The PUR/PIR thermal insulation systems (bulk density from 40 +/- 5 kg/m³ to 80 +/- 5 kg/m³) are two-component polyurethane or polyisocyanurate foams with a closed cell structure. The process is performed with high-pressure injection into alcoves. Each application is preceded with a structural assessment and the determination of the technical procedure. The systems and their reaction profiles are selected in respect of the volume to be filled with foam, the structure of the building, the nature of the operation/use and the operating thermal insulation.