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DAUGIAU INFORMACIJOS RASITE
WWW.GRENE.LT
Protection against dusts, mist and fume
Dusts
are solid particles of several sizes generated by crushing solid materials
Mists
are particles of evaporated liquid, condensed or mechanically atomised
Fumes
are small size aerosol particles (less than 0.4 μm) of evaporated or melted solids that are
rapidly cooled; generally they come from combustion, smelting or welding processes
Dusts, mists and fumes are therefore aerosol particles which need a mechanical and electrostatic filter
to be removed.
There are two types of filters against particles:
1 – filtering facepiece, indicated with FFP;
2 - masks (half mask or full face mask) combined with proper filters, denoted by “P”.
The reference standards are:
- for filtering facepieces against particles (dusts, mists and fumes)
-
EN 143
for particle filters and related masks.
Under these rules the devices are tested and then classified into three categories with growing filtering efficiency.
Recommendations for selection
The European standard EN 529:2005 sets the criteria to select and use properly a respirator basing
on the risk assessment process valuation. In this standard it is stated that the “protection factor” is
the ratio between the contaminant concentration rate and respirator inner concentration.
The standard introduced the Assigned Protection Factor (APF) that is the level of respiratory protection that can
realistically be expected in the workplace instead of Nominal Protection Factor (FPN), which is just a notional value.
Filtering facepieces/Half masks
Full face masks
Class/Filter
APF
Max conc.
Class/Filter
APF
Max conc.
FFP1/P1
4
up to 4xTLV
P1
4
up to 4xTLV
FFP2/P2
10
up to 10xTLV
P2
15
up to 15xTLV
FFP3/P3
30
up to 30xTLV
P3
400
up to 400xTLV
*TLV
=time-weighted average contaminant concentration to which the
user may be exposed without any health effects.
If the contaminant concentration is unknown, the following table shows a preliminary suggestion in the selection:
Protection factor
P1
P2
P3
TLV – contaminant
higher/equal 10 mg/m3
between 0.1 and 10 mg/m3
lower than 0.1 mg/m3