What is the minimum distance of vertical firewall projection downwards according to PD 1096?

The minimum distance of vertical firewall projection downwards specified in PD 1096, also known as the National Building Code of the Philippines, is set at 300 mm. This requirement ensures that the firewall, designed to contain and prevent the spread of fire between adjacent structures, extends sufficiently below the roofline to minimize the risk of fire traveling through penetrations or openings around the roof assembly.

This downward projection is critical for maintaining fire safety standards, as it helps ensure that any potential fire does not easily escape above the firewall, thereby protecting adjacent properties and allowing for safer evacuation procedures. A distance of 300 mm is deemed adequate to fulfill this safety measure, reflecting careful consideration of construction practices and fire dynamics.