Hello Dhwani,
The project specification is quite clear about requirement of PWHT.
ASME B31.3 is a Basis Design code , in addition for particular fluid requirements there are additional Metal characteristic requirements.
The PWHT chart requirement Table 331.1.1 is defined for Normal Fluid service.
For additional consideration to prevent other specific form of corrosion line HIC, SSC , there are more precise metal requirement as defined in API941 & NACE.
These requirements are more critical and PWHT chart of ASME B31.3 does not apply.
Regarding interpretation of IBR as similar to ASME B31.3 is needs to be evaluated against the exact clause. I am not at the moment remember the exact PWHT requirement as per IBR.
While for your question of category D fluid, as those will be Class 150 rated…. Even may not be full rated to cl. 150. So thickness of 20mm is may not be applicable. Also please refer ASME B31.3 para 331.2.2 , where code has given guidelines for above decisions.
Kind regards
Rahul
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of atul chaturvedi
Sent: zondag 4 juli 2010 16:15
To: materials-welding@googlegroups.com
Subject: Re: [MW:5853] Re: <Security Level 2>STRESS RELIEVING REQUIREMENT
Dear Desai,
Please check the maximum thickness For Category "D" fluid service Piping class for your project,it should be less than 20 mm, hence no need for PWHT.
Regards
atul
On Sun, Jul 4, 2010 at 5:15 PM, Raghuram Bathula <raghurambathula@gmail.com> wrote:
Still you need go by your design code and follow whichever is
stringent.
On Jul 4, 6:09 pm, des...@toyoindia.com wrote:
> <Security Level 2>
> Thank you. Even our understanding the same.
>
> But, in our project for various piping classes Licensor's / PMC
> specifications specify the PWHT requirement.
> Four variables are being use.
>
> For Process Carbon Steel Piping class : PWHT : As per ASME B31.3 (That
> means above 20mm thickness)
> For all NACE Service piping classes (Carbon Steel) : PWHT : YES (that
> means for all thickness unlike code)
> For Steam service class : PWHT : IBR (we concluded similar to B31.3)
> For all Alloy steel Piping class : PWHT : YES (that means for all
> thickness unlike code)
> For certain steam service class PWHT : As per ASME B31.1 (That means above
> 20mm thickness)
>
> For Category "D" fluid service Piping class : PWHT : NO (hence, the
> question)
>
> Not able to interpret the philosophy.
>
> Thanks & Regards,
> Dhwani Desai.
> TOYO - PLANNING & PIPING DEPT.
> 91-22-2573 7681.
>
> Raghuram Bathula <raghurambath...@gmail.com>
> Sent by: materials-welding@googlegroups.com
> 07/04/2010 06:24 PM
> Please respond to
> materials-welding@googlegroups.com
>
> To
> materials-welding@googlegroups.com
> cc
>
> Subject
> Re: [MW:5850] <Security Level 2>STRESS RELIEVING REQUIREMENT
>
> It is required for all P1 material >20mm, irrespective of fluid service.
>
> On Sun, Jul 4, 2010 at 5:54 PM, <des...@toyoindia.com> wrote:
>
> Hello,
>
> As per ASME B31.3; for CS material PWHT requirement is above 20mm.
> Is this applicable to category D fluid service class also?
>
> Or code has given liberty to skip PWHT for category D fluid service even
> though thickness is greater than 20mm.
>
> Pls. advise.
>
> Thanks in advance,
>
> Thanks & Regards,
> Dhwani Desai
> Planning & Piping Dept.
> Ext.-7681
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