case studies - Covac Completion Reports
For detailed documentation of some of the Cooling Towers & AHUs we have repaired and refurbishment, please see the case study links below.
Cooling Towers & Air Handler Units
Air Handler Units (AHU's)
The Problem; Corrosion
The internal surfaces of cooling towers and AHU's are often excessively corroded because the cooling tower coating previously applied to the internal surfaces has approached the end of its useful life. More often than not, we find the internal surfaces have been coated with a non-approved paint such as bitumen or epoxy. Unfortunately these products do not have the chemical resistance or elongation properties required for structures of this aggressive nature.
This results in the need for a water tank repair, cooling tank repairs or water tank lining. In other cases the internal surfaces have been coated with an epoxy or a powder coating (e.g. Baltibond) which has been infuse bonded. The cooling tower coating has usually come to the end of its useful life due to sub-film corrosion, low-film build, poor chemical resistance, inadequate elongation properties and general deterioration. If left untreated, the internal steel substrates will be endangered with a continued risk from progressive corrosion and subsequently, micro aquatic bacterial growth including Legionella (leading to Legionnaires disease), Pseudomonas and Biofilm; this can lead to further deterioration of the cooling tower coating and AHU's surface structure and subsequent contamination.
We are all now under an obligation to ensure that cooling towers and AHU's comply with the practical guidance of ACOP L8 and subsequently, utilize products that comply with WRAS/DWI Regulations and, therefore, maintain "the cleanliness of the system and the water in it" and avoid the "use of materials that harbour bacteria and other micro-organisms or provide nutrients for microbial growth".
Another on-going problem with cooling towers and AHU's is the mastic between the joints which, over time, begins to deteriorate and lose its elasticity. Consequently, the structure will start to leak from these areas which can be catastrophic in many cases. A quality cooling tower repair is the answer.
Acothane DW offers numerous economic, technical and environmental features and benefits for use in cooling tower refurbishment and AHU's.