Are bleed rings reliable?
2

Question

Are bleed rings reliable?

DGrayPPD (Mechanical)

(OP)

11 May 17 22:39

Just a general question.

I was discussing the use of bleed rings instead of a spool piece with a former colleague of mine that is now a lead piping designer at another firm, and he had an opinion about them that I would like to discuss with everyone.

The subject of the conversation was how I believed bleed rings would be a cheaper, more economical, easier installation item for bleeding pressure than the use of a flange-pipe-flange spool piece.

His words were, "Don't look at things like that to save money because it does not even come close to being pennies on the dollar of a TIC. Things like that end up costing way more all the way down the line because it's things that people spend time planning and things like that because it's out the norm. Stay with-in the norm. Besides that, they are pieces of shit and should not be used. If you spend a lot of time and energy trying to save a weld then you are not really accomplishing anything."

I am just curious if that is a common opinion of bleed rings. Last thing I want is to try to incorporate them if they aren't a reliable component to use.

Thanks,
DGrayPPD

pennpiper (Mechanical) · Answer 1 · 2017-05-12 12:37:34

DGray,
Bleed Rings are just as safe and just as reliable as a flanged Spool Piece.
Bleed Rings are in-fact much, much cheaper than the Flanged Spool Piece.
Cheaper, How?
- Bleed Ring -
a)The Bleed Ring
b)One set of Bolts (slightly longer than the standard set for a Flange make-up, but still cheaper than two sets of Bolts

- Spool Piece Requirements -
a)Two Flanges
b)The Pipe
c)The two end preps
d)The two Welds
e)The required NDE
f)The potential for a bad Weld and the requisite Weld repair
g)The cost for Potential for Post Weld Heat Treatment (Depending on the material and the wall thickness)

No matter the situation I would recommend to a Client/Owner that Bleed Rings be the first option for "Bleed" situations.

DGrayPPD (Mechanical) · Answer 2 · 2017-05-12 12:57:44

Thank you Pennpiper. I guess everyone has their own opinion. My thinking has always matched your statement.

LittleInch (Petroleum) · Answer 3 · 2017-05-12 13:07:50

The issue though is when do you include them compared to just installing a weldolet and / or a reducing tee in a line which has to be there anyway?

Bleed rings are good IMHO, if you use them instead of having a small spool piece. However in many cases you need the spool piece or bit of pipe anyway and hence the saving may indeed be negative once you include the costs of the bleed ring and another gasket.

As many of them are also threaded connections, stuff up the installation of the threaded valve and you're into issues, never mind the whole threaded vs welded scenario.

longer bolts also cause issues in fires as they are more exposed and lengthen more easily and hence leak faster.

So the devil is in the detail

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

DGrayPPD (Mechanical) · Answer 4 · 2017-05-12 18:54:16

There have only been a couple instances where I think bleed rings would be more beneficial than a spool piece. One is between a check and block valve and another situation, although it doesn't consist of a spool piece, is between a block valve and blind flange. A client wanted the blind flange tapped with a nipple and small bore ball valve to crack open before disassembling the blind flange. My thinking was that the bleed ring would keep from having to tap and weld the blind flange and would save the nipple-valve-plug from protruding out where someone could possibly clip it while rounding a corner.

mk3223 (Mechanical) · Answer 5 · 2017-05-12 21:31:22

By using the bleed ring, the space issue of the layout is normally a point of the concern, instead of the cost. The longer bolt length is a fire safety concern as mentioned above, especially for the process piping.
The blind flange tapper with a nipple and valve on the face is typical at the end of the line. Not like the bleed ring tapped on the side, it is, so called "boiler maker", used as a bleeder and/or drain connection.

KevinNZ (Mechanical) · Answer 6 · 2017-05-14 20:58:28

A bleed ring between two large valves would save cost and space. But so would a valve body tapping.

europipe (Chemical) · Answer 7 · 2017-05-16 08:59:27

I have seen the issue of the longer studbolts and firehazard more here, but when everything is burning, is that then still an issue?

DGrayPPD (Mechanical) · Answer 8 · 2017-06-09 18:03:43

Just an addition to the original question, if bleed rings are used, should they be listed as an "SP" item and be included on the specialty items list?

Just having another internal discussion and again there seems to be differing opinions.

mk3223 (Mechanical) · Answer 9 · 2017-06-09 18:24:42

IMO, whatever easy to the project to facilitate the design, MTO, and purchasing, it could be treated as an SP item, or included in the piping class sheet and used like a fitting similar the elbow, flange, etc.

DGrayPPD (Mechanical) · Answer 10 · 2017-06-09 19:16:31

Thanks mk3223,

My opinion was that if the item is not listed under the client piping specification and does not fall under any applicable ASME standard such as B16.9, B16.11, etc., then it should be treated as an SP item.

NBrink (Materials) · Answer 11 · 2017-06-09 19:22:50

Only problems I've had with bleed rings other than having the right length bolts is them getting lost during maintenance and folks installing them in a wildly impractical orientation.

Nathan Brink

pennpiper (Mechanical) · Answer 12 · 2017-06-09 19:32:52

DGrayPPD,
This is in the area of Engineering Company Piping Department and/or Client operational preference.
It can be done (Listed) either way, in the Piping Material Specification or the Specialty Item List.
The potential overall expected purchase quantity could make the difference:
- many (51 or more)- then put it in the Material Spec
- only a few (50 or less)- then go with SP Item

Sometimes its possible to do all the right things and still get bad results

DGrayPPD (Mechanical) · Answer 13 · 2017-06-09 19:35:45

Thank you NBrink & pennpiper for your responses.

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Are bleed rings reliable?
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