1. (a) In existing installations the machinery for operating elevators, when not installed in a penthouse, engine room or motor room, shall be guarded by an approved guard or standard railing as specified in section 8-1.54, set not less than 12 nor more than 20 inches from any moving part. Such enclosures shall be properly lighted. When the machine is located at the bottom of the hoistway it shall be protected with a substantial pit pan.

2. (b) In future installations the enclosure shall be of solid or open work not less than six feet high, and the entrances thereto protected by a door provided with a lock.

   Exception:

   This section shall not apply to machines hung or mounted on ceiling.

   Note:

   For counterweight guards see subdivision (b) of section 8-1.43.

In factory buildings erected before or after October 1, 1913; in mercantile establishments in buildings erected before or after November 1, 1920.