Paragraph 21 Automatic or mechanical equipment

The back-up system referred to in paragraph 20(a) must be thoroughly inspected, and the alarm system referred to in paragraph 20(b) tested, in each case not less than once every 7 days in order to check that there is no defect in it, and, if any defect is found in such system or alarm (whether or not on it being inspected or tested in accordance with this paragraph), it must be rectified forthwith.