VENTILATION UNIT

摘要

A ventilation unit for mounting at the ridge of a roof has an elongate shell of semicircular section with at least one exhaust outlet (16) provided at the peak of the shell. The shell contains thermal insulation material (3), so as to create a low temperature, low pressure zone within it, which hot air to be exhausted enters. Pressure differential with the atmosphere outside causes the hot air to be drawn out through the outlet (16). The unit is suitably made in modular form from main modules (12) containing the exhaust outlets (16) and extension modules (14) without such outlets.