Looking for Pex tubing flow rate and heat carrying capacity

Ted_9

Where can I find this online. Specificly Im looking for 5/8th pex but would like the entire chart.

Mike T., Swampeast MO

Flow rate, restriction to flow and heat carrying capacity will be similar to any smooth tubing of the same size.

It's the heat transfer ability of PEX that seems difficult to find...

hr

Depends on the delta T

5/8 pex at a 20° delta will easily move 32,000BTU 3.3 gpm, 3.9 fps and about 11.1 ft head drop per 100 feet of run

At a 40° delta T 64,000BTU

The very best program I have found is the Pipe Sizer on Siggys HDS software. A good software to own if you are hydroniclly minded www.hydronicpros.com

B&G has a sizer also but I'm not sure it covers pex. Try their website for an online version.

hot rod

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Ted_9

Yes i have the B+G card but it doesnt haVE pex or 5/8. Ill try online then.

And thanx.

Ted_9

I did a seach for B and G and got stuff on The Notorious B.I.G, what the heck is this????

Obviously the best way to seach is to use the full name. It was funny though.

Ted_9

havent found anything yet. Does anyone know of or have a chart like this for pex?

Unknown

water temperature, volume and flow rate give you the amount of heat the tube can carry. Manufacturers of tubing have flow rate/pressure loss charts for their products.

If you're looking for how much heat you can get out of the pipe in an actual heating application though, that's more complicated. Manufacturers have different charts for that info though.
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Robert Brown, Co-Owner, RPA certified Radiant Designer

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Ted_9

Yes im looking for the info for copper fin tube heating ap. Id like to use 5/8 because of the availability of the fittings but I dont know how much element i can run. A would think it will be more than 1/2 copper (25 feet).

Floyd_5

Did you try this?????

The Hydronics Design Studio has got to be one of the best investments I have ever made....

http://www.hydronicpros.com/

Geo_2

Pex chart

Why is it no one has come out with a chart for pex???, I'm talking something that will fit in your back pocket like Dan's golden rule or burnham heating helper?. And I'm still wondering about the adp's id. 1/2" pex adp's are 3/8 id, thats 24% less area than the 1/2" pex itself, are we to assume that the capacity is 24% less than 1/2"?, i.e instead of 15,000 btu's theres now 11,400 ??, instead of 25' of baseboard theres now 19' ?

doug piaza

pex flo rate

i have used alot of pex, wirsbo has the flow rate chart in there installation and design manuial, call your local rep to get a copy.you never mntioned the heat loss of the room and what you are trying to accomplish, a valid heat loss will tell you the btu and flow needed.ifyour using the pex for looping baseboard again you need to know how much base board your installing, than call your local rep. for the product your using, they,ll be happy to assist you.
i'monvacation now but will be back nextweek, if you still are unable to get the info you need, call me . e mail me with your fax number and i'll send you the charts that i have.
doug piazza, consolidated plumbing supply 914-668-3124

Ted_9

yes Im sorry i never mentioned it because I know my loads and the amount of copper fin I need.

B + G makes a great little card for referancing. Why dont pex manufacturers make this?

Ill give on of my examples that Im dealing with. We have 30 feet of 580 copper fin for the first floor loop. The 1/2 copper doesnt make it(plus Im not using 1/2 copper) but does 5/8 pex give me enough hot water to the radiation?

I also have the second floor to do.

Geo_2

5/8

5/8" should give you 33,600 btu's or 56' of BB but now were back to the adp's size witch is not 5/8", can anyone give me a straight anwser on the adp's or should I just poo-poo it and call 3/4" pex as if it were 3/4" copper... would you put 67' of BB on 3/4" pex ???

Ted_9

I just called someone from Viega and was told the fittings were not an issue. I think they are an issue though.

hr

Don't sweat the adapters!

the smaller opening presents very little pressure drop at the flow rates you are designing around. Unless you plan on having fifty or so lined up Add another foot of head to your pressure drop if you think the fittings present too much resistence, that should cover plenty of fittings

There is no simple "rule of thumb" for properly sizing pipe. Just as there is no simple rule of thumb for heatloss calcs. You really need to input the data to get the correct answer.

The fluid type, temperature of the fluid, acceptable velocity, number of fitting, delta T, all have to be calculated in to get an exact answer. Which is why you sould really use a design software program that allows you to enter all YOUR design variables. It's really not something that would fit on a wallet card.

Siggys program has a fin tube calc program that calculates the temperature drop through a circuit so as to assure the last element has enough BTU left to meet the load. It also sizes the pipe and allows you to show the piping with and without various thicknesses of insulation.

All these factors make a difference when designing. The HDS is very simple to use and very insexpensive considering what it will do for your jobs. Buy one to answer all your questions, and learn how all the variables effect one another.

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Floyd_5

Amen....(nm)

Ted_9

Thanx for more of the input. Ive been using HVAC CALC and the Slant fin program for years and I guess its time to graduate to the next level of software.

hr

The HDS

does a lot more than a heat loss calc program. Actually it take over where the calc programs end by sizing pipe, pumps, emitters, insulation, etc. You can build the entire system at your desk before tool one is is un-holstered

It also lets you play "what if's" for example changing pipe size, pump size, delta T, etc.

It's also a very powerful troubleshooting tool when loaded on your lap dancer, er I mean top, laptop! walk into any underperforming or compromised job and in an hour you can print out the corrections needed and bid the repairs or upgrades. One "sold" job pays for this software, easily. Doesn't get much better than that, does it? Try the free demo at Siggys site.

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Unknown

Well said

and I like it, too....

Ted_9

Ive actually ahd the demo loaded for months. I was just playing around with and and I was getting agrivated since I could use its full potential untill i get the Pro version, which I just ordered online.
Thank you and goodnight.

Dave Yates (PAH)

Vanguard

has a printed chart for equivalent feet of tubing for individual fittings. Very interesting numbers. Simply add in the per-foot PD & you can easuily calculate total PD per line length.

Do the math.

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