The effects of thermal overload in chimney caused by insulation damage

Abstract

Modern approach to Structural Health Monitoring of building structures demands for reliable data concerning current technical condition of analysed structure or its parts. Data are provided preferably by means of non-destructive testing or visual inspections. When the analysed object is non- or hardly accessible (like in the case of tall industrial chimneys), remote techniques based on displacement, vibration or temperature control are appreciated. The current study focuses on the problem of thermal overload induced internal forces caused by insulation damage. Condensation inside the chimney affects the internal thermal insulation and migrates through the chimney wall from the inside. Moistening of the internal thermal insulation causes a progressive loss of its insulating properties. The corrosion of concrete and reinforcing steel is therefore progressive due to the increase in the temperature gradient in the reinforced concrete wall of the chimney, causing a large increase in internal forces, mainly tensile and shear stresses, and the appearance of additional cracks in the wall. The estimation of internal forces related to thermal influences given in the presented example indicates the significant threats that these influences may generate. In conclusion, it was pointed out that the proposed thermographic tests can be very helpful in monitoring temperature changes and signalling growing problems with the durability of chimney walls.