An elevator entrapment is a stressful event; clear and frequent communication is an essential part of keeping trapped passengers calm and informed of how their rescue is progressing. Elevator mechanics, building staff, or firefighters yelling down the elevator hoist way (whilst not ideal) may work in low rise buildings, but as the number of floors increases it quickly becomes apparent that this is not an effective way to communicate.
Requirement 18.104.22.168.2 in the A17.1 Safety Code (the Code) requires a separate communication system in order to provide two-way communication with trapped passengers from within the building, where the elevator travel is 60ft (18m) or more.
Since 2000, the Code requirements have changed. Here we will break the subject down by year and highlight where changes have occurred:
Requires (‘shall be provided…’) a means of two-way communication between the elevator car and a ‘readily accessible location outside of the hoist way’. This then allows rescue personnel to quickly and easily communicate with trapped passengers in an elevator car. A “readily accessible location” is defined locally site by site.
Due to changes elsewhere in Section 2.27 of the Code, the requirement was updated to specify that the two-way communication stipulates an override any communications out of the building – this prevents a conflict between the elevator emergency telephone and the in-building system. Additional sub-requirements were also introduced:
Sub-requirements were introduced to provide for an automatic time-out of the two-way communication and the facility for the authorized personal to extend the call if they wished. This was introduced to avoid situations where the two-way communication is improperly terminated (such as a receiver being left off hook) and therefore holds the line open and blocks subsequent attempts to re-open two-way communication.
Examples of readily accessible locations can be security desks in the building lobby, building control centers, fire command centers, or elevator machine rooms.
In order to establish the physical connection between the elevator car and the readily accessible location, the communication path will inevitably run through the elevator travelling cable. Given cores are always at a premium in a travelling cable, many systems utilize the same wiring for the elevator emergency telephone and the in building two-way communication system. Nothing in the Code prohibits this practice but the system must have a way of switching between modes, allowing an external call from the elevator emergency telephone and internal calls form the in-building system.
Janus Elevator provides a wide range of A17.1, ADA and A117.1 code compliant elevator emergency telephones and accessories including the EMS5 call consolidator which provides in building two-way communication functionality.