ارزيابي عملكرد آكوستيكي مانكن سر جهت استفاده در آزمون هاي تعيين قدرت كاهندگي صداي وسايل حفاظت شنوايي

Study of the Performance of Acoustic Fixture for Using in Noise Reduction Rate Tests of Hearing Protection Devices

مقدمه: يكي از روش هاي توصيه شده جهت ارزيابي كارايي وسايل حفاظت شنوايي استفاده از مانكن سر مطابق استاندارد 3-4869 است. هدف از اين مطالعه ارزيابي عملكرد آكوستيكي مانكن سر طراحي شده جهت استفاده در آزمون هاي تعيين قدرت كاهندگي صداي وسايل حفاظت شنوايي در شرايط آزمايشگاهي مي‌باشد. روش بررسي: در اين مطالعه توصيفي تحليلي ابتدا قدرت كاهندگي صداي پنج مدل گوشي ايرماف رايج در صنايع كشور بر مبناي روش ميكروفن داخل گوش طبق استاندارد ISO11904-1 توسط دستگاه دزيمتر SV102 شركت SVANTEK مجهز به ميكروفن SV 25 قابل نصب داخل گوش در شرايط آزمايشگاهي روي 30 نفر تعيين گرديد. همچنين قدرت كاهندگي گوشي هاي مذكور با استفاده از مانكن آكوستيكي سر مطابق استاندارد تعيين گرديد. داده ها توسط نرم افزار SPSS 21 مورد تحليل قرار گرفت. يافته ها: نتايج نشان داد نسبت قدرت كاهندگي واقعي صداي گوشي ها به كاهندگي اسمي با بررسي روي افراد در محدوده بين 59% الي 94% قرار دارد. اين نسبت براي گوشي هاي مذكور روي مانكن سر بين 64% الي 92% قرار داشت. نتايج آزمون آماري نشان داد بين ميانگين كاهندگي صداي گوشي ها روي افراد به عنوان نمونه واقعي و مانكن سر اختلاف معني داري وجود ندارد (0/05

Introduction: One of the recommended methods for evaluating the effectiveness of hearing protection is the use of acoustic fixture, in accordance with the ISO 4869-3 standard. The aim of this study was to evaluate the acoustic performance of fixture for using in noise reduction rate tests of hearing protection devices in the laboratory. Methods: In this cross-sectional study, noise reduction rates of five common ear muffs used in Iranian industries were investigated based on the ISO 11904 standard, microphone in real ear method, using noise dosimeter (SVANTEK, SV102 model), equipped with microphone SV25 model, which was installed inside ear on 30 subjects under laboratory conditions. Furthermore, the noise reduction rate of earmuffs was determined using the AVASINA9402 fixture model in accordance with standard procedures. Data were analyzed using SPSS 21 software. Results: The results showed that the real noise reduction rates of the earmuffs on the studied subjects were from 59% to 94% of nominal reduction rates. Those rates for the ear muffs on the studied fixture were from 64% to 92%. The results showed that the noise reduction rates differences of the ear muffs on subjects compared with those of the ear muffs on fixture were not statistically significant (P > 0.05). Conclusions: The results showed that the accuracy of noise reduction rates of earmuffs using fixture compared with real subjects was acceptable. Hence, fixture is a good choice for environments where there is no possibility of acoustic evaluation on real subjects, also for quality control of productions for earmuff manufacturers.