Enter evacuation inputs
The form stays in a single page flow. On large screens the fields use three columns, then two, then one on smaller devices.
Example data table
These example scenarios show how route length, crowd size, and exit width change the screening estimate.
| Scenario | Occupants | Route length (m) | Exits | Exit width each (m) | Condition factor | Estimated time (min) |
|---|---|---|---|---|---|---|
| Office floor | 80 | 25 | 2 | 1.2 | 0.95 | 2.36 |
| Workshop bay | 120 | 38 | 2 | 1.2 | 0.90 | 3.28 |
| Assembly hall | 240 | 42 | 3 | 1.5 | 0.85 | 3.72 |
Formula used
1) Effective walking speed
Effective speed = Base speed × Route factor × Mobility factor × Condition factor
This lowers nominal walking speed when stairs, mixed mobility, or poor conditions are present.
2) Travel time
Travel time = Route length ÷ Effective speed
This estimates how long the limiting travel path takes before people reach the exit discharge point.
3) Exit capacity
Total exit width = Number of exits × Clear width per exit
Exit capacity = Total exit width × Specific flow rate × Condition factor
Capacity is expressed in persons per second.
4) Queue time
Queue time = Occupants ÷ Exit capacity
This represents the discharge delay caused by bottlenecking at exits.
5) Total evacuation time
Total time = (Pre-movement + Delay allowance + Travel time + Queue time) × Safety factor
This is a conservative screening method for early engineering comparison, not a substitute for detailed code review or simulation.
How to use this calculator
- Enter the total number of occupants expected to leave through the selected exits.
- Use the longest realistic travel path to represent the limiting route.
- Choose a base walking speed that fits the building population.
- Set pre-movement and delay allowances for recognition, reaction, alarms, and door delays.
- Select the route type and mobility profile to reflect stairs or assisted movement.
- Enter the number of effective exits, each clear width, and a suitable specific flow rate.
- Reduce the condition factor when smoke, clutter, or low visibility affects movement.
- Apply a safety factor for conservative planning, then press the calculate button.
- Review the summary cards, result table, and graph to see where the bottleneck occurs.
- Download the results as CSV or PDF for documentation or comparison.
FAQs
1) What does this calculator estimate?
It estimates total evacuation time from user inputs covering reaction delay, movement speed, route length, and exit discharge capacity. It is useful for early engineering screening and scenario comparison.
2) Why is pre-movement time important?
People do not move immediately after an alarm. Recognition, confirmation, communication, and collection of belongings can create major delay. In many buildings, this phase strongly affects total evacuation time.
3) What is specific flow rate?
Specific flow rate is the number of people that can pass per meter of exit width per second. It represents exit performance and is commonly used for screening egress capacity.
4) When should I reduce the condition factor?
Reduce it when smoke, poor visibility, clutter, door resistance, uneven surfaces, or crowd hesitation lowers movement efficiency. A lower value decreases both walking speed and discharge capacity.
5) Does the calculator account for stairs?
Yes. The route type applies a factor to walking speed. Stair descent and stair ascent reduce effective speed compared with a level corridor.
6) Is the result suitable for compliance sign-off?
No. This page is best for preliminary comparison. Formal compliance often requires local code checks, occupancy assumptions, travel distance rules, and sometimes detailed evacuation modeling or simulation.
7) Why might queue time dominate?
Queue time becomes large when many occupants share limited exit width. Even a short travel route can produce long total evacuation times if the discharge capacity is too low.
8) What does the safety factor do?
The safety factor adds conservatism to the final estimate. It helps planners test less favorable conditions without changing every individual input separately.