Flex Drop / Flex Head as Return Bend?
Flex Drop / Flex Head as Return Bend?
(OP)
Has anyone thought about using Flex Heads as return bends in a heated area attached to a dry system?
I can't find anywhere in NFPA 13 that states exactly what the arrangement of a return bend must be and in my mind if the tubing had a similar rise, run, drop return bend it would be meeting the same role as a standard return bend. The obvious labor advantage is huge, so I can't imagine I'm the first one to think of it.
Anyone have any ideas/guidance/experience doing this?
I can't find anywhere in NFPA 13 that states exactly what the arrangement of a return bend must be and in my mind if the tubing had a similar rise, run, drop return bend it would be meeting the same role as a standard return bend. The obvious labor advantage is huge, so I can't imagine I'm the first one to think of it.
Anyone have any ideas/guidance/experience doing this?





RE: Flex Drop / Flex Head as Return Bend?
only other thing I see is the flex could bend a little more and maybe not give the angles rigid pipe would, so would possibly defeat the purpose of a return bend???
cost would seem to be the driving factor.
oh but wait forgot to ask webster:
A pipe fitting, 1 or a preformed piece of tubing which provides a 180° change in direction.
and
design engineering) A pipe fitting, equal to two ells, used to connect parallel pipes so that fluid flowing into one will return in the opposite direction through the other.
RE: Flex Drop / Flex Head as Return Bend?
guidelines."
This still punts the question to the designer/AHJ -- I'm mostly worried that a compliance inspector comes through and decides that the bends aren't square enough (an arc instead of 2 90s with a flat bit) or something like that and I have to send fitters back to square off the drops into a "return bend like" arrangement.
cdafd: As for cost being the factor, I agree - if I have the chance I'm using flex heads for sure. It will mean I double my material cost, per drop but I'm saving a ton of time, and pressure testing before everything gets locked up behind hard lids is great.
RE: Flex Drop / Flex Head as Return Bend?
I would not touch anything but the original Flex Head with the other two manufacturers being sued as a basis for design.
The listing reports don't say return bend anywhere - or am I wrong on this also?
RE: Flex Drop / Flex Head as Return Bend?
RE: Flex Drop / Flex Head as Return Bend?
I looked into it once but everything I ran across referred to wet systems.
RE: Flex Drop / Flex Head as Return Bend?
That said, the fact that there is no mention of return bends in any manufacturer literature, and only one sheet mentions "dry systems" in passing is a bit concerning to me - but it is possible that they consider it a "no brainier" that this component could be used as a return bend and don't bother to spell it out. I am a bit skeptical of that idea, however.
RE: Flex Drop / Flex Head as Return Bend?
In my world I only have about 5-10 years of experience with these flexible hoses. Yet I have at least 100 years of carbon steel pipe. Being the conservative, albeit anal person I am, I'll stick with Schedule 40 pipe for the return bends and then connect the flexible hose if that is what the design calls for.
Please don't take my response as sarcastic - I'm just offering answers to the questions being posted.
RE: Flex Drop / Flex Head as Return Bend?
Flexhead stated that the their system is OK for a dry system (Page 5 of their submittal package) and the other vendors I have spoken to said the same thing.
I'm planning on using them, I now feel comfortable with the decision - thanks for everyone's input.