8-hour performance of loose-fitting powered air-purifying respirators in simulated hospital and coal mine environments

Abstract

Loose-fitting powered air-purifying respirators (LF-PAPRs) are increasingly used in hospitals and coal mines because of their high comfort and protection level, but the utilization faces the challenges of 8-hr continuous high protection requirements in the hospital environment and the coupling effects of high temperature, high humidity, high dust concentration in coal mines. Based on the self-developed powered air-purifying respirator simulation test system, this study explores the 8-hr changes of supplied airflow, the relative air pressure inside the inlet covering (ΔP), and total inward leakage (TIL) of four models of LF-PAPRs in simulated hospital and coal mine environments. Results show that: (1)(1) $$Q\left(t\right)=\mathit{PIF}\times \sin (\mathrm{\pi }ft/30)$$(1) In a simulated hospital environment, all four LF-PAPRs showed filter cartridge blockage within 5 ∼ 6 hr of continuous operation; while in the simulated coal mine, three models of LF-PAPRs showed filter cartridge blockage within 3 hr. (2)(2) $$\mathit{TIL}=C_{in}/C_{\mathit{out}}\times 100\mathrm{\%}$$(2) In both the hospital and coal mine environments, there are cases where the supplied airflow of LF-PAPRs dropped below 170 L/min within 3 hr. (3)(3) $$\Delta P=P_{in}-P_{\mathit{out}}$$(3) In a simulated hospital environment, the ΔP of all LF-PAPRs maintained positive within 5–6 hr; while in the simulated coal mine, the ΔP of two LF-PAPRs, respectively, appeared negative after 1 hr and 1.6 hr operation. (4) The maximum TIL of the tested LF-PAPRs, respectively ranged from 0.5–0.9% and 1.4–3% in simulated hospital and coal mine environments. (5) In both hospital and coal mine environments, the supplied airflow and ΔP of each LF-PAPR showed a decreasing trend with increasing test duration, while the TIL significantly increased with testing time. (6) The supplied airflow, ΔP, and TIL of each LF-PAPR in the simulated hospital environment performed better than those in the coal mine. This study evaluated the performance of PAPR under the most severe operating conditions, and respirator performance may differ under in-situ conditions.

Keywords:

• PAPR
• pressure drop
• respiratory protection
• supplied airflow
• total inward leakage

Acknowledgments

The authors would like to thank the financial support provided for this study.

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Disclosure statement

The authors report there are no competing interests to declare.

Additional information

Funding

This study received financial support from the National Natural Science Foundation of China (Nos. 51904291, 52174222, and 51674252), the Basic Research Program of Jiangsu Province (No. BK20190638), the Project funded by China Postdoctoral Science Foundation (No. 2020M681781), the Anhui Province Key Laboratory of Human Safety.