Product: B16.48-1997 Steel Line Blanks

[LSThill]

Hi Team Members

If you intend to specify blanks in your service classes, please be advised that API STD 590, Steel Line Blanks, has been withdrawn and replaced by ASME B16.48, Steel Line Blanks. Like the API STD, this Standard covers pressure-temperature ratings, materials, dimensions, tolerances, marking, and testing for operating line blanks in sizes NPS 1/2 through NPS 24 for installation between ASME B16. 5 flanges in the 150, 300, 600, 900, 1500, and 2500 pressure classes. I believe the documents are identical but will need to purchase a copy since our IHS service is not providing this electronically.

Product: B16.48-1997 Steel Line Blanks

Leonard Thill
Leonard@thill.biz

http://www.thill.biz

 

[reichertc]

Please also note that B16.48 is not listed in Table 326.1 of B31.3, and hence can not be used at ASME B16.5 pressure-temperature ratings, unless the designer satisfies the requirements of Para 302.2.3. (B31.3 piping systems only)

I do believe that B16.48 is listed in ASME B31.1.

I've had a few arguments over this with some owners/engineers etc. and it always surprises people when I tell them that an ASME B16.48 blind may not meet code requirements.

 

[LSThill]

Hi reichertc (Mechanical)

ASME B31.3, Process Piping:
302.2.3 Unlisted Components

(a) Components not listed in Table 326.1, but which conform to a published specification or standard, may be used within the following limitations.

(1) The designer shall be satisfied that composition, mechanical properties, method of manufacture, and quality control are comparable to the corresponding characteristics of listed components.

(2) Pressure design shall be verified in accordance with para. 304.

(b) Other unlisted components shall be qualified for pressure design as required by para. 304.7.2.

Assuming (maybe a stretch) that B16.48 has similar wording to API STD 590,
4.1.3 Line blank thickness is designed in accordance with ANWASME B31.3.

We are in compliance with B31.3.

 

[reichertc]

Isthill,

API 590 and ASME B16.48 are very similar in wording, API 590 has a little bit more background to it than the ASME standard does.

All thicknesses in ASME B16.48 are derived using the calculations in B31.3, so typically, using these values will meet code requirements.

HOWEVER...

The designer must specify a corrosion allowance to be used in the thickness calculation. The original API 590 calcs were done using 0.05" CA for carbon and low-alloy steels, and 0 for the stainless steels.

Also, the original calculations were done using ring type gaskets conforming to ASME B16.21. If these blanks are used with ASME B16.20, spiral wound gaskets, which have a slightly larger gasket ID, they may require a slightly thicker blank. I'd have to do some digging, but I believe there is two combinations of size/material/rating which don't pass using spiral wound gaskets.

Compliance is not just a matter of the fitting being designed correctly, it is also a matter of the designer properly picking the right fitting.