Design and Verification of Acoustic Room for Consumer Product Safety Testing

Shulun Mak,Chiwing Lai,Chiho Li,Waifan Tang

doi:10.11648/j.eas.20200503.11

Abstract

Sound Producing Toys consists the sound emitting characteristics to attract children’s attention, such as emitting music or simulating animal’s call. The excess sound pressure level (SPL) could damage the human hearing. The international toy safety standards are established to limit the maximum sound pressure level emitted from the product. The Chief Executive of the Hong Kong SAR established the Task Force on Economic Challenges (TFEC) on October 2008. In early 2009, the TFEC has identified six economic areas where Hong Kong enjoys clear advantages. The Six Industries are (i) testing, inspection and certification (TIC), (ii) medical services, (iii) innovation and technology, (iv) cultural and creative industries, (v) environmental industries, and (vi) educational services. The Open University of Hong Kong is offering the undergraduate degree programmes in testing and certification. For the teaching and research purpose, an acoustic room was built to support the areas of sound pressure level measurement in the Open University of Hong Kong. The acoustic room was primarily designed to serve the sound pressure level measurement of the consumer products, including toys and children’s products and gain the Hong Kong Laboratory Accreditation Scheme (HOKLAS) with reference to ISO/IEC 17025. This paper describes the flow of design, consideration of design factors, verification method, applications and limitations of acoustic chamber.

Highlights

The excess sound pressure level may damage the human hearing capability
EN 71-1 established the limit of sound pressure level for Shulun Mak et al.: Design and Verification of Acoustic Room for Consumer Product Safety Testing three different categories of toys
According to the safety standard, the table top toys shall be placed on a standard test table that complied with ISO 7779 (Figure 3)

Summary

Introduction

The excess sound pressure level may damage the human hearing capability. The ISO Guide 50: 2014 is the Guidelines for child safety and concludes fourteen different safety hazards. In order to reduce the risk of hearing damage, the regulatory bodies and standard bodies developed the toys and children’s product safety standards to limit the sound pressure level emitted by the products. The new version of EN71 Part 1 was published in 1998 and it is the first toy safety standard established the detailed safety requirement and measurement methods to measure the sound pressure level emitted from the toys. Before this standard was published, the Consumer Product Safety Acts of United States only required the impulsive sound pressure level percussion caps (Figure 1) shall be less than 138 db (A). The project team designed the acoustic room to meet the European Toys Safety Standard, EN71-1, that specified the environmental requirements of acoustic room for measuring the sound pressure level emitted by the sound-producing toys

Consideration of Factors to design an Acoustic Room

Acoustic Room Dimensions

Selection of Sound Reduction Methods

Performance Verification of Acoustic Room

Conclusion