For hydraulic safety factors (such as in fire sprinkler systems), determining whether a 5 psi safety factor is met in a design is easy. The Available Pressure must be greater than Required Pressure + 5 PSI.
However, for percentage safety factors such as 5% or 10%, is the percentage calculated based on the Required Pressure or Available Pressure?
As an example, if we have a system that requires 80 psi and the available city pressure of 88 psi, a 10% safety factor on the required pressure would be 80 psi x 10% = 8 psi safety required. In this case the minimum is met. However, a 10% safety factor on the available pressure is 88 psi x 10% = 8.8 psi safety required. In this case, the safety factor is not met.
This is an extreme example, but I'm curious what others would use when looking at determining safety factors.
Posted anonymously by a member for discussion. Discuss this | Submit a Question | Subscribe
Subscribe and learn something new each day:
Top August '23 Contributors
Get 100 Days of Free Sample Questions right to you!
PE PREP SERIES