Respiratory protective equipment (RPE) is a type of personal protective equipment that filters out contaminants and provides clean air to the wearer. This type of personal protection is designed to protect against fumes and hazardous chemicals that can be found in modern work environments such as factories with heavy machinery. This blog post will discuss different types of respirators and a respiratory selection guide for protecting your workers.

Table of Contents

Types of Respirators

Worksafe QLD classifies respirators into two main types based on the air source: Air purifying respirators and Supplied-air respirators.

Air purifying respirators

Air purifying respirators are designed to protect the wearer by using a filter that removes impurities from air breathed in. They can be either disposable or reusable, and come with two types of functionality: powered or non-powered. Powered models use a fan for an extra layer of protection against harmful substances while non-powered ones rely on users' breathing alone to draw air through the filters.

Disposable Particulate Respirators

Disposable particulate respirators are designed for protection against low concentrations of dust, mists, pollen, animal dust etc.

Advantages: Lightweight, disposable, relatively comfortable, and inexpensive.

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Re-Usable Half Mask Respirators

Air purifying half masks have a rubber face sealing part which fits over the nose and under the chin. Exchangeable cartridges and filters are designed to provide protection against different types of air contaminants.

Advantages: Relatively lightweight and offer good protection against many contaminants.

Limitations: Use is limited by the type and capacity of the filters – neither can be used in areas with high concentrations of contaminants or in oxygen-deficient atmospheres. Breathing may become more difficult because of additional effort is needed to breathe through the filters. Eye protection is not provided. Although the proper and tight fitting is essential, many factors may affect mask tightness.

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Re-Usable Full Face Mask Respirators

Air purifying full face masks work on the same principle as the half-mask respirators described above. The facepiece extends protection around the entire face, covering the eyes, nose, chin and mouth.

Advantages: Full face respirators are used where a higher level of respiratory protection is needed or where eye and face protection is required.

Limitations: Full face masks are heavier than half-masks and often less comfortable for the wearer. Cannot be used for all types of air contaminants and are limited by the type and capacity of the filters and cartridges used. They cannot be used in oxygen-deficient atmospheres. Breathing may become more difficult because of additional effort is needed to breath through the filters.

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PAPR – Powered Air Purifying Respirators

The most advanced group of personal protective equipment provides high level of protection even for long lasting applications. Battery powered portable fan unit which drives the air through a particulate or chemical filter and blows it to the headtop. Full and half mask are available as well as wide variety of hoods and helmets.

Advantages: Major advantages are derived from the positive pressure provided by the fan forcing air into the headtop – hood or helmet. This eliminates difficulty in breathing provided by the negative pressure respirators and reduces the importance of a precise facial fit.

Limitations: Higher purchase price and maintenance. Use is limited by the life time of the battery and fan. Can not be used in oxygen deficiency environments.

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Supplied-air respirators

Supplied-air respirators are a type of respiratory protection which provide clean air from an independent source that can be either the compressed air cylinder or compressor. This helps in preventing breathing contaminants, such as hazardous gases and chemicals found at construction sites.

Airline Respirators

These respirators provide clean, fresh air to the user from a stationary source such as a compressor or compressed air cylinder. Full face mask and half mask are available as well as wide variety of hoods and helmets.

Advantages: Airline respirators may be used for long periods and provide a high degree of protection from a variety of air contaminants. They provide minimal breathing resistance and discomfort, are light weight and are available at moderate initial cost and low operating costs.

Limitations: Unexpected loss of the air source terminates all protection to the user. Air must be delivered to the mask or hood through a hose which can be difficult to handle and may easily tangle or crimp. These respirators can be used for protection from the most of all air contaminants.

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Self-contained breathing apparatus (SCBA)

SCBAs provide the user with clean air from a high pressure cylinder carried on the wearer‘s back. They are equipped with a full face piece and are operated in the pressure demand mode. SCBAs provide the maximum degree of protection available from airborne contaminants.

Advantages: Users carry their air supply with them allowing comparatively free movement over an unlimited area.

Limitations: SCBA units are expensive to purchase and maintain; require the wearer to carry heavy equipment on his back, and provide no more than 40 minutes of continuous use. Personnel with facial hair which comes between the respirator sealing surface and the wearer‘s face cannot use SCBA equipment.

Selecting the right respirators

Choosing the right respirator for your work can be a difficult task. For efficient respiratory protection, it's critical to choose the correct RPE for your work. According to AS/NZS 1715:2009.

Identify which contaminants are present in your work environment

In situations where there are particulate hazards, such as dusts in a factory or sawmill, you will likely wear a filter air purifying respirator. In instances that involve the inhalation of vapors (say from solvents), you may need to equip yourself with other gear like vapor cartridges and/or combinations of both depending on the hazard. In any kind of workspace where oxygen is lacking and/or hydrogen sulfide gas (H2S) present to breathe, it may require additional equipment like a supplied air system to keep workers going without respiratory illness occurring due to their work conditions.

Australian Standard AS/NZS 1715:2009 classifies contaminated air into the following types:

Particulates

Dusts/Fibres

Solid particles generated by mechanical means such as crushing, cutting and sanding.

Examples: calcium carbonate, cement (silica) dust, sulphur, glass-wool, coal, clay, cellulose, cotton dust, flour, ferrous metals (steel, stainless steel, cast iron), wood dust and asbestos.

Mists

Airborne droplets of liquid suspended in air. They are usually formed by condensation of vapour back to a liquid state or breaking up as a liquid into a dispersed state such as splashing, spraying, or atomising.

Examples: oil mist produced during cutting and grinding operations, acid mists from electroplating, acid and alkali mists from pickling operations, the condensation of water vapour to form a fog and paint mist.

Fumes

Fine particles, usually less than 1.0μm in diameter, formed from a volatilised solid that has condensed in cool air. In most cases the hot vapour reacts with air to form an oxide. Fume is often associated with molten metals especially in processes such as welding.

Examples: welding, soldering, brazing and bushfire smoke.

Vapors and gases

Gases

Gases are formless fluids that expand to occupy the space or enclosure in which they are confined.

Examples: nitrogen, oxygen and carbon dioxide and carbon monoxide.

Vapours

Vapour is the gaseous form of a substance which is normally in the solid or liquid state at room temperature and pressure.

Examples: methylene chloride, toluene and mineral spirits.

Determine level of protection needed

The Required Minimum Protection Factor (MPF), as defined by Australian Standard NZ-1715:2009, is essentially a numerical value that contributes towards reducing the wearer's exposure below their accepted levels. MPF ranges from 10 to 100+. The equation of MPF as below:

Suitable respiratory protective equipment – particulates

Suitable respiratory protective equipment – gas and vapours

Select the right type of filter

AS/NZS 1716:2012 – Respiratory Protective Devices details the types of particulate and gas filters and their capacity that are available in Australia.

Particulate filters and cartridge

Particulate filters are designed to protect against solid and liquid particles as well as micro-organisms. However, particulates do not offer protection from gases or vapors that can be harmful such as solvents. Particulate filters are classified into categories P1 (lowest level of protection), P2 (moderate) or P3(highest).

***NOTE – Where there is a hazard of both gas/vapours and particulates, both types of filters must be used.