ᐅ Mechanical ventilation duct – screws protruding inside the duct!!!

Hello everyone,

I had a house built through a developer. A mechanical ventilation system with heat recovery was integrated into the insulation layer. The ventilation ducts are made of galvanized steel in rectangular duct design.

After the house was completed, I wanted to vacuum the ducts because a lot of dust had accumulated. I found that at every joint between two ducts, several screws protrude into the ventilation duct. This makes it almost impossible to insert the vacuum hose, and I almost couldn’t pull it back out.

According to the company that installed the system, fastening rectangular ducts/ventilation pipes with self-drilling screws is standard practice and allowed.

In my opinion, this makes it impossible to properly clean the ducts, which I consider a serious defect.

Are there any regulations, standards, or guidelines on this?

Has anyone experienced a similar problem?

Thank you very much for your help.

Thomas.