Ducts in 8 year old school - how often should they be cleaned?

Question

I have been told the filters are changed regularly but the ducts have never been cleaned. We get stuffed noses while at the school and teachers and kids have been sick more often.

How often should they be cleaned? Or what questions do I need to ask to find out if they really don't need to be cleaned?

Any websites to reference would be appreciated.

Thank you!

Answer 1

There is a test to measure (suspended particles ) used for precession areas (not for class rooms) for your information only

You can use air compressor with long hose to blow off dust away from duct internal surfaces (if it is not internally insulated) , apply blowing during the operation of the blower of AHU or fan coil , then replace the filter, I think this will help .

For large size duct and reachable places can be internally cleaned by wet clothes

Answer 2

It will be interesting to see other responses / answers to this question.  We’ve worked on forced air heating systems of houses that are 30 – 40 years old that have never been cleaned; and I’ve never seen excessive dirt or dust in the ducts.

This has lead me to the opinion that the ducts are not the cause of the type of problems you and the children are experiencing; and in fact that ducts only need to be cleaned if the filters have never been used or left unchanged for years or there has been a fire (or smokers) in the house.

As I said, I look forward to reading the answers from companies who provide duct cleaning services.