Spring Support Temperature Condition

[marchieV]

During the spring support selection,which of the follwoing temperature condition should be considered?
(a) Operating Temperature
or
(b) Maximum Design Temperature

Thank you and hope for your reply.

Regards,

marchie

 

[XL83NL]

Operating, allthough you can argue if the spring hanger will ever see the operating temperature. What's your design & operating temperature, an application? Do you have reason to believe the hanger will see the actual operating temperature?

 

[DSB123]

Size it based on your max operating temperature!!

 

[marchieV]

Ope temp.: 40C
Max. Design temp: 82C

What is the reason for using the operating temp. instead of design temp.?

 

[KevinNZ]

The deign should pass the piping code at cold, operating and design temperature. The force from the spring may be quite different in each of these cases due to the displacement. EQ and Wind loads should analysed at operating temperature/displacement. You can also check what happens when the line is empty and full.

 

[DSB123]

KevinNZ,
The Codes say that flexibility analysis should be undertaken at Max Operating Temperature NOT Design Temperature. Design Temperature is more aligned with the pressure design of the pipework. If you know different then please prove it.

 

[XL83NL]

Where does e.g. B31.3 say this

The Codes say that flexibility analysis should be undertaken at Max Operating Temperature NOT Design Temperature.

 

[KevinNZ]

DAB123 - My point is to check what effect the spring hangers are having on the system at other than design temperature. The system may be OK at design temperature but not at lower temperatures, where the support force maybe quite different due vertical movement and the spring rate.

EQ design is better carried at operating temperature, see B31E.

 

[XL83NL]

Haha, all this time I was thinking about a different aspect for the support, i.e. in the sense of the temperature the support itself sees due to design & operating conditions.
Anyways, Kevin has provided the right answer imo, default would be operating (which usually is Ok, if the difference between design & operating is not that big). There are however more (operating) cases which may require more analysis sets.

 

[DAument]

I haven't seen anything giving a solid basis for which temperature to use to design a spring, but based on experience, I have seen the deadweight load and the movement to the operating temperature used to size springs. That being said, once the spring is sized, the movement at all credible load cases should be checked to ensure that the spring is still within the working range.


DSB123 - B31.1 and B31.3 don't really discuss operating temperature, but both define design temperature (Paragraph 101.3 and 301.3, respectively). When it comes to discussing expansion stresses, both a bit vague (intentionally, I suspect) about which temperatures to consider.