Coating & painting is essential for any structure to be protected from rust and corrosion. The structure may be of steel, iron or concrete. Many a times few days after painting, peeling occurs. The root cause of paint peeling is improper surface preparation & coating before painting. The paint gets separated from the substrate leaving some paint behind. Due to peeling of paint rust, corrosion and de-lamination of the material occurs. De-lamination refers to separation of layers from each other of the structure this leads to significant loss of mechanical toughness.
During carrying out surface preparation & coating for painting it should be kept in mind that the surface is cleared of any dirty and dried properly. Special attention should be given while carrying out the surface preparation of large continuous surface as in the interiors of storage tanks, process piping and reaction vessels. Because during the period between preparing the surface and carrying out the painting small reductions in surface temperature or small increase in the humidity of the surrounding air can result in condensation, which causes immediate corrosion and negates the entire exercise.
Whatever the surface to be coated, from the preparation of the surface to the application of the first coat, the surface is subject to environmental factors. The term “Hold the Blast” is commonly used and refers to the prevention of rust bloom from forming between the blasting and coating cycles. This is essential to avoid coating failures.
General rules have been established which attempt to meet the specifications set by NACE and SSPC to maintain a 5°C differential between the air dew point and the surface to be coated in case of metals, and complete removal of dampness and moisture in the case of a non-metal like concrete.
To avoid the above problem of corrosion, dehumidifier can be used to remove enough moisture from the air at the surface so that the air dew point is lowered sufficiently for the metal.
TDS provides services for coating through desiccant based dehumidifiers along with other accessories and technical manpower to provide the desired humidity level. The desiccant based dehumidifier removes moisture from the air by chemical attraction rather than condensation. Dehumidification is used 24 hours per day until all the blasting and lining application is complete.
Dehumidifier takes moist air from outside environment, and feed dry air to the interior of the structure where coating is to be carried out. The dry air prevents condensation and high relative humidity at the surface. The main USP of TDS rust prevention and corrosion prevention services is that, it provides highly qualified technical manpower along with all the required equipments. As the service for coating is provided on rental basis it can be availed whenever required.