How do we choose combined filters?

Type of filtering and absorbing equipment

Combined filter

The combined filter is only used in conjunction with a suitable face piece to constitute equipment with varying degrees of protection effectiveness. It should also meet the requirements of PN-EN 14387 + A1: 2008.

Filtering-absorbing half-mask

Filtering-absorbing half-masks, covering the nose, mouth and chin, are made entirely or mostly of filter-absorbing material or include a face-piece in which the absorber is an integral part of this equipment, and the filters may be replaceable. The requirements for the described equipment are specified in the PN-EN 405: 2005 standard.

Equipment with assisted air flow

This consists of a face piece in the form of a mask, half mask or quarter mask and a blower connected directly or by a flexible hose, worn by the user. Often this type of equipment is used in an environment with a temporary increase in pollution. Filtering and absorbing equipment with airflow support should meet the requirements of PN-EN 12942: 2002 / A2: 2008.

Equipment with forced air flow

It is a face piece in the form of a hood or helmet, to which, by means of a blower, air is supplied through a purifying element (combined filter) and a flexible hose. The equipment should meet the requirements of the PN-EN 12941: 2002 / A2: 2008 standard.

General rules for the selection of filtering-absorbing equipment

We select filtering-absorbing equipment according to the rules relating to:

• filtering equipment, i.e. depending on the aerosol concentration - using the multiplicity of exceeding the TLV value of a given substance
• absorbing equipment, ie depending on the type of gas and / or vapor present in the air at the workplace and their volumetric concentration.

The protective class of the equipment is determined on the basis of the protection factor NPF. The nominal protection factor is equal to the reciprocal of the total inward leakage and is a unitless quantity defining the fold reduction in the concentration of a hazardous substance under the face-piece of the equipment due to the applied protection.

You should also remember to define the minimum value of the MPF protection factor, which determines the relation of the concentration of a hazardous substance to its permissible TLV values.

After determining the protection class and the type of filtering equipment, we select the absorbing equipment, paying attention to:

• type of gas and / or vapor in the air at the workplace (type of equipment),
• gas and / or vapor volume concentration in the atmosphere of the working environment (equipment class).

The protection class of the absorber / half-mask is a measure of the effectiveness of the absorbing equipment:

• Class 1 - equipment with low sorption capacity, used to protect the respiratory system against vapors and / or gases, provided that their total concentration does not exceed 0.1% vol.
• Class 2 - equipment with medium sorption capacity, used to protect the respiratory system against vapors and / or gases, provided that their total concentration does not exceed 0.5% vol.
• Class 3 - equipment with high sorption capacity, used to protect the respiratory system against vapors and / or gases, provided that their total concentration does not exceed 1.0% vol.

Marking of filtering absorbent equipment

The method of marking the filter

The marking should be placed directly on the filter housing or on a brown-white label attached to the combined filter.

Additionally, the equipment may contain information on:

• a label indicating whether the combined filter is intended for connection with dual filter equipment,
• the year and month of expiry of the shelf life,
• dated European standard number,
• identification of the producer, supplier or importer,
• reference to the information provided by the manufacturer in the form of the sentence: "see manufacturer's information" or the corresponding graphic symbol,
• the manufacturer's model designation.

Such marking consists of:

• the letters FFA denoting an absorbing half-mask designed to protect against organic gases and vapors of organic substances specified by the manufacturer, the boiling point of which is higher than 65 ° C
• the letter P for filt and / or
• the letter D, which means that the half-mask meets the requirements of the dolomite dust clogging test
• other information, such as: the marking identifying the producer or distributor,
• a mark identifying the type, number and year of this European Standard

The marking of filter-absorbing equipment with air flow assistance consists of:

• letters TM,
• digits 1, 2, 3 - strength of hoses and connections + element for combined filter
• other information, which is included in the labeling of the combined filter

The marking of filter-absorbing equipment with forced air flow consists of:

• the letters TH
• numbers 1, 2, 3 - hoses and connections strength + element for combined filter
• other information, which is included in the labeling of the combined filter