Posted By Brian Eddington We have a lab set up with large volumes of Liquid Nitrogen (off) Gas passing through.... You can only gain access via keypad access.... Do I require depleted oxygen warning signs on the entrance area (alarms are in place) or will the Authorised Personnel Only sign be enough

Posted By Jim Walker Brian, These areas are very dangerous. Without a doubt confined spaces. Have a look at http://www.bcga.co.uk/first.htm There is a good powerpoint called Oxygen deficiency - two breaths and you are dead.

Posted By Alec Wood Signs are cheap, if you think it would be helpful in that situation then stick one up, even if the law doesn't require it. This stuff is very nasty, and injuries from it are often severe. I remember having a near miss with liquid nitrogen in Edinburgh myself (a different incident to that mentioned above) ten or more years ago when I was an engineer. As part of the same incident another chap I was with almost died and suffered debilitating injury which prevents him working, or doing much else, to this day. Why my then employer was never prosecuted I can only guess at. Alec Wood Samsung Electronics

Posted By Jane Blunt Brian, it sounds as though you have already done a lot - you have oxygen alarms. I am not clear from your posting whether this is liquid nitrogen itself, or whether it is a gas line fed from a liquid nitrogen tank. We have around 35000 litre storage capacity for liquid nitrogen, and we also run a helium liquefaction plant, so have faced some of the same issues. We don't have any areas with key pad access, but we do have oxygen alarms in key areas. One thing we have done is put up notices telling people what to do in the event that the alarm is going off. We also issue personal oxygen alarms to Security guards who enter the building at night, in case there has been a leak when no-one was around to see/hear it. I am not aware that there is a standard pictogram in the UK for an asphyxiating atmosphere. However, putting up warning notices would not be a bad idea, so that people know WHY they are not allowed access. e-mail me personally if you want further information on our (still evolving) procedures. Jane