ASME Sec VIII Div 2 REQUIREMENT ON inconel 625

[jerin james]

Good day to all.

We are currently working on an project (supply of filter vessels). The shell material is cladded (SA 516 Gr 70 + 625 Clad). There is an internal tubesheet (to accommodate filter catridges) which is subject to a differential pressure of 1.25 barg. The material of the tubesheet is made of Solid Inconel 625 as per datasheet. I wanted to reconfirm that we can use Solid inconel (UNS N06625) plate as per ASME Sec VIII Div. 2 for this tubesheet material. Can the expertise hands confirm.

Thanks in advance
Jerin

 

[jerin james]

Dear All,

Can someone pls advise..

Thanks

 

[TGS4]

What would be the SA number of the tubesheet plate?

 

[jerin james]

SB-443 UNS N06625 Grade 1

 

[DriveMeNuts]

As per 3.5.3.2, welded structural attachments can use any grade of N06625.

However, as the tube sheet experiences greater than 1 bar differential pressure it is considered a pressure component. SB-443 would need to be mentiond in Div 2 as an approved material. I can't find it anywhere in the code, so i would say it is not allowed as a pressure component.

I would question, that if the tube sheet were redesigned so that the pressure differential is less than 1 bar, could the tubesheet be re-classified as a structural attachment and therefore be acceptable?

 

[goutam_freelance]

Interesting excerpts from Sec VIII-Div-2 Cl.U1-Scope (2)

Since your vessel is a filter, it may not fall under Div-2 scope.
Now it is up to you to decide whether to use SB443 material or not. Of course applicability of other ANSI/ASME piping codes needs to be checked.

 

[DriveMeNuts]

That looks like the paragrapgh of an old code. The new wording is below.

(d) Structures consisting of piping components, such as pipe, flanges, bolting, gaskets, valves, expansion joints, and fittings whose primary function is the transport of fluids from one location to another within a system of which it is an integral part, that is, piping systems, including the piping system between a pressure relief device and the vessel it protects, see Part 9.

(e) Pressure-containing parts of components, such as strainers and devices that serve such purposes as mixing, separating, snubbing, distributing, and metering or controlling flow, provided that pressure-containing parts of such components are generally recognized as piping components or accessories.

The vessel itself is within the scope of Div 2 (according to the OP). The filter cartirdge is covered by the clause above, however the tubesheet isn't. It is either an attachment or a pressure part.

The following "may" be used to classify it as an attachment, if you can get the pressure down to 1 bar. However it refers to vessels, not sub parts:

(h) Vessels with an internal or external design pressure not exceeding 103 kPa (15 psi) with no limitation on size, for multi-chambered vessels, the design pressure on the common elements shall not exceed 103 kPa (15 psi).

If it fails, would a court judge accept this clause as a valid reason to classify the tubesheet as an attachment?

 

[XL83NL]

Have you checked if Code Case 2468-3 would be of any use for your case here?

Huub
- You never get what you expect, you only get what you inspect.