#ETprotec
Filters Don't
Last Forever
Understand the importance of their replacement.
Important: the selection of filters should be carried out by a competent person with full knowledge of the respiratory risks in the workplace.
There are Several Types of Filters. Which Ones?
Particle Filters
Only protect against particles, such as dust, vapors, and fumes, aerosols, molds, bacteria, etc.
Gas and Vapor Filters
Only protect against gases and vapors. For various types of gases, there are different types of gas and vapor filters.
Combined Filters
Protect against particles and gases. Different combinations of gas, vapor, and particle filters are used, depending on the gas or vapor present in the air.
Particle Filters
Particle Filters
HOW DO THEY WORK?
A layer of randomly arranged fibers is used to create a filter.Treated fibers are used to attract and trap particles as they flow through the filter material. Increasing the thickness and capture efficiency of the filter material improves the filter’s efficiency in retaining particles. Particle filters are tested according to the EN 143 standard. According to the physical theory of particle capture, the most difficult size range to retain corresponds to particles with an equivalent diameter of 0.02-0.2 microns and a mass median diameter of approximately 0.3 to 0.6 μm. The particle filter is tested with a sodium chloride test aerosol consisting mainly of particles of this size.
COMMON FILTRATION MECHANISMS:
1.
Capture by interception
2.
Inertial impaction
3.
Capture by diffusion
4.
Electrostatic attraction
Particle filters designed for respiratory protection capture particles of all sizes; the main difference is the relative performance in the range between ~0.1 and 1 μm.
Each class of filters must perform above a certain level concerning the test aerosol and then be classified according to EN 143.
EN 143 uses a classification system to identify the particle filtering efficiency in P1, P2, P3.
Particle filters are classified according to their filtering efficiency. There are three classes of particle filters: P1, P2, and P3 in increasing order of filtering efficiency.
- A P1 filter must have a filtering efficiency of at least 80% concerning the most penetrating particle size (0.3 to 0.6 μm).
- A P2 filter filters at least 94% of particles, including those of the most penetrating size.
- The P3 filter must have a filtering efficiency of at least 99.95% concerning the most penetrating particle size.
As particle filters become loaded with contaminants, the passage of particles becomes increasingly limited, resulting in more intensive filtering.
However, in these situations, it is much more difficult to breathe. The user will notice an increase in breathing effort and at some point will realize that the restriction is quite high and that the filter needs to be replaced.
The moment this happens varies depending on the amount of particles in the inhaled air.
A workplace with a high level of dust will obviously clog the filter faster than a relatively clean workplace.
The decision to replace the filter can vary from person to person, as some people are more sensitive to increased breathing load than others.
3M particle filters should be replaced when:
- The breathing resistance is too high for the user (varies from person to person).
- The filter is damaged.
- It becomes unhygienic, i.e., if the user coughs/sneezes and the interior is in an unacceptable state.
- Some workplaces, for example, healthcare environments, require the replacement of masks/filters after each use due to infection control procedures.
There are several situations where particle filters should NOT be used:
- When it is not guaranteed that the oxygen level in the environment is >19.5%. Filters do not generate oxygen.
- For capturing gases or vapors, as a specifically rated gas/vapor filter is required.
- When the concentration of contaminant particles in the air is high, i.e., above the standard for the type of device in question.
- When local regulations require the use of another type of equipment for specific applications.
Gas and Vapor Filters
HOW DO THEY WORK?
3M manufactures gas and vapor filters to reduce user exposure to various types of gases and vapors.
These filters use a material that absorbs gas and vapor molecules. Generally, the absorbent is carbon grain with specific treatment. Depending on the chemical treatment of the carbon surface, this material will absorb different types of gases or vapors.
Activated carbon is generally obtained from coal or renewable resources such as wood or coconut shells. It can be “activated” by heating the material in nitrogen or steam at temperatures of approximately 800 – 900°C. The resulting material has a considerable number of micropores that aid in the absorption of various organic vapors. These micropores can be measured and optimized for specific needs and performance.
EN 14387 uses a classification system to identify the different types of contaminants that these treated carbon grains capture, for example, A, AX, B, E, K, and Hg.
THE PROCESS
When gases and vapors pass through an organic vapor filter, the air is filtered as the vapors condense in the carbon pores. The vapors move through the filter from one pore to another. This occurs more rapidly in small volatile vapors with lower boiling points (e.g., acetone). Some migration of organic vapors may occur even during storage, so this should be considered before reusing the filter. The effective life is the time until vapors start to exit the filter.
Unlike particle filters, the lifespan is not indicated due to changes in breathing resistance. Instead, filters should be replaced according to local regulations; or if irritation occurs due to the contaminant; or as calculated by the 3M™ service life software, whichever comes first.
By itself, activated carbon cannot absorb other types of gases or vapors, such as acid gases, ammonia, formaldehyde, etc. In some cases, additional metals and salts are introduced to the carbon to selectively remove these compounds. For this reason, 3M offers a diverse set of filters and masks that help protect workers in different environments and match personal preferences.
The EN 14387 standard uses a classification system to identify the different types of contaminants that these filters capture. 3M filters follow this marking and color coding system.
Gas and vapor filters are classified according to their absorbent capacity.
According to the level of increased capacity, the classifications are: Class 1, 2, or 3. This means there are filters of type A1 or B2 or multigas, such as an A2B2E2K1.
The service life (i.e., durability) of any gas and vapor filter is affected by many factors: concentration and nature of contaminants, breathing frequencies, humidity levels, ventilation, temperature, type of carbon, etc.
- Concentration by exposure
- Temperature
- Humidity (water vapor occupies the space of the carbon pores)
- Breathing frequency
- Filter class
To obtain an estimate of the service life of 3M gas and vapor filters, the 3M™ service life indicator software allows calculating the estimated service life under respective working conditions.
- The expiration date indicated on the sealed package has expired.
- If odor or taste is noticed and/or when the user coughs or feels discomfort. These are indicators that the filters are not being replaced frequently enough and the filter replacement schedule needs to be adjusted. Smell should not be considered a primary indicator.
- According to the established filter replacement schedule.
ALSO KNOW...
TO AVOID THE ODOR OR TASTE OF THE CONTAMINANT WHEN USING 3m™ GAS AND VAPOR FILTERS, FOLLOW THESE STEPS:
- Check the expiration date on the back of the filter at the time of first use.
- Write the date on the filters when using them for the first time.
- Use the filters in the normal work environment.
- Replace the filter immediately when the odor or taste of the contaminant is detected.
- Take note of the durability of the filters compared to the date recorded on the filter and the current date.
- If work practices remain the same and vapor/gas levels are consistent, replace filters at more regular intervals.
- Or according to the established filter change schedule.
ARE THERE SITUATIONS WHERE GAS AND VAPOR FILTERS SHOULD NOT BE USED?
- When there is no guarantee that the oxygen level is> 19.5%.
- When the goal is to capture particles, such as dust, mists, fumes, or fibers.
- When the contaminants present cannot be captured by the gas and vapor filter.
- When the concentrations of polluting gases and vapors in the air are very high.
- When local regulations require the use of another specific type of device for certain situations.
What is a Filter Replacement Schedule?
A filter replacement schedule is a specific period after which the chemical filter must be replaced. This period can be defined based on the estimated service life of the filter, workplace conditions, among other factors such as contaminant concentration, relative humidity, temperature, work activities, respiratory PPE usage pattern (e.g., continuous or intermittent use), presence of other materials, potential for contaminant migration/desorption, effects of gases or vapors on health, and quality of warning signals, if they occur. The filter replacement schedule should be based on objective information that ensures gas and vapor filters are replaced before the end of their service life. The purpose of a replacement schedule is to establish the time period for filter replacement. The data and information used to establish the schedule should be included in the respiratory protection program.
FAQ
As long as they are sealed in the original packaging, filters last between three to five years (depending on the product) from the date of manufacture.
When not in use, 3M™ masks and filters should be kept clean and dry, away from oils, sunlight, and corrosive environments to prevent deterioration. For this purpose, a dedicated container or a sealable bag can be used.
In many situations, the effects of particles and gases/vapors are present at the same time. The particle filter removes small droplets or particles in the air (e.g., spray paint mists). Gas and vapor filters do not filter these particles. If a particle filter is not used, these may be inhaled.
- In the case of particle filters or masks, whenever the breathing resistance becomes excessive for the user.
- When damage occurs, such as a damaged strap, a burnt hole in the mask, etc.
- When it becomes unhygienic, i.e., if the user coughs/sneezes and the interior is in an unacceptable state.
- In the case of combined filters (particles and gases and vapors), the capacity of each type of filter will depend on the concentrations present in the air; these will become saturated at different rates and will need to be replaced, probably at different times from each other.
- The service life (i.e., durability) of any gas and vapor filter is affected by many factors: capacity, concentration and nature of contaminants, breathing frequency, humidity levels, ventilation, temperature, type of carbon, etc.
- Some workplaces, for example, healthcare environments, require the replacement of masks/filters after each use due to infection control procedures.
There is No Specific Time for Replacement, and the Frequency Varies Depending on the Type of Work, Situation, and Filter.
Each Workplace Has its Own Characteristics and should be Evaluated According to its Specificity to Define an Appropriate Filter Replacement Program.
MONITORING
It is important to know the contaminant and specific exposure levels to determine the appropriate mask and filter for the work environment.
Standards and Regulations
- Regulation (EU) 2016/425, of March 9, 2016, covers the design, manufacture, and marketing of personal protective equipment.
- Directive 89/656/EEC, of November 30, 1989, relates to the minimum safety and health requirements for the use of personal protective equipment at work.- EN 529 is a standard designated as “Respiratory Protective Devices – Recommendations for Selection, Use, Maintenance, and Storage” that can serve as a guide in the selection, cleaning, and maintenance of respiratory protective devices.
- EN 136: Respiratory Protective Devices. Full masks EN 140: Respiratory Protective Devices. Half masks and quarter masks.
- EN 143: Respiratory Protective Devices. Particle filters. EN 405: Respiratory Protective Devices.
- Half-mask respirators with valves for protection against gases or against gases and particles.
- EN 14387: Respiratory Protective Devices. Gas filters and combined filters.
