Al Hamly General Contracting supplies Corrosion Resistant Coatings for Air Handling Equipments. What is it, that makes Al Hamly Group's Corrosion resistant coatings superior to that of the others.....

  • Absolute heat conducting

  • Up to five years Guarantee

Corrosion is nowadays widely accepted to be the main cause of an early deterioration of heat exchanging coils, the most vulnerable part of air sided HVAC equipment. If corrosion occurs and pollution will adhere, without any corrective or preventive measurements the performance will decrease by up to 80% in some scenarios.

Technical - Information

The two most common forms of corrosion occurring in HVAC/R equipment are known as galvanic corrosion and climate impact corrosion. Each of these corrosions can lead to equipment failure.


Corroded coil due to lack of protective treatment

Galvanic Corrosion

When dissimilar metals are electrically connected in the presence of an electrolyte, a reaction occurs. this reaction is known as galvanic corrosion. There must be a bi-metallic coupling between two dissimilar metals in the presence of an electrolyte solution, without these ingredients, there exists a risk of galvanic corrosion. Galvanic corrosion most often causes degradation, which may ultimately lead to destruction of the coil. Galvanic corrosion of the unprotected coil begins at the bi-metallic coupling between copper tube and the metallic fin. Consumption of the fin continues until the coil performance is affected and severe visual deterioration results.

Coil protected from corrosion by use of special treatment

Climate Impact Corrosion

The corrosion caused by a reaction with the environment, such as oxidation and chemical attack by the environment. Copper will be affected by sulphur containing gases. the result is a formation of a no protective layer on the metallic surface, which will continue until the performance of the machine does not meet the requirements. Unprotected copper in industrial environments will lead to failure of the refrigeration system. Sulphur and nitrogen are often the initiators of the corrosion process.

A wide range of solutions is offered to protect the heat exchanging elements from corroding. The price must not exceed the performance of a coil protection, however the quality of the solution varies from 'for ever lasting' to 'cosmetic solutions.'

To come to a presentation on the facts of coil corrosion and the possible solution we would like to asses the different exposure possibilities. Different circumstances call for different solutions. Potentially corrosive outdoor environments include areas to the sea coast, industrial sites, heavily populated urban areas, some rural locations, or a combination of any of these environments. In air handling applications, some indoor environments such as swimming pool areas, water treatment facilities, and industrial process areas can produce corrosive atmospheres.


Many emerging HVAC markets have a majority of their populations located in coastal areas. This leads to an increased number of air-conditioning applications located in potentially corrosive environments. Coastal or marine environments are characterized by the abundance of sodium chloride (salt) which is carried by sea spray, mist or fog. Most importantly, this salt water can be carried as for away as 5 miles from the coast. Even if the HVAC equipment is a substantial distance from the ocean, corrosion from salt water contamination can still occur if the equipment is not properly protected. Line-of-sight distance from the ocean, prevailing wind direction, relative humidity, wet/dry time, and coil temperature will determine the severity of corrosion potential in the coastal environment. As a result, the following should be considered when the potential for coastal contamination exists:

Is the unit within 5 miles of the ocean?

Visit the proposed installation sight. Is the ocean visible from the building roof or outdoor mechanical area? If so, the potential for severe coastal corrosion should be expected and appropriate protection is strongly recommended.

Will the condenser coil face the ocean?

If the the condenser coil faces the ocean or faces into the prevailing winds from the coast, there is high probability of sea water contamination. appropriate protection is strongly recommended.

If there is corrosion on the exterior structures, other HVAC equipment, or other equipment with dissimilar metals?

Look around the installation sites and the surrounding areas. If there is evidence of corrosion, chances are high that coastal corrosion exists and suitable protection is required.


Industrial applications are associated with a host of diverse conditions, with the potential to produce various atmospheric emissions. Sulphur and nitrogen oxide contaminants are most often linked to industrial and high density urban environments. Combustion of coal and fuel oils release sulphur oxides (SO2, SO3) and nitrogen oxides (NOx) into the atmosphere. these gases accumulate in the atmosphere and return to the ground in the form of acid rain or low pH dew. Not only are industrial emissions potentially corrosive, many industrial dust particles can be laden with the harmful metal oxides, chlorides, sulphates, carbon compounds. These particles, in the presence of oxygen, water, or high humidity environments can be highly corrosive.

Combination Marine/Industrial

Salt-laden sea water mist, combined with the harmful emissions of an industrial environment, pose a severe threat to HVAC equipment life. the combined effect of salt mist and industrial emission can accelerate corrosion. this environment requires superior corrosion resistant properties for air conditioning components to maintain optimum level of product quality. Complete encapsulation of the coil surface and all copper construction is recommended.


Highly populated areas generally have high levels of automobile emissions and increased rates of building heating fuel combustion. both conditions elevate sulphur oxides and nitrogen oxides concentrations. Corrosion severity in this environment is a function of the pollution levels which in turn depend upon several factors including population density for the area. Any HVAC equipment installed immediately adjacent to diesel exhaust, incinerator discharge stacks, fuel burning boiler stacks, or areas exposed to fossil fuel combustion emissions must be considered an industrial application.

The solution to all these problems........


Generic Type: Air drying phenolic
Recommended usage: Heresite VR-500 air dry phenolic series coatings are specially formulated to permit applications by brush, spray or roller. Some of their outstanding properties are excellent durability, good adhesion, good film building characteristics and flexibility. When thoroughly aged, they produce hard corrosion resistant films. Recommended as a heavy duty maintenance coating for exposures to splash, spillage and fumes.

Successful applications include: agricultural implements, chemical plants, canning factories, construction equipment, marine finishes, steel plants, sewage disposal plants, textile industry, underground and underwater service and ventilating systems. The VR-514 brown coating is a primer finish combination material, specially formulated for salt water service.