Elevator Pit Depth Calculator

Required Pit Depth is a straight sum of six clearance terms: buffer stroke, buffer compressed height, running clearance below the car, guide shoe clearance, an optional compensating-sheave allowance, and a fixed 600 mm code-required refuge space, plus whatever Additional Margin you add -- then the total is rounded up to the nearest 50 mm. Buffer stroke is the one term that actually depends on Rated Speed, and it is calculated as v-squared over a deceleration constant, but the formula also floors it at a minimum (65 mm for spring buffers, 150 mm for oil buffers). At the calculator's own default speed of 1.5 m/s, an oil buffer's calculated stroke (about 115 mm) never clears that 150 mm floor, so Rated Speed has no visible effect on pit depth until it climbs past roughly 1.7 m/s -- below that, the buffer floor is doing all the work, not the speed you entered. Additional Margin (mm) is the input that most reliably moves the total: every increment adds straight to the sum before rounding.

Toggling Compensating Sheave on inserts a flat 450 mm clearance term for the sheave hardware. Car Inside Height (m) is declared as an input and echoed in the calculation steps, but it is never read by the formula -- pit depth here depends only on buffer stroke, code clearances, and your margin, not on how tall the cab itself is. This tool follows ASME A17.1 / EN 81-20 clearance logic in simplified form; it does not replace a manufacturer's certified pit drawing, and it does not check overhead (top-of-shaft) clearance, which is a separate calculation.