Unmanned Assessment of Respirator Carbon Dioxide Levels: Comparison of Methods of Measurement

Abstract

A study was performed to determine average inhaled carbon dioxide (F_ICO₂) concentrations of multiple respirators using unmanned test methods, and to compare results among test procedures to determine whether they could be used interchangeably. Respirator experiments were performed according to the National Institute for Occupational Safety and Health (NIOSH) (NF_ICO₂), standard European (ENF_ICO₂), and a modified method of the European test (BF_ICO ₂ ) using full-facepiece air-purifying respirators and one air-purifying escape respirator. Bland-Altman statistics for determination of limits of agreement were applied to assess agreement among the various test methods. A considerable lack of agreement was found between NF_ICO₂ and ENF_ICO₂ methods and between BF_ICO₂ and NF_ICO₂ methods for average F_ICO₂. The modified EN136 method produced F_ICO₂ averages about 0.13% to 0.23% above unmodified EN136 values, but the agreement between methods was generally acceptable. These results demonstrate that NIOSH and European unmanned test methods for determining respirator average F_ICO₂ concentrations produce different results for like respirators. However, the findings suggest that the ENF_ICO₂ and BF_ICO₂ unmanned methods could be used interchangeably for quantifying respirator F_ICO₂ concentrations.

Keywords:

• carbon dioxide
• respirators
• unmanned testing

ACKNOWLEDGMENTS

The authors would like to express their sincere gratitude to the Office of Law Enforcement Standards, National Institute of Standards and Technology for financial support. Also, to Gary Walbert, EG&G Technical Services, for performing data collection, data analysis, and for providing details concerning the test methods and equipment utilized at the NPPTL facility, and to Cindy Ching, Science Applications International Corporation, for data collection and analysis in our Edgewood laboratory.

The findings published herein are the sole responsibility of the authors.

Notes

^A Significantly different from both NF_I CO ₂ and BF_I CO ₂.

^B Significantly different from both BF_I CO ₂ and ENF_I CO ₂ methods.