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RichJ  
#1 Posted : 29 March 2018 08:49:09(UTC)
Rank: New forum user
RichJ

I work on a large biotech site with multiple buildings including labs / plant buildings / manufacturing buildings etc.  Many of these have O2 monitoring in place to identify oxygen depletion as we use a lot of liquid nitrogen.  There are discrepancies across these alarm systems as to which value for Oxygen they alarm at, and hence the area is evacuated.  These range from 18%-19.5% (atmospheric concentration is 20.95%).

Does anyone know what the HSE's recommendations for O2 depletion alarm settings are? I am struggling to find anything concerete.


Thanks

UncleFester  
#2 Posted : 29 March 2018 09:43:48(UTC)
Rank: Forum user
UncleFester

Still nothing concrete, but good research here:

http://www.hse.gov.uk/research/rrpdf/rr973.pdf

JayPownall  
#3 Posted : 29 March 2018 09:46:10(UTC)
Rank: Forum user
JayPownall

...beaten to it by UncleFester!...

Have a look at the HSE Research Report 973. 'Review of alarm setting for toxic gas and oxygen detectors'.

There's a lot of waffle but some good snippets of industry best practice is quoted within.

Jamie 

Edited by user 29 March 2018 09:47:03(UTC)  | Reason: Beaten to the post!

Bigmac1  
#4 Posted : 29 March 2018 19:36:40(UTC)
Rank: Super forum user
Bigmac1

19.5% for confined space, taken from OSHA as we do not have a standard.

Are you sure you havnt got confined spaces?? 

Messey  
#5 Posted : 31 March 2018 07:33:09(UTC)
Rank: Forum user
Messey

We have a hypoxic fire prevention system that runs around 16.4 to 17% O2 with the alarm set at 15%

We restrict the exposure hours to 4hrs - and allow access for rescue down to 13% in extremis

andrewcl  
#6 Posted : 04 April 2018 14:53:31(UTC)
Rank: Forum user
andrewcl

RichJ, I used to do atmosphere tests for confined space entries, and all I really knew was that all the oxygen monitors had a "warning alarm" level at 19.5% oxygen and then a "you need to leave this confined space" alarm at 18%.

Answering your question to the best of my ability, I don't know for sure if there is anything in law, or that the HSE recommend (the confined space lead above may be worth following up), but the first place I thought about looking for info, when I saw your post, was the British Compressed Gases Association (BCGA) website.  They have loads of good info including this guidance note, which includes the alarm levels I mentioned earlier.

http://www.bcga.co.uk/assets/BCGA%20GN%2011%20-%20Revision%204%20-%20For%20Publication.pdf

Hope this is of use

thanks 1 user thanked andrewcl for this useful post.
RichJ on 06/04/2018(UTC)
stevedm  
#7 Posted : 14 April 2018 08:59:34(UTC)
Rank: Super forum user
stevedm

There isn't anything set in law...however part of the C&G training syllabus gives O2 Min 19.5% - Max 23.5%..

:)

stevedm  
#8 Posted : 19 April 2018 06:39:18(UTC)
Rank: Super forum user
stevedm

This might help also....

https://en.wikipedia.org/wiki/Limiting_oxygen_concentration

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