Impact Testing of Spacers as per ASME B31.3 Table 323.2.2A, Note 1 1

[Steven R]

Hi,

Regarding impact test requirements of spacers (ASTM A516-70N) in ASME B31.3, as per table 323.2.2A, can note 1 be applied to spacers?

Note 1- (1) For blind flanges and blanks made from materials with a letter designation in the Min. Temp. column of Table A-1 or Table A-1M,T shall be 1∕4
of the total thickness, where the total thickness is the thickness of the blind flange or blank including the thickness of the facing(s), if
applicable.

The reason for this question is the governing thickness for spacers should be in the radial direction (OD-ID), which is treated similar to a pipe or vessel, and not the thickness of the blank (paddles).
This would result in a much larger thickness for most cases, and in a lot of cases would require impact testing for spacers @(-29 deg C for example)
It seems this is not common practice in most company standard pipe classes and the paddles and spacers are all specified with the same requirements, so if anyone could shed a light on this would be greatly appreciated. Thanks!

 

[akpipelineengr]

Spacers are considered to be covered by 323.2.2A note (1). The referenced standard is ASME B16.48, which covers both blanks and spacers, and you are making the spacers from the same plate material, so why should spacers be any different than blanks? Why would the governing thickness be the radial thickness?

If you were making spacers from pipe material, I could see an argument for evaluating on the radial thickness. But the low temperature requirements for flat, nonwelded parts, such as blanks and spacers, in both B31.3 and Section VIII, are based the specific metallurgical characteristics of flat plate steel, which are governed by the thickness of the plate.

 

[Steven R]

@akpipelineengr

Thanks for the answer.

My understanding was that physically, the radial thickness of the spacer would be considered governing thickness, for any pressure containing situations.

However, it makes sense that the governing thickness for impact testing of steel plates should be the thickness of the plate, and the results are based on/compared to the specific metallurgical characteristics of the steel plate as per the code.