Varian VHS-6, Instruction Manual

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i. Cold Coolant – Liquid nitrogen, a cryogenic liquid, is used in traps. If it is splashed on body tissues
or eyes, it can cause severe frostbite or blindness. The extremely low temperature of liquified nitro-
gen can cause skin damage similar to high temperature burns. Contact with the cold gas evolving
from the liquid may produce the same effect. Delicate tissues, such as the eye tissues, are most
easily damaged by exposure to cold gas or liquid. To minimize the risk of hazardous contact of cold
gaseous nitrogen with any part of the body, wear personal safety equipment recommended for use
with cryogenic materials including face shield, full-sleeved lab coat, and clean, dry gloves which fit
loosely so they can be thrown off quickly if frozen by contact with the gas.
j. Asphyxiation – If a large amount of liquid nitrogen is spilled in a small, poorly ventilated room or
equipment, death from suffocation can result. All diffusion pumps are typically cleaned with acetone
or alcohol. Acetone, alcohol, and most other solvents are very volatile (unstable). During cleaning,
the volatility of these cleaners may permit their gases to displace air and its life-supporting oxygen
which could cause death or serious injury by asphyxiation. Always ensure that cleaning operations
are performed in large, well-ventilated areas.
j. While still hot, the diffusion pump may also contain decomposed and/or overheated pump oils
which can also be an asphyxiant.
k. Large, Heavy Weights – Diffusion pumps larger than 10 inches in diameter require power-
assisted equipment and the use of trained moving/installation personnel in order to avoid
dropping, slipping, and/or overturning the pump thus severely injuring personnel. Check weight
of equipment before lifting and do not stand under equipment being moved.