Pure ammonia comes in two forms: gas and liquid.
Ammonia is a naturally occurring substance that has been successfully used as a refrigerant in industrial refrigeration plants for more than 140 years. Liquid ammonia is a clear fluid, colorless that evaporates quickly at room temperature. Liquid ammonia also has a high compression ratio. The ratio of liquid to gas is 1 to 800, which means that 1 litre of liquid ammonia expands to form 800 litres of gas. It is a colorless, strong gas that liquefies under pressure and has a pungent odor. It is also much lighter than air. If ammonia gas escapes from a refrigeration system or a storage container, it tends to collect in high areas
or ceilings. Ammonia has negligible environmental impact with zero ozone depleting potential (ODP= 0), no direct global warming potential (GWP = 0) and low operational emissions due to high efficiencies.
GWP = 0, ODP = 0
Ammonia carries a B2 safety classification, meaning that it has a medium flammability and high toxicity risk. A major ammonia spill is potentially disastrous because liquid ammonia evaporates quickly when exposed to air and creates an explosive fire hazard at high concentrations. Due to the high affinity of ammonia for atmospheric humidity it is otherwise rated as ‘hardly flammable’. Ammonia can cause chemical burns on all body surfaces.
Ammonia vapour reacts with moisture in the air to form moist ammonia, which attacks copper, tin, zinc, cadmium, and most of their alloys. Ammonia is toxic to the skin and mucus membranes, but has a characteristic, sharp smell, which gives a warning below concentrations of 300 ppm. In amounts of 300ppm, prolonged exposure will become unpleasant, and in amounts over 700ppm it can cause burns and serious damage to eyes. In amounts of 5,000 ppm or above, exposure can be lethal to humans within five minutes. Ammonia gas is very irritating to the eyes, nose, and respiratory system, which makes it easy to detect low concentrations in the air.