Round Trip Time (RTT)
Estimate an elevator's round trip time (RTT), RTT = 2·(H ÷ v) + stops × t_stop, from the travel height H (m), the speed v (m/s), the number of probable stops and the average time per stop (s, including deceleration, door opening/closing and boarding). The result, in seconds, is the time of a complete up-and-down cycle with stops — a central parameter of vertical traffic analysis. The higher the RTT, the lower the handling capacity and the longer the interval between cars. Enter the height, the speed, the number of stops and the time per stop.
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Tempo de viagem redondo (RTT)
O tempo de viagem redondo (round trip time, RTT) é o parâmetro central da análise de tráfego vertical: o tempo que um elevador leva para completar um ciclo — subir do térreo atendendo às chamadas, e voltar. Uma estimativa simplificada é RTT = 2·(H ÷ v) + paradas × t_parada, somando o tempo de percurso (subida e descida da altura H à velocidade v) ao tempo gasto nas paradas (cada parada custa o tempo de desaceleração, abertura e fechamento de portas, embarque/desembarque, e reaceleração — tipicamente 8-15 s no total por parada, aqui simplificado). O RTT real depende do número de paradas prováveis (calculado probabilisticamente a partir dos passageiros e andares), do andar mais alto alcançado, das acelerações e dos atrasos de porta. O RTT é a base de tudo: dele derivam a capacidade de transporte (quantas pessoas por 5 min) e o intervalo entre elevadores (tempo de espera). Reduzir o RTT — com mais velocidade, portas mais rápidas, ou algoritmos de despacho inteligentes que agrupam chamadas — é o objetivo da engenharia de tráfego de elevadores. Informe a altura, a velocidade, o número de paradas e o tempo por parada.
Related Tools
Probable Stops
Calculate the probable number of stops of an elevator, S = N × (1 − (1 − 1/N)^P), from the number of served floors N and the number of passengers P in the car. The result is how many floors, on average, the elevator actually stops at during a trip (probabilistically, two passengers may go to the same floor). It is an essential parameter of the round trip time calculation: more stops raise the RTT. The formula assumes passengers choose destination floors randomly and uniformly. With a full car, S approaches N (stops at almost all). Enter the number of floors and passengers.
Elevator Traffic Interval
Calculate the traffic interval (average waiting time) of an elevator group, INT = RTT ÷ N, dividing the round trip time RTT (s) by the number of elevators N in the group. The result, in seconds, is the average time between elevator arrivals at the main floor — the main service-quality indicator perceived by users (waiting time). Intervals up to 30 s are excellent; above 50-60 s, poor. More elevators in the group reduce the interval. It is the key criterion in sizing the number of elevators. Enter the RTT and the number of elevators.
Number of Elevators Required
Calculate the number of elevators required, N = peak demand ÷ capacity per elevator, dividing the peak transport demand (people in 5 min) by the handling capacity of a single elevator (people in 5 min). The result is the minimum number of elevators in the group to meet peak demand. In practice, round up and also check the resulting traffic interval (waiting quality). Peak demand comes from the building population times the peak percentage (12-15% in offices). Undersizing causes queues and long waits. Enter the peak demand and the capacity per elevator.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.