What is fit testing?


Health and safety specialist, Shawcity – a distributor of the OHD QuantiFit2 CNP Fit Testing system in the UK and Ireland – explains what respiratory protective equipment fit testing is, and outlines its significance.

For obvious reasons, there has been a lot of discussion in recent months regarding the different types of respiratory protective equipment (RPE) and how to wear them correctly. There is also growing momentum to switch from disposable respirators to reusable ones; for economic and sustainability reasons.

RPE such as disposable filtering face pieces (FFPs), reusable half-masks and full-face masks have been standard pieces of protective equipment within many working environments for years. However, according to the British Safety Industry Federation (BSIF), research indicates that a significant amount of the RPE in use does not offer the user the expected level of protection because it does not fit properly.

People come in various shapes and sizes, so there is no ‘one size fits all’ solution. If the RPE leaks, it may be down to poor fit, so ensuring it is properly assessed for each individual is a vital and legally required step in the UK. This process is known as fit testing.

Who regulates fit testing?
RPE fit testing is the subject of The Health and Safety Executive’s (HSE) INDG 479 guidance document, and a competent person must carry it out.
Working closely with the HSE, the BSIF developed the Fit2Fit Accredited RPE Fit Test provider scheme to improve the health of those wearing tight-fitting RPE by providing a list of accredited and competent providers. The list shows the tester’s geographic location, the area they cover and the methods of fit testing they have been accredited against.

Who needs a fit test?
A fit test should be carried out on any individual who is required to wear tight-fitting RPE, which relies on a good seal between the mask and the wearer’s skin. The test should be carried out at the mask selection stage, before a particular type of respirator, whether a disposable mask, half mask or full mask, is used for the first time. A range of suitable mask options should be on offer for the wearer to try.
Respiratory devices that include a loose-fitting hood or constant-flow airline breathing apparatus do not need to be fit tested but separate appropriate measures should be taken to ensure it is being worn correctly.

How often should I fit test?
A fit test should be repeated whenever there is a change to the RPE type, size, model or material, or whenever there is a change to the circumstances of the wearer that could alter the fit of the RPE. These changes could include weight loss or gain, substantial dental work, facial changes (scars, moles, effects of ageing etc.) around the face seal area, facial piercings, introduction or change in other head-worn personal protective equipment (PPE).

The HSE does not stipulate a frequency of testing; however, the Fit2Fit RPE Fit Tester Provider Accreditation Scheme recommends that a suitable interval for repeat fit testing is two years. More frequent repeat fit testing may be appropriate in some situations, particularly where RPE is being used as a primary or sole means of control.

Is fit testing a legal requirement?
It is a legal requirement that workers using tight-fitting respiratory protective equipment (face pieces/masks) must be fit tested by a competent person.

The Health and Safety at Work Act 1974 and the Management of Health and Safety at Work Regulations 1999 require employers to provide and maintain a safe working environment. In addition to the COSHH Regulations 2002, RPE may need to be used to satisfy requirements in the following pieces of legislation:

• Control of Asbestos Regulations 2012
• Control of Lead at Work Regulations 2002
• Ionising Radiations Regulations 1999
• Confined Spaces Regulations 1997.

These Regulations are supported by Approved Codes of Practice (ACOPs), give practical guidance on compliance and have a special status in law. For RPE use that is not covered by any of the above Regulations, employers and employees have duties to follow under the Personal Protective Equipment at Work Regulations 1992.

Who can perform a fit test?
RPE fit testing should be conducted by a competent person who is appropriately trained, qualified and experienced in providing appropriate guidance to respiratory wearers. A list of Fit2Fit-accredited fit testers can be found at www.fit2fit.org.

A pre-use wearer seal check should be carried out each time a fit-tested facepiece is worn and before entering a hazardous environment. This check determines whether the wearer has correctly donned a facepiece before entering a contaminated work area. This pre-use seal check is not a substitute for a fit test.

Types of face-fit test
There are two types of RPE fit testing – qualitative and quantitative methods.
Qualitative fit testing (QLFT) is a pass/fail test based on the wearer’s subjective assessment of any leakage through the face seal region by detecting the introduction of a bitter- or sweet-tasting or fragranced aerosol as a test agent. The test subject will wear a hood for the duration of the test, and the process relies on manual record-keeping and has a risk of operator error or subjective results based on an individual’s sense of taste and smell.

QLFT methods are suitable for disposable and reusable half respirators but are not suitable for full-face. This type of test is based on individual responses by the RPE wearer, and it must be administered by a fit tester competent in using this method.

Quantitative fit testing (QNFT) provides a numerical measurement of how well a facepiece seals against a wearer’s face, known as a fit factor. There are two types of QNFT methods: Controlled negative pressure (CNP) and ambient particle counting (APC).

CNP fit testing can be carried out in any environmental conditions, clean or dirty air, indoors or outdoors, as it measures the amount of air leaking out of the respirator when controlled negative pressure is applied to create a vacuum. CNP tests full- and half-face respirators but not disposables. It has no contamination issues or consumables and therefore offers low maintenance and cost of ownership.

APC requires specific indoor test conditions as the instrument counts the number of particles inside the respirator, compared to the number of particles external to the mask. If there is not enough particulate in the air, the tester will introduce artificial particulates using consumables such as salt fog or alcohol wicks. APC is suitable for testing full- and half-face masks as well as disposable FFPs. It requires a certain level of maintenance due to particulate contamination of the unit and a need for consumables, which incurs an ongoing cost of ownership.

Each method of fit testing offers different advantages, so it’s a matter of understanding the options available and selecting the right mask type and test method for applications on a case-by-case basis. The BSIF’s Fit2Fit scheme (www.fit2fit.org) and the HSE (www.hse.gov.uk) have both produced a series of guides clearly explaining the different methods in detail.



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