Bathrooms usually have an exhaust linked to the light switch. This will suck smoke in from the house as bathroom doors are usually ventilated in old houses.

Fire exits of high rise buildings have a pressure duct to prevent smoke from entering the staircase.

The Philippines has a strict fire code which cannot be retroactively applied to old structures, however it may in some instances. Old houses and townhouses in New Manila were built before these codes and tend to be constructed with more fire prone materials.