Selecting the Correct Respiratory Protective Equipment
Respiratory protective equipment such as masks and respirators can provide a protective barrier for workers, mitigating the risk of certain airborne contaminants and aerosols from entering respiratory systems. Masks can offer varying levels of protection dependent on factors such as fit, filtration capability, use and contaminants.
There are two standards in Australia that cover personal respiratory protection and risk management. The first is AZ/NZS 1715:2009 which covers the use and maintenance of RPE and provides employers and users with information on the basis of selection, use and maintenance of respirators. The second standard is AS/NZS 1716:2012 for respiratory protective devices which specifies the requirements, performance and testing criteria for the manufacture of respiratory protective devices (respirators) intended to provide protection against atmospheres containing substances that may be harmful if breathed and atmospheres that may be deficient in oxygen.
What are the Differences Between Respirator Masks?
Image Credit: RESP-FIT
When choosing a respirator, it is important to consider two key factors. The first is whether the respirator’s protection is adequate for the potential hazards. The second is whether the filter is suitable for airborne contaminants that the worker may be exposed to. Australian standards set out three classes of respirator masks; P1, P2 and P3. To ensure workers have access to the correct respirator, it is important to understand the differences between commonly found types.
Respirator Class
Application
Cloth Mask
Cloth masks are widely available in commercially made or homemade variants and are not certified according to a regulatory standard.
Surgical Mask
Surgical masks do not form a facial seal and thus do not offer protection from airborne contaminants, such as small particles, aerosols, gases or vapours. Commonly used in medical settings as they protect the wearer from splashes of body fluids such as blood. Surgical masks must be certified to Australian Standard 4381:2015.
P1 Face Mask
P1 respirators are certified as filtering 80% of airborne particles, such as dusts, grass clippings, and mould spores (>1μm in size).
P2 Face Mask
The P2 class is certified as filtering 95% of small airborne particles (>0.3 μm in size). This class is useful for filtering certain toxic dusts such as welding fumes and asbestos.
P3 Face Mask
P3 offers the highest protection to users and filters out 99.95% of particles (particles <0.3 μm in size). This class of respirators can be used for toxic dusts including fumes and asbestos, however, this level of protection is only achieved with a powered air-purifying respirator or a full-face respirator.
N95 Respirator
N95 conforms to US NIOSH standards and is similar to the Australian standard of P2 masks, however there are some minor differences.
Elastomeric Half-Face Respirator
Reusable masks that can allow users to replace filters. The half face variant covers the nose and face, protecting against gases, vapours, or particles when equipped with the appropriate filter.
Elastomeric Full-Face Respirator
Full face variants of elastomeric respirator masks that cover the face and eyes for eye protection.
Choosing the Right Respirator for Your Needs
The best respiratory protective equipment changes from application to application. Each class of mask has specific uses to ensure adequate protection against airborne hazards. It is important to consider the following factors when choosing a suitable respirator:
Work being conducted
Type of exposure hazard
Work environment
Level of protection required
Other environmental factors
Ensuring an Adequate Fit for Respiratory Protective Equipment
Respirator face masks – both half-mask and full-face - are designed to form a close seal around the nose and mouth when correctly fitted to protect users from airborne particles. To ensure that the seal is effective in protecting the user, fit testing with a respirator fit tester, such as the OHD QuantiFit 2, is an important practice that can ensure the expected level of protection is being provided.
Under Australian New Zealand Standard AS/NZS 1715, fit tests on tight-fitting respirators are required annually, with further fit tests are required when a worker wears a new size, style, model or make of face mask, as well as if there are significant facial changes that may affect fit.
There are a number of accepted and validated fit test methodologies, however, the three most common methodologies utilised to fit test respirators, that are also covered under the RESP-FIT.
Aerosol taste tests are subjective as the test requires a person to taste the selected challenge agent. If a person can't taste the aerosol when wearing a mask, then an acceptable fit has been achieved.
Controlled Negative Pressure (CNP), as utilised by the OHD QuantiFit 2 and Condensation Nuclei Counter (CNC) as utilised by the TSI PortaCount Respirator Fit Tester are able to accurately determine a higher fit factor than aerosol taste tests as both these methodologies are not subjective to the mask wearer.
Respirator masks are effective methods of protection. However, they are only as good as their fit. Masks with poor fits allow airborne contaminants to enter through the gaps between skin and material, leading to the potential for workers to breathe in harmful particles. Respirator fit testing is an important practice that ensures that respirators are protecting their users and providing an adequate seal.
Efficient Fit Testing with Controlled Negative Pressure
Quantitative fit tests can be conducted on any half-face or full-face tight-fitting respirator. The QuantiFit 2 is a cost-effective fit tester that utilises CNP technology to quantitatively determine the effectiveness of the seal to the wearer. The QuantiFit 2 can also increase the efficiency of fit testing programs onsite as it removes the requirement to test in a controlled environment, as well as removes the need for consumables. Available to be serviced and calibrated locally at Air-Met Scientific, the QuantiFit 2 leads to less equipment downtime, and reduced freight costs allowing for continual fit testing with minimal interruptions. OHD’s fit tester is available for sale and rental from Air-Met Scientific and is ideal for work sites looking to start fit testing employees or increase the efficiency of their current fit test program. Air-Met Scientific is the exclusive distributor for OHD Global in Australia.
