ASME B16.5 Flange DN550 / NPS 22 1

[wcw1985]

Dear all forum member,

Can anyone enlighten me, why is it B16.5 do not have flange size of 22" ? I try to read through the B16.5 but still catch no ball. Thanks in advance.

Regards,
Wcw

 

[pennpiper]

wcw1985,
Is this a rhetorical question or do you have an actual situation that requires a 22" flange?

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

 

[wcw1985]

Hi pennpiper,

I have an actual situation that require the use of 22" ASME Flange WNRF.

 

[gr2vessels]

Flanges DN 550 are listed in AS 2129.
Cheers,
gr2vessels

 

[LittleInch]

Why don't you use MSS-SP44? They list 22"/550 flanges and are in the standard ASME pressure classes. Beware they are designed for pipelines and have different temperature ratings, but it is a recognised standard. 2006 is the latest version I have but there might be a newer one around.

See this for details as well.

http://www.zmcsteel.com/PDF/Flange/ANSI Flange/ASME B16.47 Series A Flange.pdf

Why 16.5 doesn't list them? - Probably simply no call for them, but lots gets lost in history with these standards.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[wcw1985]

Thanks for reply gr2vessels and littleinch,

My company recently received a job that require to use a 22" flange as manhole.

Horizontal Vessel, Combination is 22" WNRF Flange (manhole with davit) + 22" Shell + 22" Cap. (U-stamp required)

Normally in the drawing i will create a table of nozzle stating nozzle detail.

Example:
Item | Type | Rating | Size | Qty |
N1 | ASME B16.5 | CL300 | DN200 | 2 |

How about "Type" for this case? Is it like:
Item | Type | Rating | Size | Qty |
N1 | ASME B16.5 | CL300 | DN200 | 2 |
M1 | MSS SP44 | CL300 | DN550 | 1 |

 

[LittleInch]

Looks good to me.

With vessels you need to be a little more careful and you could ask a similar question in the pressure vessels forum and get a different answer(!) I don't know how ASME VIII treats MSS SP-44.

A 22" manhole is normally regarded as being too small (min 24" and 30" is better. Can't you just use a 24" one instead?? I've entered vessels via 24" and it is a real squeeze - and I'm not that fat(!!)

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[LittleInch]

Just found out that min manhole dimension is 16"!!

Point still remains though - Can't you substitute a 24" pipe and flange?

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[MJCronin]

A 16 inch manway can only be used by four-year olds....

They are frequently specified by "Value Engineers" (MBAs who try to keep the cost down) who blame others at the end of the job.

24 inch manways are a good choice.... but don't forget a divot and associated hardware to enable maintenance to get the cover out of the way. Allow space in the layout drawing to show the "pivot of the divot"

http://www.standardequipmentclosure...M-BHfCcXoeaDBmK9gGbhNWioaXqRxrK0cFBoCHyPw_wcB

MJCronin
Sr. Process Engineer

 

[wcw1985]

Dear Littleinch,

The manhole for this vessel is for user to replace the filter elements only ( as long as hand is reachable to the filter element to do some tighten/un-tighten and removing works of the element) is sufficient). The 22" is the design size to fit enough filter element into the vessel.

I saw some internet source that they got sell ASME B16.5 22" flange! example: texas flange

http://www.texasflange.com/images/Catalog/catalog-c.pdf

Is it valid for them to classify their flange as B16.5 for the size of 22" when B16.5 do not have any 22" flange.

 

[LittleInch]

Fair enough for the size issue.

You would need to ask them how they would certify / sell these flanges and maybe they've just used the MSS-SP44 dimensions?

Interestingly though in some pages, e.g. page 14 bolt lengths, 22" suddenly disappears(!). Let us know what they say.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way