagnetic interference and how it may affect fire alarm 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.