1. What are cryogenics? Outline the advantages and the risks involved in the storage of cryogenics.
Cryogenics are substances, generally gases, which are stored at very low temperatures, usually below 150 degrees Celsius. At these temperatures they become liquids, at higher temperatures they cannot exist as liquids.
The main advantage in storing cryogenics is that they are stored outside, and so do not present the same internal fire risk as portable cylinders which are kept inside.
However, the quantities of gas involved are considerable, with the added hazard of the liquid gas being at very low temperatures, which presents serious health risks to those in the vicinity of escaping gas.
2. Briefly define these terms:
a) Flash Point
The flash point of a liquid is the minimum temperature at which vapour is given off in sufficient concentration to form an ignitable mixture with air. It is used in determining a liquids relative degree of flammability.
b) Vapour Density
Vapour Density is the ratio of the weight of a particular vapour to the weight of the same volume of air. Essentially it describes the vapour as being heavier or lighter than air.
This refers to a measurement for short-term toxicity. By feeding animals with increasing quantities of a chemical, the amount that proves lethal to 50 out of 100 animals is called the Lethal Dose for 50 per cent, or LD50.
3. Describe local and systemic effects in about one paragraph each.
Local effects refer to those reactions that occur when a chemical first comes in contact with or enters the body. This can be by way of skin irritation, tissue damage, or irritations of the eyes or mouth.
Systemic effects are slightly more in-depth and look at the reaction of the body, or more particularly the organs. Most poisons have a target organ which suffers the most damage or the largest adverse reaction, when the body is exposed to that chemical. Systemic effects, therefore,...