Sprinkler systems, standpipe systems, fire alarm systems, and other fire protective or extinguishing systems or appliances which have been installed in compliance with any permit or order or because of any law or ordinance, shall be maintained in operative condition at all times, and it shall be unlawful for any owner or occupant to reduce the effectiveness of the protection so required; except this shall not prohibit the owner or occupant from temporarily reducing or discontinuing the protection where necessary to make tests, repairs, alterations or additions. The Commissioner shall be notified before such tests, repairs, alterations or additions are started unless the work is to be continuous until completion.