C RYOGEN S AFETY Safe Use of Liquid Nitrogen (LN2) By Reece Stockport Departmental Cryogenic Safety Advisor 1

T RAINING O UTLINE Hazards Personal Protective Equipment Exposure Safety Procedures General Use Container Filling Procedure Questions 2

HAZARDS 3

Liquid Nitrogen (LN 2 ) can cause severe frostbite or eye damage upon contact. Liquid nitrogen is liquefied by cooling nitrogen gas down to (or below) its boiling point [-320ºF (-196ºC)]. Substances may become brittle upon contact with LN 2 and shatter. Expands by a factor of 700 upon vaporization 4

H AZARDS (2) May cause explosion of a sealed container Can Cause Asphyxiation LN 2 should be used and stored in well ventilated areas! 5

6 P ERSONAL P ROTECTIVE E QUIPMENT

PPE- E YES ANSI approved safety goggles must be worn when handling LN 2. When filling your Dewar from the larger vessel a full face shield must be worn. Safety glasses do not provide adequate protection from potential splash hazard of large quantities. 7

PPE- H ANDS Cryogenic gloves are required when Dispensing from LN 2 container. At any point whilst transporting and handling LN 2 Limited resistance to direct exposure to liquid nitrogen (splash resistant) 8

PPE- B ODY & F EET When handling LN 2 Fully enclosed shoes are required (no open-toe or canvas shoes, sandals, or clogs) Long pants and long sleeve tops or a lab coat must be worn (no shorts or short-sleeved shirts ) 9

H OW YOU SHOULD LOOK ! 10

11 E XPOSURE

E XPOSURE - S KIN C ONTACT Skin contact can cause severe cold burns and frostbite. Flesh freezes very rapidly, flesh may be torn attempting to be withdrawn from object 12

W HAT SHOULD I DO IF IT OCCURS ? If frostbite or freezing occurs, the following steps should be taken: Call a first aider! Who will; 1. Flush area thoroughly with tepid water Do not apply direct heat Do not rub affected area 2. Protect area with bulky, dry, sterile dressings 3. Seek medical attention 4. Notify supervisor 13

E XPOSURE - E YE CONTACT Eye exposure can cause permanent irreversible damage Delicate eye tissue can be damaged by exposure to the cold gas alone 14

W HAT SHOULD I DO IF IT OCCURS ? If liquid is splashed into eyes, do the following: Call a first aider! Who will; 1. Flush with water for 15 minutes 2. Seek medical attention if needed 3. Notify supervisor 15

E XPOSURE - ASPHYXIATION With asphyxiation, unconsciousness may happen without warning If the person becomes dizzy, move them to a well- ventilated area and seek a first aider Notify supervisor 16 Oxygen content (vol %) Effects and symptoms (at atmospheric pressure) 11-16Reduction of your physical and intellectual performance without the person being aware. 8-11Possibility of fainting without prior warning. 6-8Fainting within a few minutes, resuscitation possible if carried out immediately. 0-6Fainting almost immediate. Fatality!

17 S AFETY P ROCEDURES

G ENERAL SAFE USE All Activity must be Risk Assessed by a competent person! Have a procedure when working with LN 2 ; procedure should include: Use only in well ventilated and low traffic areas Wear appropriate PPE LN 2 should only be handled in approved containers Avoid breathing LN 2 vapors Carry containers away from body and face Do not leave open containers unattended Leave to ventilate in a corner on completion (do not throw on floor or pour down sink) 18

F ILLING C ONTAINERS Double check your small Dewar has no cracks or any problems Check the pressure relief valve is pointing away from people Wear the appropriate PPE Take care when transporting your Dewar (DO NOT OVER FILL) I will now give a demonstration of the filling procedure. 19

20 Q UESTIONS ?