The RPF (Respirator Protection Factor) in the Control Banding Risk Assessment Report
RPF value in the Risk Assessment Report is calculated using CPs with a series of steps in the logic to provide the minimum required protection factor using the correct values on the SDS.
Background Information (For further reading)
The Respiratory Protective Equipment (RPE) is a type of personal protective equipment (PPE) designed to protect the wearer/worker. It is important to choose the correct type of respirator. for example, the more contaminated the workplace air, the more protective the respirator needs to be. The two main types of respirators are:
| Air purifying respirator | Utilises a filter to purify the air being breathed in. Disposable or reusable Non-powered Powered |
| Supplied air respirator | Air supplied from an independent source, e.g., air compressor, compressed air cylinder |
Selection of the most suitable respirator for a situation depends on understanding the two factors:
- The hazard against which protection is required
- The limits of protection - knowing both the concentration and the occupational exposure limits of the harmful contaminants
The correct type of filter for the work task must be appropriately chosen. Generally, the SDS provides PPE details in section 8.
Protection Factor (FP) of a Respirator
The Protection Factor (PF) of the respirator can be calculated by using the following formula:
PF = Contaminant Concentration divided by OEL.
For example, given the information in the table of Protection Factors and Respirators; the contaminate concentration/m3 ambient air is 500mg/m3 and the OEL is 10mg/m3, then the protection factor is calculated.
PF (Protection Factor) = 500/10 = 50
Hence the minimum protection factor required is 50 for this contaminant concentration.
A respirator with particle filter for a Quarter/Half Mask with Filter Type and Class Number, P3 will have a Protection Factor of 50.
Key indicators for the filter types and class number:
Filter Type | Meaning |
P | Indicates a particulate filter in general |
FFP | Indicates particle filtering face piece |
Class# 1, 2 and 3 describe the capacity of a filter:
Filter Capacity | Meaning |
Class 1 | denotes “Small” |
Class 2 | denotes “Medium” |
Class 3 | denotes “Large” |
Australian Standards
Respirators used at workplaces in Australia must comply with Australian Standard AS/NZS 1716 (the number is usually displayed on the respirator or its packaging or even written in procedures.
Filter Types for gases and vapours
Filter | Examples of contaminants / uses |
Type A – organic vapours | Solvents (with boiling point above 65°C) |
Type B AUS or B1 – acid gases | Chlorine / sterilisation of water, chemical manufacture, hydrogen chloride / chlorinated organic chemical manufacture, steel pickling |
Type B2 and B3 – acid gases and hydrogen cyanide (HCN) | Plastics manufacture, gold ore refining, HCN fumigation |
Type E – sulphur dioxide (SO₂) | SO₂/casting of metals, bleach manufacture, manufacture of sulphuric acid, fertiliser manufacture, metal cleaning, petroleum refining |
Type G – agriculture chemicals | Low vapour pressure (below 1.3 Pa at 25°C) organic vapours, pesticide spraying, mixing, manufacture |
Type K – Ammonia (NH₃) | NH₃/refrigeration, manufacture of fertilisers, explosives, plastics, low boiling point amines/chemical manufacture |
Type AX - Low boiling point organic compounds (below 65°C) | As specified by the manufacturer (e.g. dimethyl ether, vinyl chloride) |
Type NO - Oxides of nitrogen | Oxides of nitrogen |
Type Hg – Mercury | Metallic mercury/chemical industry, inorganic mercury compounds |
Type MB - Methyl bromide | Fumigation |
Other types | For use against specific chemicals not falling in the above type description as specified by the manufacturer (e.g. hydrogen fluoride) |
Respirator Selection Tables (Positive and Negative pressure respirators)
The following tables show examples of minimum RPE required depending on the level of air contamination based on AS/NZS 1715:2009 Selection, use and maintenance of respiratory protective equipment.
Table A: Positive pressure respirators
Air contamination level | Powered air (PAPR) | Air-hose | Air-line | SCBA | ||||
| Particles | Gas/Vapour | Particles | Gas/Vapour | Particles | Gas/Vapour | Particles | Gas/Vapour |
Up to 10x WES | P1* | Class A US (1) |
|
|
|
|
|
|
Up to 50x WES | P2 | Class 2 (2) |
|
|
|
|
|
|
Up to 100x WES | P3 | Class 2 (2) |
|
|
|
|
|
|
Over 100x WES | P3 | x | Yes | Yes | Yes | Yes | Yes | Yes |
Unknown level |
|
| Yes | Yes | Yes | Yes | Yes | Yes |
Oxygen level of less than 19% |
|
| Yes | Yes | Yes | Yes | Yes | Yes |
*P1 filters not suitable for particles produced by hot processes e.g. soldering and welding.
Note 1–Class AUS and Class 1 are not suitable where maximum gas/vapour concentration is over 1,000 parts per million.
Note 2–Class 2 filters are not suitable where maximum gas/vapour concentration is over 5,000 parts per million.
Table B: Negative pressure respirators
Air contamination Level | Half-face disposable | Half-face reusable | Full-face | |||
| Particles | Gas/Vapour | Particles | Gas/Vapour | Particles | Gas/Vapour |
Up to 10x WES | P1* | Class AUS (1) | P1* | Class AUS (1) | P1* | Class AUS (1) |
Up to 50x WES | x | x | x | x | P2 | Class AUS (1) |
Up to 100x WES | x | x | x | x | P3 | Class 2 (2) |
Over 100x WES | x | x | x | x | x | x |
Unknown level | x | x | x | x | x | x |
Oxygen level of less than 19% | x | x | x | x | x | x |
*P1 filters not suitable for particles produced by hot processes (e.g. soldering and welding).
Note 1–Class AUS and Class 1 are not suitable where maximum gas/vapour concentration is over 1,000 parts per million.
Note 2–Class 2 filters are not suitable where maximum gas/vapour concentration is over 5000 parts per million.
These tables are based upon the content of tables 4.2, 4.3, 4.5 and 4.6 from Australian standard AS/NZS 1715. Refer to this standard for further information on the selection of suitable RPE based on the required minimum protection factor.
RPE British Standards
The RPE factors are based on those in the BS(British Standards) 4275. The RPE table below provides respiratory protective equipment at work: A Practical guide HSG53 (Third Edition) HSE Books 2005 ISBN 978 0 7176 2904 6.
The respiratory calculation is based on hazard rating, scale of use and dustiness/volatility as shown in the RPE tables
The RPE calculation is mapped with the respective RPE phrase.
| RPE | Phrase |
| 4 | Minimum Respiratory Protection Factor: 4 |
| 10 | Minimum Respiratory Protection Factor: 10 |
| 20 | Minimum Respiratory Protection Factor: 20 |
| 40 | Minimum Respiratory Protection Factor 40 |
| 2000 | Minimum Respiratory Protection Factor: 2000 |
Hint!
Generally, the higher the filter capacity, then higher the protection factor needed.
For more information, click on the link below to download the COSHH Control Banding Toolkit
The Technical Basis for COSHH Essentials
OSHA Standards
OSHA Standards can found in the US Department of Labor website below for preambles to final rules and Federal Register notices and any revised respiratory protection standards for the general, shipyard employment, marine terminals, long-shoring and construction industries.
https://www.osha.gov/respiratory-protection