Guide to fit testing respiratory masks
The correct fitting of respiratory protective equipment (RPE) is critical to ensure a tight seal is made around the face and the respirator is able to prevent exposure to contaminants.
However individual facial structure, facial hair such as stubble, beards, moustaches and sideburns, long hair, jewellery and makeup can all prevent a tight seal from being formed, meaning that regular fit testing is essential. When prescription glasses are worn in conjunction with RPE, both should be tested to ensure neither’s effectiveness is compromised.
Comfort is also important as it will encourage wear. A good respirator should provide a tight seal without being uncomfortable.
The Australian Standard AS/NZS 1715:2009 Selection, use and maintenance of respiratory protective equipment cautions against overtightening the respirator to achieve a tight seal because “the wearer may be unable to tolerate using the RPE for any length of time.”
Fit and seal testing
The Standard describes two types of respirator fit tests – qualitative and quantitative – that can be used to determine an adequate match between the facepiece of the RPE and face of the wearer.
It states that a qualitative or quantitative fit test should be performed before a respirator is used and then “at least annually or whenever there is a change in the wearer’s facial characteristics or other features which may affect the facial seal of the respirator”, such as weight changes, loss of teeth or when biological tests indicate exposure to a contaminant.
Furthermore, before each use, the respiratory protective equipment should be worn prior to the worker entering a contaminated area and a simple positive or negative pressure check performed by the user to check the fit. These are only suitable for tight-fitting respirators and “should be used only as a very gross determination of fit,” according to the Standard.
Commercial qualitative testing kits are available and while qualitative tests are fairly easily performed they are subjective to the user and so not necessarily reliable.
Quantitative test methods remove this subjectivity by using equipment to measure the efficiency of a respirator in preventing materials in the atmosphere from entering a user’s breathing zone.
Pro Choice Safety Gear recommends qualitative and quantitative respirator testing is carried out with the help of, or by a specialist who will determine a suitable approach tailored to your requirements.
However neither should substitute for pre-use positive and negative fit testing which are essential and will function as a simple backup seal assessment.
Negative pressure fit check:
When negative pressure fit testing disposable RPE, the Standard states the wearer should completely cover the filter with both hands or a non-permeable substance before inhaling sharply.
An adequate seal is indicated by the facepiece sinking onto the face while a poor seal is indicated by the feel of an airstream channelling through the leak.
Negative pressure fit testing reusable RPE requires the user to close off air supply and inhale gently. If the facepiece collapses slightly and remains that way, the RPE is probably well fitted, according to the Standard.
Positive pressue fit check (only suitable for close-fitting respirators)
Positive pressure fit testing of disposable RPE without exhalation valves requires the wearer to completely cover the filter with both hands or a non-permeable substance before exhaling sharply.
A poor seal is indicated by the feel of an airstream channelling through the leak – readjust the respirator mask.
When testing reusable RPE for positive fit, the wearer should close of the exhalation valve and exhale gently. If slight positive pressure can be built up inside the facepiece without any evidence of outward leakage, the seal is probably satisfactory.
The Standard recommends the wearer does not remove the exhalation valve cover when performing this test.
Silicone Half Mask Respirator with PressToCheck Filters
The Pro Choice Silicone Half Mask Respirator with PressToCheck Filters is a unique system, engineered to enable self-assessment of the Silicone mask’s seal for better protection every time.
PressToCheck is a personal, negative pressure fit test system that can be easily performed anywhere and anytime. However it does not replace a qualitative or quantitative fit test in accordance with AS/NZS1715.
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