RE: Criteria for selecting branch connection

From: <elie>
Date: Sun Aug 21 2005 - 23:06:00 EDT

I just completed a comprehensive study for a client on this subject

For pigging (not smart pigging or MFL tool), the pig is usually 1.5D:

For thr reciver and launcher, the barrel is always 1.5D + 6" or longer.

For the the receiver:
After the isolation valve, the pipe before the reducer (pipe) must be at least min 1.5D+6" to clear the pig so you can shot down the isolation valve. The Pig passage indicator shall be installed in this piece of pipe closer to the reducer to indicate the arrival of the pig.
I suggest installing a 2" equalizer line between the pipe and the barrel, so when you blow down the trap, the pig would not move back toward the valve, or hit you in the face when opeing the door.

For the launcher:

There is no specific requirement for the length of the   piece of pipe between the reducer and the isolation valve, however, the piece of pipe downstrem of the valve (leaving the trap), should be min 1.5D+6" with a pig passage indicator at its end to indicate that the pig has cleared the isolation valve.

For MFL tool, replace 1.5D by length of tool, length of tool is obtain from your MFL provider.

I hope this helps,

This just my humble opinion. Elie.

• ali vaseghi <vaseghi_a@yahoo.com> wrote:

> DEAR ALL
>
> HAVE YOU ANY CRTERIA FOR CALCULATION OF REDUCER
> LENGTH?
>
> HOW I CAN DETERMINE THE LENGTHS BEFORE AND AFTER THE
> REDUCER IN PIG TRAPS ?
>
> REGARDS
>
>
>
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