Approximately how many psi should be added to the desired engine pressure for each floor above the standpipe connection?

When calculating the pressure needed for each floor above the standpipe connection, it is essential to consider the elevation of the water column due to gravity. A common guideline in firefighting operations is to add approximately 5 psi for each story or floor above the standpipe connection. This accounts for the pressure loss that occurs as water is pumped vertically through the standpipe.

By adding this 5 psi for each floor, firefighters ensure that there is sufficient pressure to deliver water to the upper floors where it is needed, effectively overcoming the force of gravity that affects the water's flow. This practice helps to ensure that adequate water pressure is available to combat fires effectively on higher floors of a building.

Therefore, the correct answer underscores the importance of adjusting pump pressure based on elevation to maintain operational efficiency and safety during firefighting operations.