Personal Respiratory Protection

by Kevin P. Fennelly, M.D., M.P.H.

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• Preventing Inhalation of Airborne Hazards
• When in Rome...
• Principles of Respiratory Protection
• Types of Respirators
  • Case Study #1
  • Case Study #2
  • Case Study #3
• Healthcare Workers and the Prevention of Tuberculosis
• The National Jewish Personal Respiratory Protection Program
• Additional Information
• References

Preventing Inhalation of Airborne Hazards

The human body has marvelous defense mechanisms against air pollutants which ensure effective functioning of the lungs. However, when exposed to specific hazards in the workplace including certain chemical vapors, bioaerosols, mineral dusts or agricultural dusts, we require additional protection to prevent the development of disease. Some of these occupational lung diseases include asbestosis, lung cancer, beryllium disease, silicosis, asthma and tuberculosis. Often, inhaled agents do not target the lungs themselves, but rather use the respiratory tract as an organ of uptake. Therefore, protecting the lungs from these noxious materials will prevent not just respiratory disease but other forms of disease as well.

When in Rome...

The concept of respiratory protection is not new--as early as the first century A.D., Roman mine workers, wearing masks made from dried animal bladders, shielded their lungs from the toxic red oxide of lead. Today, technological advances continue to create thousands of new chemicals and new occupational hazards. These advances, ironically, have also meant the development of more sophisticated methods for protecting workers. While the challenges may be new, the principles remain the same.

Principles of Respiratory Protection

In general, a respirator is any device designed to protect the wearer from hazardous air. More specifically, a respirator is a face piece, hood or helmet that is equipped with a filter or connected to a breathable air source. (A surgical mask, designed to protect a sterile environment from the wearer, is not a respirator) It is important to note that engineering and administrative strategies (e.g., using less hazardous materials) should be the primary factors in preventing worker exposure. When these measures are not adequate, not feasible or not yet implemented, a respirator may be required to protect the employee and mitigate the hazard.

The Occupational Safety and Health Administration (OSHA), a division of the Department of Labor, determines and enforces the regulations for the use of respirators.

Under current OSHA standards, the employer is responsible for implementing a respirator program and assuring that regulatory requirements are met. A complete program, detailed in written guidelines, is necessary to instruct workers on the fit, care, use and limitations of a particular respirator so that protection is optimized. Without such a program, a respirator may not be used in the workplace.

An initial medical evaluation is required to determine whether or not a worker is able to use a respirator. A "high-risk" worker with cardiac disease, for instance, would not be able to support a heavier respirator like a self-contained breathing apparatus, which could weigh as much as 30 pounds. The medical screening may involve a specially designed questionnaire, or, if necessary, a more thorough physical exam conducted by a physician. Finally, the program administrator, who is trained in respiratory protection, considers the kind of exposure, the demands of the job and the physical characteristics of the worker to select which type of respirator is most appropriate.

A successful respiratory program encompasses three basic principles: obtaining information about a hazard; following an employer's written program; and, using a respirator properly. This last concept sounds simple--but respirator protection can be rendered ineffective when not given the careful attention it requires.

Types of Respirators

There are two major categories of respirators: air-supplied respirators and air-purifying respirators. With air-supplied respirators, air travels to the mask or suit through a hose from an independent source outside the environment or from a compressed air cylinder worn on the back. Air-supplied set-ups offer the greatest amount of protection, but can be heavy or cumbersome.

Air-purifying respirators, however, remove hazardous agents from the air that is present in the work environment. This is accomplished through filtration, adsorption or chemical reaction. Within this category are negative-pressure respirators, which work when a user sucks in air through a filter. A second type, powered air-purifying respirators (PAPRs), use a fan unit to blow air through a filter to a mask, helmet or hood. The motorized air pump, battery and filter usually are worn on a waist belt.

Negative-pressure respirators are frequently used because of their versatility, light weight and low cost. The N95 disposable particulate respirator, named for its classification and filter efficiency, looks similar to a surgical mask and is often found in health care environments. The elastomeric respirator, available in half-face or full-face designs, is similar to the disposable particulate respirator but is reusable and made from flexible materials that create a more effective face-mask seal. A tight-fitting face piece--though essential for protection--can become uncomfortably hot and can hinder the ability to communicate. Also, any obstruction on or around the face such as hair, eye glasses or even deep creases in the skin can interfere with a tight face-mask seal.

All respirators are tested and certified by the National Institute for Occupational Safety and Health (NIOSH). It is this data that OSHA uses when formulating health standards. An assigned protection factor (APF) represents the protection expected for a particular type of respirator when it is worn by workers who have been fitted and trained in its use. The protection factor is the ratio of the contaminant concentration outside the respirator to the contaminant concentration inside the face piece (i.e., a protection factor of 10 means that the concentration inside the mask is one-tenth that outside).

The Personal Respiratory Protection Program (PRPP) at National Jewish provides training, fit testing and medical clearance for the use of respirators. The following three examples illustrate how an individual's unique circumstances are evaluated to determine the most appropriate respiratory protection:

Case Study #1

Occupation: Farmer

Problems:

1. He performs multiple duties around the farm. His exposures include grain dust, hog confinement houses, pesticides and diesel fumes.
2. He is unable to wear a negative-pressure respirator due to the following:
   1. he has a beard
   2. he has discomfort during hot weather
   3. he has claustrophobia
   4. some of his work requires a hard hat and eye protection
   5. he has mild asthma
   6. he wears glasses

Solution: He came to the PRPP at National Jewish for a consultation. Our respiratory fit technician determined that the loose-fitting helmet of a PABR Air Hat would accommodate his beard, while delivering a constant flow of cool air for comfort during a long summer work day. He received literature on the product as well as information on where to purchase the respirator set-up.

Powered air-purifying respirator (PAPR) helmet. This device provides a higher level of protection than disposable particulate and half face negative pressure respirators, and i is the only type of respirator which is effective for men with beards. The constant flow of air keeps the respirator cooler and more comfortable than non-powered air purifying respirator.

Case Study #2

Occupation: Welder

Problems:

1. He needed a half-face negative-pressure respirator that would fit under a welding mask and not restrict his movement.
2. He forwarded his Material Safety Data Sheets containing information on the treated metals he works with.

Solution: The PRPP was able to consult on the proper filters to wear on his mask. He had a quantitative fit test for a backpack set-up with a harness system to keep away the filters from the exposure. This arrangement allows a welding shield to be placed over the mask and keeps the filters tight to the body and away from the immediate exposure area.

Half-face negative pressure respirator with backpack harness. This allows the wearer to fit a welding shield over the respriator.

Case Study #3

Occupation: Respiratory Therapist

Problems:

1. She has a latex allergy
2. She works on a medical/surgical floor, occasionally caring for patients with TB
3. She needs personal respiratory protection against TB because she occasionally assists with bronchoscopies and intubations.

Solution: The PRPP conducted a fit test for a latex-free N95 duckbill respirator for the therapist to wear in TB isolation rooms. In addition, she received training on a powered air-purifying respirator (PAPR) with a hood to provide a higher level of protection during bronchoscopies.

N95 disposable particulate respirator. These are now commonly used in healthcare settings for protection against tuberculosis because of acceptable appearance, low cost, and practicality.

Healthcare workers are in a unique position--they work in close proximity to infectious diseases like tuberculosis and need adequate protection, yet do not want to isolate or frighten a patient by using a respirator that hinders communication or looks intimidating. There must be a balance between this need for protection and the need for comfort, communication, practicality and efficient patient care. The bottom line is that only certain types of respirators protect a healthcare worker from TB.

Since the resurgence of tuberculosis in the late 1980's, there has been an increased interest in the prevention of occupational tuberculosis (i.e., transmission of tuberculosis from patients to healthcare workers). This outbreak, attributed to a new multidrug-resistant TB bacteria, spurred the research for better preventative actions. In 1990, the Centers for Disease Control first recommended the use of disposable particulate respirators for the prevention of occupational TB. Data showed that the surgical masks being used leaked and did not prevent transmission of TB. In 1993, this recommendation was changed to the use of disposable respirators with high efficiency particulate (HEPA) air filters. In 1995, NIOSH updated and modernized the process for certifying non-powered, air-purifying, particulate-filter respirators. These "Part 84" respirators have passed more demanding testing criteria than used previously. OSHA now mandates the use of this N95 class (N=not resistant to oil; 95=95% efficient) of respirators, at minimum, for protecting against tuberculosis. A final TB standard for respiratory protection is pending.

Most respirators recommended for protection against TB are air-purifying respirators like the disposable N95, a negative-pressure particulate respirator that is most commonly used in healthcare settings because of its unintimidating appearance, low cost, and practicality. A major disadvantage, however, of the N95 is the difficulty in assuring a reliable face-mask seal with each use.

It is important to note that a respirator with an exhalation or exhaust valve should never be provided to patients with infectious TB: exhaust valves allow droplets and particles exhaled by the patient to escape, potentially releasing infectious aerosol.

Another commonly used respirator for TB protection is the elastomeric negative-pressure respirator that is reusable. The body is made of flexible materials that provide a tight face-mask seal. Though it comes in both half-face and full-face designs, the former is more frequently used in health care settings. The masks have a head-strap and neck-strap that allow the respirator to be removed and replaced quickly and easily.

The importance of using a respirator properly can't be emphasized enough. Understanding how to fit, care for and use a respirator is the only means to ensure protection. Adhering to regulations seems that much more challenging for healthcare workers treating and caring for patients infected with tuberculosis. But respiratory protection, when not give the careful attention it requires, is ineffective.

The National Jewish Personal Respiratory Protection Program

The National Jewish Personal Respiratory Protection Program (PRPP) benefits both employers and employees by helping to protect workers exposed to potentially harmful air contaminants on the job. The program is designed to help safeguard workers' health and to enable both companies and workers to comply with government standards.

Serving both industries and individuals concerned with their own protection, the National Jewish PRPP provides comprehensive training in the use, care and limitations of specific masks, including "hands on" instruction, fit testing and take-home pamphlets of information. For larger groups, the PRPP is able to perform on-site quantitative fit testing using the TSI Portacount®, a portable state-of-the-art instrument that meets all regulatory requirements for respiratory protection. The program provides a choice of 12 different brands of negative pressure respirators in three different sizes. Many of these brands are available in both full-face and half-face models. Several positive pressure respirators also are available for demonstration and training.

The program places special emphasis on medical assessment for respirator use. In fact, physicians in the Environmental and Occupational Health division are part of a research program that continues to investigate the use and limitations of respirators.

Worksite evaluation, a vital component of any effective respiratory protection program, is available from National Jewish to assure continued compliance with OSHA requirements. A certified industrial hygienist provides onside consultation with personalized services that include air sampling, exposure analysis, hazard communication, toxicology assessment and ventilation evaluations.

In summary, the National Jewish PRPP offers the following services designed to meet all OSHA requirements that apply when a respirator is provided to an employee:

• selection of a respirator on the basis of the hazards to which the worker will be exposed
• examination by our Environmental and Occupational Health physicians to determine whether the worker is able to wear a respirator
• training of the worker in the proper use, cleaning, storage and limitations of respirators
• quantitative and qualitative fit testing of a respirator
• provision of written standard operating procedures governing respirator use, selection, cleaning and storage

Quantitative fit testing procedure		Qualititative fit testing procedure

Additional Information

Questions about respiratory protection can be addressed to local OSHA or NIOSH offices.

Individuals, industries or physicians with patients in need of respiratory protection services should refer to a qualified respirator fit program in their state. They may also contact Dr. Kevin Fennelly or David Brody at the NationalJewish Research Center Division of Environmental and Occupational Health sciences, (303) 398-1539.

References

1. Respiratory Protection Guidelines. Am J Respir Crit Care Med 154: 1153, 1165, 1996.

2. NIOSH Guide to the Selection and Use of Particulate Respirators Certified under 42 CFR84. DHHS (NIOSH) Publication No. 96-101, 1996.

3. Protect Yourself Against Tuberculosis: A Respiratory Protection Guide for Healthcare Workers. DHHS (NIOSH) Publication No. 96-102, 1995.

4. Fennelly, K. Personal Respiratory Protection Against Mycobacterium Tuberculosis. Clinics in Chest Med 18: 1-17, 1997.

The Medical Scientific Update, a publication of the Office of Professional Education at National Jewish, provides information to physicians about our clinical and research programs in allergic, respiratory, and immune system disorders. The Web edition of the Medical Scientific Update published by the Gerald Tucker Memorial Medical Library.