Answer:
The value is

Step-by-step explanation:
From the question we are told that
The height of the highest fixture above the top floor is

The floor to floor height is

Generally given that the building is a four story building then that height of the building is

=>

Generally the height of the highest fixture is

=>

=>
Generally the pressure loss is mathematically represented as

Here
is the density of water with value

and g is the acceleration due to gravity with value

=>

=>
converting to psi

=>

=>
