Powered air-purifying respirators: Benefits for respiratory protection

How an advanced type of respirator can help workers breathe easier

Workers in the industries IHSA serves are often exposed to airborne contaminants such as dusts, fumes, vapours, mists, and bio-aerosols (e.g., moulds). When airborne contaminants can’t be isolated, ventilated, or substituted, workers must be given respirators to limit their occupational exposure—and powered air-purifying respirators (PAPRs) are recognized as an effective and comfortable form of protection.

Employers must select the right respirator for the work, considering the type of hazards present, the demands of the task, and the equipment’s comfort, breathing, and overall usability.

Compared to non-powered air-purifying respirators (APRs), PAPRs put less strain on the wearer’s respiratory system. They cause little to no breathing resistance, and most models don’t require a tight seal. They also offer a greater level of protection than some traditional air-purifying respirators.

Key differences between a PAPR and APRs

There are two main respirator classes: air-purifying and supplied-air. PAPRs are battery-powered air-purifying respirators.

Both APRs and PAPRs work by drawing air through filters or cartridges to remove contaminants such as gases, vapours, or particles. They don’t supply oxygen from a tank or other external source.

APRs come in a variety of styles, ranging from basic disposable masks (e.g., N-95s) to tight-fitting full facepiece respirators, while PAPRs are typically worn as a helmet or loose-fitting hood.

But the key difference between PAPRs and APRs is made clear in their names. Where traditional APRs rely on the wearer’s breathing in and out to supply clean air, PAPRs have a battery-powered fan that pulls in air, filters it, and then pushes it into the wearer’s breathing zone via a tube or hose. Depending on the model, PAPR battery life ranges from about four hours to upwards of 18 hours.

The benefits of PAPRs

High assigned protection factor (APF): A respirator’s APF is the expected level of protection that it would provide a properly trained worker. Some PAPRs can have an APF of up to 1,000—meaning they can reduce the concentration of a hazardous substance in the air by a factor of 1,000. Non-powered APRs have an APF of up to 50.

Positive pressure: Because PAPRs continuously push air toward the user’s breathing zone, the air pressure in the hood or helmet is greater than the air outside of it. Air always moves from high pressure to low pressure areas: the pressurized air inside the respirator creates a barrier that keeps contaminants out.

Easier breathing: During prolonged use, regular APRs can strain the wearer’s lungs and respiratory system because they must pull air through a filter with every breath. This extra effort can cause fatigue and discomfort, making the worker less likely to follow safety protocols. But a PAPR’s continuous airflow means there is very little breathing resistance—a major benefit over the course of a physically demanding workday.

All-day comfort: PAPRs’ continuous supply of filtered air helps keep the breathing zone cooler, reduces moisture buildup, and prevents the hot, stuffy feeling often associated with tight-fitting respirators. It also reduces fogging on visors or face shields.

No fit check needed: Many respirators depend on a perfect seal against the face to work properly. Workers need to check the fit and seal each time they use the respirator. The positive pressure of a PAPR keeps out contaminants without the need for a tight seal. This makes it easier to accommodate a wider range of workers, including those who have facial hair or who wear glasses. (Some PAPRs use a tight-fitting facepiece. These models do require fit testing.)

Integrated PPE: The closed hood or helmet of a PAPR combines respiratory, face, and eye protection in one unit, avoiding the need for layering multiple pieces of personal protective equipment and ensuring overall ease of use.

How to select the right PAPR

Selecting the right respirator for a job is a complex, scientific process that should be left to a certified occupational hygienist. These professionals help workplaces perform hazard and risk assessments, identify airborne contaminants, and choose the most effective respirator for worker protection based on the Canadian Standards Association (CSA) standard Z94.4-18: Selection, use, and care of respirators. The standard sets out the requirements for selecting respirators and administering respiratory protection programs in workplaces. It also includes guidance on respirator fit testing, use, and maintenance.

Among many considerations, an airborne hazard and risk assessment should look at:

• What contaminants workers are exposed to
• Whether the contaminants are particulates, gases, or vapours
• The concentration of the contaminants in the air
• The occupational exposure limits (OEL) for each contaminant
• What work activities will be performed while wearing a respirator
• How long workers will have to wear their respirators
• Working conditions (e.g., heat, confined space)
• The physical demands of the work tasks

Each respirator must be matched to the hazard it’s designed to protect against. PAPRs can be equipped with a combination of filters and chemical cartridges to protect against a variety of particulates, vapours, and gases.

Workplaces must also consider the work environment the respirator will be used in. For example, PAPRs may be ideal for physically demanding or time-intensive work, since they don’t cause breathing resistance. On the other hand, because they rely on air from the environment, PAPRs cannot be used in toxic or oxygen-deficient conditions, such as confined spaces.

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