The Suction Ceiling: Altitude, Temperature, and the Two-Stage Answer for the Treadle Pump

Maximum treadle-pump suction lift is 9.39 m at sea level and 20 C, 9.06 m at 35 C, 8.15 m at 1,000 m altitude, and 6.87 m at 2,000 m with warm water; 100 W leg power at 50 percent efficiency gives 152.9 L/min at 2 m total head falling to 30.6 at 10 m, and two-stage pumping buys back suction geometry but not the power bound. SIMULATED, NOT MEASURED.