What is the diameter of hoses in a Class II standpipe system designed for occupants?

In a Class II standpipe system, which is typically intended for use by occupants of a building who may not be trained in firefighting, the hose diameter is standardized at 1 1/2 inches. This size strikes a balance between being manageable for average individuals while also providing sufficient flow for effective firefighting efforts.

Larger diameters, such as 2 inches or 2 1/2 inches, are generally found in Class I standpipe systems, which are designed for use by trained firefighters and require more robust equipment to handle the greater volume and pressure needed for fire suppression. The smaller 1 inch hose is not utilized in these systems because it does not provide adequate water flow to combat fires effectively. Thus, a 1 1/2-inch diameter hose is optimal for occupants in a Class II system, ensuring that it is not only usable but also capable of delivering the necessary water supply for controlling small fires.