Final answer:
The most common supply line size for fire hoses in metropolitan areas is a hose with an inside diameter of 6.40 cm, capable of handling high pressures and carrying 40 liters of water per second.
Step-by-step explanation:
The common supply line size used in metropolitan settings to supply large volumes of water to large fires typically has an inside diameter of 6.40 cm. This size of fire hose can carry a flow of 40.0 liters per second at a gauge pressure that can be quite substantial to ensure that water can reach high up or far into a structure. It is important for fire hoses to carry water efficiently and at high pressures to ensure firefighters can extinguish large fires quickly and effectively. When connected to a nozzle of a smaller diameter, such as 3.00 cm, the pressure in the nozzle can be calculated to understand the flow dynamics and ensure it is suitable for fire suppression.
Considering the complexities and critical nature of fluid dynamics in firefighting, several engineering projects have been developed over the years to increase water supply capabilities. These include historical undertakings such as the Great Conduit in the thirteenth century or the New River canal by Sir Hugh Myddleton in the seventeenth century. Presently, fire hoses and hydrants are designed to meet the demands of varying pressures and flow rates, ensuring that water can be delivered to fight fires effectively.