Controller Replacement in an Occupied Building: Alteration or Repair?
A six-story office building has one passenger elevator installed in 1988: 2,500 lb (1,134 kg) capacity, 200 ft/min (1.0 m/s), 208 V three-phase, SCR drive, and relay interface. The owner has signed a contract to replace the SCR controller with a new VVVF controller and to replace the car door operator, while keeping the original car door panels, hoistway doors and interlocks, safeties, governor, machine, and ropes. The contractor's proposal states that because the building is existing, only ASME A17.3 applies and no other upgrades are required. Work starts Monday and is scheduled to last three weeks. The building is fully occupied, this is the only elevator, and a medical office on the third floor has asked how patients will be moved during the outage. The local AHJ has not yet been contacted about the project.
1. Is the controller replacement an alteration or a repair, and which standard governs which parts of the job?
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It is an alteration, not a repair. A17.1 defines an alteration as a change to the equipment other than maintenance, repair, or replacement with equipment of like kind. Swapping an SCR drive for a VVVF drive changes the machine's speed, acceleration, deceleration, and leveling behavior, and the car door operator change alters door timing and kinetic energy. The contractor's statement that only A17.3 applies is incorrect.
The correct framing is two-part:
- The work being performed is governed by A17.1, including its alteration provisions, plus any amendments adopted by the jurisdiction. The new controller must be listed/certified elevator electrical equipment and must be compatible with the retained machine, brake, governor, and safeties.
- The retained, unaltered equipment continues to be judged under A17.3 for existing elevators.
A17.1 does not normally require the whole elevator to be rebuilt to current new-installation requirements, but the alteration must not reduce safety and the altered portion must comply. The AHJ makes the final call on scope, so the scope should be confirmed with the AHJ before work starts rather than after the car is torn apart.
2. Which retained components must be evaluated once the controller changes, and what is likely to be pulled into the scope?
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Start with interfaces, because a new drive changes duty on old hardware:
- Machine brake: coil voltage and rectifier, pick-up and holding current, air gap, stopping torque, and heat. A VVVF drive can change stopping profiles and brake wear.
- Door system: car door operator, car door protective device, door open/close timing, and the forces/knots? forces and kinetic energy limits.
- Hoistway door interlocks and car door contacts: condition and function, since the new controller monitors them differently.
- Terminal stopping, normal and final limits, and the leveling/leveling zone: verify the new drive does not rely on software alone where hardware is required.
- Emergency operation, alarm, and communication features, and standby power provisions if the building has them.
A17.1's alteration provisions identify related items that must be brought up to date when a controller is replaced; the exact list depends on the edition adopted in Minnesota, so read the adopted text and the AHJ's amendment rather than assuming only the controller changes. The safe approach is to submit the scope with the alteration and let the AHJ confirm it before the equipment is ordered.
3. What Minnesota procedural steps apply before the car carries passengers again, and what should be done about the medical office?
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Minnesota's elevator rules (Minn. R. ch. 1307) adopt ASME A17.1/A17.1s and A17.3 by reference with amendments, require elevator work to be done by a licensed elevator contractor using licensed elevator constructors, and require notification/inspection by the AHJ (DLI) before equipment is placed in service. Verify the currently adopted edition and the specific permit and inspection requirements with DLI before starting, because the job is not legal to energize and turn over on the contractor's word alone.
Practically, the sequence is: confirm scope with the AHJ, obtain the required permit, perform the alteration, complete the tests the code requires for altered equipment, and have the AHJ inspect and witness what it requires before the car goes back into service. Temporary operation for construction use is not the same as returning the elevator to public service.
For the medical office, the elevator code does not solve the access problem. The owner should be told in writing that the only elevator will be out of service for three weeks, and the owner must plan an accessible route or relocate appointments. Put that notice in the contract and document it; do not let the building assume the contractor will work around patients.