pipe support

[mario1815]

can i lay down a 3" line piping just resting on sleepers of a pipeway, the piping is low presure

 

[pennpiper]

I am going to assume that this 3" pipe line is carbon steel (CS) and schedule 40 or better. If so, then yes you can rest the 3" CS line directly on the pipi support.

If it is some other material and or is a thinner wall you may, I say may, need some other assistance such as a cradle under the pipe.

 

[BigInch]

Might watch for corrosion problems developing. If the sleepers are concrete, you may develop some corrosion. Movement may damage or scrape away the coating after some time has passed.

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[pipingdesigner]

Mario1815,

If you look under the tools section of

http://www.pipingdesigners.com

you will find a pipe span chart.

This will guide you on the required minimum spacing required for you sleeperway.

http://www.pipingdesigners.com/Tools.htm

pipingdesigner

http://www.pipingdesigners.com

 

[STYMIEDPIPER]

Mario1815
I noticed you are in petroleum

Not knowing your specific application:

Recently, I was involved in a piping upgrade at a refinery facility. The owner required all piping which transported product to have pipe shoes attached. The reasoning behind the request was that in the future, if they had to transport a different product thru the line (after slight modifications, cleaning, etc) the line can be insulated if required. Hence, all spacing on the pipe racks had to incorporate allowances for insulation (3 in thickness) which resulted in some situations requiring a new level be added to the pipe racks. This particular client took a proactive approach that it was easier and less expensive to make provisions now than later when the space would not be readily available.
Just something different to consider depending on your application or future projects.

 

[DSB123]

Mario1815,
You say the pipe is resting directly onto the sleeper. Are you sure it will not be resting on a steel insert into the sleeper. Many companies use a flat strip "tanged" into the top of concrete sleepers or worse still a round bar to minimise corrosion problems. In these cases the actual support to pipe contact is very small and the "local" stress levels induced into the pipe (if spans are significant or pipe is thin walled and there is fluid in the line)can easily be exceeded. This needs to be checked when pipe is resting directly onto steel where the contact length is small compared to the size of the line. The Pipe Support Design Book by Van Laan shows how this is done.

 

[STYMIEDPIPER]

DSB
I have been in refinery that has previously laid pipe directly on steel rack.
I agree that this is not the ideal approach and would recommend against such practice.

 

[NozzleTwister]

STYMIEDPIPER,

While there will always be exceptions, why do you recommend against resting bare lines directly on the rack steel?

This is typical practice in refineries and has a long history of many years of trouble free service.

I've seen refineries in the Caribbean that experience high corrosion rates from the salt air put bare pipe on shoes but I wouldn't recommend against running the pipe directly on the steel without qualification.


NozzleTwister
Houston, Texas

 

[DSB123]

STYMIEDPIPER,
Please read my post again. I am not saying you cannot rest bare pipe on steel. What I am saying is that you cannot do it without considering the contact length between the pipe and the steel. You can develop very high circumferential bending stresses in the pipe wall if the pipe/steel contact length is small compared with the pipe diameter/thickness. Don't forget to check the circumferential bending stresses as they are additive to the hoop pressure stress. These need to be Code compliant as well as the longitudinal stress levels