Evaluating the effect of training along with fit testing on foam earplug users in four factories in China

Abstract

Objectives: To gain insight into the hearing protection practice of Chinese workers and the value of hearing protection fit testing.

Design: The Field Attenuation Estimation System (FAES) was used to measure the personal attenuation ratings (PARs) of one foam earplug used at the work sites in China. Intervention was provided to workers who needed it. Follow-up fit testing was conducted approximately six months later. Paired t-tests were conducted to compare the baseline, post-intervention and follow-up visit PARs.

Study sample: Fit testing was conducted on 335 workers in four factories with 269 workers intervened. Follow-up visit was conducted on 97 intervened workers in three factories.

Results: The mean PAR baseline was 10 dB. Significant improvement was shown on post-intervention PARs (p < 0.05) as well as follow-up visit PARs (p < 0.05). Comparing follow-up visit PARs to post-intervention PARs, good sustainability was shown in two factories (p > 0.05), while a significant decline (p < 0.05) was observed in another.

Conclusions: Hearing protection fit testing demonstrated value for verifying sufficiency of attenuation. The training along with fit testing contributed to improve PARs and maintaining effectiveness over time. Employer’s attention and follow-up actions are important in sustaining the training effectiveness.

Keywords:

• Hearing protection device (HPD)
• earplug
• foam earplug
• fit testing
• personal attenuation rating (PAR)
• China

Note

Acknowledgments

We thank Enmin Ding, Jun Wu at Jiangsu Provincial Center for Disease Control and Prevention on industrial hygiene field assistance. We would like to express our great appreciation to Elliott H. Berger, Division Scientist of 3M Personal Safety Division for his careful review and comments from scientific point of view on this manuscript.

Disclosure statement

One of the authors, Yufei Liu is an employee of 3 M China Ltd. Personal Safety Division, the manufacturer of the tested earplugs and 3M^™ E-A-Rfit^™ Dual-Ear Validation System.

Notes

1 Throughout this article, PAR₈₄ will be referred to simply as PAR. However, in the discussion section a PAR₅₀ will be introduced which is approximately equal to PAR₈₄ plus 7 dB.