In Scotland, listing was begun by a provision in the Town and Country Planning (Scotland) Act 1947, and the current legislative basis for listing is the Planning (Listed Buildings and Conservation Areas) (Scotland) Act 1997.  As with other matters regarding planning, conservation is a power devolved to the Scottish Parliament and the Scottish Government . The authority for listing rests with Historic Environment Scotland (formerly Historic Scotland ), an executive agency of the Scottish Government, which inherited this role from the Scottish Development Department in 1991. Listed building consent must be obtained from local authorities before any alteration to a listed structure. 
There are structures tagged as buildings which are missing a foundation or are even moveable. For example many mappers are using the key building =* to describe moveable objects and buildings for example building = static_caravan , building = houseboat or trailers. While houseboats (often self propelled), ships (for example museum or theatre ships) or docks may be moved once, there are also building = floating_home s which are built on floating logs and do not get moved. Some mappers are additionally using floating = yes to indicate this property.
In our implementation, the state allOff is the initial state, indicated by its double frame. The transition T1 is used to switch the pumps on. Once the pumpsOn state is active, there are two alternate paths. Either transition T2 may fire, which would switch the boiler on, or T4 may fire, which would return to the allOff state. Hence, the boiler can only be on when the pumps are on. From the state boilerOn , the only next step can be to transition to the state pumpsOn . Note that the transitions T3 and T4 only fire when their input is true for the entire duration of 10 seconds. Hence, the pumps and the boiler must run for at least 10 seconds before they can be switched off.