BS9991 2015

[GB]

Could someone help me to understand the logic behind this:
 
Section 7.5 BS 9991 for buildings with a storey height of less than 11m refers to figure 6 which states that in effect that the maximum travel distance in the common corridor if ventilated can be 7.5m. There is no allowance if the apartments are fitted with sprinklers.

If the building is over 11m and still only has 1 common stair, you can increases the dead end TD to 15m if the apartments are fitted with sprinklers.

I don't follow the logic.

[colin todd]

Dont try...............