Recommendation ITU-T Y.4478 (ex Y.IoT-SCS) introduces requirements and functional architecture for smart construction site (SCS) services with a concept, its goals and key components. SCS services offered by a system integrator can deploy and operate various techniques for construction units to effectively improve the remote management level of the construction site and accelerate the speed of handling hidden dangers. This Recommendation analyses common characteristics and specifies requirements of SCS services and describes a functional architecture of smart construction site service platform (SCS-SP) and smart construction site devices (SCS-D).