On a dry pipe valve with a 5 to 1 ratio and system psi of 75, what pressure will the valve trip at?

To determine the pressure at which a dry pipe valve will trip, it's essential to understand the relationship between the pressure in the dry pipe and the pressure required to open the valve. The 5 to 1 ratio indicates that for every five psi of system pressure, there is one psi of pressure that the valve requires to trip.

Given that the system is set at 75 psi, we can calculate the trip pressure by taking the system pressure and dividing it by the ratio of 5 to 1:

75 psi / 5 = 15 psi.

This calculation shows that the pressure at which the valve will trip is 15 psi. Understanding this ratio is crucial, as it ensures that the valve operates correctly under the specific system conditions. Therefore, when the system pressure reaches 15 psi, the dry pipe valve will open, allowing water flow into the system as needed during a fire event.