Select and fit test respiratory protective equipment (RPE)

Why correct RPE selection matters

Respiratory protective equipment (RPE) is the last line of defence against inhaling hazardous substances at work. When workers are exposed to dust, fumes, gases or vapours that cannot be fully controlled by other means, RPE protects their lungs from irreversible damage.

However, RPE only works if it is:

• right for the hazard, because different hazards need different types of RPE
• adequate for the exposure level, with a high enough Assigned Protection Factor (APF)
• properly fitted to the wearer, because a poor seal lets contaminated air leak in
• correctly maintained, because dirty or damaged RPE does not protect

RPE selection errors are a leading cause of inadequate protection. This is particularly critical for high-hazard substances such as respirable crystalline silica, isocyanates and lead, where exposure can cause cancer, chronic lung disease or other irreversible harm.

The requirements follow HSE guidance HSG53 - Respiratory protective equipment at work (4th edition).

Before selecting RPE: check the hierarchy of controls

Under COSHH 2002 and the PPE at Work Regulations, RPE must only be used as a last resort or as an additional safeguard alongside other controls. Before selecting RPE, you must have considered:

1. Eliminating the hazardous substance or process
2. Substituting with a less hazardous alternative
3. Engineering controls such as local exhaust ventilation (LEV), water suppression, or enclosed processes
4. Administrative controls such as reducing exposure time or job rotation

Your COSHH assessment must document why RPE is needed and show that you have considered higher-level controls first. HSE inspectors will challenge employers who rely solely on RPE without evidence that other controls were considered.

Identify the hazard

The type of RPE you need depends on the hazard your workers face. Workplace airborne hazards fall into distinct categories, and each requires a different approach to respiratory protection:

• Dust and particulates, such as silica, wood, flour and metal grinding dust and the particulate part of welding fume, need particulate filters (P1, P2 or P3).
• Gases and vapours, such as solvent vapours, paint fumes and chemical gases, need gas or vapour cartridges specific to the substance.
• Combined hazards, such as spray painting (vapour and particulate) or welding in confined spaces (fume and gas), need combined filters.
• In oxygen-deficient atmospheres, such as confined spaces, tanks and silos, filtering RPE will not work and you need supplied air (self-contained breathing apparatus or an airline).

Using the wrong type of filter for the hazard provides no protection. A particulate filter does not protect against gases, and a gas filter does not protect against dust. If you are in doubt about the hazard, get expert advice before selecting RPE.

Determine the required protection level

Once you know the hazard type, you must select RPE with a high enough Assigned Protection Factor (APF) to reduce exposure below the relevant Workplace Exposure Limit (WEL).

The APF tells you by how much the RPE reduces exposure. For example, RPE with an APF of 20 should reduce the concentration inside the mask to 1/20th of the outside level.

Calculating the required APF

Divide the measured or estimated workplace concentration by the WEL:

Required APF = Workplace concentration / WEL

Then select RPE with an APF equal to or greater than the result. For example, if the silica dust concentration is 1.0 mg/m3 and the WEL is 0.1 mg/m3, the required APF is at least 10 - meaning an FFP2 disposable (APF 10) or a half-mask with P2 filters (APF 10) would meet the minimum, but an FFP3 disposable or half-mask with P3 filters (both APF 20) would provide a better margin of safety.

Choose the right RPE type

With the hazard identified and the required APF determined, select the RPE type that best suits your workplace:

Disposable filtering facepieces (FFP masks)

• FFP1 (APF 4) - Low-risk nuisance dust only. Not suitable for substances with a WEL
• FFP2 (APF 10) - Medium-risk dust and mist. Suitable where the required APF is 10 or less
• FFP3 (APF 20) - High-risk dust including silica, hardwood dust, lead. Minimum standard for most COSHH-regulated substances

FFP masks are single-use or single-shift items. They must be discarded when they become damp, damaged, or difficult to breathe through.

Reusable half-mask respirators

• APF depends on the filter: P1 = 4, P2 = 10, P3 = 20 (gas filters typically APF 10)
• More comfortable for prolonged wear than disposable masks
• Filters must be replaced according to manufacturer schedules
• Must be cleaned and stored properly between uses

Full-face respirators

• APF 40 with P3 particulate filters (APF 20 with gas filters)
• Also provide eye protection
• Essential where the substance also causes eye irritation (isocyanates, some solvents)

Powered air-purifying respirators (PAPRs)

• APF 20 (loose-fitting) or APF 40 (tight-fitting)
• A battery-powered fan draws air through a filter and delivers it to the wearer
• Essential for workers with facial hair - loose-fitting PAPRs do not rely on a face seal
• More comfortable for extended wear, especially in hot environments
• Higher initial cost but may be more cost-effective than disposables for regular use

Assess suitability for the wearer

RPE must be suitable for the individual worker, not just the hazard. Conduct a suitability assessment before issuing RPE:

Key considerations for RPE suitability

• Not all RPE fits all face shapes and sizes, so offer a range of makes and models.
• Any facial hair where a tight-fitting mask seals to the face, including stubble, beards, sideburns and moustaches that extend under the mask edge, will prevent an effective seal. Workers with facial hair must either shave the seal area or use loose-fitting powered respirators.
• Standard spectacles break the seal on full-face masks, so prescription inserts or special frames may be needed.
• Some respiratory or cardiac conditions may make RPE use inadvisable. Get occupational health advice where concerns arise.
• RPE must work alongside hard hats, hearing protection and eye protection without compromising any of them.
• RPE increases breathing resistance, so consider the physical effort of the task and the ambient temperature.

Fit test all tight-fitting RPE

Fit testing is a legal requirement for all tight-fitting RPE. This includes FFP masks, half-mask respirators and full-face respirators. A fit test checks that the specific make, model and size of RPE creates an adequate seal on the individual wearer's face.

Qualitative fit testing

The wearer puts on the RPE and is exposed to a taste agent (usually a bitter or sweet aerosol) inside a hood. If the wearer can taste the agent, the fit is inadequate. This is a pass/fail test suitable for half-masks and FFP masks.

• Quick to perform (takes approximately 15-20 minutes)
• Does not require expensive equipment
• Relies on the wearer's subjective taste response
• Not suitable for full-face respirators

Quantitative fit testing

Uses a machine (typically a PortaCount or similar device) to measure the actual ratio of particles outside and inside the mask. This provides a numerical fit factor.

• More accurate and objective than qualitative testing
• Required for full-face respirators
• Provides a measured fit factor that can be compared against the required APF
• Requires specialist equipment and a trained tester

When to fit test

• Before first use of any tight-fitting RPE
• When changing to a different make, model or size of RPE
• After significant weight change (gain or loss) that could affect face shape
• After dental work or facial surgery that could alter the seal area
• At regular intervals (HSE does not set a fixed retest interval; the Fit2Fit scheme recommends at least every two years, more frequently in high-risk environments)

Keep a record of each fit test showing the wearer's name, the RPE tested (make, model, size), the test method used, the result (pass/fail and fit factor if quantitative), and the date. Issue each worker with a fit test record card showing their approved RPE.

Implement a facial hair policy

Facial hair is the most common cause of RPE fit failure. You must have a clear policy:

• Workers who use tight-fitting RPE must be clean-shaven in the seal area every day they wear RPE
• Even one day's stubble growth can significantly reduce the protection provided
• Workers who wish to keep facial hair for religious, cultural or personal reasons must be provided with loose-fitting powered respirators that do not rely on a face seal
• Communicate the policy clearly, explain the safety rationale, and enforce it consistently

Maintain RPE and replace filters

RPE must be maintained in efficient working order and good repair:

Disposable RPE (FFP masks)

• Single-use or single-shift only - discard after each shift or sooner if damaged, wet or difficult to breathe through
• Store in a clean, dry place before use
• Check for damage before each use (bent nose clip, torn straps, crushed filter)

Reusable RPE

• Clean after each use following manufacturer instructions
• Inspect before each use for cracks, perishing, damaged valves or worn straps
• Replace filters according to manufacturer schedules or when breathing resistance increases
• Store in a clean container when not in use, away from contamination
• Replace worn parts - straps, valves and seals deteriorate over time

Powered respirators

• Charge batteries fully before each shift
• Check airflow using the manufacturer's flow indicator
• Replace filters when airflow drops below the minimum or on the schedule specified
• Clean headtop/visor and check for damage

Train your workers

Everyone who uses RPE must receive training covering:

• Why RPE is needed and what hazards it protects against
• How to wear it correctly including how to adjust straps and perform a user seal check before every use
• Limitations of RPE - what it does not protect against, maximum wearing times, when to leave the area
• How to check for damage before use
• Facial hair policy and why a clean shave in the seal area is essential for tight-fitting RPE
• Filter replacement schedules and how to change filters
• Cleaning and storage procedures
• What to do if RPE fails or becomes uncomfortable during use

RPE selection for specific high-risk substances

Some hazardous substances have specific RPE requirements:

• For silica dust (RCS), use FFP3 (APF 20) as a minimum, with a powered respirator preferred for prolonged tasks.
• For isocyanates, use a full-face respirator with an A2P3 combination filter, or supplied air. Full-face protection is needed because isocyanates also affect the eyes, and you must combine it with health surveillance.
• For lead dust, use FFP3 as a minimum, and full-face with P3 filters if grinding or cutting lead-containing materials at high rates.
• For mild steel welding fume, which is classed as a human carcinogen, use FFP3 as a minimum, with a powered respirator recommended for prolonged or confined welding.
• For licensed asbestos work, use FFP3 as a minimum, and full-face or powered respirators for higher-risk tasks, following the Control of Asbestos Regulations 2012.

Common RPE failures found by HSE

• Using the wrong RPE type for the hazard, such as dust masks for gas or vapour hazards
• Using RPE with too low an APF, such as FFP2 where FFP3 is needed (common for silica dust)
• Issuing tight-fitting RPE without fit testing each wearer
• Allowing beards or stubble under the seal of tight-fitting RPE
• Reusing disposable masks across shifts or when visibly soiled
• Using gas or vapour cartridges beyond their service life
• Not showing workers how to wear RPE or carry out seal checks
• Using RPE as the only control without considering the hierarchy of controls first