Travel Distance to Exit Lookup

How to work it out

1. Establish the occupancy, which sets the base distance. Nurseries and elderly care are strictest, entertainment venues next, then medical buildings (with different values for ward and non-ward areas, and for low-rise versus high-rise), then schools, hotels and exhibition, then other buildings.
2. Distinguish door position: between two exits, or on or at the end of a dead-end corridor. Dead-end corridors allow markedly shorter distances because there is only one direction of escape.
3. Apply the corridor correction: open external galleries gain 5 m because smoke disperses; where the route leads directly to an open stair, deduct 5 m between two stairs or 2 m on a dead-end corridor, since an open stair can become a smoke path.
4. Where the whole building is sprinklered, increase the result by 25%.
5. Mind the order: apply the corridor additions and deductions first, then multiply by 1.25. Reversing the order changes the answer.
6. Verify the actual travel path measured along the corridor centreline to the nearest exit — not the straight-line distance. Corners and thresholds all count.

Where it goes wrong

• Substituting straight-line distance for the travel path. The real route follows the corridor around columns and bends and is typically 30-50% longer.
• Reversing the order of corrections. Multiplying by 1.25 then adding 5 m differs from adding then multiplying by up to 1.25 m. The code adds first, multiplies second.
• Applying the between-two-exits value to a dead-end corridor. A dead end allows roughly half, because escape is possible in one direction only.
• Applying the 25% uplift for partial sprinkler protection. The code requires the whole building to be protected.
• Forgetting the limit on travel within the room to its door, which is separately regulated at roughly 15-22 m, in addition to the door-to-exit distance.

Material and cost

Remedies for excessive travel distance: add an exit stair (200,000-500,000 CNY each), reconfigure partitions (cheap but disruptive to the layout), or provide a refuge corridor. Settle this at concept stage — discovering it at detailed design usually means redesigning the layout.

On site

• Travel distance starts at the room door, but the distance from the furthest point in the room to that door is separately limited. Both must be satisfied.
• Fire doors and shutters closing during a fire change the route. Assess escape with them closed, never assuming they stay open.
• The 5 m credit for open galleries is conditional: the gallery must genuinely be open with adequate openings. Glazing it in disqualifies the credit.
• Travel distance and exit width are independent criteria, both mandatory. Adequate distance with undersized exits still fails.

Basis

• GB 50016-2014 (2018 edition) Code for fire protection design of buildings, travel distance to exits
• GB 50016-2014 (2018 edition) Code for fire protection design of buildings, means of escape and refuge
• GB 50099-2011 Code for design of schools, means of escape