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Appendix 3

Health & Safety

EMERGENCY PROCEDURES AND FIRST AID

(a) Emergency procedures

The method described in Appendix 1 allows the effects of a liquid nitrogen spill on the oxygen content of a room to be assessed. The results of the calculations may identify a need for evacuation if a spillage above a certain size occurs. If this is the case, then the risk assessment should identify this limit and should also specify what to do if such a spill occurs, or if the low oxygen alarm (18 vol %) is triggered. It should take into account:

  • who may be affected by the spill
  • the means of raising an alarm
  • possible escape routes
  • the means of isolating the supply of liquid nitrogen, especially if supplied from a bulk tank
  • the means of preventing access to the area until the oxygen content returns to normal
  • the possibility of liquid nitrogen affecting other areas (e.g. by penetrating floors, or by accumulating in ducts).

The assessment should specify what to, and what not to do, if someone has collapsed in an area of low oxygen concentration. Attempts at rescue by poorly equipped and untrained rescuers are likely to lead to more casualties. Rescue should not be attempted if this is likely to put the rescuers in danger (such attempts have led to deaths or casualties amongst rescuers). Instead, the supply of liquid nitrogen must be isolated and attempts must be made to ventilate the area (e.g. by opening external doors and windows, but without entering the oxygen-deficient atmosphere). The Fire Service must be called as fire-fighters are the only persons likely to be suitably prepared for such rescues.

(b) First aid - inhalation of oxygen-deficient atmospheres

Remove conscious casualties to fresh air and keep them warm. A first aider must assess their condition or medical attention should be sought.

If the casualty is not breathing, then basic life support must be started and an ambulance must also be called.

(c) First aid - cold burns and frostbite

Flush the affected skin with copious amounts of tepid water, or place the affected part in tepid water, and do not apply any form of direct heat. If possible, move the casualty to a warm room. A first aider must assess all cold burns, or medical attention should be sought to confirm the extent of any tissue damage.

(d) First aid – liquid nitrogen splashes in the eye

Flush the eye with running water for at least 15 minutes and ensure the casualty is taken to the Eye Hospital for assessment.