Re: [PipingDesign] instrument tappings

Just to add some info, pressure taps from orifice flanges are often taken-off at a 45 degree angle (above the piping centreline for vapour flow, below for liquid flow). This is done to simplify access to the ports that are tapped into the flanges. Even on 150# piping orifice flanges are 300# because the flange thickness isn't enough to drill into.

Paul

Richard Beale wrote:
> Hi Shanavas,
> The quick answer is that there's no reason to restrict pressure and
> temperature connections to be at the top position only, although I
> wouldn't go below the horizontal for pressure connections for fear of
> crap settling into and clogging the impulse lines. The long answer or
> question (sorry to answer your question with a question) is: where are
> you getting this from? Do you have a standard you're following that
> mandates top orientation only? Practical reasons, as Paul said, ease of
> access, is certainly a consideration. There's commonly more clearance
> above a pipe than to the side. For temperature connections you require
> clearance to install/remove the thermowell and any associated
> temperature gauge/connections. For pressure connections there has to be
> clearance for the connection assembly of TOL or SOL, nipple, root valve
> (possibly DB&B) and the associated gauge/connections. But side
> connections would work also if that were your only option. I suspect
> that you are following a standard that, for the aforementioned reasons,
> is detailing a preferred not mandatory arrangement. I doubt that it's
> stating that top orientation is your only choice. Let us know if I'm
> wrong.
>
> Regards,
> Richard B.
> Calgary, Canada
>
>
> -----Original Message-----
> From: PipingDesign@yahoogroups.com [mailto:PipingDesign@yahoogroups.com]
> On Behalf Of Paul Bowers
> Sent: April 1, 2009 10:13 PM
> To: PipingDesign@yahoogroups.com
> Subject: Re: [PipingDesign] instrument tappings
>
>
>
>
> Yes. The July 2007 New York City Steam "explosion" was apparently caused
>
> (at least in part) by an injected flange sealant that eventually clogged
>
> steam traps. Luckily, this event didn't cause a lot of loss of life.
>
> http://www.coned. <http://www.coned.com/messages/ABSReport.pdf>
> com/messages/ABSReport.pdf
>
> It's quite an interesting read if you like engineering forensics.
>
> Paul
>
> Manish K wrote:
>> Hi
>> For oil /process lines if we provide it at any other position there r
>> chances that the capillary part of the instrument may get chocked and
> give
>> erratic results and obb the other reason is ergonomics
>> I hope this is the reason in my opinion
>>
>> regards
>> manish
>>
>> On Thu, Apr 2, 2009 at 7:40 AM, Paul Bowers <pbowers@pipingdesig
> <mailto:pbowers%40pipingdesign.com> n.com>wrote:
>>> Ease of access?
>>>
>>> Paul
>>>
>>> shanavas.cholli wrote:
>>>> hi,
>>>> why the pressure and temperature tapping of horizontal lines are
> given at
>>> the top most point(12 clock position)in oil lines?
>>>> Best regards,
>>>> shanavas s
Received on Fri Apr 03 22:42:00 2009