A Rigger is someone who sets up equipment and prepares it before work can commence. The term "rigger" originates from sailing where sailors were responsible for raising the sails and rigging on board a ship. Scaffolding is a temporary structure built to support people and materials during repairs and maintenance of buildings and other structures. In the oil and gas industry, scaffolding is used on oil rigs to allow access to parts of the rig for maintenance and other work. An offshore scaffold will usually have to obtain safety certification for working at extreme heights.