Summary of our seminar RESPIRATORY PROTECTION

Types of Masks

Particle-filtering half masks consist mainly of filter material themselves. For reasons of hygiene they are intended to be used only once. Their protective effect corresponds to that of half masks with particle filters of the corresponding filter class. Half masks enclose the mouth and nose. Full face masks cover the entire face. They provide better protection than half masks as they fit more tightly to the face and also protect the eyes.

Fundamental Information on Filtering Devices

Limiting values have been laid down for hazardous materials which must not be exceeded in the workplace (NPF=Nominal Protection Factor). If the concentration of the substances is higher, protection is essential. Mode of Operation The principle of filtering devices is to free the air before inhalation from components which are hazardous to the health. To this purpose special filter materials are used which have to be adapted to the hazardous materials present. It is therefore important to know which hazardous materials the air contains. Period of Use The operational life of the filters depends on the filter class, the surrounding conditions (temperature, humidity, hazardous substance content ...) as well as the rate of breathing of the user. Gas filters are exhausted when the odour or taste of the gas becomes apparent; particle filters and particle-filtering half masks when the respiratory resistance noticeably increases.

Filter Types

Particle filters protect against dust, smoke, spray and mist, as well as micro-organisms, viruses and spores. Gas filters protect against gases and vapours, whereby these are subdivided into several categories, and the filters into the corresponding types. Combined filters are gas and particle filters in one. Multi-type filters include several types of gas filters, combined filters, combined gas and particle filters. For the subdivision into filter types and categories see the following tables:

Filter Type	Main Application (Type of Hazardous Material)	Categories	Colour Marking
A	Organic gases and vapours with boiling point >65 °C	1,2,3	Brown
AX	Organic gases and vapours with boiling point < 65°C of the low-boiling groups 1 and 2 (see official guideline)	-	Brown
B	Inorganic gases and vapours such as: hydro-cyanic acid (hydrogen cyanide), chlorine, hydrogen sulphide, but not against carbon monoxide	1,2,3	Grey
E	Acidic gases such as hydrogen chloride (hydrochloric acid vapours) and sulphur dioxide	1,2,3	Yellow
K	Ammonia and organic ammonia derivatives	1,2,3	Green
SX	Special gases as stated on the filter	-	Violet
NO	Oxides of nitrogen (e.g.: NO, NO2, NOx,)	-	Blue
Hg	Mercury vapour and mercury compounds	-	Red
Reaktor	Radioactive iodine including iodomethane	-	Orange
CO	Carbon monoxide	-	Black
P	Particles	1,2,3	White

Classification of the Gas Filters
Class:	1	2	3
Capacity:	low	medium	high

Higher Capacity:
--> longer service life with same gas concentration
--> can be used for higher pollutant concentrations

Classification of the Particle Filters
Class:	P1	P2	P3
Separation efficiency:	low	medium	high

Higher separation efficiency:
--> reduced leakage, i.e. higher protection
--> can be used for higher concentrations of hazardous materials