Part A is aimed specifically at the structure of a building. In short, Part A of the regulations aim to ensure that the building will stay up, in normal circumstances and not collapse ‘disproportionately’ in the course an abnormal event.
A1 – Loading
The building needs to be constructed in such a way that all combined loads are sustained and transmitted to the ground. This includes the physical weight of the complete building together with any additional loads, such as wind and snow, imposed through its use.
This needs to be achieved safely and without affecting the stability of any other building.
A2 – Ground Movement
The building needs to be constructed so events such as swelling or shrinking of the subsoil or subsidence will not adversely affect the integrity of the building.
A3 – Disproportionate Collapse
The building must be constructed so that it will not collapse disproportionately in the event of an accident.
Put simply, if the building is hit by a car then the damage caused should be proportionate to such an impact and no more.