Newton's Third Law?
After I fry this fresh cloud based sprinkler applet I'll check your
math Allan and respond off Forum if need be. :)
You know I worked with the inventor of the Hose Monster? He told me
when where and how he got the idea.
I'm the Forest Gump of this industry:
*worked with inventor of sprinkcad
*worked with inventor of autosprink
*worked (and still do) for the first person to print the first
density/area curves for TC consideration.
You can see a pic of him here:
https://www.fsc-icalc.com
Brad
Quoting AKS-Gmail-IMAP <[email protected]>:
So what is this jet effect that is going to lift the sprinkler? The
forces on this sprinkler are going to be the end pressure force and
any momentum change force.
Lets say this is a 5.6k sprinkler having a .438” diameter orifice.
The orifice area is about 0.1507 square inches. That is about 1lb
for 7 psi and about 12 lbs for 80 psi since those pressure numbers
are gage pressure referenced from atmosphere pressure. The orifice
end pressure force must be why we have the last sprinkler surge
restraint rule where there is not much piping for counter balance.
Now what is the momentum change? The water comes streaming out the
nozzle and slams into the deflector that is connected to the nozzle.
There is a canceling out. Then the water changes momentum to go
radially. Lets say that is equal in all directions. So the radial
momentum changes cancel each other. Think of a Hose Monster. The
momentum change situation is not the same as that of hose nozzle
stream needing some beef to hold it.
It would not take much to demonstrate this. Take a flex drop and
operate it with an open sprinkler and compare to operating it also
with a busted off sprinkler that has no deflector and arms. Pick a
nice hot day to do this.
On May 30, 2018, at 10:59 AM, Richard Mote
<[email protected]> wrote:
I have a AHJ <> that is questioning the use of Flex Drops
especially the Victaulic ones. He says that they are so flexible
that when a sprinkler goes off the jet effect is going to lift the
sprinkler up through the ceiling. I told him that the drops are
mechanically attached to the ceiling grid and in order to lift up
they would have to lift the entire weight of the ceiling grid,
ceiling tiles, the lights and HVAC diffusers. His answer prove, it
either by letter from the manufacturer or from someone a lot higher
up the food chain than either he or I am. Or something specific in
NFPA <> 13 that says he is wrong.
Richard Mote
Design Manager
W: 877.324.ROWE · F: 570.837.6335
PO Box 407 · 7993 US Route 522, Suite 1 · Middleburg, PA 17842
505 A Cornerstone Court · Hillsborough, NC 27278
RoweSprinkler.com · [email protected]
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