RE: Re: Friction Effects in Piping Systems

From: <Steve>
Date: Tue Apr 22 2003 - 03:46:00 EDT

Having just got home late because a gasket blew out, I am disinclined to believe anyone who says ignore friction.Without friction, soft gaskets would not work.
Friction is a fact of life. Sometimes the effect is small, sometimes predominant. Arbirtarily ignoring its existence is a recipie for failure. Estimating the friction effect and deciding it is negligible is another matter entirely.
Engineers are trained to calculate forces. Ignoring physical effects because a top hat said its OK is exchanging time for blind belief. Go figure........

Cheers

Steve McKenzie

-----Original Message-----
From: hankl46 [mailto:hleveret@aol.com]
Sent: Tuesday, April 22, 2003 3:02 AM
To: PipingDesign@yahoogroups.com
Subject: [PipingDesign] Re: Friction Effects in Piping Systems

This is where engineering judgement comes in play. When you think friction forces (takes place during thermal transient and seismic condition) would effect your piping system and the equipment nozzles where the pipe connects, then you must included friction in the analysis. Otherwise, as rule of thumb, friction coefficient is set to zero. Your consultancy & EPC company suggestions are correct.
On very long straight pipe run you may want to consider friction when the pipe ends at an equipment nozzle. Watch where you place your anchors and expansion loops.

• In PipingDesign@yahoogroups.com, "KAUSTUBH JOSHI" <kvj@e...> wrote:
  > Hello All,
  >
  > A few days ago, a world known consultancy & EPC company suggested
  us the following:
  >
  > 1) While performing the static analysis (flexibility analysis) of
  the piping systems, it is not necessary to consider the friction forces. The friction forces are short time generated loads, and act on the system during the thermal expansion. The friction forces diappears after the thermal movement of the piping. That's why friction should be excluded from static piping stress analysis (flexibility analysis).
  >
  > 2) There will be no friction at the guide side surfaces or the
  limit stops. The friction will be there only for the resting supports.
  >
  > What are your views on these?
  >
  > Regards,
  >
  > Kaustubh
  

  ---

Discussion List sponsor: The fluid flow calculations website - www.LMNOeng.com - LMNO Engineering,
Research, and Software, Ltd.

---

unsubscribe: PipingDesign-unsubscribe@yahoogroups.com

---

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ Received on Tue Apr 22 03:46:00 2003