Go with the 1.5 value. If you use the ASME B31.3 equation to size your line
blind requirements you will find that by using the 1.5 x the PSIG design
value and then use the 1.3 x the same value the material minimum thickness
between the two is miniscule. Try it. You could also consider this 1.5 as
an added safety factor. I would opt for going with off the shelf blinds
versus homemade. Most manufactures of these blinds design them for full
B16.5 pressure ratings. If someone was to forget or had a need for a
permanent blind, then they would hold up to the working pressures. This
saves from having to sketch, procure and fabricate. Plus the manufactured
blinds also come with a gasket facing on the blinds. In the USA - Mack Iron
Works is a very good supplier. Everett Nichols
> i can understand that Christopher. I don't have a copy of the latest
B31.3,
> but if you do - has there been a change in the b31.3 code allowables? Im
> trying to save on the fabrication of blinds during the coming turnaround.
I
> just want to have a blind that i can use either for piping, tanks,
exchagers
> or vessels using the 1.3 factor.
>
> -----Original Message-----
> From: Christopher Wright [mailto:chrisw@skypoint.com]
> Sent: 26 May, 2001 9:08 PM
> To: ?
> Subject: Re: [PipingDesign] Hydro Test Pressure
>
>
> >Has there been any changed to the
> >latest edition of the process piping code with regarrds to the material
> >design factor and the hydro test rquirement ?.
> The change was made to the ASME Code as a result of the increased
> allowable stress made a couple of yous ago. The proof factor was
> decreased from 1.5 to 1.3 to maintain the same margin against yielding
> during the hydrotest. If the piping code allowables didn't change, then
> the proof factor wouldn't change.
>
> Christopher Wright P.E. |"They couldn't hit an elephant from
> chrisw@skypoint.com | this distance" (last words of Gen.
> ___________________________| John Sedgwick, Spotsylvania 1864)
> <a href="http://www.skypoint.com/~chrisw">http://www.skypoint.com/~chrisw</a>
>
>
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Received on Mon May 28 09:41:00 2001
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