Flex head pipe again

[cdafd]

So educate me on this minimum bend stuff??? as found on page 5

http://www.flexhead.com/pdf/submittalpackage.pdf

http://www.flexhead.com/pdf/Commercial-

... -Guide.pdf

so is there a maximum bend ??? according to manufacture the answer is no!!


"""Q: Do putting additional bends in the product greatly affect my friction loss calculations?

A: No. The published friction loss data is a worst case head loss calculation. Each hose was tested with the maximum amount of bends physically possible bent to the minimum bend radius top create a worst case head loss calculation. """"

 

[chevy4x4trucks]

I believe the minimum bend would refer to the radius in which you can bend the flexible tube. Most manufacturers allow you to have three 90 degree bends that must maintain a 6" radius.

 

[cdafd]

well I talked to flex and was told that there is no max, even though paperwork says "do not overbend"

and still do not understand the 3 inch minimum???

fm allows 7 inch minimum bend????


not very clear what is right and what is wrong????

 

[TravisMack]

FM and UL have different listing / approval criteria, that is nothing too unusual. Also, because of the different minimum bend radius, FM has less equivalent footage in the calcs.

The minimum bend is simply the minimum radius allowed for the bend. It is 3" for UL and 7" for FM.

Think of a typical gooseneck (return bend) for a hard piped system. You have a 4" nipple up, a 6" nipple over and then a drop nipple. With hard pipe, you could get a close nipple in there and have the center to center dimension between the elbows of about 3-3½".

With a flex head, the minimum bend is 3" using UL listed criteria. Therefore, the up and down portion of a typical return bend can be no closer than 6" center to center. With FM criteria, they would have to be 14" apart.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[cdafd]

but all the paperwork does not say there is a max bend, or am I just not seeing the big picture????

if you look at page 5 the picture to the right on the bottom, if you bend that pipe more is it legal????

http://www.flexhead.com/pdf/submittalpackage.pdf

 

[cdafd]

my boss set me straight again, with paperwork also provided in my file


if there is any bend in the pipe as long as it is three inches or more it is good to go.