Comparison of Workplace Protection Factors for Different Biological Contaminants

Cho, Kyungmin Jacob; Reponen, Tiina; McKay, Roy T.; Dwivedi, Alok; Adhikari, Atin; Singh, Umesh; Shukla, Rakesh; Jones, M. Susan; Jones, Gordon F.; Grinshpun, Sergey A.

doi:10.1080/15459624.2011.585094

Cited by 14 publications

(13 citation statements)

References 32 publications

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“…The above results indicated that the protection factors of full masks against aerosols were better than half masks or surgical masks. Previous farm studies showed that the protection factors of N95 filtering facepiece respirators against particles not only were increased with particle size, but also varied depending on the types of pollutants (e.g., dust, fungi, bacteria, endotoxin, (1→3)-beta-D-glucan) (Lee et al, 2005;Cho et al, 2011), which indicated that both determination methods (e.g., sensitivity, working principle) as well as particle properties (e.g., shape, size) affected the results of PFs.…”

Section: Fit Factors and Protection Factors Of Ffrsmentioning

confidence: 99%

Performance Evaluation of Full Facepiece Respirators with Cartridges

Lee

Chen

Hwang

et al. 2017

Aerosol Air Qual. Res.

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Full facepiece respirators (FFRs) with charcoal cartridges are very common wearable devices for industrial or military purposes preventing respiratory tract, face, eyes, and mouth from hazards exposure. However, related research for performance evaluation was rare. We aimed to use a self-developed testing system investigating (1) filtration efficiency (FE) of aerosols in charcoal cartridges; (2) breakthrough time of cyclohexane in charcoal cartridges; (3) fit factors (FFs) and (4) protection factors (PFs) of FRRs. The results showed that FE of charcoal cartridges against 0.3 µm of sodium chloride (NaCl) and dioctyl phthalate (DOP) particles under 85 L min -1 were 99.93% and 99.89%, respectively, which did not meet the standard 99.97% regulated for filters such as P100 and HEPA. As for 42.5 L min -1 condition (dual canisters), the FE against NaCl (99.97%) did meet the requirement set for HEPA (99.97%); however, that against DOP (99.95%) failed to meet the standard. In addition, the breakthrough time of 3000ppm cyclohexane was 31 min under 32 L min -1 , which was longer than the 30 min standard described in CNS6636 Z2023 and JIS8152. As to the results of fit test among 21 subjects, only 1 failed to meet the requirement (fit factor = 500) and the average of fit factors was 8342 ± 5892. The mean value of protection factors was 112.3 ± 54.6 while 3 users had lower PFs than the assigned protection factor (APF = 50) regulated by Occupational Safety and Health Administration (OSHA). APFs obtained for particles less than 100 nm were smaller than the APF standard regulated by OSHA, indicating APF standards may be overestimated for such particle size. Therefore, users should be aware of potential risks caused by such substances in nano-sized scale (e.g., nanoparticles or viruses) when wearing FFRs.

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Section: Fit Factors and Protection Factors Of Ffrsmentioning

confidence: 99%

Performance Evaluation of Full Facepiece Respirators with Cartridges

Lee

Chen

Hwang

et al. 2017

Aerosol Air Qual. Res.

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“…Subsequent studies have used flow rates up to 10 L/min without a discernible effect on WPFs. (27–29) Pressure drop of current NIOSH-certified U.S. particulate respirator filters is low, typically on the order of 10 – 20 mm water for N95 and P100 classes, respectively, at a flow rate of 85 L/min. (30) Because pressure drop decreases directly with decreased flow rate, the measurements at 10 L/min will be significantly lower than these values.…”

Section: Site Selection Subject Selection and Preparation Sampling mentioning

confidence: 99%

“…(13–24, 28,29) Nonetheless, some investigators have suggested positive corrections to C i measurements to account for sample losses such as retention of particles in the respiratory tract, respirator dead space, and loss of particles on cassette walls. (27,41) While theoretically correct, some of the suggested corrections rely on models using assumptions that may be incorrect in the workplace.…”

Section: Site Selection Subject Selection and Preparation Sampling mentioning

confidence: 99%

“…However, it can be said that most WPF studies published in the United States have used the lower 5th percentile point estimate of a log-normal WPF distribution as a plausible and conservative value for an APF for the class of device under evaluation. (14–16,18–22,24,27–29) OSHA also used this method to establish several legally mandated APFs for several types of RPD. (56) …”

Section: Site Selection Subject Selection and Preparation Sampling mentioning

confidence: 99%

“…While substitution of an analytical LOQ or a fraction thereof has been common practice, random effects, nonparametric, and censoring regression models have also been used. (29,57,58) When most or all C i samples in a study are below the quantification limit, as is often the case in studies of high-performing respirators, (17,20,23,24) meaningful WPF distributions cannot be calculated. In these cases, reporting WPFs as values “greater than” a minimum value calculated using the quantification limit as the C i mass (for example) may be most appropriate: This process avoids bias and error introduced by assumptions regarding the C i distribution or the expected level of performance (APF) for the device.…”

Section: Site Selection Subject Selection and Preparation Sampling mentioning

confidence: 99%

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Criteria for the Collection of Useful Respirator Performance Data in the Workplace

Janssen

Zhuang

Shaffer

2014

Journal of Occupational and Environmental Hygiene

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Workplace protection factors (WPFs) are intended to measure the ability of a respiratory protective device (RPD) to reduce contaminant exposure when used in the context of an effective respiratory protection program. In 1992, members of the American Industrial Hygiene Association Respiratory Protection Committee (RPC) published a review of important issues and considerations for measuring respirator performance in the workplace. The RPC recognized that respirator testing in workplaces can have a variety of objectives and endpoints, and that not all workplace measurements are WPFs. That paper addressed concerns in the general categories of 1) study objectives; 2) site selection; 3) subject selection and preparation; 4) sampling and analytical methods; and 5) data analysis. No specific protocol for measuring WPFs was recommended by the RPC, and attempts to reach a U.S. consensus on a WPF protocol since 1992 have not succeeded. Numerous studies have implemented the principles for WPF measurement described in the RPC paper. Modifications to the original recommendations have been made to reflect the current state of the art. This article describes what has been learned in recent years in each of the five categories identified in the 1992 discussion. Because of the wide variety of workplaces and work activities, contaminants and respiratory protective devices, a strict protocol is not appropriate for collecting WPF data. Rather, the minimum requirements for the collection and presentation of meaningful respirator performance data in the workplace are described. Understanding of these principles will permit useful RPD performance data to be generated.

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