Before deciding to use respiratory protective equipment, consider whether or not certain air pollution by dangerous substances can be avoided, e.g., through the use of less hazardous substances or air ventilation to reduce the pollution level below the limit. Respiratory protective equipment should always be used as a last resort.
Respirators must be used when the breathing air is polluted or whenever contamination with particles, gases, fumes or smoke in concentrations exceeding the maximum level is suspected. Respiratory protective equipment must also be used if the oxygen content in the air is below 17% by volume. Before any work commences, respiratory protective equipment users must have thorough theoretical and practical knowledge in the use and maintenance of such equipment. We recommend that employees be fit tested.
we have a 3 hour rule in Denmark? Using respiratory protection equipment is a burden for the body. Therefore, the duration of use is limited for some types of equipment. Filtering respiratory protection, where the user breaths through a filter, may only be used 3 hours per day. If the job is expected to take longer, the user must use a respiratory protection with a turbo unit or a self-contained breathing apparatus.
The protection factor indicates how many times the respiratory protective equipment can reduce the concentration of harmful substances inside the mask in relation to the concentration in the surrounding environment. For example, if the contamination is 400 mg/m3 and the respiratory protection of the respiratory protective equipment is 200, the contamination in the air inhaled will be 2 mg/m3.
This protection factor is measured in ideal conditions by laboratory testing and is called the nominal protection factor. The actual protection factor will decrease considerably over time due to wear, ill fitting etc. It is therefore important to take these factors into account when choosing respiratory protective equipment. Fit testing ensures high protection.
Respiratory protective equipment must be used from the commencement of the work and during the whole time a person is in the contaminated area. Even a short stay without respiratory protective equipment will significantly reduce the expected protection.
The particle filters for half- and full-face masks are divided into 3 categories (P1, P2 and P3), which are an expression of their ability to filter dust, mists and aerosols. Colour code: White. Some filters protect against all particle types such as smoke, asbestos, bacteria, viruses and even radioactive fallout. The highest category P3 covers both P1 and P2. The particle filters must be exchanged when the user notices increased breathing resistance.
|P1 R/NR*||Solid and wet particles||80%|
|P2 R/NR*||Solid and wet particles||94%|
|P3 R/NR*||Solid and wet particles||99.95%|
”R” = Recyclable. ”NR” = Not recyclable.
Similarly, the gas filters for half- and full-face masks are divided into 3 categories based on capacity and concentration.
|1||0.1 percent by volume = 1000 ppm*|
|2||0.5 percent by volume = 5000 ppm*|
|3||1.0 percent by volume = 10000 ppm*|
*ppm = part per million
The expected protection factor at 100% service life is specified for each respiratory protective equipment certification class. The protection factor indicates how many times the air inside the mask is cleaner. If the actual useful life of the respiratory protective equipment decreases, the actual protection factor will drop dramatically! See the table below. Generally speaking, it does not matter what type of respiratory protective equipment will be used in case of a useful life of 80%. The protection factor will be almost the same!
|Percent of the working time in contaminated environment where respiratory protective equipment is used. 100 % means that respiratory protective equipment is used at all times.||100%||95%||90%||80%||Example of respiratory protective equipment|
|Effective protection factors||25||11.40||7.40||4.30|
|1000||19.60||9.90||4.98||Blast cleaning helmet with air supply|
According to the general guidelines for choosing respiratory protective equipment, the following must be selected:
|Filtering half masks with replaceable filters|
|Filtering full-face masks with replaceable filters|
|Filtering respiratory protective equipment with turbo unit|
|Self-contained breathing apparatus|
Depending on the ambient atmosphere.
|AGAINST PARTICLES||AGAINST GASES & VAPOURS||AGAINST PARTICLES, GASES & VAPOURS|
|Face mask with particle filter||Face mask with gas filter||Face mask with combi filter|
|Face mask filtering particles||Face mask filtering gases and vapours||Face mask filtering particles, gases and vapours|
|Filtering turbo unit with particle filter||Filtering turbo unit with gas filter||Filtering turbo unit with combi filter|
|INDEPENDENT RESPIRATORY PROTECTION||DEPENDENT RESPIRATORY PROTECTION|
|Fresh air hose breathing apparatus||Compressed-air line breathing apparatus||Self-contained open-circuit air breathing apparatus||Self-contained close-circuit air breathing apparatus|
|Without blower||With continous air supply||With automatic lung with normal pressure||With compressed oxygen|
|With manually-driven blower||With automatic lung||With automatic lung with overpressure||With liquid oxygen|
|With moter-driven blower||With automatic lung with overpressure||With oxygen expansion|
Will gradually clog because of the particles accumulated in the filter. Therefore, the service life depends on the concentration of pollutants in the air. The filter has to be replaced when breathing resistance has become so great that it feels burdensome. Particle filters are ineffective for gases and lack of oxygen!
Consist of activated carbon with a very large surface. 1 gram has a surface of 1200 m2. The gases are adsorbed by the activated carbon without any major change in breathing resistance. A gas filter has a certain capacity depending on the amount of carbon it contains (class 1, 2 or 3). The useful life of gas filters can be calculated using the pollution concentration, the user's air requirement and the filter capacity. This calculation is very uncertain as it includes many variables. When the filter is almost used up, leakage will gradually increase. The filter should be replaced before leakage occurs. The contamination must not be smelled so the filter has to be replaced before odour can be detected. To ensure that the replacement is done in time, develop regular experience-based routines. Gas filters are ineffective for particles and lack of oxygen.
If simultaneous protection gas and particle protection is needed, combi or multiple filters must be used. The useful life is described above in particle or gas filters.