What is the main purpose of standpipes in buildings?

The main purpose of standpipes in buildings is to supply water to firefighters. Standpipes are a crucial part of a building's fire protection system, allowing firefighters to access water from various floors without needing to rely solely on fire engines. They are typically located in stairwells or hallways and come equipped with fire hoses and nozzles, enabling a quicker and more efficient response during a fire incident.

Standpipes facilitate an effective firefighting strategy, especially in high-rise buildings, where it can be challenging to transport large quantities of water to upper levels. This system ensures that firefighters have a reliable water source close to the scene of the fire, enhancing their ability to combat the flames swiftly.

The other options do not relate directly to the primary function of standpipes. Although power supply and ventilation systems are important in building infrastructure, they do not pertain to firefighting operations. Additionally, while extinguishing electrical fires is a critical aspect of firefighting, it is not a direct function of standpipes.