Such sites used to be surrounded by corrugated steel fences, which were often the subject of complaints for their ugliness, their inability to absorb noise, and their tendency to be blown apart by the wind and injure passersby.
以往建築工地常以鐵皮當作圍籬，不但醜陋、有被狂風吹倒傷人的危險，也無法吸收噪音，常引發民怨。