Respiratory Protection

Selection of Respiratory Protective Equipment

Respiratory Protective Equipment (RPE), like all other types of Personal Protective Equipment should be used in case technical or procedural measures can not totally exclude exposure to contamination in the ambient air, or the risk of oxygen deficiency. North Safet Products cannot be held liable for the incorrect use or choice of respiratory products. Suggestions on specific items will be made based on information from the user.

Respiratory Protection Equipment Can Be Divided Into Two Main Groups:

A. Filtering Respirators (dependent on the ambient air)

The air is cleaned when drawn through the filter. Respirators are not suitable for use in the IDLH environments including oxygen-deficient atmospheres.

Subdivision in this group

  • Negative pressure filtering devices for instance disposable-, half- and full face masks with filters
  • Positive pressure filtering devices for instance powered air hoods and masks.

B. Breathing (Independent on the ambient air)

The breathing air is supplied from an external source, f.i. compressed air or cylinders. BA may be suitable for use in IDLH environments including oxygen- deficient atmospheres.

Suitable Choice

Whether a filtering device or breathing apparatus is chosen, depends on criteria like oxygen content, nature and concentration of contamination, mobility of user and the required protection level. The level of protection is expressed in the Protection Factor. Note that filtering respirators should never be used in situations dangerous to life and health.

Protection Factor (PF)

The PF is a measure of the respirator efficiency and follows from the EN standard - it expresses its ability to protect against dangers. If the PF is 50 this means that the air inhaled through the respirator is 50 times cleaner than the surrounding air. The higher the PF, the better protection can be expected.

Occupational Exposure Limit (OEL)

Most individual hazardous substances have been assigned a concentration level, below which RPE is not necessary. Please refer to your local exposure limit sources for specific guidance.

In Practice The Protection (PF) Is Used As Follows:

The PF multiplied by the OEL gives the maximum allowed ambient concentration of the contaminant.

Note that in some European countries rules have been established that introduce a so called Assigned Protection Factor (APF). This APF is typically lower than the EN standard PF (Nominal Protection Factor).

PF (Protection Factor)
Multiplicator to find max allowed concentration.
NPF (Nominal Protection Factor)
PF that follows from the relevant EN Standard for the device.
APF (Assigned Protection Factor) PF relevant to national rules.
OEL (Occupational Exposure Limit)
Concentration connected to a certain chemical substance.

Due to the fact that the APF is not the same in all European countries, only the NPF is mentioned in the brochure.

Workplace Protection Factor

Multiply the stated figure by the TLV (Threshold Limited Value) of the contaminant you want protection against. Lists are published in each country to find TLV’s for most chemicals and aerosols. The value found (APF x TLV) is the maximum concentration the selected respiratory product can be used in.

Warning About Overuse of Filters

A gas filter is saturated as soon as the penetration of contamination is noticed by the odour or taste. The filter must then be replaced immediately! ABEK filters may not be used after one another in different gas environments. Always use a new filter!


FFP1 - Offers protection against inert dust such as dust from stone, plaster, grain.
FFP2 - Offers protection from harmful fine dust such as dust from metal, wood, glass fibre.
FFP3 - Offers protection from toxic fine dust such as from spores, colourants, bacteria.

When Is A Dust Filter Saturated?

A dust filter is saturated if the inhalation resistance increases notably. From a hygiene point of view our advice is: replacement daily.
Gas filters are saturated when you notice a change of smell or taste.

What is parts per million (PPM)?

The ratio of the amount of one substance to the amount of another, expressed as a unit of solute dissolved in one million units of solution. It denotes the number of units of one substance relative to one million units of another substance. It may be further expressed in terms of mass-to- mass, volume-to-volume, or another relationship of units of measure.

What is immediately dangerous to life or health (IDLH)?

The purpose for establishing this IDLH value was to determine a concentration from which a worker could escape without injury or without irreversible health effects in the event of respiratory protection equipmentfailure (e.g. contaminant breakthrough in a cartridge respirator or stoppage of air flow in a supplied-air respirator) and a concentration above which only “highly reliable” respirators would be required. In determining IDLH values, the ability of a worker to escape without loss of life or irreversible health effects was considered along with severe eye or respiratory irritation and other deleterious effects (e.g., disorientation or incoordination) that could prevent escape.

Classes and Marking of Filtering Devices

Particulate filter media is mostly a fine paper type material that filters liquid and solid aerosols. This media can not filter gasses and vapours. Gas/ vapour filter media is typically activated carbon, whereby porous carbon flakes bind the contaminant chemically. Activated carbon is chemically impregnated to improve binding of certain groups of chemicals. To clearly identify which filter media is used the different filter types are marked. The marking consists of a letter and a colour code.

Filter type Colour Code Application
Particulates (Aerosols)
Organic gasses and vapours with a boiling point > 65 C
Organic gasses and vapours with a boiling point < 65 C
Inorganic gases and vapours
Organic acids, acid gasses and generally gaseous acids
Mercury vapour
Carbon Monoxide
Reactor P3
Radioactive iodine, methyl iodide and radioactive particulates

Special Carbon

North uses top quality Carbon produced from coconut shells. After the activation process an average class 2 filter contains an extremely porous carbon that represent the surface of some 20 football fields.

Number Marking (Classification)

Particulate filters and devices are marked with the numbers 1, 2 or 3. This refers to the Protection Factors (see Table).

GAS FILTERS NEGATIVE PRESSURE (used with half or full face mask) (EN141)

Filter Class Maximum allowed concentration
1 (low) 0.1 percent by volume or 1000 p.p.m.
2 (medium) 0.5 percent by volume or 5000 p.p.m.
3 (high) 1.0 percent by volume or 10 000 p.p.m.

GAS FILTERS POSITIVE PRESSURE (used with powered air system) (EN12941/12942)

Filter Class Maximum allowed concentration
1 (low) 0.05 percent by volume or 500 p.p.m.
2 (medium) 0.1 percent by volume or 1000 p.p.m.
3 (high) 0.5 percent by volume or 5 000 p.p.m.

- Gas filters for Powered Air units are classified into three classes according to the absorption capacity.

- Combinations of filter media are possible. For instance an A2P3 filter is a commonly used filter.

No respiratory protection or using the wrong kind of respiratory protection for your application can be extremely dangerous or even fatal. North Safety Products offers a complete range of respiratory protection so that a ready-to-wear solution can be offered for any work situation. North’s respiratory protection can be broken down into the following groups: disposable APR masks, half masks, full- face masks, filters, powered air respirators and compressed airline systems.

Filter Selection Guide