44
2)
Precautions regarding equipment
Warning: cylinders are pressurised!
-
Handle cylinders with care.
-
Secure cylinders in place.
-
Do not expose cylinders to excessive temperatures.
-
Treat valves with care (operate gently, do not dismantle or lubricate valves).
-
Ensure that hoses and pressure regulators are fit for use. Check the condition of gaskets and use original parts
only.
-
Before installing the pressure regulating valve, open the valve briefly to expel dust (do not stand in front of the
valve outlet at this time).
-
Never transfer gas from one cylinder to another.
-
Never lay a cylinder on its side during use.
After use:
-
Close the valve carefully.
-
Drain the coolant outlet.
-
Loosen the adjustment screw on the pressure regulating valve.
-
Close the valve on the receiving equipment.
-
Regulations apply to the transportation of cylinders.
-
Frames must be handled with care in the same way as cylinders.
Users of the equipment, who are fully aware of the conditions of use and thus best placed to monitor the equipment,
are solely responsible for proper use.
11.2
L
IQUID
N
ITROGEN BACKUP
1)
Precautions for the use of nitrogen
Strict rules must be followed when handling cryogenic fluids such as liquid nitrogen. These rules are intended to prevent
two key risks:
asphyxiation and burns
from contact or splashes. Air contains 21% oxygen and 78% nitrogen, by volume.
At atmospheric pressure, liquid nitrogen evaporates at temperatures greater than –196°C.
In a cryogenic room, natural evaporation from recipients, filling, and handling of stored samples result in continuous
evaporation of liquid nitrogen. This can increase significantly if a default occurs. If the room is not well ventilated, the
nitrogen gas generated can cause the atmosphere to be depleted in oxygen.
Properties of nitrogen liquid:
-
Does not sustain life or combustion.
-
Present in air (78%).
-
The evaporation of one litre of liquid nitrogen generates 680 litres of gas.
-
Heavier than air at low temperatures.
-
Non-flammable and colourless.
Ensuing risks:
