Full-Featured Protection

Powered air is a smart new addition to the air-purifying product line.

• By Luanne Freund
• Nov 01, 2005

THE need to protect employees against air contamination in the workplace has become more critical than ever before. From hospitals to petrochemical plants, the use of sophisticated processes and exotic materials is growing and, in turn, increasing the possibility of dangerous accidental exposure to breathable hazards.

In addition, recent history has taught us that virtually nowhere is completely safe from the mindless ravages of terrorist attack. In today's workplaces, safety and thorough domestic preparedness demand careful examination of potential air quality risks and the implementation of methods and materials to address that potential. When it is determined that personal protective equipment is required to protect workers, workers often still gravitate to one of two common respirator types: facepiece and cartridge or supplied airline, each with its own pros and cons.

While full-facepiece respirators with cartridges offer excellent protection from breathing hazards and feature a broad range of facepiece and filter options for protection against various environments, long-term, continuous wear is often limited by the user's comfort level. Supplied air respirators provide workers with extended wear times and protection, but the supplied air hose can be heavy and cumbersome to drag as the worker moves from one location to another.

A third choice for respirator protection that offers unique advantages is powered air-purifying respirators. PAPRs offer protection equal to or greater than full facepieces with cartridges in environments requiring the extended wear of air-purifying equipment.

Benefits of PAPRs
In simple terms, a powered air-purifying respirator uses a small blower to force ambient air in through air-purifying cartridges and into the user's facepiece or headtop. This basic design allows the wearer to feel virtually no breathing resistance during inhalation. In environments requiring the extended wear of air-purifying equipment, this type of comfort and ease of use take on critical significance to workers' ability to perform their jobs. And, compared with the extra weight of a supplied air hose attached to a supplied air respirator, powered air-purifying respirators provide more mobility, yet also allow for extended use of protection.

Another benefit of PAPRs is the cooling, fanning effect created by the air that is blown into the user's facepiece. This constant flow of cool air allows the wearer to perform longer work functions. This is an important feature, especially in emergency situations where shifts are long and breaks may not be available.

Situations Requiring Extended Wear
Job productivity can be dramatically affected by the stress of working. In jobs requiring heavy physical exertion, reducing pulmonary stress can improve a worker's comfort and productivity on the job. In environments requiring the extended wear of air-purifying equipment, in locations where elevated heat and humidity exist, or in jobs requiring heavy physical exertion such as extraction of victims or decontamination, comfort and ease of use become critical. Productivity can be significantly affected by the stress of working in some protective gear.

Another feature of some PAPRs is a microprocessor that constantly manages and adjusts air flow to the user to ensure an adequate, easy-to-breathe air supply. The system ensures comfortable air flow to the user by automatically compensating for changes in air flow resistance. The unit increases air flow output when a user's breathing rate increases or when the filter becomes "loaded" with enough particulate material to cause an increase in breathing resistance. Because air flows through the facepiece, fogging is virtually eliminated and there is a cooling effect on the user's face.

Because PAPRs are designed for extended wear, weight, comfort, and durability are primary design considerations. A PAPR's power source should be not only lightweight, but long-lasting to be reliable throughout the work day. In addition, if the intended use for the PAPR is in environments where high heat, impact, chemical exposure, or electrical sparks are present, each part of the unit should be resistant to these exposures, including the main unit, hoses, filters and facepiece (or hood).

Ergonomics should be considered in a well-designed PAPR. Most PAPRs place the bulk of the unit's weight on the user's lower back to minimize strain and to position the unit out of the way of operations.

Unit Alarms and Displays
PAPRs can include additional safety features, such as a display showing the unit's battery status and blower power, in addition to flashing and audible warnings if the battery is low or if the optimal air flow rate (6 cfm) is compromised. This on-board alarm system eliminates the need for a separate air flow indicator and provides continuous monitoring.

Regardless of the type of respirator, a comfortable, adequate flow rate is always important to the user. While one- and two-filter configuration PAPRs provide adequate flow rates and meet the minimum NIOSH requirements, the highest flow rates can be experienced using three-filter PAPRs. These make breathing easier and more natural in most work environments. Positioning filters upside down helps protect them from possible contamination and provides virtually waterproof use for shower-friendly operation and to facilitate decontamination.

In tracking and servicing PAPR respirators, a datalogging function can be useful. Datalogging can automatically record information about the use and performance of the blower unit to establish a use and performance history for each unit.

A Valuable Part of the Respiratory Arsenal
PAPRs are an excellent choice for health care first receivers, industrial workers, military personnel, and police departments. They are versatile, easy to use, and provide excellent respiratory protection in non-IDLH environments that require respiratory protection for an extended duration or during physical exertion.

While powered air-purifying respirators may not be essential for every job, they are playing an increasingly important role in protecting workers in a variety of health care, service, and industrial settings. It is hard to imagine a respiratory protection arsenal in which a PAPR would not be a welcome and valuable addition.

This article appeared in the November 2005 issue of Occupational Health & Safety.

This article originally appeared in the November 2005 issue of Occupational Health & Safety.