Due to the vast number of chemicals and their different properties, no general decontamination procedure exists. The best way to decontaminate must be decided for the specific chemical encountered. This decision may only be taken by people educated for this task and with a good knowledge of chemistry. Ansell Protective Solutions AB may be contacted for advice.
As a first rule a pre-decontamination must always be performed before doffing the suit - the safety of the wearer is the most important! This predecontamination should include rinsing with large amounts of water, if possible containing a detergent.
After this initial procedure the real decontamination can take place and since all chemicals can be divided into groups, depending on chemical and/or physical properties, the following three groups are the most relevant when it comes to decontamination:
- Soluble or reacts with water
- Insoluble in water
Depending on which group a chemical falls into, the decontamination procedure will be different. A special group of chemicals are the chemical warfare agents, for which we recommend a special decontamination procedure.
NOTE: There are many effective cleaning and decontamination agents available on the market. However, some of them contains corrosive chamicals which may affect the suit materials or components after long time use or repeated use. Therefore, if you are unsure, always contact Ansell Protective Solutions AB for advice before use.
Chemicals that have lower boiling temperature than 80 °C are regarded as volatile. These are typically solvents like ethyl acetate, heptane, benzene, chloroform, acetone and many others.
To decontaminate a suit which has been in contact with a volatile compound you air the suit outdoors or in a well-ventilated area, if possible at a slightly elevated temperature (30-40 °C). Hang the suit with the zipper fully open and enough space around it, so that the air can flow freely around the suit. The required time for ventilating the chemicals depends on the temperature and airflow rate around the suit. After having aired the suit check for odour/smell of the chemicals and test the air for residual chemicals by using simple gas detecting tubes.
Water soluble chemicals
Chemicals that have higher solubility than 60 g/l water are regarded as water soluble. Also, the solubility is dependent on the temperature; an increase in temperature increases the solubility. Examples of water-soluble chemicals are: phenol, ethylene glycol, sodium, all acids and alkali (see further below).
When decontaminating a suit which has been in contact with a water soluble compound you rinse the suit thoroughly with water, preferably with some added detergent. To further enhance the solubility you can use warm water (40 °C).
Acids and alkali
Examples: sulphuric acid, hydrochloric acid, sodium hydroxide, ammonium hydroxide.
Since both acids and alkali are soluble in water, a suit which has been in contact with either one of them should be rinsed with water. Residual acid may first be neutralised with a dilute solution of alkali and vice versa for residual alkali. Afterwards, rinse thoroughly with water with some added detergent. The pH should be checked during the decontamination, when the pH is neutral the decontamination is finished. pH can easily be checked with a pH-stick.
Water insoluble chemicals
Chemicals that are not water soluble are soluble in some type of solvent, for example alcohol or white spirit. Chemicals that have lower solubility than 60 g/l water are regarded as water insoluble. Examples are: styrene, pyridine, nitrobenzene, diesel and crude oil.
If the suit has been in contact with a water insoluble compound you wipe the suit thoroughly with a cloth soaked in alcohol or white spirit (depending on what solvent will solve the chemical). Afterwards, rinse thoroughly with water with some added detergent.
There are chemicals that are so sticky that it is more or less impossible to get the suit completely clean. If this occurs the suit must be scrapped.
Chemical warfare agents
To decontaminate chemical - and also biological - warfare agents we recommend using a 30% water slurry of calcium hypochlorite (also known as chloride of lime or HTH). The suit is washed with the slurry and the slurry is allowed to react with the agents for about 15 minutes before it is washed off with water. After this procedure the suit is washed thoroughly with lots of water, preferably with some added detergent.