These may be used in multistory buildings to transport small loads between levels.
Generally too small to carry an operator or passenger, dumbwaiters are cars that are raised or lowered like elevators. They may be powered controlled by push buttons or manually operated by pulling on ropes. Powered dumbwaiters can automatically handle from 100 to 500 lb at speeds from 45 to 150 ft /min. They are available with special equipment for automatic loading and unloading. They also are designed for floor-level loading suitable with cart-type conveyances.
The American National Standard Safety Code for Elevators, Dumbwaiters, Escalators and Moving Walks, ANSI A17. 1, contains safety requirements for dumbwaiters. Powered dumbwaiters may be constructed like electric elevators with winding-drum or traction driving machines or like hydraulic elevators. Many of the safety requirements for elevators, however, are waived for dumbwaiters. Standard heights for a dumbwaiter are 3, 31â„2, and 4 ft. ANSI A17.1 restricts platform area to a maximum of 9 ft2. Rated load capacity usually ranges from 20 to 500 lb. Like elevators, hoistways should have fire-resistant enclosures.
