Systems & Code
Elevator Types & Governing Code
The two main elevator types and the safety code that governs them.
Traction vs. Hydraulic
Two primary elevator types: • TRACTION — the car is raised and lowered by steel ropes (or belts) over a grooved drive sheave, driven by a hoisting machine, balanced by a COUNTERWEIGHT. Used for mid- and high-rise buildings; faster and more efficient. • HYDRAULIC — a piston/plunger powered by a pump pushes the car up; gravity lowers it. Used for low-rise (typically up to ~5-6 floors). No counterweight.
Know that traction uses a counterweight; hydraulic uses a piston and pump.
The Governing Code
Elevators in North America are governed by ASME A17.1 / CSA B44, the Safety Code for Elevators and Escalators. It sets requirements for design, construction, installation, testing, and maintenance.
Inspections and tests (including periodic and acceptance tests) verify ongoing safety. Local jurisdictions adopt and enforce the code.
Major Components
Key parts: the CAR, HOISTWAY (shaft), MACHINE (motor/drive), CONTROLLER (the 'brain'), GUIDE RAILS (keep the car aligned), counterweight (traction), buffers at the pit bottom, and the door operator.
The controller manages dispatching, leveling, door operation, and safety circuits. Many faults trace back to the controller or door system.
📖 Key Terms
- Traction elevator
- Uses ropes over a drive sheave and a counterweight; for mid/high-rise.
- Hydraulic elevator
- Uses a piston and pump to raise the car; for low-rise buildings.
- ASME A17.1 / CSA B44
- The Safety Code for Elevators and Escalators.
- Controller
- The system that manages dispatching, leveling, doors, and safety circuits.
💡 Exam Tips
- ▸Traction elevators use a counterweight; hydraulic use a piston and pump.
- ▸Hydraulic elevators are typically for low-rise buildings.
- ▸ASME A17.1 / CSA B44 is the governing safety code.
- ▸Guide rails keep the car and counterweight aligned in the hoistway.