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en54-23 and deaf pager
#11
(16-02-2017, 09:09 PM)Monkeh Wrote: Sounders need to be 5db above the background noise.
Bear in mind, dB is an exponential rather than linear scale so it's much more difficult and dangerous to jump from 95db to 100db than from even 60db - 75db

I was having a discussion with one of our project guys yesterday regarding the sound pressure level required above the ambient background noise, he was saying that a consultant on one of our new installs was looking for 10 db above background noise, i said that i always thought it was 5 db required. 

Is there any special circumstances where 10 db above ambient is required, or is the consultant just being a Consultant ?
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#12
Quote:2)  where the sound pressure level of background noise is greater than 60  dB(A), the sound pressure level of the fire alarm signal should be 5 dB above the sound pressure level of the background noise; NOTE 1  Background noise that is unlikely to persist for longer than 30 s may be ignored.
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#13
(17-02-2017, 07:24 AM)MW63 Wrote:
(16-02-2017, 09:09 PM)Monkeh Wrote: Sounders need to be 5db above the background noise.
Bear in mind, dB is an exponential rather than linear scale so it's much more difficult and dangerous to jump from 95db to 100db than from even 60db - 75db

I was having a discussion with one of our project guys yesterday regarding the sound pressure level required above the ambient background noise, he was saying that a consultant on one of our new installs was looking for 10 db above background noise, i said that i always thought it was 5 db required. 

Is there any special circumstances where 10 db above ambient is required, or is the consultant just being a Consultant ?

A Consultant never gets it wrong !!!!! Bow
All posts are of my own opinion and knowledge and do not reflect the views of the Company I work for.
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#14
(17-02-2017, 01:28 AM)Monkeh Wrote:
(17-02-2017, 12:33 AM)Adi Wrote: Another case of the ***** idiots profitering.

It would not have cost that much to add sounder beacons and given a better system, anyhow, customer pays for them anyway.

Whens this licensing coming in, lol.

May have been competing against other companies for the install and trying to cut costs for the quote

No doubt, shame though.
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#15
(16-02-2017, 09:51 PM)AnthonyB Wrote: EN54-23 doesn't cover pages, just VADs so it's a bad sign they are talking about 'EN54-23 fire pagers' as  they don't exist.

If replacing new for old I'd expect like for like unless an FRA and/or independent design specification says it needs to be different (which could be less or more)


This is what worries me (copied and pasted in italic and underlined from the companys response):

The sounder beacons at that time of Tender were being re-instated which is why the drawings shows them as beacons. VAD’s were removed from the design as there was a fire pager system in place which complies with EN54 part 23.  


Additionally there is no reason to have beacons fitted into the main hall areas are there are no compliance issues as the DB levels achieve a minimum increase of 5Db above the ambient noise pressure level, and no Fire Risk Assessment or specification was been provided at design stage suggesting the VAD’s are a requirement in the main hall, as the design would have been significantly different. 


Due to the design being underwritten by ***** the decision was made by ***** as the design / installation complies with the issued certificate and EN 54 pt 23 - DB levels are compliant and were taken during the working day and the certificate / drawings certify this.

(***** is the name of the fire alarm company.) They are kind of admitting they are the designer/installer/commissioner and have done this system without an fra.
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#16
Easy solution. Take dB readings with and without the fire alarms sounding and see if there's an increase of at least 5dB.
If there isn't then they need some visual warning.
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#17
Although a further consideration would be that in areas of high background noise you would expect people to be wearing ear defenders which would make vad's or at least good old fashioned strobes a good idea in any event. 

Going off on a tangent, has anyone else noticed that it can sometimes actually be easier to pick out the fire alarm if you're wearing ear defenders in an area with high background noise? It will obviously reduce the sound waves actually getting to your ears but fire alarm sounders seem to penetrate better than the noise of machinery.
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#18
interesting.
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#19
Its because all frequencies have different level of penetration.
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#20
As a rule we don't push past a background/total noise level of 85Db.
From there we look for visual enhancements or other means of alarming people.
http://awacsuk.com

advanced warning and communicated systems
installation...integration...innovation....

any comments or views posted are mine and I'm keeping them.
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