Chimney repair

A chimney is an essential functional element in the utilities system of power and industrial equipment. It is designed to carry the products of combustion (large amounts of flue gases) away by natural draught to a height that is safe for people.


Given that chimneys rise hundreds of meters above cities, they can be perfectly called a symbol of warmth, comfort and industrialization.


The most common chimneys are made of ceramic brick, heat-resistant concrete, metal and asbestos cement.


The materials used in the construction of chimneys must meet the highest requirements for operation, given that they are affected by a number of various destructive factors. These are the corrosive effects of the external environment such as exhaust gases, fuel ashes, condensation, rain, large temperature fluctuations, UV light, lightnings, seismic vibrations and weathering. Water vapor, smoke, ashes, cinders, tarry soot, soot and tar rise up through the chimney shaft and can settle on its surface. These factors result in the wear of both the external and internal structural elements.


An inspection of an industrial chimney includes a sequence of preparatory measures and is carried out by specialists who have received professional training and obtained a permit to work at height using an industrial climbing method.


Defects that are not corrected in time will quickly grow worse, which may affect the functional condition of the structure on the whole. Regular and comprehensive inspections of chimneys are aimed at preventing the occurrence of emergency conditions. During a regular inspection the chimney is to be inspected to maintain its working condition, and in case any defect or damage is found that could cause an emergency condition, both the individual components and the structure as a whole, a decision is taken to carry out more detailed, comprehensive inspections.


The inspection is meant to diagnose the technical condition of the chimney, evaluate its operational reliability along with the need to perform repair or rehabilitation work and their scope.


In some cases, the best solution in the current situation to dismantle the chimney. Boiler house brick chimneys erected in the Soviet era have already lost their functional purpose, since the heating system is now centralized in towns and cities. Over time, brick structures lose their strength and begin to collapse, which poses risks to the lives of people being in close proximity. Boiler houses are surrounded by heated houses; therefore, the chimney should be dismantled extremely carefully by industrial climbers in compliance with occupational health and safety rules. Further, damaged chimneys are dismantled according to complex feasibility studies; in some cases, the damaged section of the chimney shaft and liner is dismantled partially.


The repair of industrial chimneys is carried out according to the findings of the inspection and according to the work project, which takes into account the causes and nature of the damage and  the method and rules for using specially selected materials to eliminate the damage.


The brick chimney repair package includes:

  • Repair of the blind area and basement;
  • Replacement of the chimney blocks or rebricking of the chimney crown;
  • Repair of the chimney shaft;
  • Repair of the liner;
  • Repair and corrosion prevention treatment of auxiliary steel structures (lightning rod, bracing ropes, retaining rings, brackets, stairs, platforms, etc.);
  • Painting.


The reinforced concrete chimney repair work includes:

  • Installation of a reinforcing reinforced concrete collar made of fiber-reinforced concrete over the entire height of the chimney shaft;
  • Shotcreting or sealing of the chimney shaft sections having a decaying concrete protective layer with exposed reinforcing bars using non-shrinking repair mortars;
  • Rehabilitation and corrosion prevention treatment of steel structures (lightning protection systems, service ladders, guard rails, platforms and balconies);
  • Cleaning the ash box and the liner from ash deposits over the entire height;
  • Restoration of the daytime marking paint layer of the chimney shaft and the night warning light system;
  • Painting.


An inspection of metal chimneys is carried out to check the condition of the corrosion-resistant coating of steel structures, welds, joints of parts and fasteners, thermal insulation, protective coating, and to detect any corrosion spots underneath the protective coating. The inspection is  meant to evaluate the technical condition of the chimney, determine the degree of wear of metal, check the condition of the welds and joints, and to estimate the amount of repair work.


The scope of repair work for metal chimneys includes:

  • Replacement of damaged chimney sections or the whole shaft;
  • Back welding;
  • Corrosion protection for defective spots and for mechanically damaged areas (stop drilling, beveling and welding up);
  • Reinforcement of structures using structural sections (angles, channels);
  • Installation of additional components (guy wires and others);
  • Corrosion protection coating for the outer surface of the shaft;
  • Rehabilitation of thermal insulation;
  • Painting.


All of the listed works must be performed by trained personnel in compliance with all  occupational health and safety requirements according to the developed project and the technology of applying the appropriate materials to the surface to be protected.


This work can be carried out by construction organizations that have a special license and permit to work of of higher risk activities.


Our company has at its disposal equipment and, most importantly, specialists who have a depth of experience in such work and are ready to competently and efficiently perform work to the highest specifications!


Inspection of the condition of the liner of a 90-meter-high reinforced concrete flue gas stack using a thermal imager mounted on a quadcopter. The inspection provided photographic and video recorded images of different colors of the stack surface and the specified stack surface temperatures, and the temperature of flue gases flowing from the stack. The image clearly shows zones with a dramatically increased temperature up to 60 °C (in red color) against the temperature of the main surface being within 20 °C, which indicates that there are no lining or insulating layer in these areas.