Lightweight Retractable Noise Barrier in Hong Kong

Abstract

Construction noise is one of the major noise pollution sources in urban area. In Hong Kong, the Noise Control Ordinance (NCO) states that construction works at night time and holiday with Powered Mechanical Equipment (PME) are only allowed if the PME noise levels are controlled within the Acceptable Noise Level (ANL) calculated at nearby Noise Sensitive Receivers (NSRs). In many cases, night works require noise barriers to minimize the PME noise levels. However, conventional noise barriers of 3m to 6m height require a heavy base in order to sustain occasional heavy gust wind loading. Those heavy bases require cranes to install and relocate which may not feasible under some site constraints. SilentUP(r) Retractable Noise Barrier has been invented in Hong Kong to meet this demand. It is a 7m high noise barrier without concrete foundation. The modular design and magnetic connecting mechanism allow SilentUP(r) to form a continuous wall. It can be installed, uninstalled and relocated by people without using any machines. The entire process is quiet enough to be completed at night. To enhance the stability and safety features, a patented automatic wind load relieving mechanism is incorporated so that the lightweight structure remains safe during occasional gusts. It reduces up to 95% structural loading requirement and hence a lightweight design can be adopted. The on-site insertion loss performance of SilentUP(r) Retractable Noise Barrier is varied from 11-21 dB(A) depending on the noise source and size of barrier / enclosure.