Hi there,

I am doing a stress analysis for a high pressure steam line (300C) will be constructed per CSA Z662. In section 4.3, there is no temperature factor for steel pipe higher than 230C. While CAESAR doesn't have Z662 section 14 modelling for steam distrubition piping. How can I model this piping or what would be the temperator factor at 300C?

Thanks,

First of all ensure that your work is being well checked as any misktakes with 300 C steam can have deadly consequences.

Caesar is likely referencing Z662 4.8.4, 4.8.5 or 4.7.1 when asking for the T factor to determine the maximum allowable stress whereas Clause 14 directs the designer to look to B31.3 for guidence. 14.2.5.1 references B31.3 319.1 to 321.4. Clause 14.2.5.2 b) directs the analyst to "use of an appropriate method of stress analysis so that stress levels do not exceed those allowed by B31.3."

As well if you are designing using the rules in Annex I you must follow some of the high pressure piping B31.3 IX rules as outlined in I.2.3.1 and I.2.3.2 and I.2.4.

Thanks Greg. So should I use B31.3 to analyses the pipe stress?

In the past I have done this but you have to convince yourself or your lead that this is what the Code is directing you to do. The high pressure and temperature nature of this system means that you need to be 100% confident that the method you are using is correct. Also check how the SIF are supposed to be applied. I don't remember off hand if the code says to use Z662 SIF's or B31.3 SIF's or if they are the same. I can't really offer you any advice on how to proceed as I don't have any detailed information on the situation so all I can do is point you to the relavant sections of the code.

I would suggest that you read through Clause 14 and make your decision based what it says. As well, check with who ever wrote your specs if they used Annex I to determine wall thickness or just Clause 14 because the requirements for each vary.

This is the first time I use CSA code to a steam line. Our client required the line to be designed per CSA code but the steam header is B31.3. I will check if there is a solution for this.

Thanks a lot for your help.