Default Kr and MNFA for RDs non-ASME 1

[Bill3752]

I am evaluating installation of a bidirectional RD. To properly calculate the capacity of the RD and related piping I need an estimate of the Kr and MNFA of the candidate RDs. However, this is not an ASME application (MAWP<15 psig and MAEP = -8 psig). I remember running across some documentation some years ago to use Kr = 1.5 when one doesn't have a certified value, but I don't remember for sure.

I can't apply the original Kd = 62 method.

Any input would be appreciated.

 

[Latexman]

The default velocity head (K) value I use for rupture disk assemblies is 2.4.

Also, take a look at Converting Kr to C for Rupture Disk Flow.

Good Luck,
Latexman

 

[pierreick]

Hi,
Consider reviewing this document: ASME => KR=2.4

https://www.hydrocarbononline.com/doc/asme-code-changes-for-rupture-discs-are-now-m-0001

Pierre

 

[Latexman]

Excellent find, Pierre!

Good Luck,
Latexman

 

[Bill3752]

All, thanks for the great input. I had forgotten where I had seen the Kr = 2.4 value.

I ended up using that value when I had no additional information, and did the conversion from "C" in a case where that was available (yielding a slightly lower Kr).

I appreciate the help!