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Hello all, I was checking the ASME B31.1-2004 and ASME B31.1-2007 and I noticed that the maximum allowable stress values in tension (table A-1) have changed from 2004 to 2007. Did you know that? Why has it changed? Materials have physical properties fixed Thank you very much, Regards, Rocio

Hi all, For pipeline ball valves (2500# gas service at 85ºC), my client wants stem packing instead of O-rings + gasket design, however, the suppliers give us the O-rings + gasket. Is it normal that the client want? What does he mean with "stem packing"? Thank you very much, Rocio Rodriguez

The temperature quoted is the fluid temperature. The problem is that the material specification says that the bolts used must be CK35 galvanized, however, people of the yard say that the black carbon steel bolts (without any protection) are better than galvanized. But, is not it better to use...

Hi all, I have a material specification where the stud bolt used for steam, condensate and hot-water at 300 ºC and 20 barg is CK35 galvanized. I would like to know if the stud bolt material given is ok for these services. On the other hand, is it possible used the galvanized piping...

Thank you for the aclaration, Regards, Rocio

Thank you very much Gerhardl, I will use the linf for my purpose. Bye, Rocio

I understand what you are saying but, in my job, I have to prepare the valve specifications before to make an offer request to the suppliers. Therefore, I need a criterion to select valves which it can be based on experience, other projects, etc. The data that I normally have for preparing the...

Hello all, I would like to know if exist some rule in the selection of the wedge type (solid, flexible, parallel slide, double disc, etc) of the gate valve. In the valve specifications that I have, the solid wedge is used for all diameters in 150# and for diameters lesser than 2" for 300# to...

What I am trying to accomplish with the insulation is that the fluid inside the pipe (water in my case) doesn´t freeze when the temperature exterior is under -15ºC. I have to insulate a tank in these same conditions too. The insulation type considered "polyethylene reinforced with fiber glass"...

Hello all, I have to calculate the insulation thickness for a carbon steel (A 106 Gr.B) pipe of 4" sch.40, whose conditions are: - temperature exterior: - 15ºC - temperature interior (liquid inside pipe): 20ºC How can I calculate this thickness? I am considering as insulation material, the...

Thank you very much for the link "PED cat.selection", I am using it to check my data. Only two questions more regarding to the program: 1. Pressure: is the pressure PS in bar(g) or in bar(a)? I think is bar(g). Please, confirm 2. Diameter: if I have a pipe of 8", the data that I have to...

Hi again, I know that if the fuel is a gas, the category is II, but, what is happen when the fuel is a liquid? According to PED, exist a division between the liquids. If the liquids have a vapor pressure bigger than 1,5 bara (Pv>1,5) they belongs to a different "group" that if they have a vapor...

The client doesn´t want to us the composition of the fuel. The project is a "biomasa plant". The fuel line will be with steam traced under a client requirement and in order to avoid the solidification of the fuel and keep the fluidity. The operation conditions for this fuel are: Pop = 7 bara T...

Hi all, I am preparing a list of lines classification according to PED/97/23/EC and I have a problem with the fuel oil. I do not know the composition of the fuel. The data that I have are: Pdesign(max) = 18 bar(a) Tdesign(max) = 80ºC piping diameter = 4" I know that the fuel belongs to...

Hi all, I need to know the vapor pressure for the fuel oil at 80ºC but I do not have the composition of this fuel. The pressure and temperatutre design conditions for this fuel are: Pd = 18 bar (a) Td = 80ºC Thanks in advance, Rocio Rodriguez

Thank you very much for your help, On the other hand, in ASME B31.3 ed.2004, I understand for calculating the wall thickness it is required to multiply the value E/F given in the table by the maximum allowable stress, I mean in this case we have S·E, is it like that? Thanks in advance, Rocio

Hi all, In ASME B31.1 ed. 2004, the SE to be used in the wall thickness calculation formula (para. 104.1.2) has to be taken from Appendix A. The value given in the Appendix provides "Maximum Allowable Stress Values in tension" and E/F (joint efficiency/cast factor) in separate columns. In...