Copper gasket.

Even the nonstandard solution is being adapted and in most cases the site personnel do violate the codes and standards to find some solutions specifically without even consulting the engg. office.

So I go by what Bhattaji says as, it does pose serious hazard being a 1500# rating and with a gas service. A big potential for a high speed accident. The reasoning for this is simple. The B16.5 flanges does increase in the OD and thickness of the flange and the hub as the size increases and does have the backing for those dimensions under those Max. Working Pressures. Already it is a weak point in a piping system and if you are prescribing a flange dimensioned for 2" and going to use as a 2.5" connection, moreover a bored flange without a hub, which makes it the most weakest point. A 6mm fillet weld cannot substitute a hub.

So use of SPW / copper gasket can be at the descretion of site and if from engg. office it is to be replaced with a 2.5" reducing flange. As Bhatta refered the bore dim., which is a purchased defined parameter and the para 6.8 very well says that the hub will be as per 2" and thk/od as per 2.5". So I do not find any problem in going for it.

Sometimes such decision is like being with angel / devil.

With regard to your other query, in ethylene plant copper is used only in some cold fraction part and not as a flat gasket but as a V groove O-ring gasket. Aluminium and copper are also used in air seperation units . The torquing calc is the standard procedure and same as the ring joints. But I remember some posting was there by Raghuram some time back on the subject. Pl. check the group's archive.

You can also check http://www.futek.com/boltcalc.aspx

With regards,
Kannan



Thanks Kannan,

 
Kannan, please ignor questions in earlier mail.  
As you said the comparision of diameters was done and we were able to eleminate most of the cases which were originally thought to be problematic.  On most of the cases comparing the gaskets ID and instrument tube OD, it was found that standard 16.20 spiral wound gasket can be used.  So the problem was reduced down to small numbers.
 
As you have said that standard SPW gasket torquing cannot be used for copper gaskets.  Is there any reference to calculate the required torque?
 
regards
yogesh

Copper gasket.

Dear Kannan,

Good Morning!
I do repeat again that the problem case is a simple SPW gasket case.
I find it difficult to convince myself while wasting my effort on
somebody's fertile idea of using copper gasket.
Regarding your sportive comment, please do appreciate it is a non-code
example of using expanding flange. Such type of flange is indeed a safety
hazard for higher pressure rating.
I can do the "re-inventing of wheels", if I have time and certainly not in
this unsafe case.
Pertaining to your alternative solution "...Coming to B16.5 compliance, the
other alternative, if it is few points in the plant, replace the 2" flange
with 2.5" x 2" ...", kindly ckeck the boring size limit in the B16.5 table.
Thank you again.

Kind Regards,
Bhatta.

*********
Additionally, for our Bhattaji as quoted below,

"I think that you should also similarly respond to site, without breaking your
head."

These problems do occur due to the negligence of the white color engineers siting
in A/C office and doing poor engineering. So white colors do have to break thier
heads to find solutions to thier mistakes as we are called as engineers by our
site colleagues. So we have to engineer it.

This problem is a well known purposeful ignorance by the piping material engineer
who does not co-ordinate with the instrumentation specialist. And he ignores to
comment or talk to piping material engineer. The big excuse and a fact is that the
orders of the intruments are placed after the instrument assembly specification
prepared by the piping material engineer is closed and forgotten and IFC
isometrics is in progression.

So the site can be spared only at the will of the two colleagues involved.

Just a sportive reply dear bhatta.

Happy piping.
Kannan.

Copper gasket.

Temporarily ignoring the subject of expanding flange as being not covered under B16.5,

considering your pipe thk as sch160 for 2", doing a small check, the SPW gasket inner dia is 58.68mm for 2" and outer is 85.85mm. The pipe inner dia is 42.82mm for 2" and 53.94mm for 2.5". So using a SPW gasket without inner ring, the protrusion/obstruction of gasket is not going to be there. And the flange and blind flange are 2" and will not have problem in diff of RF facing dia. Also the step of hole dia change is 5.56mm which is not an issue for any instrument item for sure. So you can use SPW without inner ring, however for the service indicated by you it will definitely be required frequent replacement than with a inner ring.

Speaking in general of the use of copper gasket, yes what the vendor says is true in case of cyclic loading, else it can be used. I do not feel any cyclic loading is going to be there for the service mentioned by you. After every maintenance it will have to be replaced like the soft rubber or metal ring gaskets.And you can never apply the SPW torquing for it.  For your info even Aluminium gasket are used.

Now the solution as copper gasket for your situation is not suitable and you have to go soft iron. But not as a flat one but as o-ring gaskets on a V-groove flange. This could be an alternative solution for you. You could use 90 deg. V groove of 2.1 mm depth on the RF at 80mm diameter which is near to the outer dia of a SPW gasket and use a soft iron of 5mm dia. Finish/tolerance of the groove shall be similar to a ring joint flange. This innovative site solution is used in normal 125 to 250 AARH, RF, B16.5 flanges and have been a proven solution. But you have to calc. your torquing table for these joints. But the torquing data is very similar to the ring joints. In case of 2" it would coincide, but verify from your end. Moreover your services would go well with soft iron.

For the SPW gasket property info the best resource would be the inventors of SPW gaskets, the flexitallic (http://www.flexitallic.com/pro_semi_spiral.html) Also they do give reply in a day or two.

Coming to B16.5 compliance, the other alternative, if it is few points in the plant, replace the 2" flange with 2.5" x 2" reducing WN flange, and with 2.5" bored blind flange, this will ensure you are in line with B16.5.

With regards,
Kannan

yogesh modak <yogeshm28@yahoo.com> Sent by: piping_valves@yahoogroups.com 04/09/2008 09:55 Please respond to piping_valves@yahoogroups.com

To piping_valves@yahoogroups.com cc Subject Re: [piping_valves] Copper gasket.

Thanks for your mail.  

Will go through the tables and other material mentioned by you.  
However another query regarding mechanical properties of copper under compression. Can we use standard bolting torques while using copper gasket?
Any informatino on mechanical properties of Spiral wound gaskets?
 
thanks & regards
yogesh

----- Original Message ----
From: "Bhattacharyya_Bibekananda@ke0.grp.kaneka.co.jp" <Bhattacharyya_Bibekananda@ke0.grp.kaneka.co.jp>
To: piping_valves@yahoogroups.com
Sent: Thursday, September 4, 2008 2:21:10 AM
Subject: Re: [piping_valves] Copper gasket.

Hi! Yogesh,

Thanks for the input.
I understand the situation. And it is a straightforward case indeed!
Please refer ASME B16.5 Table 6 or Table 7 (I do not have it in front of me
right now.) with title as “Reducing … Flanges for Classes … “. Please read
the table and notes very carefully.
The case of modified flange (as indicated by you) is basically an
“Expanding Flange”. Code only permits reducing flanges with boring size
limits. Please read the table.
I hope that it will be clear to you.
For non-Code and poor engineering practice cases, finding a solution is
like “re-inventing wheels”.
I am sorry that I cannot help you in this case.
For additional reading, you can refer ASME B31.3 paragraph 304.4, 305 and
306, which talk about listed and unlisted components.
I think that you should also similarly respond to site, without breaking
your head.

Kind regards,
Bhatta.

yogesh modak
<yogeshm28@yahoo.
com> To
Sent by: piping_valves@ yahoogroups. com
piping_valves@ yah cc
oogroups.com
Subject
Re: [piping_valves] Copper gasket.
09/03/2008 11:38
PM


Please respond to
piping_valves@ yah
oogroups.com


Requested parameters:

1. #1500

2. design temp. 100°C

3. Fluid type - Glycol / De-Emulsifier (De-oiler) / Nitrogen Gas

Flange details

Piping side is having standard 16.5 raise face flange.

Instrument side is having Modified blind flange. 2" blind flange bored to
accomodate approx 2.5" instrument meter pipe. Due to this the raise face width at
instrument side is reduced and so standard 16.20 dimension gasket does not fit.
The flange type based on the drawing of vedor is similar to fig. 4a

ASME SECTION VIII DIV 1 appendix 2.

I have done the stress calculations as per ASME but that does not answer the point
raised by vendor i.e copper work-hardens and hence after
couple of cycles leak proof joint cannot be guranteed. As against spiral wound
gasket which has springing property and hence good for cyclic loadings.

Also the required torque calculated using the Min design seating stress required
for flat copper metal gasket (Table 2-5.1 of ASME) is very low as compared to the
standard torque values used for bolting. And if that values are used than the
initial stress on copper gasket goes beyond UTS. Since gasket will always in
compression comparing with UTS may not be correct. Is there any value fo copper
gaskets upto which the copper gaskets can be initially compressed?

Also would like to know if available, mechanical properties of sprial wound
gakset.

Regards
Yogesh

----- Original Message ----
From: "Bhattacharyya_ Bibekananda@ ke0.grp.kaneka. co.jp"
<Bhattacharyya_ Bibekananda@ ke0.grp.kaneka. co.jp>
To: piping_valves@ yahoogroups. com
Sent: Wednesday, September 3, 2008 9:12:33 AM
Subject: Re: [piping_valves] Copper gasket.


Dear Yogesh,

Request you to indicate the following parameters please ...

1) Pressure Rating of the Flanges, in question;
2) Temperature of fluid, which will be wetting the flanges and gasket;
3) Name of fluid, which will be wetting the flanges and gasket;
4) Both flanges' facing details, like type, RF dimension, finish etc.

All these parameters are needed to do a quick check for the flanged joint's
integrity.
Guessing: What is the problem, if soft iron is used?

Kind Regards,
Bhatta.

yogesh modak
<yogeshm28@yahoo.
com> To
Sent by: piping_valves@ yahoogroups. com
piping_valves@ yah cc
oogroups.com
Subject
Re: [piping_valves] Copper gasket.
09/03/2008 01:22
AM


Please respond to
piping_valves@ yah
oogroups.com



At site on one of the flow meters flange facings of flowmeter flange and standard
piping flange do not match for the raise face dimension.


The raise face width at flowmeter end is less than standard flange. Hence
standard spiral wound gasket does not fit. Site came up with option of using
copper gasket. We enquired with gasket vendor and one of them said that copper is
not suitable for cyclic loading. He say's copper work-hardens and hence after
couple of cycles leak proof joint cannot be guranteed. As against spiral wound
gasket which has springing property and hence good for cyclic loadings.

Also for copper, can we use standard bolt torque for tightening?

Regards

Yogesh _,___

locking devices

In continuation of the earlier email on the subject, the following companies are few prominent manufacturers.

http://www.smithflowcontrol.com/new/wheel-valves.htm

http://www.gst-systeme.de/Steuertechnik%20Download%20englisch.htm

http://www.netherlocks.com/

Check out the animation also.

With regards,
Kannan

Ball valve soft seat materials and temperature limitation

In general you may refer Table A323.4.3 of ASME B31.3

Bathula Raghuram

Ball valve soft seat materials and temperature limitation

This compilation done by Yayati-TICB. Source: Shell SPE.

Take note this is not an exahaustive list and various brands of PTFE does exist having different limits. So take the advice of the valve manufacturer before detailing your seat spec.

SEAT MATERIALS	Temperature range (deg.C)
Filled PTFE	-100	220
PEEK	-100	260
Modified PTFE	-200	200
EPDM	-20	110
VITON (fluoroelastomer)	-30	200
NEOPRENE	-20	85
NITRILE (NBR) (BUNA-N)	-10	100
STYRENE (SBR) (BUNA-S)	-40	70
NYLON POLYAMIDE	-40	90
ZYFLON	0	100
POLY OXY METHYLENE (POM)	-50	110
DEVLON -V (API GRADE)	-100	150
PER FLUOR ALKOXY (PFA)	-100	200
ETFE	-198	149
PCTFE	-250	150
VESPEL	-150	150

swapnil gorantiwar <gorantiwar_swapnil@yahoo.com> Sent by: piping_valves@yahoogroups.com 29/08/2008 10:20 Please respond to piping_valves@yahoogroups.com

To piping_valves@yahoogroups.com cc Subject [piping_valves] piping_valves

i want to know the temperature range of non-metallic seat material for ball valves. for which temperature range which non-metallic seat material is to be used in ball valves?   Regards, Swapnil Gorantiwar

.

__,_._,___

Finex and Corex furnaces.

As in the past we found few questions on furnaces and felt to add this to those messages.

Just today I read an interesting second page article in newspaper on Finex furnace which are new generation furnaces without ovens able to operate using fine coal instead of the traditional coking coal which is a high pollutant. Using this furnace the energy cost and pollution is reduced. And yet it does produce the pig iron suitable for high grade steels.

Posco with Siemens, then VAI has developed this in the past 10 years spending heavily and Posco's new plant in India and Vietnam are planned to be build with these Finex furnaces. This is a modification of Corex furnaces as per the article.

They claim the cost is reduced by 10% in overall and as the current fine coal price and coking coal price gap is increasing, they hope it should be more profitable in the coming years.

Good for Nature and Environment and in having a competitive steel price.

Regards,
Kannan.

PWHT by Induction Heating Method

I understand that in projects like Borouge, Ruwais the main construction contractor CCC is using and are prefering the induction heating.  As per my conversation the same as you have highlighted of the prefabrication spooling had been found to be more efficient and less time consuming and very acurate control of temperature, in comparision.

With regard to portability as per the contractor, they are using both portable and as well as fabrication shop stationed machine. It is available on lease by quite a no. of suppliers in the gulf region in particular. I havn't checked out the names of manufacturer nor the leasing agents, but can find out.

CCC also does have its own facility in the region in catering to various project sites of them. So in that sense it could be more efficient and cheaper solution on the run though the initial investment is high.

With regards,
Kannan



Dear members

Please share your experience on the subject method for pipe welds
(PWHT to be carried at site), one of our client insisting for
Induction heating instead of PWHT by conventional resistance coil
heating.

tho' i have seen literature on this I need info on availability (first
hand experience) of the equipment, portability etc..

I understand it is faster but advantageous in mass production, and may
not be easier for site activities. i don't see any reason for this
method over resistance heating

Raghuram Bathula

Material discrimination color.

The term is not used in our sector except in the shipping of our materials. Though I am much sure about it, to what I have once heard from a supplier that the containers are scanned like our baggage to know the content without opening, in specific to know if any internationally export  banned materials are shipped like radioactive elements etc. The scanner is capable of displaying in diff. colors the materials in the containers. Like steels, super alloys, rare metals in diff. colors. This caused the shippment delay which was how I came to know of it.

With regards,
Kannan


I have one query:what is mean by "Material descrimination color".Is it related to material identification using colors, like cs pipes with one color ss pipes with another color.

Sheetal Patil
Design Engineer(Piping)

Extended bonnet valves for high temperature service

Though such high temp valves do exist, but few in the plants and are specialized construction, due to the temp/press and service and the location of the valve and safety requirements.

The extended bonnet construction is one option to dissipate heat and to lower the heat at the stem packing similar to the reduction of cryogenic valve temp propagation to the stem packing and to avoid subsequent failure of the packing and operation of the valve. In all, the subject of concern is the stem packing failure. Other options are finned bonnet constr, stem packing with separate cooling system.

Protection for valve handwheel operation is not a major concern as it can be chosen as Motor/Pneumatic operated valve. Most of the hand operated valves requires once in a year operation in such high temp service.

Coming to the stem packing,
1)The usual ones are in one or more combination of graphite, metal rings, Elastomer rings, Lip seals, simple TEFLON rings etc.
2) In the moderately higher temp. range, only Graphite+alloy is used in diff. arrangements.
3) For very high temp such as your case, cooling system or the extended bonnets and same as 2) packings are used. Also many new proprietary packing arrangements are available in the market. Evaluating them is an important part of a material engineer's role.

Additional one to be noted is, the valve basic design is also to be reviewed. Process engr. is not a valve specialist. So the material engineer is supposed to evaluate such cases. In this case a rising stem valve type design to be avoided as it has vertical and rotation wearing on the packing. For controlling a butterfly valve could be evaluated. For Gate types, a knife gate valve could be thought of. Pl. take note that such evaluation has many things to be accounted for such as leakage allowance, emission, hazops, ATEX concerns, operation difficulty, trim erosion and not the least process parameters like pressure drops, zigma allowance, opening/closing period, service fluid etc.

Coming to your question,
1) Parameters controlling the bonnet height ...depends on the stem packing design and heat propagation to the packing. As a thumb rule for alloy constr. 250mm shall be the min. height.
2) On tests....apart from the usual tests, service condition test is required to be performed. But if the manufacturer has a prototype test certificate, it could be accepted. Again it depends on the application of the valve. In your case prototype should be OK, in my opinion.
3) Create these valves as special parts and specify the individual condition of operation and design to ensure correct valve/packing design is offered by manuf.

*****
Important note is the temp you specified and the valve material specified does not go well together. Being a HP steam and at 700 deg. c(which itself is very unusual), SS is no good and it has to high alloy grade. Or your design condition is to be verified. B16.34 defined the temp. limits in the notes of every rating table.
*****

Regards,
Kannan.


Dear friends

I have a query related to valves used at very high temperature for the refinery in Russia Im working on. The service are high temperature hydrocarbon, process with hydrogen or hot air and high pressure steam with ratings of 300# and 2500#. Design temperatures(stream list not yet issued by process) in FEED contractor piping class are 700 to 750 degC. Valve material(CF8, C>0.04)The FEED contactor has put a note against the valves(gate and globe) in his pipng class ' valves shall be supplied with extended bonnet and heat dissipating elements to obtain a packing temperature of 450degC maximum'. We have come across extended bonnet valves for cryogenic service.I would like to know if members have experience with extended bonnet valves for high temperature service. What are the parametres to be considered by the vendor in deciding the height of the bonnet? What are the tests/set up to be performed by the vendor to demonstrate that temperature at packing is <450°C.Is it feasible to have a extroordinarily long bonnet in order to maintain T<=450 deg C?? What are the other packing materials other than graphite that can be used to compensate for the height of the bonnet. line gaskets are spiral wound with SS304H windings and mica/graphite filler.

Regards
Shyam

Snamprogetti