Insulated pipe condensations

[refrigeracioncr]

Hi every body
We are doing some refrigerant replacing, including pipe change and insulation replacing too.

The original refrigerant is R22, and we are designing instalations to use R507. But we are having problems because suction line has condensations.

In different installations, we have changed between insulation's tickness and brand, but the problem is the same.

Evaporating temperatures are -35 / -40 ºC (-31/-40 F). Insulation brand is Armacell / Armaflex and Insulation tickness are 19 or 40 mm (3/4" - 1 1/2" approx)

Does any one know which is the reason of this problem, and any probable solution?

Thanks a lot.

[Brian_UK]

Has the insulation been properly installed to ensure good vapour sealing?

Is the condensation inside the insulation or outside?

Have you used cable ties to fix the pipework and pinched the insulation?

[refrigeracioncr]

Hi Brian
Thanks for your help...

The insulation has been properly installed. There in no discontinuity on insulation surface.

The condensation is outside of the insulation wall.

We don't use to use cable ties to fix pipes. We allways use isofonic suports outside or inside of the insulation material, already properly isolated.

The problem is that we can see water outside the insulation pipe.

[nike123]

The insulation has been properly installed. There in no discontinuity on insulation surface.

The condensation is outside of the insulation wall.



The problem is that we can see water outside the insulation pipe.

Condensation outside mean that insulation thickness is insufficient for insulation surrounding air temperature and humidity and that surface temperature of insulation is below dew point of surrounding air.

What is max humidity and temperature of surrounding air?

Check here (http://www.armacell.com/www/ArmWinAS/armwinb.nsf/webcalc?OpenForm&Seq=2&Country=UK&Language=English&a) your required insulation thickness for your conditions (pipe temperature, air temperature, humidity, pipe dia).

[refrigeracioncr]

Hi Nike
Thanks a lot for the link.
We will use it to calculate the adecuated insulation tickness and correct it to solve the problem.
I had made some calculations and its very probably that thickness is too thin.