UVC Lamps and Cooling Coil Corrosion

I have no experience with UVC lamps, but UV from sunlight can accelerate PVC breakdown in certain types of PVC. It is dependant on the inhibitors used in different types of PVC. Not all PVC is created equal. Don't ask me why, but there are a lot of variations in the "PVC" family of plastics. In this case, I am not surprised to hear that UVC lamps are suspected in degrading the PVC jackets and leaching out Cl or other nasties.

I am also not surprised about the effects of marine air on uncoated HVAC coils. I was on a facility condition inspection near Jacksonville FL. Uncoated coils 1/2 mile from ocean were severely corroded after 16 months. Coils with epoxy or Heresite coatings were in good condition. There are firms that specialize in coating coils with a variety of materials. Also, larger equipment manufacturers are aware of this issue and will offer it as an option if they know where the equipment will be supplied. I am a bit surprised that the people you are discussing this in the Seattle area are unfamiliar with the effects of marine air on equipment.

Thank you for the reply. What is confusing about the marine air is that the AHU without UVC uses the same air with no affects. Also, all other AHU's around the facility (this a large hospital) have no corrosion. The UVC seems to be the only common denominator.

Check out Rorshach and Strider6 responses, I gave them both "good reply" votes. Especially check grounding of equipment and stray currents, this can cause a lot of corrosion issues.

I agree, I am reading one of the articles right now. I think the grounding is a good lead.

marine atmosphere can cause severe corrosion on many materials, in your case seems that the corrosion in affecting different materials at the same time (copper, aluminum, stainless steel). In HVAC unit there is a typical form of corrosion, formicary corrosion, that causes several problems.

maybe you've to investigate in this direction..

http://www.pdhcenter.com/courses/m133/m133content.pdf

hope this can help u

s

corrosion prevention

Other than what was noted before with the breakdown of PVC due to UV light, I cannot think of any other reason why the light would accelerate corrosion. Could there be a galvanic cell caused by (or enhanced by) stray current leakage into the ductwork from the UVC lamp ballasts? Make sure that the ductwork is grounded well at the lamp connections to prevent that. It only takes a couple of volts to really eat up aluminum.

I think the ground is a good lead. Of course the manufacturer of the PVC is saying that the insulation is UV resistant but that may mean sunlight vs. UVC lamps.

Hi Jqsmc,

I also had the same problem. That why cause my rivet rusting for holding the AHU ducting inside the AHU connect with the fan . Now i know why my screw rust inside AHU. Thank for the information.

So how u solve ur AHU problem ?