The tunnel was made as long as possible without having to add forced ventilation to dilute carbon monoxide from automobile exhaust, and a shaft was built mid-way along the tunnel to provide passive ventilation, with the capacity to add a fan later for forced exhaust through the shaft, if necessary.
12.
The compact design of the main stand building, the shadowing of internal areas by the extended roof ( reduced air condition / passive ventilation ) joined by natural daylight due to the translucent roof cover, use of grey water ( water conservation / rainwater; 50 % + reduction of potable water use ), permanent local gas cogeneration ( usually 30 % higher energy efficiency than general power grid ) and roof integrated solar panels not only reduce the energy necessity of the stadium but contain also the chance for the stadium operator to supply the neighbourhood with excessive power.
