Define "Class I standpipe" and its purpose in fire protection.

A Class I standpipe is specifically designed for use by firefighters. It plays a critical role in fire protection systems, as it provides firefighters with a means to quickly access water in an emergency situation. This type of standpipe is typically installed in buildings to allow trained personnel to easily connect their hoses and deliver water to combat fires in the structure.

Class I standpipes usually feature larger diameter pipes (typically 2.5 inches) and are equipped with hose connections or outlets located strategically throughout the building, allowing firefighters to get water to various floors and areas quickly and efficiently. The purpose of this design is to ensure that emergency responders have adequate water supply to extinguish fires and contain them effectively, particularly in multi-story buildings where access to water sources may be more challenging.

The other choices represent different types of standpipes or systems not meant for firefighter use, such as those designed for occupants (Class II), those intended for automatic sprinkler systems, and those for irrigation, making them unsuitable in the context of the question regarding the role and purpose of Class I standpipes in fire response scenarios.