HEALTH & SAFETY @ LITTLE FRANCE LN 2 SAFETY TRAINING

1. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Welcome to an on-line health and safety training package intended for staff and students working within UofE buildings on the Little France campus. Information contained within these pages is intended for use by University of Edinburgh staff and students only.

2. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING This on-line training package is intended for laboratory users of liquid nitrogen, but it is not a substitute for practical training, which will be organised by laboratory managers as required. A separate training package is available related to compressed, and laboratory gas safety. Last updated: February, 2018

3. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Please take time to view the following material, and direct any urgent questions to your H&S Advisor, Laboratory Manager, or the Little France Buildings H&S Manager (the contact details for whom are shown on the last page of this presentation). Thank you

4. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Characteristics (1) • Colourless, odourless, tasteless, non-flammable, non-toxic, water- like liquid, readily yielding an ice- fog in air. • Boiling point -195.9oC • Gaseous N2 is slightly lighter than air, and will rise upwards. • Liquid N2 (LN2) is heavier than air, and will fall to the ground.

5. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Characteristics (2) • LN2evaporates rapidly in contact with any surface at temperatures above its boiling point (-195.9oC). • Volume expansion rate = 696x (i.e. 1 m3 of LN2 will expand to 696 m3 of gaseous N2 at 21oC). • Boiling LN2 can displace 02 from the air and rapidly create an oxygen depleted environment.

6. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Principal Hazards (1) • Risk of serious burns if LN2 comes into contact with skin. • Serious risk of asphyxiation if a large quantity of LN2 vaporizes in a confined space. • LN2can spatter (possibly into eyes) while being decanted. • Flying chunks of frozen material may cause eye injury.

7. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Principal Hazards (2) • Skin contact with extremely cold metal components of LN2 plant etc. • Explosive ejection ofsample vessel cap as samples warm up and expand, with potential to cause an eye injury. • Cryogenically stored sample vessels bursting open and liberating contents as they warm up.

8. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Oxygen Depletion (1) • There isnormally ~21% O2 in air • At 18-21% O2 health effects. gradually become apparent. • At 15-18% O2 physical and mental performance becomes impaired, often without the exposed person even being aware.

9. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Oxygen Depletion (2) • At 10-15% O2 respiration deepens and pulse increases, co-ordination, perception and judgement becomes increasingly impaired, followed by giddiness and possibly fainting. • At 8-12% O2 mental impairment becomes severe, and nausea, vomiting and fainting occur.

10. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Oxygen Depletion (3) • By 6-8% O2 mental impairment is severe, and nausea, vomiting and fainting are almost inevitable. • By 0-6% O2 fainting occurs almost immediately, and death rapidly ensues.

11. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Oxygen Depletion (4) For a variety of reasons, partly related to plant design and operation, onset of asphyxia in a liquid nitrogen plant room is most likely to be gradual as O2 level falls, but an affected person may not be aware of a problem until it’s too late to be able to self-evacuate from the room (though it may be apparent to an observer looking into the room from outside).

12. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Oxygen Depletion (5) • The onset of symptoms may occur earlier in those with impaired lung function (e.g. tobacco smokers). So, in a group, one or two people may become symptomatic earlier than others. • In all cases, emergence of symptoms in any individual(s) should result in all those within the room exiting promptly to fresh air, as a precaution, until a proper assessment can be made.

13. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Precautions (1) • Ensure that LN2 plant rooms are well-ventilated. • Maintain plant properly. • Prepare Risk Assessments and put Safe Systems of Work (SSW) in place. • Only persons who have completed appropriate training should handle LN2 • Employ O2 depletion monitoring.

14. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Precautions (2) Buddy system always, always, to be used.

15. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING There is absolutely no valid reason why it would ever be acceptable for anyone to be working unsupported in a liquid nitrogen plant room … ! Never, ever!!

16. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING • And by “support”, it is insufficient merely to inform a colleague that you have gone to the plant room and ask them to raise the alarm if you don’t return by a certain time. • You need your “Buddy” to have eyes-on contact with you all the time that you’re in the plant room.

17. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Precautions (3) • Use the personal protective equipment provided in each LN2 plant room. • Remove metal jewellery, wrist watches etc before handling LN2 in order to avoid the gas becoming trapped close to the wearer’s skin. • Comply with all safety signage, written instructions, and manufacturer’s guidance.

18. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Precautions (4) • Only ever decant LN2 into approved and properly-fit vessels. • Handle LN2 plant and containers with care, avoiding knocking vessels together or allowing objects to fall to the floor. • Never misuse LN2 plant.

19. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Precautions (5) • Exercise caution when introducing LN2 to warm vessels etc to minimise thermal shock and pressure build-up. • Avoid build-up of N2 vapour in confined spaces. • Avoid breathing N2 vapour. • Employ safe technique when moving LN2

20. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Personal Protective Equipment (1) Wear the personal protective equipment provided (as dictated by the work to be done and an allied risk assessment): • Properly fastened lab coat (and perhaps also a robust apron). • Full-face shield. • Cryogenic protection gloves. • Appropriate footwear covering the whole foot (no open-toed sandals). • Do not tuck trousers into shoes/boots. • Skirts or shorts are unsuitable.

21. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Personal Protective Equipment (2) • Avoid the possibility of LN2 collecting or pooling in gauntlets or footwear. • Report damaged/missing PPE, and do not proceed/continue to work with inadequate/absent personal protection. • Ensure that a personal oxygen depletion meter is being used within the room.

22. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING “Traffic Light” Oxygen Depletion Alarms Do not enter a LN2 plant room if alarms are sounding and red or amber beacons are illuminated. QMRI CB

23. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING SCRM

24. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Personal Oxygen Depletion Alarms • These must be used whenever there is a need to enter a plant room. • Calibration must be done outside the room, where O2 levels are more certain. • Before entering the plant room, the alarm should be tested by gently and steadily exhaling over the sensor and listening for the alarm sound. • If the meter fails to work, do not commence work in the plant room.

25. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Access to Plant Rooms (1) • Plant rooms must be kept locked when not in use. • When work is being done, all doors leading into the room must be unlocked. (NB: There are two access doors in the Chancellor’s Building LN2 plant room).

26. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Access to Plant Rooms (2) • Doors must be relocked after completion of work. • Keys will be issued only to authorised workers (a list is kept at Reception in both buildings). • Breach of standing rules may result in authorisation being withdrawn.

27. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Buddy System (1) A person trained in LN2 plant room procedures, and accredited as a LN2 plant room worker by their senior laboratory manager, may enter the room to assist while acting as a buddy, but only after the lead worker has first confirmed that the room is safe (noting the room monitors/alarms and by using a portable oxygen depletion monitor).

28. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Buddy System (2) If not already trained in LN2 plant room procedures, and not formally accredited by their senior laboratory manager as a LN2 plant room worker, a person may not act as a buddy (under any circumstances at all).

29. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Buddy System (3) But unless the buddy really is required to be inside the plant room (perhaps to assist with manual handling or inventorying), he or she should remain at the door and not enter the room - even if alarms begin to sound. The main role for the buddy is to obtain urgent help if there is a need to rescue a person in the plant room who has been overcome by asphyxia.

30. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Plant Room Alarms (1) If plant room or personal oxygen depletion monitor alarms sound while you are in a LN2 plant room, leave the room … IMMEDIATELY!

31. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Plant Room Alarms (2) Do not ever try working through an alarm, because “It’ll only take me another minute to complete this task”, or “I can see what caused the alarm, and it’ll settle down soon”, because you won’t know how fast O2 levels are dropping, and you can’t be certain that there’s not something else going wrong, and you may end up in a environment so depleted of O2 that you can no longer safely make that judgement.

32. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Plant Room Alarms (4) • Do not place yourself at risk by entering a plant room when O2 depletion alarms are already sounding. • Where extrication of an unconscious casualty is required, summon the Fire & Rescue Service by dialling (9)999 from any extension at a safe location.

33. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Building Alarms If building alarms (e.g. a fire alarm) sound while you are in a LN2 plant room, leave the building immediately using the NEARESTEXIT!

34. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Late and Lone Working with LN2 Only in exceptional circumstances (and with all relevant training and risk assessments in place) should LN2 be handled outside hours of expected building occupancy (see Section 9 of the LF Buildings H&S Manual) and never ever on a lone working basis (see Section 10) at http://www.ed.ac.uk/schools-departments/medicine-vet-medicine/staff-students/staff/health-and-safety/manual Late Working

35. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Cryogen Vessels (1) • Vacuum cryogen storage vessels are typically formed from a double-walled stainless steel construction with multi- layer insulation filling the annual space. • The design of cryogen vessels is intended to minimise heat in-leak from the environment into the vessel, reducing vaporisation of LN2 and build-up of pressure within the vessel.

36. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Cryogen Vessels (2) The physical properties of LN2 may eventually result in severe weakening of welds within the structure of vessels, so it is necessary to comply strictly with each manufacturer’s instructions regarding periodic inspections, maintenance and ultimate decommissioning of sufficiently aged vessels.

37. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Pressure Relief Devices • LN2 to N2 conversion in storage is ~2.3% day-1 however good the vessel. • In unused vessels, gas pressure will increase until released via a control valve. • Dewars etc must, therefore, be stored in a well-ventilated area. • Ensure that safety valves etc are undamaged and properly maintained. • Vessels will empty after a period of time, even when not being used.

38. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Moving LN2 Storage Vessels (1) • Consider LITE (Load, Individual capability, Task and Environmental) factors before commencing movement. • Employ a buddy system. • Wear appropriate PPE. • Do not handle vessels by safety devices (e.g. pressure relief valves). • Use trolleys, etc.

39. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Moving LN2 Storage Vessels (2) • If the container tips over, let it go and clear the area until the vapour has vented-off. • Never use a passenger lift. • Use a freight elevator, and ensure that no passengers accompany the load at any stage.

40. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Moving LN2 Storage Vessels (3) • Typically, a full LN2 pressure vessel (containing 200 litres of LN2) will weighs something in the order of 275kgs. • LN2 will also move around in a vessel being transported, further complicating movement and adding to the risk of spillage.

41. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Handling Samples etc • Exercise caution when introducing LN2 to warm vessels etc to minimise thermal shock and pressure build-up. • Take care also when handling sample containers, as these too will be extremely cold initially, but they will warm up quickly and may explode and eject ice shards as well as liberating contents.

42. Do not use a funnel. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Dispensing LN2 (1) • Remain present throughout filling operation. • Do not hold dispensing tube or receiving vessel with unprotected hands. • Dewars (> 20 litres capacity) must be lifted and poured by two people.

43. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Dispensing LN2 (2) • Do not allow LN2 to fall over a distance to reach the receiving vessel – Raise the vessel safety up to the delivery tube (but don’t hold it there with your hands). • Do not bend the fill tube unnecessarily. • Do not touch any item that has been immersed in LN2 until it has warmed to room temperature.

44. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Dispensing LN2 (3) • Do not dispense LN2 into a container with a tight-fitting lid as the lid may blow off as the liquid boils and increases pressure inside the vessel. • Never dip a hollow tube into LN2 as boiling liquid may spurt through it. • Boiling and splashing always occur when filling warm containers with cryogenic liquids or inserting warm objects into cryogenic liquids.

45. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Dispensing LN2 (4) • Always fill warm Dewars slowly to minimise temperature shock effects and to reduce splashing. • Do not fill Dewars etc to more than 80% capacity since expansion of LN2 during warming can result in excessive pressure build-up. • Perform tasks slowly to minimize boiling and splashing. • Never dispose of excess LN2 by pouring it onto the floor.

46. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING Accidents and Emergencies • Treat any exposure/injury. • Report any injury/spillage.

47. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING First Aid (1) Liquid nitrogen boils at -196oC. Contact with skin is likely to result in cold burns and frostbite. Burns are often initially painless. Frozen tissues appear waxy, with a pale yellow colour. But as tissues begin to thaw, pain may be considerable, and the casualty may suffer shock.

48. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING First Aid (2) Skin Contact: If LN2 has been in contact with skin for more than a couple of seconds, cold burns can occur. If these are extensive, the damage may be severe enough to result in the need for amputation. Bathe the affected area in tepid water and seek immediate medical help.

49. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING First Aid (3) Eye Contact: Flush with water while summoning immediate specialist medical help from the Infirmary.

50. HEALTH & SAFETY @ LITTLE FRANCE LN2 SAFETY TRAINING First Aid (4) If Swallowed: LN2 temporarily trapped in the mouth is likely to cause burns to the inside of the mouth and may also result in cracking of teeth and damage to the throat. Urgent medical attention must be sought.