Safety Factor
Safety Factor
(OP)
All, can anyone give input on how they personally design the safety factor percentage when required? I can't seem to find consensus on what is used.
Ex. We have a system demand of 65 psi. Available water is 100psi. We have a safety factor of 35psi.
If we say "how much "extra" water is there over the demand, I'd divide 35/65 and have a safety factor of 53.8%
If we say "How much of the "extra water" is in relation to the supply, I'd divide 35/100 and ahve a safety factor of 35%.
Just curious, as we have some AHJ's that mandate (10%) but don't stipulate what that is off of. It's cut and dry when your required to decrease the supply by 10%, or an AHJ states 10psi, but when a generic 10% is the altered code, we have a little debate in the office right now.
Ex. We have a system demand of 65 psi. Available water is 100psi. We have a safety factor of 35psi.
This is the easy part.
The tricky part (at least for me) is....what is the percentage a factor of?If we say "how much "extra" water is there over the demand, I'd divide 35/65 and have a safety factor of 53.8%
If we say "How much of the "extra water" is in relation to the supply, I'd divide 35/100 and ahve a safety factor of 35%.
Just curious, as we have some AHJ's that mandate (10%) but don't stipulate what that is off of. It's cut and dry when your required to decrease the supply by 10%, or an AHJ states 10psi, but when a generic 10% is the altered code, we have a little debate in the office right now.
Talk To Other Members
RE: Safety Factor
In the example above, I would say you have a 35% margin.
Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, LLC
www.mfpdesign.com