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| Operation Manual C 2214 | Safety
1.11 Special notes for working with chlorine gas metering units and the usage of
chlorine
DANGER!
Chlorine is a hazardous material. The chemical element chlorine is a green-yellow, toxic gas with pungent
odor. It is 2.5 times heavier than air and accumulates at ground level. It is toxic when breathed in. In severe
cases chlorine may lead to death. It irritates the eyes, the respiratory system and the skin. It is very toxic for
water organisms. The reason for the toxicity of chlorine is its extraordinary reactivity. It reacts with animal and
vegetable tissue and thus destroys it.
Air with a chlorine content of 0.5-1% leads to a quick death of mammals and humans, because the respiratory
tract and the pulmonary alveolus are attacked (formation of hydrogen chloride or hydrochlorid acid).
DANGER!
Breathing in air with a chlorine content of 0.01% for hours may lead to mortal intoxications. Already a chlorine
content of only 0.001% (10 ppm) severely attacks the lungs. 0.0001% (1 ppm) of chlorine in breathing air
irritates the respiratory systems and is easily detected due to its odour. It is not hazardous in this case. The
threshold limit value is at 0.5 ppm.
In order to avoid hazardous incidents, make sure to do a maintenance of the chlorine gas metering units at
least once a year. In some cases, regional regulations may require shorter intervals of maintenance. Working on
the system requires special safety precautions and may only be carried out by instructed technical personnel.
The operating personnel must be instructed and must know all operating instructions and regional regulations.
These must be available on site. The devices/system must be checked daily and after each maintenance or
repair work for leak tightness.
DANGER!
Leakages may cause a chlorine gas escape. Breathing in chlorine gas may lead to death! Make sure to im-
mediately eliminate any leakage. For all work on gas-conveying system parts, make sure to wear a functioning
respirator mask with filter and and to evacuate all chlorine from the system. This is also important when chang-
ing the chlorine cylinders. In the case of an escape of chlorine gas, use a self-contained breathing apparatus.
Only use sealings once, a second usage is not allowed and leads to leakage.
Before starting work on chlorine gas metering systems the cylinder valves must be closed. All chlorine leading
pipes must be evacuated using the ejector.
Liquid chlorine must never enter chlorinators not being explicitly authorized for liquid chlorine.
In case that the pressure gauge at the vacuum regulator still indicates a pressure, the pressure has to be
discharged using the ejector.
Before startup of the chlorination installation all connections must be carried out properly and tightened using
the suitable tools. The tightness of the whole installation must be tested using ammonia vapor (ammonium
hydroxide solution).
Chlorine gas is highly hygroscopic. Therefore humidity penetrates the system at every open connection of the
units or pipes resulting in the formation of hydrochloric acid thus inevitably causing damage of the units. In
such cases, damages of the devices are inevitable. Therefore all connections (at the vacuum units and vacuum
pipes as well) must be closed at any time.
If chlorinators must be used with other gases than chlorine gas, the chemical resistance of the unit must be
checked after consulting the manufacturer.
