What is the minimum depth of tread for a curved stair, measured 305 mm from the narrowest end, according to RA 9514?

The correct answer indicates that the minimum depth of tread for a curved stair, when measured 305 mm from the narrowest end, is set at 280 mm according to RA 9514. This regulation is part of the National Building Code of the Philippines, which provides standards for building design and safety.

The specification of the tread depth is crucial for ensuring user safety and comfort on stairs. A minimum depth of 280 mm allows for adequate foot placement, reducing the risk of slips or missteps, especially on curved stairs, which can be more challenging to navigate than straight staircases. This depth standard helps to ensure that users can maintain balance and stability while ascending or descending.

In the context of building laws and regulations, adhering to these specifications is mandatory for compliance and the overall safety of the structure. Understanding the nuanced measurements related to design features, like treads on stairs, is essential for architects, builders, and safety inspectors. This knowledge equips professionals to create safer environments for end-users, in line with established building codes.