I have never done the safety approval on a product containing liquid nitrogen, but I have worked with it for many years. So here are my comments,
Liquid Nitrogen is not that dangerous if you know what you are doing. Saying that if you are careless, or inexperienced, then it can be pretty evil stuff. So make sure you have been correctly instructed before handling it. Burn hazards from handling it are the immediate concern, eyes being very vulnerable so a face guard is always required. Small splashes onto the hands will evaporate before any serious damage is done. Long term immersion or large spills will cause surface burns and in severe cases frost bite. Always make sure your gloves are designed for handling cryogenic gases. The old style leather gloves are no longer permitted as the leather has a tendency to crack after repeated use. These days it is the nylon fiber packed gloves that should be used. Trouble is these tend to soak up moisture and get very cold if you are filling a large vessel of Liquid Nitrogen. >From a product safety point of view, over pressure relief and accidental spillage control will be your biggest concern. Never put liquid nitrogen in a sealed container, it will not stay there for long. If you are making a dewer system, in the UK and the EU there are specific regulations for pressure storage vessels and cryogenic liquid storage. I can not remember the specifics but try the Pressure Equipment Directive 97/23/EC and the Simple Pressure Vessel Directive 87/404/EEC. Also in the UK, liquid nitrogen is classed as a chemical, so you will have to apply all relevant COSH requirements. A good web site to try is BOC (British Oxygen Cylinders) who have a whole host of literature available on handling and storing pressurized gases and cryogenic gases, plus the relevant BS/EN standards. Andrew Carson - Senior Compliance Engineer, Xyratex, UK Phone: +44 (0)23 9249 6855 Fax: +44 (0)23 9249 6014 -----Original Message----- From: Crabb, John [mailto:jo...@exchange.scotland.ncr.com] Sent: 06 August 2002 10:39 To: emc-p...@majordomo.ieee.org Subject: RE: Liquid Nitrogen Safety This is way out of my normal range of Product Safety experience, but I can say "BE VERY CAREFUL" with liquid nitrogen. My memory bank reminded of a fatality in Scotland not that long ago, and after a short search on liquid+nitrogen+death, I came up with the following : ------------------------------------------------------------- Chemical spill kills lab technician Gerard Seenan Tuesday October 26, 1999 The Guardian A man was killed and four others injured yesterday after a chemical spillage in a human genetics laboratory. The laboratory assistant, who has not been named, was discovered in a medical research council laboratory in the Western general hospital, Edinburgh, yesterday morning. Four colleagues who attempted to go to his aid sustained minor injuries and were treated for the affects of chemical inhalation. A spokesman for Lothian and Borders fire brigade said liquid nitrogen, a coolant used in medical and chemical laboratories, had escaped from a tank. The spillage was confined to a basement laboratory, well away from the main hospital building. Around 40 people were evacuated from the four-storey building after the spillage, which firefighters managed to quickly isolated. The MRC said no member of the public was ever at risk. The four co-workers who attempted to help the man suffered minor injuries and were treated for the affects of chemical inhalation in hospital. All four were released yesterday evening. The fire brigade spokesman praised their bravery. "His colleagues saw that he was in trouble and tried to take him out of what was a very dangerous area," he said. A spokeswoman for the health and safety executive, which is investigating the incident, said the cause of death was not yet known. Liquid nitrogen is capable of causing severe burns and, in the confined space in which the man was working, asphyxiation is also a possible cause of death. The HSE will also be looking at whether the man, who had considerable experience in working with the chemical, died from a medical condition before the spillage. Nicholas Hastie, director of the genetics research laboratory, said liquid nitrogen was used commonly. "We believe we have all the right safety precautions in place." The Edinburgh research laboratory is is one of the MRC's largest units, monitoring genetic factors in disease and in normal and abnormal human development. Liquid nitrogen is used to freeze human cell samples for use in the lab's genetic research. The dead man, who had worked for the MRC for 10 years, was using liquid nitrogen at the time of the accident, but it is not clear what led to the spillage. Professor Hastie said: "This person was very experienced. We have very good safety measures and I have no idea what led to the death." Guardian Unlimited (c) Guardian Newspapers Limited 2001 --------------------------------------------------------------------- Regards, John Crabb, Development Excellence (Product Safety) , NCR Financial Solutions Group Ltd., Discovery Centre, 3 Fulton Road, Dundee, Scotland, DD2 4SW E-Mail :john.cr...@scotland.ncr.com Tel: +44 (0)1382-592289 (direct ). Fax +44 (0)1382-622243. -----Original Message----- From: brian_ku...@leco.com [mailto:brian_ku...@leco.com] Sent: 05 August 2002 16:38 To: emc-p...@majordomo.ieee.org Subject: Liquid Nitrogen Safety Greetings all, We are designing an instrument for laboratory use that will use liquid nitrogen. We will need to design our own dewar system too. Being new to the use of liquid nitrogen we want to make sure we apply all the necessary safety requirements to our product. We have searched the internet and have found the MSDS and several websites that give safety suggestions to avoid burns, over pressure of the container, and asphyxiation. Is there any standards that we should apply other than the normal EN61010-1 and equivilent? Does any country have special requirements that we need to keep in mind? Thanks, Brian Kunde LECO ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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