# Thread: Help! Calling all Engineers!

1. ## Help! Calling all Engineers!

In the 3rd Edition of Norman's Book on Tactics, he poses the following question (page 122):

"The static pressure at the street is 100 psi, what is the flow pressure at the fourth floor outlet?"

I need some help here to settle an arguement.

Thanks in advance. Be safe!

2. Originally Posted by ChipKillian
In the 3rd Edition of Norman's Book on Tactics, he poses the following question (page 122):

"The static pressure at the street is 100 psi, what is the flow pressure at the fourth floor outlet?"

I need some help here to settle an arguement.

Thanks in advance. Be safe!
I am not sure if you can answer that one with regular fireground hydraulics calculations.

3. The flow pressure is whatever the engineer sets it less FL, Elev +/-, & Appliances.

4. Originally Posted by ChipKillian
In the 3rd Edition of Norman's Book on Tactics, he poses the following question (page 122):

"The static pressure at the street is 100 psi, what is the flow pressure at the fourth floor outlet?"
This sounds like one of those stupid "theoreticals" that only occur in the textbook...
Theoretically the hydrant pressure is 100psi.
Theoretically the Engine is adding 0psi to the mix, and is not incurring any friction loss in the piping.
Theoretically, the hose incurs no friction loss no matter how many GPM you're flowing through it.
Theoretically the better way to ask the question would have been: "What's the elevation loss for a line going up to the fourth floor?" Then, people wouldn't try to read too much into the question and outsmart themselves.

Elevation loss = 5psi/story (or 10ft) above ground level (roughly).
Fourth floor is 3 stories above ground level, ergo EL = 15psi.
The pressure at the fourth floor would be roughly 85psi, give or take (100-15).

At least that's what I figure without getting into all those pesky "real world" variables...

5. Yeah the question is simply wanting to know the pressure loss for going up 3 floors.

Don't add any other variables that the question does not already have.

6. If the fourth floor outlet is a dry standpipe, the pressure is zero.

These are the type of questions you love to see on a promotional exam.. they can't be answered, because all of the information isn't there, therefore, everyone gets the point for the question due to the test preparer's error!

7. Originally Posted by CaptainGonzo
If the fourth floor outlet is a dry standpipe, the pressure is zero.

These are the type of questions you love to see on a promotional exam.. they can't be answered, because all of the information isn't there, therefore, everyone gets the point for the question due to the test preparer's error!
Once again CaptainGonzo has hit the nail on the head!

Any answer would be a guess unless you had all the design information from the system which would have to come from the Engineer that designed it.

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