If you want to see a dramatic illustration of pipe expansion, look at CPVC
in a hotel hallway after they run a salamander for a couple days. Witnessed
this on one of our jobs 2 years ago, couple feet of zig-zag side to side.

I'll worry about long-term effects if the Owner pays us the last $27,440 he
stuck us for as he ran out of money at end of job.

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Chris Cahill
Sent: Wednesday, November 10, 2010 12:19 PM
To: [email protected]
Subject: Re: Pipe Expansion

The expansion is the expansion no matter what fittings are employed, well on
unrestrained steel.  A fitting does not in itself restrain the pipe.  Either
the pipe moves or the want to move is translated into some internal force.
The effect of the expansion it dependent on the fittings and the
restraintment.  
-----Original Message-----
From: David de Vries <[email protected]>
Sender: [email protected]
Date: Wed, 10 Nov 2010 08:40:57 
To: <[email protected]>
Reply-To: [email protected]
Subject: Re: Pipe Expansion

You are right about whether this is a continuous run of pipe.  Putting
back-to-back swing joints in a long run can change the dynamics completely.
 
Cast, ductile and malleable iron all have about the same thermal coefficient
of expansion as steel.  So screwed fittings would be the same as continous
welded pipe.
 
The difference that grooved couplings could make depends on the style.  If
rigid, then it would be the same as screwed fittings, but other couplings
have some ability to flex and move, so might be better for such a situation
(long, continous run of pipe with big temp swings).

Railroad track layers (don't know if that is the right trade name) have this
figured out for welded track.  Every mile or two they stretch the track with
a hydraulic puller to simulate the condition at the highest foreseeable
temp.  The track then is in tension at colder temps, but does not buckle on
a hot, sunny day.  Not applicable to sprinkler trade, just a curious thing I
learned from the Chief Engr for a railroad here in Chicago while we were
surveying his totally destroyed wood trestle which burned following some
hotwork by an outside contractor.  BTW, a mile of track expands 4'3" from
-10F to 110F.

Dave 

David A. de Vries, P.E., CSP 
Firetech Engineering Incorporated 




--- On Wed, 11/10/10, Todd Williams <[email protected]> wrote:


From: Todd Williams <[email protected]>
Subject: Re: Pipe Expansion
To: [email protected]
Date: Wednesday, November 10, 2010, 10:08 AM


Of course that assumes a continuous run of 200 ft. The inclusion of 
cast iron screwed or grooved fittings may have an impact



At 10:52 AM 11/10/2010, you wrote:





>Carbon steel:  expansion = 6.7 x 10^-6 x L. x delta T.
>
>Example:  200 feet of steel pipe installed at 30 degrees F and 
>raised to 100 degrees F.
>
>6.7 x 10^-6 x 200ft x 12in/ft x 70degrees = 1.13 inches
>
>Copper:  9.3 x 10^-6
>
>The source, Perry's Engineering Manual, puts a range on that 
>coefficient of 32 to 212 degrees F.  For down and dirty purposes, 
>this should work to foreseeable colder temps.
>
>Dave
>
>David A. de Vries, P.E., CSP
>Firetech Engineering Incorporated
>
>
>
>--- On Wed, 11/10/10, Charles Thurston <[email protected]> wrote:
>
>
>From: Charles Thurston <[email protected]>
>Subject: Pipe Expansion
>To: "sprinklerforum" <[email protected]>
>Date: Wednesday, November 10, 2010, 8:10 AM
>
>
>Hello sprinklerforum,
>
>   Does anybody know of a down and dirty chart or calculator to 
> figure pipe expansion lengths due to temperature change ?
>
>--
>Best regards,
>Charles Thurston                          mailto:[email protected]
>   Coastal Fire Protection/ Myrtle Beach Fire & Safety Group.
>   AFAA Guest
>
>Electronic Privacy Notice:
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Todd G. Williams, PE
Fire Protection Design/Consulting
Stonington, CT
860.535.2080
www.fpdc.com

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