Uninsulated portions of insulated piping

[Metallurgistrbi]

Hello all

I came across the term painting for "Uninsulated portions of insulated piping ex flanges", in one of my client coating spec.

I have seen lines with flanges insulated.

Can some one throw some light, what will decide if the flanges need to be insulated or insulation terminated before flanges and flanges painted?

Thanks in advance for your feedback

 

[Andrew ONeill]

what I've come across
Practical considerations
1) Ease of maintenance for things that a regularly un-bolted
2) concerns over corrosion of studs / flange itself (can be somewhat mitigated by coatings / material choice)
3) Ease of leak identification if left un-insulated.

Technical / Design
1) When a flange is insulated it's design temp = the fluid temp, meaning the designer may require a next class up flange to meet the pressure / temp requirements, if left un-insulated there are provisions to claim a lower design temp than the fluid (the design temp in the flange being a function of the fluid temp and the ambient air temp), which may be enough to "sneak in" a lower flange class.


Andrew O'Neill
Specialist Mechanical Engineer
Australia