Mandatory in Singapore houses. Practically used for live-in maid or general storage. But effectively involves a massive metal box in the middle of your house. Given the information (a.o. Sunlight as a electrical contractor) in the blog the OP is living in Singapore.
The red circle in his first image will like be much more distorted in practice by the bomb shelter, meaning his home WiFi will have a lot of trouble reaching whats behind the shelter (i.e. the bathroom and the Mr Bedroom in particular). Basically he got a pretty horrible spot for his router. Study/bedroom3 would have been substantial better.
Swiss law does not require shelters in all private dwellings, (you can pay a small amount at the time of construction for a place in a communal shelter) and I'm not sure that even that is required any more.
Large public buildings maybe still need shelters by law.
