RE: valve stem location

From: <Steve>
Date: Wed Dec 05 2007 - 01:15:00 EST

Hi Quayam
Further to the helpful comments from Hafiz Ali Alvi concerning handwheel location, there are other factors influencing stem location which you might want to consider:
When the valve stem is downwardly inclined towards the handwheel, any solids or debris in the fluid stream have increased opportunity to accumulate within the valve body around the stem/gland area by action of gravity. When the valve is operated, the solids are displaced by stem movement and can damage the stem gland or may even jam the valve. There is also increased opportunity for stem corrosion by condensate accumulation and/or galvanic action . By orientating the stem inclination above horizontal, solids tend to fall towards the bottom of the pipe and are swept away.
A less common reason reason for avoiding downwards stem is that it is more difficult to capture and control gland leakage which may otherwise run down the stem and possibly over the handwheel.
The guidelines about stem orientation only apply to certain types of valve in certain applications. If a situation arises where it is difficult not to have a vertically downwards inclined stem, it may be OK to do so if plant rules permit and special precautions are taken.

Cheers

Steve

To: PipingDesign@yahoogroups.comCC: PipingDesign@yahoogroups.com; <a href="/group/PipingDesign/post?postID=wPonzhXImUzhsR-DDJ8eLQEieRgS2AIET9xCoA6xY4cKpaEFjIm_47h_v07SCJqSXNx3FnnS00xJdpkMFVhlng">qayamhadi@yahoo.comFrom</a>: <a href="/group/PipingDesign/post?postID=aRt7JoqlydQhlqdVi8YGgoAr8sw4aYvlE3TjOSGGsvAIaKmYi0Ki8RJ1PyGu9vlNM5ZrAMhefHcNGVG6enOCz6U">halvi@jgc-descon.com.pkDate</a>: Wed, 5 Dec 2007 10:14:02 +0500Subject: Re: [PipingDesign] valve stem location

Helloits is always praticable to install valve in vertical line at operateable heigt. the recomended height of hand wheel of valve is from 1m to 1.3 meter. u can't install the the valve above this height. remeber we always care of hand wheel rather than STEM as u mention.difference design engineering companies have made their own standard for valve installation interms of height and operatability like Aramco, Shell or JGC. the basic standar is from 1 meter to 1.3 meter from where operator can operate valve easily. valve handwheel must not below 1 meter or above 1.5 meter. if it is necessary to install valve at 1.5 or above then there is a danger or striking head of operator with valve stem. so there is a issuve of safety beyound 1.5 meter.hopefully it will be helpfull for

you ******************************************************** Hafiz Ali

AlviPIPING DEPARTMENTPIPING DESIGN ENGINEERE-MAIL halvi@jgc-descon.com.pk PHONE

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<qayamhadi@yahoo.com>Sent by: PipingDesign@yahoogroups.com12/05/2007 09:45 AMPlease respond to PipingDesignTo: PipingDesign@yahoogroups.comcc: Subject:
[PipingDesign] valve stem locationHi All,Can anyody please help me on valve stem
location. I have read that when we have a valve at elevation it is not reccommended to place the the stem of valve below horizontal level . WHY? what is the reason for this ?Also can some one tell me how we determinr the Valve Stem height ?Waiting for a replyMany Thanks,Qayam [Non-text portions of this message have been removed]

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Received on Wed Dec 05 01:15:00 2007