Observation of the bag

On receipt, the bag is unpacked and then carefully inspected prior to sampling:

• Observation of the dust layer (quantity, colour, aspect, presence of pellets/crusts, adhesion)
• Observation of the state of the filtration bag (general aspect, presence of perforations, holes, tears, etc.)
• Observation of the clean air side of the felt (presence of dust, location of any pollution, presence of rust, etc.)
• Observation of the state of the felt (colour, flexibility, fragility, etc.)
• Photography of any specific zones.