Guide
Select and fit test respiratory protective equipment (RPE)
How to select the right respiratory protective equipment for your workplace hazards and ensure it is properly fit tested. Covers hazard identification, RPE types and Assigned Protection Factors, fit testing methods, facial hair policies, maintenance and filter replacement. Based on HSE guidance HSG53.
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 - different hazards need different types of RPE
- Adequate for the exposure level - the RPE must have a high enough Assigned Protection Factor (APF)
- Properly fitted to the wearer - a poor seal allows contaminated air to leak in
- Correctly maintained - 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 (HSE 2025/26 enforcement priority), isocyanates and lead, where exposure can cause cancer, chronic lung disease or other irreversible harm.
This guide follows 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:
- Eliminating the hazardous substance or process
- Substituting with a less hazardous alternative
- Engineering controls such as local exhaust ventilation (LEV), water suppression, or enclosed processes
- 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.
Step 1: 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 particulate: Silica dust, wood dust, flour dust, metal grinding dust, welding fume (particulate component). Requires particulate filters (P1, P2 or P3)
- Gas and vapour: Solvent vapours, paint fumes, chemical gases. Requires gas/vapour cartridges specific to the substance
- Combined hazards: Spray painting (vapour + particulate), welding in confined spaces (fume + gas). Requires combined filters
- Oxygen-deficient atmospheres: Confined spaces, tanks, silos. Filtering RPE will not work - requires supplied air (self-contained breathing apparatus or airline)
Critical point: Using the wrong type of filter for the hazard provides no protection. A particulate filter does not protect against gases. A gas filter does not protect against dust. If in doubt about the hazard, seek expert advice before selecting RPE.
Step 2: 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 a half-mask with P3 filter (APF 10) would be the minimum, but an FFP3 disposable (APF 20) would provide a better margin of safety.
Step 3: 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 10 with particulate, gas or combined filters
- 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 20 with particulate, gas or combined 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
Step 4: 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
- Face shape and size: Not all RPE fits all face shapes. Offer a range of makes and models
- Facial hair: Any facial hair in the area where a tight-fitting mask seals to the face will prevent an effective seal. This includes stubble, beards, sideburns and moustaches that extend under the mask edge. Workers with facial hair must either shave the seal area or use loose-fitting powered respirators
- Glasses: Standard spectacles break the seal on full-face masks. Prescription inserts or special frames may be needed
- Medical conditions: Some respiratory or cardiac conditions may make RPE use inadvisable. Seek occupational health advice where concerns arise
- Compatibility with other PPE: RPE must work alongside hard hats, hearing protection and eye protection without compromising any item's effectiveness
- Physical demands: RPE increases breathing resistance. Consider the physical effort of the task and ambient temperature
Step 5: 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 recommends at least every two years, more frequently in high-risk environments)
Record keeping: 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.
Step 6: 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
Step 7: 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
Step 8: 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:
- Silica dust (RCS): Minimum FFP3 (APF 20). Powered respirator preferred for prolonged tasks. HSE 2025/26 enforcement priority
- Isocyanates: Full-face respirator with A2P3 combination filter, or supplied air. Full-face required because isocyanates also affect eyes. Must be combined with health surveillance
- Lead: Minimum FFP3 for lead dust. Full-face with P3 if grinding or cutting lead-containing materials at high rates
- Welding fume: Minimum FFP3 for mild steel welding fume. Powered respirator recommended for prolonged or confined welding. Welding fume reclassified as a human carcinogen
- Asbestos: Minimum FFP3 for licensed work. Full-face or powered respirator for higher risk tasks. Refer to Control of Asbestos Regulations 2012
Common RPE failures found by HSE
- Wrong RPE type for the hazard - using dust masks for gas/vapour hazards or vice versa
- APF too low - using FFP2 where FFP3 is needed (common for silica dust)
- No fit testing - issuing tight-fitting RPE without fit testing each wearer
- Facial hair under the seal - allowing beards or stubble with tight-fitting RPE
- Disposable masks reused across multiple shifts or visibly soiled
- Filters not replaced - using gas/vapour cartridges beyond their service life
- No training provided - workers not shown how to wear RPE or perform seal checks
- RPE used as sole control without considering the hierarchy of controls first
What to do next
- Review your COSHH assessments to identify where RPE is required
- Check the hazard type and exposure level to determine the required APF
- Select appropriate RPE with an adequate protection factor for each hazard
- Arrange fit testing for all workers using tight-fitting RPE
- Implement a facial hair policy for workers who use tight-fitting RPE
- Train all RPE users on correct wear, seal checking, maintenance and limitations
- Set up maintenance and replacement schedules for reusable RPE and filters
- Keep records of fit tests, training and RPE issued to each worker