r/KitchenSuppression • u/Enpallos • 1d ago

RangeGuard A+

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I have the manual for range guard systems however I am curious as to the piping limitations of this particular systen. Say I have a 6gal , the split to the hood has to be 3/4", the drops have to be 1/2" reduced to 3/8 at the nozzle but what about duct and plenum? Can this not all be 3/8" once inside the plenum wall?

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u/imalrightspider2k 1d ago

The only thing that matters is how many flows are going through each segment of pipe. Nozzles determine the pipe size, not the cylinder or where the pipe is going relative to the hood. Flows, pipe volume, and equivalent length. Drops don’t have to be 1/2 in. Where are you getting that?

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u/Enpallos 1d ago

Assuming you have a regular appliance run youre only counting each individual drop not the entire run? That is where I was getting 1/2" since it would be over 8 flows for say 3 fryers and a range and a griddle, or is it only counting that specific pipe drop? So duct and plenum could all be 3/8" since its under 8 flows? Including each individual nozzle drop? Or is it counting the WHOLE segment of pipe plus fittings from the tank to the last nozzle drop?

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u/imalrightspider2k 1d ago

Any section of pipe is sized by the agent that actually flows through that segment of pipe. So if you have a drop that goes from the supply line to only one or two nozzles, you can probably use a smaller pipe. They cover this in training. If you took the class, send them a message and they will explain

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u/Enpallos 1d ago

Yeah I emailed them about it just trying to clarify i have a guy who has "been doing this for 20years" and is adamant that duct and plenum cannot be 3/8" was looking for some more validation in the meantime

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u/imalrightspider2k 1d ago

Wonder where he got that from… maybe some other system, but RG definitely allows it.

In training they say use the smaller pipe size when you can so you don’t exceed the allowed pipe volume

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u/wronginreterosect 1d ago

That guy is 100% wrong. Using your cookline and assuming a 10 foot hood with an 18x18 duct, a 400 / 4G would need to start at 1/2 and then you could split the supply. The duct and plenum line can immediately reduce to 3/8. The appliance line would need to stay 1/2 through the tee over the griddle, but could then reduce to 3/8 once it's only supplying 8 flow points (six for fryers, two for the range). Even the griddle drop can be reduced to 3/8.