Large Diameter Flange Specifications 1

[pulp1]

We are currently designing a piping system for a pulp mill in South America. Most of our systems are designed to ASME B31.1 or B31.3.

The problem: As our plants increase in output our pipe sizes are becoming larger and larger. Unfortunately the listed components (of B31...) no longer cover the size ranges that we are using.

Example - We have a titanium specification that goes up to 24 inch with class 150 lapjpoint flanges (175 psig @ 400F). Our process people have now sized lines in the system that are 28 and 30 inch. Calculating requirements for pipe, fitting and stub-ends is not difficult. The problem is with the flanges. For 24 inch and below our specification is a lap joint flange (A105, B16.5).

The solution: Cast Iron Flange lap joint flange to B16.1; Weld neck flange to B16.47 $$$; Fabricated plate flange.

Anybody have any advice or good ideas?

Thanks

 

[unclesyd]

We ran into the same problem on large size flanges especially for Class 150 Lap Joints. All backup flanges were SS for any alloy. At times we designed the flange either from a rolled ring or plate. The engineer that designed most of the flanges was an advocate of many small bolts instead of few large ones. The mechanics loved him, they didn’t have to handle the heavy wrenches and they seemed to get better results with preventing leaks. .

We did purchase a flanges from the following company.

http://www.pacificflange.com/

 

[JStephen]

Large water-works pipe uses AWWA C207 flanges, available in different classes up to 72" or so. They can be hub-type slip-on or more commonly plate-type slip-on, normally cut from plate. Class B&D match 150# drilling. Normally flat-faced.

 

[LSThill]

TEAM MEMBER'S

How do you do the calculation if in not listed in AWWA C207 flanges?

Please give detail

Leonard Thill

 

[pulp1]

I appreciate the responses.

In this case I have decided that we will provide plate flanges, either back-up or slip-on per BPV code (Requirement of B31... for non-listed components).

Because the piping system (below 24") is designed with A105 lap joint flanges I cannot use AWWA flanges as they do not have the same ratings (I believe they are designed for 150 psig at some ambient temp).

Thanks again.