The type of decontamination will be based on a number of factors:

• The level and type of personal protective equipment (PPE) (structural fire kit, liquid-tight or gas-tight chemical protection or re-usable or disposable protection)
• The type and quantity of contaminant
• The type and availability of decontamination additives
• The ability to monitor and/or detect contamination
• The availability of drainage and/or containment options
• The conditions of the weather (rain and wind)
• The topography of the area
• The availability of equipment to conduct the decontamination

The location of the decontamination area should take into account the following:

• The topography of the ground - it should be a flat area or sloped away from unprotected personnel in the cold zone
• Wind direction should be blowing away from unprotected personnel
• Any drainage in the area should be identified as either surface, foul or combined drainage and then blocked using a suitable drain blocker or mat
• It should be set up in the cold zone until ready to receive contaminated members of personnel, at which point it should become the warm zone
• It should be appropriately marked to prevent unprotected people from entering the decontamination zone
• Operational circumstances and the risk assessment
• The level and method of decontamination
• The weather conditions
• Location of breathing apparatus (BA) entry control
• Location of a pumping appliance if wet decontamination is being provided