प्री-फैब्रिकेटेड (पूर्वनिर्मित) भवन निर्माण में आमतौर पर निम्नलिखित में से किस उपकरण का उपयोग नहीं किया जाता है?

Which material is used for shuttering/formwork equipment that requires very little maintenance and can be reused multiple times for years?

A mechanized construction site has planned to make use of tower cranes for the transport of materials and components. The locality has a 220 kV overhead power line passing through it. According to IS 8969:1978, as a precautionary measure of safety, the minimum vertical clearance of any member of the crane with respect to the overhead power line shall be: