Friday, October 24, 2008

Hydro test-max holding period


The holding period depends on the time needed for inspecting the system thoroughly. Minimum is 10 minutes. Especially the gas tests calls for 100% weld and mechanical joints being examined.
Also we have to ensure the limits of test pressure defined by individual components also to be taken care not to damage the components for eg. the soft seating or lining or to replace them with pipe spools.

To my info the repeated call for Hydrostatic test on the same system, the pressure need not be changed from the code to its design pressure as most of the case if any major leaks are identified, the test is performed again at the same pressure and not to reduced pressure. It is independent of the holding time. Holding time risk are purely defined by inspecting time and the in-line components and not of the piping components. It is a usual practice to remove all in-line components which has reduced testing pressure conditions.

The maximum test pressure is the pressure at which the pipe reaches its yield stress. In most of the cases the problems can be tracked back to the original thickness calc of the piping system where in somecases you may find the thickness not sufficient to take the test pressures but will suit the design pressure. When you design the piping class for rating condition you may have some margins to accommodate the test pressure but not always especially in the larger size range above 24". This makes the site testing team to reduce the test pressure adjusting to actual pipes purchased and being used and of the elevation impact of the system. Also piping connected with vessels pose a diff. situation and defining the test pressures requires a different judgement as the approach differs from company to company.

Most important thing is to question the need of hydrotest for a system to process dept. who defines the requirement.

Regards,
Kannan.



Aarpee <ramprasad.chari@gmail.com>
Sent by: materials-welding@googlegroups.com

24/10/2008 08:29

Please respond to
materials-welding@googlegroups.com

To
"Materials & Welding" <materials-welding@googlegroups.com>
cc
Subject
[MW:1236] Hydro test-max holding period






As per B31.3 Hydro test is carried out at 1.5X Design Pressure.Holding
time for Piping spools is normally 30 minutes but at times 4-6 hours
for Gas applications.Can this be held for 24 hours?What is the
potential risk?It is normally indicated that after Hydro inspection
for 10-30 minutes at 1.5X Design Pressure,if you intend doing further
inspection then same can be done at a pressure not more than the
design pressure.Opinion of the group is being sought thro this mail
Regards
Aarpee


Thursday, October 23, 2008

Vacuum Insulated Piping - VIP & Thermal Compensation Guide - TC


Members involved in LNG could be interested in the TC guide / Thermal Compensation guide applied in LNG. The liquifaction units of Hydrogen, oxygen etc. supplied by Linde are using this and such ones were used in the ISRO's cryogenic engine testing bed facility where the Chandrayaan's PSLV was tested.  For literatures follow the link below

http://www.phpk.com/products-pipe-vacuumlng.htm

Moreover the Hadron corridor where the 2/3 degree kelvin super magnet accelarators used these VIP-Vacuum Insulated Piping and additional advanced hi-tech insulation for the cooling system. Though the current failure is blamed on the cooling system but being highly complex, the source of the problem is still to be identified.

Regards,
Kannan.

Wednesday, October 22, 2008

Netherlocks information


Dear Mr. Gielissen,

 
Thanks for your concern and reply.
 
I am happy to communicate in this public platform with you and of the reach this platform has. More happy I am, about the seriousness as an organisation Netherlocks is of the market reach and basic problems some customers had faced.
 
I am sure the group members will also be happy to know of Netherlocks position and seriousness it has with its existing and potential new customers.
 
I am also sure you know me as the same Kannan Sundaram from Munich and we had met each other sometime back.
 
I never had the doubt about the product or the improvements and innovation happening in your product range. And of the reliability of Netherlock products in the long run having seen your product at few plants, I had been. I am aware of those client's satisfaction and long term relation they have with Netherlocks. Infact the name Netherlocks has become a synonym of mechanical interlocking to many in the industry.
 
The fundamental issue of concern is the response time for certain technical clarification on your products and solutions. As you know some companies who does small process or utility units may not have significant requirements of mechanical interlocking devices and some companies who have significant requirement but are more cost concerned. These are known to the suppliers and more specifically the local trading partners and they have a practice in not responding or slow in response, similar to the situation faced by one of the member who raised the question with Netherlocks. And to me during my handling of LNG terminal, Hazira, Gujarat project.(A Shell company). And others who had other different experiences.
 
Unfortunately some engg. companies do not have a comprehensive company standards and designers go by thier understanding of the product. This kind of platform helps people share thier personal experience and the understanding of the product. Personally I feel a company confident of having the best product should also help in having the product understood in the industry utilising the oppurtunity of people seeking advices or who may ask the very basic questions, irrespective of having the potential of recieving the order and the more Netherlock will dominate the market having the first opinion as the best opinion in the young minds who may lead a project someday. I do agree your website give quit exhaustive details but still open question does exist always. I have seen process engineers and safety engineers who are not aware of the sophistication and complexities possible with the mechanical interlocking, who are supposed to be the originators of such requirements.
 
In conclusion I suggest Netherlocks should lay down rules to its local partners in their way of approach to the local customer base. And you could possibly have a blog opened similar to the way the Microsoft  or HP's IPAQ choice have independant websites for each product and they clarify the simplest questions and discuss things out of the manuals and reference materials of the product itself. May be that could help Netherlocks to have a direct contact for plethora of new ideas and to have an insight of situations at site and at engineering office, especially from the process/safety engineers, helping to understand the other side of the world apart from the feedback from your service engineers at site, having said the channel of communication is also long due to the multi-tier protocol in certain companies, in overall can bridge the gap for mutual benifit and override the word of mouth views of the company.
 
Lastly, to start with, I did develop an alternative design solution avoiding the one and the only spring in your MRL series. Similar to the key hole closing pre-stressed metal plate can be used as the typical position of the valves in the plant makes it more prone to collection of sand particles in the crevice area. The location of the spring currently is in the corner, when the sand accumulates, the spring functioning is more likely to be obstructed. Using the pre-stressed plate the area is cleared off and lever piece can slide on the coated stem freely hanging on the metal plate. The sliding movement can clear off any sand. The plate can be located and oriented to ensure there is even erosion of the stem coating. Refer the attached sketch. Hope this reduces the cost and simplifying the device.
 
Your team could evaluate that and let us know of Netherlock's feedback of it.
 
Thanks again for this interaction and helping the group members to know the interest and concern of Netherlock towards its customers.
 
The above views are of my own and do not reflect the opinion of the organisation I work for or have worked for.
 
Kind Regards,
Kannan.
 


From: Frank Gielissen <FGielissen@netherlocks.com>
To:
"kannan_cit@yahoo.com" <kannan_cit@yahoo.com>
Sent:
Tuesday, October 21, 2008 12:24:36 PM
Subject:
Netherlocks information

Dear Mr. Kannan,

 

I saw some correspondence on the piping and valve information Blog from last August regarding Interlocking.

 

Firstly you are quite well informed on the subject, have you worked with our company in the past?

I see you are located in Germany, are you still working there and for what company may I ask.

 

I am sorry to see your experience with Netherlocks is not that positive since you mention we only reply for big orders, I would like to emphasize we are always looking to assist companies were possible, actually we are known for our good relation with clients and custom made solutions.

 

SoI hope we can be of assistance in the future, even on small projects and if you would like to get in touch with any of our sales people for an update on our products I would be happy to introduce you.

 

I look forward to hear from you.

 

Kind regards,

Frank Gielissen

Sales Director

 

NETHERLOCKS

Valve datasheet templates


I am sure no one will be able to share such company proprietary information. However you have enormous information in the internet available for general education purpose, which you could adapt to your needs. Also a vendor catalog gives the breakup of a valve with the bill of material which you could start with.

One particular thing to be taken care of is not to be too detailed and very specific which will pose problems in getting offers from vendors and with much non conformity issues after order.

The following sites will be help to you to understand the framework of piping classes and specification content and ofcourse of the relevant valve specification. PIP.org has good resources with a cost.

http://www.pip.org/downloads/Sample-PN01CS2S01.pdf
http://www.pip.org/downloads/Sample-PNSMV003.pdf

Regards,
Kannan.

--- On Tue, 10/21/08, Ahmed Eissa <ahmedeissa16@yahoo.com> wrote:

From: Ahmed Eissa <ahmedeissa16@yahoo.com>
Subject: data sheet
To: materials-welding@googlegroups.com
Date: Tuesday, October 21, 2008, 4:09 AM

dear,eng
 
can any one send me specification data sheet for valves (globe,gate,check,ball),or any sample format, i have to prepare it for my company, and i do not have good experience about this matter, so please any help wil be apreciated .
thanks



Rising and non-rising stem gate valves


Thanks Vinayak for letting me know of this principle which I was not aware of. Always I found the vendors offering rising stem only.
Now I have to dig out what size ranges such valves are available and the reliability of that stem/internal threaded disc design.


Thanks

Kannan.



Dear Deepak ,

Plz find attached document , which shows details view of rising and non-rising stems
 

Regards,

Vinayak Nivendkar
.

Rising and non-rising stem gate valves


I was hoping someone will share a fantastic glossy catalog....nevertheless deepak, the gate valve's basic function is ...a gate moving up and down. So the stem has to rise up and down. So no question of non rising stem gate valve. Only difference it makes in the handwheel being fixed to the stem or not. If fixed the handwheel will rise else the stem alone will rise. Same is for globe valve as the port is not in line of the flow axis of pipe to help throttling. The principle is same up and down movement. non rising stems are the butterfly, plug, ball valves.

Check this glossy site of flowserve. http://www.flowserve.com/fls/Products/Valves

Regards,
Kannan.



"Paranjape, Deepak V" <deepak.paranjape@shawgrp.com>
Sent by: piping_valves@yahoogroups.com

17/10/2008 07:26

Please respond to
piping_valves@yahoogroups.com

To
<piping_valves@yahoogroups.com>, <materials-welding@googlegroups.com>
cc
Subject
[piping_valves] rising and non-rising stem gate valves





Dear all,

I am looking for a cross-sectional view for a rising stem and non-rising stem gate valve which shows exactly the working of both these types of valves.

Regards

Deepak Paranjape

.

__,_._,___

Wednesday, October 15, 2008

ANSI v/s PN Rating flange - Comparision table


To be precise, we cannot really equate the two different standards, even above 150# of ANSI. The best reliable action will be to look into EN 1092 part 1 to 4 , and look at the pressure / temp limitation table. Take note of the name diff. Working pressure vs. Allowable pressure. And the special note on agreement between manuf. and purchaser.

The above is due to the reason that to my awareness, I have not found any official standard stating the equivalent of each other. All equivalent tables are provided by only manufacturers who may or may not guarantee what they write in thier catalog explicitly. Just to have a general idea such tables can help but not for practical technical solutions.

It would be interesting to just have a look at the dimension variation of a choosen flange between EN and BS and ASME.

I like to make a reference here of a case I came across. A butterfly valve manufacturer who supplied sizes of 36", 48", 56", 64" ANSI double flanged ends. I found the flanged end OD and thickness was reduced by 40mm on an average, just around 6 to 7 mm near the bolt hole....!   When asked he says the flange will not fail even at full rating condition. By which he simply violates the ANSI and says still he can satisfy the PT limits of ANSI and it is his standard practise to follow the reduced dimension. The valves are ready for dispatch and now considering the big cost involved in cancelling the order and time delay, it had to be approved with the gaurantee letter.  In practice it does not have any problems because the operating conditions are below the rating limits, but not a safe design. Moreover it is a big cost saving for the manufacturers considering such big material, weight, machining cost reduction. The vendor is Tyco.

So take caution while considering such equivalent ones and even the ones where even the ANSI is violated as we tend to overlook the standard dimensions on the drawings.

Regards,
Kannan
Germany.



"Agrawal Sunil \(Mumbai -Stequ\)" <s.agrawal@ticb.com>
Sent by: piping_valves@yahoogroups.com

15/10/2008 06:33

Please respond to
piping_valves@yahoogroups.com

To
<materials-welding@googlegroups.com>
cc
<piping_valves@yahoogroups.com>
Subject
[piping_valves] RE: 934] RE: 932] ANSI v/s PN Rating flange  - Comparision table





Can any one guide me what is the ANSI equivalent rating for PN below 20 (PN 2.5, PN 6, PN 10, PN 16)?

Thank you…

 

Best regards,

 

Sunil S. Agrawal

Static Equipment Dept. (STEQU)

Engineering & Design Tecnimont ICB

101/102, Interface-11, Link Road, Malad (w), Mumbai - 400 064 ( +91.22.6777.7237 * s.agrawal@ticb.com


From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Agrawal Sunil (Mumbai -Stequ)
Sent:
Thursday, July 17, 2008 11:33 AM
To:
materials-welding@googlegroups.com
Subject:
[MW:934] RE: 932] ANSI v/s PN Rating flange - Comparision table

 

Please find below the comparision:

 

PN         ANSI rating

20                             150 #

50                             300 #

68                             400 #

100                          600 #

150                          900 #

250                          1500 #

420             2500 #              

 

Source: Handbook of TC

 

I am not sure about reliability of above data and hence I request other member to contribute.

 

 

Best regards,

 

Sunil S. Agrawal

Static Equipment Dept. (STEQU)

Engineering & Design Tecnimont ICB

101/102, Interface-11, Link Road, Malad (w), Mumbai - 400 064 ( +91.22.6777.7237 * s.agrawal@ticb.com


From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Darji Nilesh (Mumbai - Machinery)
Sent:
Thursday, July 17, 2008 10:19 AM
To:
materials-welding@googlegroups.com
Subject:
[MW:932] ANSI v/s PN Rating flange - Comparision table

 

Can any one provide me a subject table.

 

Nilesh.



Monday, October 13, 2008

PSV interlocking


Sorry I came after a long weekend.

In the HP steam service, in situations where to be in line with API area limitation, it is necessary to distribute the capacity with multiple valves to achieve the relieving capacity needed. Where such 20 PSV collectively are used to discharge in which one is left as spare.  So to ensure all 19 valves are open, the interlocking is applied and simple carseal open is not used. Actually for plant operators CSO is easier. But when situation arises where it is only channelized to a diff. PSV and not really meant for maintenance, CSO does not perfectly suit.  Yes we can reduce the number of PSV considering the specialized ASME sectionwise highcapacity PSVs, but it is left to the discretion of the safety engineer. But the pressure in the need of the valve dimensions for the piping layout group is forcing the safety to adopt this API config. solution where the dim. is already available in the standardized form and can still proceed in layout engg while awaiting for the order being placed.

As only one is accounted as a spare out of the 20, all of equal capacity lined up parallelly, I am afraid if any backpressure would develop, as the margin of all put together is equal to one PSV capacity minimum, even if one fails the remaining 18 would still take care of. This multiple distribution is better off than fewer in such failure cases and to ensure least chattering happening.

Regards,
Kannan
Germany.


On Oct 8, 2008, at 4:41 AM, kannan.sundaram@linde-le.com wrote:

> Additionally, where in some cases where a network of 20+ PSVs are
> interlocked the CSO does not serve the purpose.
Just for my own curiosity, how do guarantee that a PSV can operate
independently if it's interlocked with 19 others. I was always taught
to avoid like the plague the possibility that the operation of one
valve might interfere with the operation of another. What sort of
situation requires 20 interlocked safety valves? How do you avoid a
circumstance where one of the valves might put a back pressure on one
or moe of the others?

Christopher Wright P.E. |"They couldn't hit an elephant at

chrisw@skypoint.com | this distance" (last words of Gen.
.......................................| John Sedgwick, Spotsylvania
1864)

http://www.skypoint.com/members/chrisw/

Wednesday, October 8, 2008

Strip check test and wedge material


Two possibilities

1) Copper strip test for LPG gases. check the link.

http://symp15.nist.gov/pdf/p153.pdf
http://www.onyxnet.co.uk/clients/mastrad/copper.htm

The COS impurity can form H2S which comes under NACE. So is why the copper strip test is done. In your case it has no meaning as it is relevant in the msd activity of basic engg.

Other metal strip tests are existing like the silver etc.

2) It is corrosion test.(By coupons as in NACE)

http://www.freepatentsonline.com/4338097.html

Also check perry's handbook 28-10 on testing methods.

This test gives the measurement of rate of corrosion simulating the actual process condition. Like the background of nelson curves. This is not the job of the EPC contractor but the job of the Basic engg company and licensor to define what choice of material to withstand the life of the plant and define the required corrosion allowance. Detail engg. is NOT basic engg. In detail engg. we can just ask the vendor to comply with NACE std. for the ITB material prescription. Such corrosion test is very expensive and time consuming as it takes weeks to corrode the metal and measure the reduction of thickness. Calling the vendor to do such test is nonsense. If he can stamp NACE compliance, it is understood he has done such a sample test to get the accreditation for a few years period.

The third possibility I am waiting for the vendor's reply latest by tomorrow and it seems it was done few years ago for a project by one of his colleague.
 
On acceptance of forged and casting, in general till 4" the forging is offered by default. It is better not to define it in your datasheet. If required you can use the same breakup of the body(forged/cast). If you have not defined and vendor offers all in casting reject and ask him to follow the body size break as a min. However there are some good cast materials used for stem against barstock. Such castings can be accepted depending on the process area and your overall understanding and judgement of the frequency of operation and the operating pressures.

The above is applicable for all kinds of obstructer.

With regards,
Kannan


********************

One more query..
Whether to accept cast material for disc/plug/wedge instead of forged.I m really confused ,becaus all our vendors have offered cast material.


-Strip check test is required for 1% of total ordered quantity of valves (min. 1 no) for all valves in process / NACE / Hydrogen application
 
This is our ITB requirement.& vendor has regretted to give the same.
I have searched on net....but didnt get exact test procedure, related to valves.

Regards,
Sheetal Patil

Aker Solutions

Thursday, October 2, 2008

Piping supports.


This piping support manufacturer has a big spectrum of products and does custom designed supports catering to the special needs.

To members who are not aware of this supplier check this site for more information.

www.lisega.de

With regards,
Kannan Sundaram.

Blog visits