Elevator Bank Configuration Calculator

5-Min Peak Demand is a pure, unconditional product of exactly two inputs: Building Population × Handling Capacity %. Number of Floors, Car Capacity, Car Speed, and Floor-to-Floor Height never touch it -- demand is entirely a function of how many people are in the building and what fraction of them the code target expects to move during the up-peak. Expected Stops Per Trip comes from the Barney probabilistic formula for expected stops -- S = N x (1 - ((N-1)/N)^P) -- the classical round-trip-time methodology documented in CIBSE Guide D's lift traffic calculation chapter, not an invented approximation.

Round-Trip Time (s) responds to Car Speed and Floor-to-Floor Height in opposite directions: Car Speed only appears in the denominator of inter-floor travel time, so a faster car always shortens Round-Trip Time, while a taller Floor-to-Floor Height always lengthens it, verified across each input's full declared range. Elevators Required, by contrast, is computed with two nested ceiling (round-up) functions -- fractional demand rounds up to whole cars, so a small change in Handling Capacity % near the calculator's own default often lands inside the same "whole car" bracket and produces no visible change, even though a larger swing clearly changes the recommended car count. Service Quality Rating buckets the computed Up-Peak Interval into four bands (≤25s Excellent through >40s Poor) -- it responds only through whatever combination of inputs moves Round-Trip Time and Elevators Required, never directly to any single input on its own.