Limiting the travel distance to a place of relative safety has a number of benefits, namely:

• limited travel time; safety may be reached without serious exposure to smoke;

• limited size and complexity of enclosure;

• provision of sufficient alternative escape capacity within a reasonable distance. If there is a choice of exits, occupants should be able to escape in a direction away from the fire;

• increased likelihood that an exit is visible, and remains so during a fire;

• reduced likelihood that a fire can occur unseen, or grow large before detection/alarm; and

• reduced likelihood of a fire between occupant and exit.

The maximum travel distance from any point within the building to a final exit or a storey exit is given in table 1 below.

Notes:

1. The dimensions in the table are travel distances. If the internal layout of partitions, fittings, etc, is not known when plans are deposited, direct distances may be used for assessment. The direct distance is taken as 2/3rds of the travel distance.

For existing buildings, the RRO Guide (ref) offers some flexibility in the suitable travel distances depending on whether the building or compartment has been assessed as low, average or high risk. The figures in table 1 correspond to ‘average’ risk; for low/high risk the distances lengthen/shorten respectively, by about 30% ~ 50%. Consult the RRO Guide Part 2, section 4 (ref) for more details.

4.3.2.3 Limits on travel distance