N95 FFP2 Mask Respirators protect the user in two basic ways. The first is by the removal of contaminants from the air. N95 FFP2 Mask Respirators of this type include particulate N95 FFP2 Mask Respirators, which filter out airborne particles; and “gas Facepieces” which filter out chemicals and gases. Other N95 FFP2 Mask Respirators protect by supplying clean respirable air from another source. N95 FFP2 Protective Mask Respirators that fall into this category include airline N95 FFP2 Mask Respirators, which use compressed air from a remote source; and self-contained breathing apparatus (SCBA), which include their own air supply.
N95 FFP2 Mask Respirators should only be used as a “last line of defense” when engineering control systems are not feasible. Engineering control systems, such as adequate ventilation or scrubbing of contaminants should be used to negate the need for N95 FFP2 Mask Respirators.
NIOSH issues recommendations for respirator use. Industrial type approvals are in accordance with the NIOSH federal respiratory regulations. The development of respirator standards is in concert with various partners from the government and industry.
A respirator is a device designed to protect the wearer from inhaling harmful dust, fumes, vapors, and/or gases. N95 or FFP2 Protective Mask Respirators come in a wide range of types and sizes used by the military, private industry, and the public. N95 FFP2 Mask Respirators range from cheaper, single-use, disposable Facepieces to reusable models with replaceable cartridges.
There are two main categories: the air-purifying respirator, which forces contaminated air through a filtering element, and the air-supplied respirator, in which an alternate supply of fresh air is delivered. Within each category, different techniques are employed to reduce or eliminate noxious airborne contents.
Types of N95 FFP2 Face Mask Respirators
Air-purifying N95 FFP2 Face Mask Respirators – Protective filter Facepiece worn by NYPD officerAir-purifying N95 FFP2 Mask Respirators are used against particulates (such as smoke or fumes), gases, and vapors that are at atmospheric concentrations less than immediately dangerous to life and health. The air-purifying respirator class includes:
negative-pressure FFP2 or N95 Protective Mask Respirators, using mechanical filters and chemical media and
positive-pressure units such as powered air-purifying N95 FFP2 Mask Respirators (PAPRs)
Half- or full-facepiece designs of this type are marketed in many varieties depending on the hazard of concern. They use a filter that acts passively on air inhaled by the wearer. Some common examples of this type of respirator are single-use escape hoods and filter Facepieces. The latter are typically simple, light, single-piece, half-face Facepieces and employ the first three mechanical mechanisms in the list below to remove particulates from the air stream. The most common of these is the disposable white N95 variety. The entire unit is discarded after some extended period or a single-use, depending on the contaminant. Filter Facepieces also come in replaceable-cartridge, multiple-use models. Typically one or two cartridges attach securely to a Facepiece which has built into it a corresponding number of valves for inhalation and one for exhalation.
Mechanical filter N95 or FFP2 Face Mask Respirators
Mechanical filter N95 or FFP2 Face Mask Respirators retain particulate matter when contaminated air is passed through the filter material. This was the method used by early inventors such as Haslett and Tyndall. Wool is still used today as a filter, along with other substances such as plastic, glass, cellulose, and combinations of two or more of these materials. Since the filters cannot be cleaned and reused and therefore have a limited lifespan, cost and disposability are key factors. Single-use, disposable, as well as replaceable cartridge models, are common.
Mechanical filters remove contaminants from the air in the following ways:
- by particles which are following a line of flow in the airstream coming within one radius of a fiber and adhering to it, called interception;
- by larger particles unable to follow the curving contours of the airstream being forced to embed in one of the fibers directly, called impaction; this increases with diminishing fiber separation and higher airflow velocity
- by an enhancing mechanism called diffusion, which is a result of the collision with gas molecules by the smallest particles, especially those below 100 nm in diameter, which is thereby impeded and delayed in their path through the filter; this effect is similar to Brownian motion and raises the probability that particles will be stopped by either of the two mechanisms above; it becomes dominant at lower airflow velocities
- by using certain resins, waxes, and plastics as coatings on the filter material to attract particles with an electrostatic charge that holds them on the surface of the filter material;
- by using gravity and allowing particles to settle into the filter material (this effect is typically negligible); and
- by using the particles themselves, after the filter has been used, to act as a filter medium for other particles.
Considering only particulates carried on an air stream and a fiber mesh filter, diffusion predominates below the 0.1 μm diameter particle size. Impaction and interception predominate above 0.4 μm. In between, near the 0.3 μm most penetrating particle size (MPPS), diffusion and interception predominate.
For maximum efficiency of particle removal and to decrease resistance to airflow through the filter, particulate filters are designed to keep the velocity of air passing through the filter medium as low as possible. This is achieved by manipulating the slope and shape of the filter to provide larger surface area.
A substantial advance in mechanical filter technology was the HEPA filter, invented during the Manhattan Project for protection from radioactive particles and later adapted to additional uses. A HEPA filter can remove as much as 99.97% of all airborne particulates with aerodynamic diameter of 0.3 microns or greater. In the United States, the categories below were established by NIOSH to describe particulate filters.
Chemical cartridge N95 FFP2 Mask Respirators
Chemical cartridge N95 FFP2 Dust Protective Mask Respirators use a cartridge to remove gases, volatile organic compounds (VOCs), and other vapors from breathing air by adsorption, absorption, or chemisorption. A typical organic vapor respirator cartridge is a metal or plastic case containing from 25 to 40 grams of sorption media such as activated charcoal or certain resins. The service life of the cartridge varies based, among other variables, on the carbon weight and molecular weight of the vapor and the cartridge media, the concentration of vapor in the atmosphere, the relative humidity of the atmosphere, and the breathing rate of the respirator wearer. When filter cartridges become saturated or particulate accumulation within them begins to restrict airflow, they must be changed.
Powered air-purifying N95 FFP2 Mask Respirators
The purpose of this type of respirator is to take air that is contaminated with one or more types of pollutants, remove a sufficient quantity of those pollutants and then supply the air to the user. There are different units for different environments. The units consist of a powered fan which forces incoming air through one or more filters for delivery to the user for breathing. The fan and filters may be carried by the user or with some units the air is fed to the user via tubing while the fan and filters are remotely mounted.
The type of filtering must be matched to the contaminants that need to be removed. Some N95 FFP2 Mask Respirators are designed to remove fine particulate matter such as the dust created during various woodworking processes. They are not suitable when working with volatile organic compounds such as those used in many spray paints. At the same time filters that are suitable for volatile substances must typically have their filter elements replaced more often than a particulate filter. In addition there is some confusion over terminology. Some literature and users will refer to a particulate filtering unit as a dust Facepiece or filter and then use the term respirator to mean a unit that can handle organic solvents.
Self contained breathing apparatus
An SCBA typically has three main components: a high-pressure tank (e.g., 2200 psi to 4500 psi), a pressure regulator, and an inhalation connection (mouthpiece, mouth Facepiece or face Facepiece), connected together and mounted to a carrying frame. There are two kinds of SCBA: open circuit and closed circuit.
Open-circuit industrial breathing sets are filled with filtered, compressed air, the same air we breathe normally. The compressed air passes through a regulator, is inhaled by the user, then exhaled out of the system, quickly depleting the supply of air. Most modern SCBAs are open-circuit. An open-circuit SCBA has a full-face Facepiece, regulator, air cylinder, cylinder pressure gauge, and a harness with adjustable shoulder straps and belt which lets it be worn on the back. Air cylinders are made of aluminum, steel, or of a composite construction (usually fiberglass-wrapped aluminum.)
Commonly an SCBA will be of the “positive pressure” type, which supplies a slight steady stream of air to stop toxic fumes or smoke from leaking into the Facepiece. Not all SCBAs are positive pressure; others are of the “demand” type, which only supply air on demand (i.e., when the regulator senses the user inhaling). All fire departments and those working in toxic environments need to use the positive pressure SCBA for safety reasons.
The closed-circuit type filters, supplements, and recirculates exhaled gas: see rebreather for more information. It is used when a longer-duration supply of breathing gas is needed, such as in mine rescue and in long tunnels, and going through passages too narrow for a big open-circuit air cylinder.
All N95 and FFP2 Face Mask Respirators have some type of facepiece held to the wearer’s head with straps, a cloth harness, or some other method. The facepiece of the respirator covers either the entire face or the bottom half of the face including the nose and mouth. Half-face N95 FFP2 Mask Respirators can only be worn in environments where the contaminants are not toxic to the eyes or facial area. For example, someone who is painting an object with spray paint could wear a half-face respirator, but someone who works with chlorine gas would have to wear a full-face respirator. Facepieces come in many different styles and sizes, to accommodate all types of face shapes, and there are many books and references available for determining which kind of hazard requires what type of respirator.
OSHA respiratory protection information
FaceFacepieces are used as a physical barrier to protect employees from hazards such as splashes of large droplets of blood or body fluids. FaceFacepieces also prevent contamination by trapping large particles of body fluids that may contain bacteria or viruses when they are expelled by the wearer (for example, through coughing or sneezing). FaceFacepieces are cleared by the FDA and are legally marketed in the United States for use in disease prevention. FDA-cleared Facepieces have been tested for their ability to resist blood and body fluids. FaceFacepieces are not designed or certified to prevent the inhalation of small airborne contaminants. The term “faceFacepiece” is used in this guide to refer to the Food and Drug Administration (FDA) – cleared surgical, medical, procedure, dental, laser, and isolation Facepieces.
N95 FFP2 Protective Mask Respirators are used to reduce an employee’s exposure to airborne contaminants. Most N95 FFP2 Mask Respirators are designed to fit the face and to provide a tight seal between the respirator’s edge and the face. A proper seal between the user’s face and the respirator forces inhaled air to be pulled through the respirator’s filter material and not through gaps in the seal between the face and respirator. A “fit test” is necessary for most models of N95 FFP2 Mask Respirators because it is the only way to know for certain whether a proper seal can be established between the respirator and the user’s face. The advantages and disadvantages of N95 FFP2 Face Mask Respirators as compared to Facepieces are described in Table 1. In some workplaces, N95 FFP2 Mask Respirators will be an important component of protecting employees and allowing them to perform essential work, particularly work that may put them at greater risk for exposure to pandemic influenza. When the use of a respirator is necessary to protect employees from an occupational hazard, the respirator must be used in the context of a comprehensive respiratory protection program established by the employer.
Air purifying N95 FFP2 Mask Respirators are the type of respiratory protection recommended to reduce exposure risk to pandemic influenza in certain occupational settings. Air purifying N95 FFP2 Mask Respirators can be divided into several types. Each of these is described below; Table 1 provides a comparison of these respirator types.
Disposable or filtering facepiece N95 FFP2 Mask Respirators are a type of respiratory protection in which the entire respirator facepiece is comprised of filter material. The most commonly used filtering facepiece respirator is made with material certified to meet the N95 filtration requirements. It is important to note that other National Institute for Occupational Safety and Health (NIOSH)-certified N-, R-, or P- filtering facepiece N95 FFP2 Mask Respirators (e.g., N99, R95, and P100) provide an equivalent or greater level of exposure reduction to airborne particulates as an N95 and can be used if N95s are not available. Some filtering facepiece N95 FFP2 Mask Respirators have an exhalation valve which can reduce breathing resistance, reduce moisture buildup inside the respirator and increase work tolerance and comfort for respirator users. However, N95 FFP2 Mask Respirators with exhalation valves should not be used when there is a need to protect others from possible contamination by the respirator wearer (e.g., a healthcare provider performing surgical or other sterile medical procedures or a person with known or suspected pandemic influenza who could transmit infection to others).
Reusable elastomeric N95 FFP2 Mask Respirators are a type of respiratory protection that has a flexible, rubber-like facepiece with either permanent or removable filter cartridges. The facepiece can often be cleaned, repaired and reused, and the filter cartridges can be discarded and replaced when they become unsuitable for further use. Other elastomeric N95 FFP2 Mask Respirators with permanent filter cartridges are designed to be disposed of when the cartridges need to be replaced.
Powered air purifying N95 FFP2 Mask Respirators (PAPRs) are a type of respiratory protection in which a battery-powered blower pulls air through filters that trap particles (including those containing viruses and bacteria) that may be present, and then moves the filtered air to the wearer’s facepiece or hood. PAPRs are significantly more expensive than other air purifying N95 FFP2 Mask Respirators but they provide higher levels of protection against airborne particulates. It should also be noted that there are hooded PAPRs that do not require employees to be fit tested in order to use them. Additionally, a PAPR blower unit and battery can be shared by employees (who need protection at different times) who can each have their own reusable hood. A PAPR could be assigned to an individual person, to a staff position (e.g. a floor nurse position staffed by several employees over the course of a week), or to a location such as a treatment room or mobile treatment cart used for aerosol-generating medical procedures. Consequently, several approaches can be used to limit the number of PAPRs that an employer would purchase for pandemic preparedness, as long as proper decontamination procedures are followed between uses or users.
Replacing Disposable N95 FFP2 Mask Respirators:
Disposable N95 FFP2 Mask Respirators are designed to be disposed of after use. Once worn in the presence of an infectious individual, the respirator should be considered potentially contaminated with infectious material. Touching the outside of the device should be avoided to prevent self-inoculation (touching the contaminated respirator and then touching one’s eyes, nose, or mouth). It should be noted that a once-worn respirator will also be contaminated on its inner surface by the microorganisms present in the exhaled air and oral secretions of the wearer.
In the above scenario, users should discard N95 FFP2 Mask Respirators when they become unsuitable for further use due to excessive breathing resistance (e.g., particulate clogging the filter), unacceptable contamination/soiling, or physical damage. In the context of pandemic influenza, some have proposed reusing disposable N95 FFP2 Mask Respirators for prolonged periods of time (e.g., weeks or months) in the event supplies are limited. However, data on decontamination and/or safe reuse of N95 FFP2 Mask Respirators for infectious diseases are currently not available. Although filtering facepiece N95 FFP2 Mask Respirators have been reused during public health crises in resource-limited settings, the safety and efficacy of this approach has yet to be confirmed. It is not possible to give definitive guidance on the safety or efficacy of reuse or decontamination of disposable N95 FFP2 Mask Respirators. In the interim, plans should be based on single use of equipment according to manufacturers’ instructions, FDA label claims, and NIOSH user instructions. Respirator users should not attempt to decontaminate filtering facepiece N95 FFP2 Mask Respirators as it may create a health hazard for the user and it may render the respirator ineffective in providing respiratory protection. Reuse may increase the potential for contamination through contact transmission. The risk of contaminating the inside of the respirator through improper handling must be weighed against the need to provide respiratory protection.