Pipe trench vs. Pipe Sleeve???

[movasra]

Hi everybody,
we are designing pipes in ConocoPhillips refinery and a 3-inch sour water pipe needs to cross a road which is subject to a very heavy traffic. Does anyone know if there is any reason (i.e. inspection,...) we can not use sleeves instead of a trench. the road is 16 ft long. another word, I am looking for a very strong reason to use trench instead of sleeve.
Thanks

 

[pennpiper]

Movasra,
Is this refinery in the USA?
Is this road subject to public traffic?

If the answer to these questions is yes then you need to check with the local office of the Department of Transportation (DOT). They have very specific rules for such things.

If not in the USA then you may have some other local agency that will have their own rules.

You said 16' long. Did you mean 16' wide?
Why do you want a "Trench"? You will still need to place some king of bridge to allow traffic.

I would recommend a Heavy Wall Pipe Sleeve with the ability to check for leakage in the future.

 

[movasra]

Pennpiper,
The refinery is located in Rodeo, California and the road is inside the refinery but it is a main road that big trucks with very heavy loads such as big vessels can go on that and the road is 16' wide which I said 16' long by mistake. what would you recommend now?
Thank you very much

 

[pennpiper]

I would talk with the CIvil Engineer about the type of soil and the potential loading on a 6" Schedule 80 pipe sleeve buried 3" down from the road surface to the top of the sleeve.
Both ends of the sleeve would enter a vertical well (round or square) for line entrance/exit, access and inspection.

Remember your option is more expensive. That option is to go overhead which will require pipe supports, possibly a bridge and must be high enough to allow large loads to pass under.

 

[movasra]

Thanks a lot Pennpiper!

 

[LUDPEKA1]

movasra,

The COP location that I have done some work at has a set of REP’s (Refinery Engineering Practices).

I would start by looking at sections 5-1-2 Piping Layout & 10-3-3 Corrosion Protection for Underground Piping.

Your COP contact should be able to give you this information or point you to what your particular site uses for specifications.

 

[pennpiper]

I made a mistake on my response.
"I would talk with the CIvil Engineer about the type of soil and the potential loading on a 6" Schedule 80 pipe sleeve buried 3" down from the road surface to the top of the sleeve."

It should have been:
"I would talk with the Civil Engineer about the type of soil and the potential loading on a 6" Schedule 80 pipe sleeve buried 3' (feet) down from the road surface to the top of the sleeve."

Sorry

 

[11echo]

We do this type of design alot here in central Calif. oil fields. Normally we sleeve the pipe and have centralizers on the pipe to keep the pipe off the bottom of the sleeve for corrosion and to limit thermal transfer. With the use of a sleeve we normally try to have 12" minim cover over the top of the sleeve when used in road crossings (NOT state/federal roads! …That requires more cover & a vented sleeve in hydro-carbon use). In my experience trenches look good on paper, but in the field they tend to collect water and trash and nobody seems to want to deal with those problems all the time. Also they offer a easy spot to cross the road in the future and piping ends up being stuff into them ...making maintenance all the more a head ache! IMHO