Q21 of 22 · Scenarios
How would you test an elevator?
ScenariosJuniorscenarioelevatorlateral-thinkingfunctionalsafety
Short answer
Short answer: Clarify whether it's a single or multi-elevator system and what safety protocols apply. Then cover functional floor navigation, door behavior, safety systems, edge inputs (rapid button presses, capacity), and compliance requirements.
Detail
Clarify first
- Is this a single elevator or a multi-elevator dispatch system?
- What is the rated weight capacity, and does the elevator have a load sensor?
- Are there special operating modes — fire evacuation, maintenance, accessibility mode?
- What safety standards apply (local building code, EN 81, ASME A17.1)?
Functional
- Pressing a floor call button → elevator arrives at that floor in a reasonable time
- Door opens on arrival and closes after the configured timeout
- Internal floor buttons illuminate when pressed and cancel when that floor is reached
- Floor indicator display shows the current floor accurately during travel
- Emergency stop button halts the elevator immediately; releases only from inside or by authorized personnel
Negative / error handling
- Pressing a non-existent floor (basement button in a building without one) → no response or error indicator
- Door obstruction → doors reopen automatically (safety sensor activated); reclose after obstruction is removed
- Power failure mid-travel → elevator stops safely, emergency lighting activates, intercom or alarm functions
- Overweight (load at capacity + 1 person) → doors do not close; overload indicator displayed; audible warning
Edge & boundary
- Rapid repeated presses of the same floor button → registered once, not queued multiple times
- Press "open door" immediately followed by "close door" → doors respect the last command safely
- Multiple passengers press different floors — does the elevator optimize the stop order?
- Call button pressed when the elevator is already at that floor → doors open, do not travel
Safety & compliance
- Fire mode: elevator returns to the ground floor and holds doors open; all floor calls disabled
- Emergency intercom functions and connects to a monitoring service
- Maximum rated capacity label visible; braille on buttons; audible floor announcements
- Door re-open on obstruction meets the required reaction time specification
Performance
- Door-to-door travel time within the specification; response time from call to arrival
Close: safety and compliance testing is always manual — requires physical verification, certified test equipment, and sign-off by a qualified inspector. Scheduling algorithm efficiency and control-panel logic can be covered by software simulation or unit tests of the controller logic.
// WHAT INTERVIEWERS LOOK FOR
Fire mode and the safety compliance distinction. The multi-elevator dispatch system question. Mentioning that safety compliance requires physical testing, not just software simulation — this shows engineering maturity.
// COMMON PITFALL
Listing only floor navigation and door open/close. Missing safety systems (fire mode, overweight, emergency stop, power failure), compliance requirements, and the distinction between software logic testing and physical hardware safety testing.