Elevator Door Closing Kinetic Energy and Force

The two limits are independent and they fail differently. CLOSING FORCE is a static measurement at the leading edge with a calibrated gauge, and it catches a door operator adjusted too hard. KINETIC ENERGY is dynamic and catches a door that is heavy rather than forceful -- a wide two-speed door with substantial panel mass can be within the force limit and well outside the energy limit, because energy carries the mass term that force does not. A 140 lb moving assembly at 1.0 ft/s average closing speed carries 2.18 ft-lb. The square on speed is what makes compliance manageable: energy goes as the square, so reducing closing speed by a fifth cuts the energy by more than a third, and a door that fails the energy limit can usually be brought in by slowing it a little rather than by lightening it -- at the cost of door time, which across a day of service is real traffic capacity and is the trade being made. The mass side moves proportionally, so a 20 lb panel upgrade takes that same door to 2.49 ft-lb with nothing else changing, which is why door panel changes are not cosmetic. THE PROVISION THAT MATTERS MOST IN SERVICE is the reduced limit that applies when the reopening device is inoperative. A door running with its detector edge or light curtain out of service must close under a much lower energy limit -- effectively nudging closed -- because the only thing preventing a strike is now the passenger. A door that closes at full speed with a failed reopening device is a defect, not an inconvenience. A kinetic energy calculation. The applicable limits, the portion of travel over which the average speed is measured, and the measurement procedure are set by the adopted code edition and are entered here rather than shipped, and the reduced limit is a separate value. It does not measure the door mass, which includes panels, hangers, linkage, and the moving portion of the operator and is commonly underestimated, and it does not evaluate the reopening device's own performance, the code requirements for detector edges and light curtains, door timing, dwell, nudging operation, or the fire operation requirements that change door behaviour. ASME A17.1 and A17.2, the door equipment manufacturer, the elevator authority having jurisdiction, and a licensed elevator mechanic govern.

kinetic energy = one half x (door weight / 32.174) x closing speed squared; the speed that lands on a target energy = the square root of (2 x target x 32.174 / door weight); closing time = clear opening width / speed.

The door closing kinetic energy relation, by name, checked against the ASME A17.1 closing energy limits -- the normal one and the lower one that applies when the reopening device is inoperative -- with the closing force limit named as a separate, statically measured criterion. Both limits are entered from the adopted code edition.

Elementary kinetic energy on a door weight and speed the user measures, against limits they enter from the code.

Estimate. AHJ and licensed professional govern.

Field names used by the API: door_mass_lb, closing_speed_fps, ke_limit_normal_ftlb, ke_limit_reduced_ftlb, measured_force_lbf, force_limit_lbf, opening_width_in, added_mass_lb, kinetic_energy_ftlb, speed_for_reduced_limit_fps, closing_time_s, ke_with_added_mass_ftlb

• Force and energy are separate limits a heavy door can pass the force check and fail the energy one, because energy carries the massASME A17.1
• Speed is the practical lever energy goes as its square, so a modest slowdown buys a large reductionkinetic energy
• The reduced limit is the service case a door with its reopening device out must close under a much lower energy limitASME A17.1