Quick Summary
The number of lifts a building needs is the output of lift traffic analysis modelled against building population, peak demand and performance benchmarks — not a floor count formula.
Under-specifying creates a structural problem that cannot be corrected after construction without major cost. Over-specifying wastes capital on elevator maintenance, energy and unused capacity.
There is no universal formula.
This is the most common misconception in vertical transportation planning. Developers and builders apply a floor count ratio or a rule of thumb. The result is a system sized around a generalisation rather than the actual demand profile of the building.
The correct number of lifts is the output of lift traffic analysis — a modelling exercise that accounts for building population, peak demand patterns, floor count, car capacity, speed and control system type. The interaction between those variables cannot be resolved by approximation for any building beyond the most basic configuration.
What lift traffic analysis actually measures — and the benchmarks it targets
The analysis models vertical movement through a building during peak periods. For a commercial office building, the critical period is the morning up-peak — the first 30 minutes of the working day.
The two primary performance outputs:
- Handling capacity: the percentage of building population the system can move in any five-minute peak period. Property Council of Australia guidance for commercial offices targets 12 to 15 percent.
- Average interval: the average time between lift arrivals at the main lobby. The commercial office benchmark is under 30 seconds during up-peak. Above 40 seconds, tenants notice — consistently.
CIBSE Guide D provides the recognised international methodology. Simulation software is required for mixed-use buildings, destination control systems and any project with a non-standard traffic profile.
The relationship between wait times and tenant satisfaction — and what that costs a building commercially — is covered in our article on nobody notices a good lift, everyone notices a bad one.
What happens when a building gets it wrong
Under-specification cannot be corrected after construction without structural intervention. ILCPL has been involved in assessments for buildings where under-specification at design stage produced measurable impacts on tenant satisfaction and lease renewal rates within three years of opening. Retrofitting adequate lift capacity — where structurally possible at all — consistently costs multiples of what an independent lift traffic analysis would have.
Over-specification is the quieter problem. A building with more elevator capacity than its population requires pays capital cost, ongoing elevator maintenance cost and energy cost for capacity never used. For residential and mixed-use developments, this is common when commercial office benchmarks are applied without adjustment.
Developers wanting to understand how vertical transportation integrates with the broader construction programme should read our article on the lift is 1% of your budget — why does it cause 20% of your delays?
Independent analysis vs manufacturer-supplied analysis
| Independent Traffic Analysis | Manufacturer-Supplied Analysis | |
|---|---|---|
| Conducted by | Independent lift consultants; no product to sell | Supplier with equipment to sell |
| Benchmark | CIBSE Guide D; Property Council of Australia guidance | Internal standards aligned to own product range |
| Output | Specification optimised for building population and lifecycle cost | Specification aligned to available product |
| Procurement | Fully tender-ready across all suppliers | Proprietary advantage to the issuing manufacturer |
| Risk of mis-specification | Low | Moderate to high — shaped by commercial interest |
| Long-term cost | Optimised for lifecycle | May carry hidden over or under-specification cost |
A manufacturer's analysis is shaped by the products in their range. That is a structural reality, not a cynical observation. An independent analysis conducted by independent lift consultants with no product to sell produces a result that is tender-ready across all suppliers — telling the building owner precisely what is needed and what the ten-year elevator maintenance cost profile looks like, before any supplier is engaged.
ILCPL provides independent lift traffic analysis, design specification and procurement management for commercial, residential, mixed-use and institutional buildings across Australia.
Call 0417 784 245 to commission an independent lift traffic analysis before the design is locked.
