Fire Alarm noise levels

[Mike Buckley]

I am carrying out FRAs on a chain of hotels. Most of the Hotels are looking at a delayed evacuation policy for mobility impaired guests. the issue I have is that they have measured the noise level from the fire alarm and it is in the region of 95dB in the bedrooms and refuge areas. Obviously the minimumof 75 dB at the bed head applies but is there any guide on the maximum level. I am suggesting that the guidance in the Noise at Work Regs is followed and a maximum level of between 80 and 85 dB should be applied. Note I am only suggesting this for areas where guests are expected to remain prior to a decision to evacuate.

[colin todd]

Only max in the code is 120 dB(A).  It is unnecessary for such high levels and you would need to watch that the level is not so high that refuge comms become a problem.

[Mike Buckley]

Thanks Colin, I thought as much.

Bearing in mind this is a hotel, I am recommending a maximum level in the refuges of 85 db based on the Noise at Work Regulations. I know Noise at Work does not apply to this situation but at least it gives me a basis to work from as opposed to plucking a figure out of the air.

[BLEVE]

Occupational exposure is based on a time weighted average! It's not the sound pressure level but the exposure duration to the sound pressure level. i.e 85 dB(A) over 8 hours exposure is equivalent to 87 dB(A) over 4 hours, 90 dB(A) over 2 hours etc. 

120 dB(A) would not be recommended

[Mike Buckley]

Yes I know that the occupational levels are based on a daily average, however I am looking for a reasonable upper level for disabled hotel guests to stay in whilst they are in a place of safety as part of a delayed evacuation policy. We bear in mind that the lower level will be 75 dB however the upper level must be reasonable so that the guests can use the communications required for refuges and can remain in the area without distress. This upper sound level would only apply for areas used as refuges.

I chose the Noise at Work Regs as it does give a figure which gives it a bit of justification. 

[Graeme]

Do you what type of sounders are installed Mike?

[Mike Buckley]

It varies from hotel to hotel, some have the horn type, some have the sounder incorporated into the base of a detector in the ceiling. The sounders can either be in the room or in the corridor.

[Graeme]

are the horn types outside the bedrooms and none in the bedrooms.

I find sounders commonly installed and left at max volume (factory set level) especially non addressable ones.

[Mike Buckley]

The horn types can be fitted insode the bedrooms.

Please understand that I am only concerned about the sonders fitted inside rooms and refuge areas where mobility impaired people are expected to remain with the fire alarms sounding. As far as the rest of the hotel is concerned, appart from the reception where again a member of staff is expected to remain to communicate with the guests in the refuges, the maximum sound level can be up to 120 dB.

[BLEVE]

LOL
120 dB(A) over 3 seconds is equal to 8 hour exposure to 80 dB(A) and so NIHL would be likely. Good luck with that then

[BLEVE]

BTW
That's not even taking into account frequency masking and typical response of human hearing to 1/3 octave band.

[Mike Buckley]

Let's not over complicate the issue. With regard to most of the building where everybody is expected to evacuate the sound levels in BS5839 apply. The only areas I am concerned about are the areas which are used as refuges in a delayed evacuation procedure where people are expected to remain for some time. Given the way some people react to a fire alarm, the idea that people are forced out of the building because they can't stand the noise has some merit. However there are some people who are expected to remain inside the building in a place of relative safety until assistance is available to evacuate them and we can't deafen them.

Hence I propose a maximum limit of 85dB in these areas, which is above the 75dB bedhead level but gives some spread for the engineers to work with. I am going for 85dB as I can point to other regulations as guidance and show I am not just pulling a figure out of the air.

The original question was to ask the panel if anyone knew of any guidance which I have missed.

[BLEVE]

65 dB(A) min or 5 dB(A) above background LA₉₀ noise level . Unless sleeping accomodation where SPL should be 75 dB(A)

[Graeme]

Hi Mike

Do you know the make of the "horn types" out of interest?

[kurnal]

Is it wise to have the alarm so loud in protected staircases  and especially refuges? BS5839-1 suggests that lower levels are appropriate in staircases?