A building characteristic on the city map at ul. Jaczewskiego 7 in Lublin is the seat of the largest oncology hospital in the Lublin region and the only full-profile, highly specialized oncology center both in the Lublin Voivodeship and in Eastern Poland. Health care facilities are places where the priority is the safety and health of patients, hence it is important to take care of their cleanliness, sterility, and what is invisible but no less important - clean air. Sealing works at COZL included seven ventilation installations, three of which were responsible for supplying air to operating rooms. Before the sealing process, the channels did not meet any tightness class, but after the work carried out with the AEROSEAL® technology, they meet class B and C standards.