September 30, 2015 by Danny Fung, President & Senior Technical Consultant, Newtron Group
Based on many years of experience, we have found that the success rate for restoring equipment is consistently better than 90% if acted upon quickly. The cost is typically less than 30% of the net replacement value of the equipment – and that is not counting secondary costs associated with the loss of use of the equipment. This article provides an understanding of what equipment corrosion is, how it causes equipment failure, how to properly restore equipment and how cost effective restoration can be.
Smoke & Chemical Equipment Contamination
Smoke is the end product of combustion. Its composition varies greatly depending on the material that combusted.
The black soot that gives smoke its distinctive colour is often carbon. It is produced from the burning of wood, plastic, petroleum, and other organic products. As carbon conducts electricity, it can cause short circuits in electrical and electronic equipment. Furthermore, it can cause overheating problems in heat producing equipment because of carbon’s heat-insulating properties. Carbon does not dissolve in water or solvents, and must be removed by mechanical means such as wiping, scrubbing and vacuuming.
Sulphate and nitrate are contaminants that are also commonly found in smoke. They are produced from the burning of rubber, lacquer paint, petroleum based lubricants, and fuel oil including diesel fuels. Combined with moisture, sulphate and nitrate can turn into various forms of sulphurous and nitrous acids. These acids can cause serious corrosion in metals and electrical contacts, and the corrosive action can accelerate many orders of magnitude upon the application of electricity.
The most harmful substance often found in smoke is chloride. In a majority of fire losses chloride is produced by the combustion of PVC plastic, which is commonly used in insulated electrical wires, plastic sheets, and containers. Chloride reacts readily with moisture and turns into various forms of highly corrosive hydrochloric and hydrochlorous acids. In a typical fire scene, the bright orange flash rust found on bare metal surfaces, and the yellowing of enamel finish on appliances, are their signatures.
Similar problems can occur in the case of chemical contaminations such as the release of acid vapours or fumes, or chlorine gas, and the discharge of chemicals including dry powders from fire extinguishers. It is the water soluble components in the contaminants that react with moisture to cause corrosion problems.
Water & Moisture Equipment Damage
Water damage, other than by direct absorption, is often caused by the same substances that make water conduct electricity – the minerals and other deposits that are in it. Tap water carries a certain amount of minerals such as calcium, sodium, and magnesium, originating from mineral latent rocks buried deep underground in the water table. Rain water typically contains weak carbonic acid which originates from carbon dioxide dissolving in rain drops as they fall from the sky. It can also contain more harmful acids from pollutants – such as Sulphur dioxide and nitrous oxides – that are commonly found in polluted air. By the time the water from a broken pipe reaches the equipment, it often carries many surprises.
The most harmful deed water can do is to introduce acids, minerals, and dirt into the equipment. In the presence of water, such contaminants will break down into various ions and start to corrode as soon as they make contact. If the equipment is energized by electricity while it is still wet, the ions released by the minerals will act as conductors and cause short circuits. More seriously, the corrosion process can accelerate by many orders of magnitude upon the application of electricity by way of electrolysis actions. Catastrophic failures can occur within minutes or seconds of flipping the switch.
After the water dries, those ions will re-combine into mineral molecules and will stay behind and remain inert. If they are not removed, they will slowly react with moisture in the air, re-activate, continue to corrode and eventually cause the equipment to fail.
Moisture exposure is a costly, and often, an overlooked hazard to electronic equipment. This is particularly problematic in situations where the equipment had been accumulating dust in the interior due to air convection or mechanical cooling by fans. When air becomes very humid, dust particles begin to absorb moisture and collapse into a wet, dense mass. If the equipment is switched on, this wet, dense mass can conduct electricity and cause short circuits. If the moisture is allowed to dry, the caking of collapsed dust particles can act as heat insulation that will not allow the equipment to cool properly, or start to obstruct air flow because of the new denser structures. This, in turn, may cause overheating and eventually failures even though the equipment had never been in direct contact with water.
The Decontamination & Restoration Process
The key is dealing with the situation before corrosion has a chance to inflict any damage that is significant or permanent.
Since water must be present in order for corrosion to take place, the first step is to make sure the equipment remains powered off and stay dry. Without water or moisture, the entrapped minerals cannot break down into ions and therefore will stay inert.
The next step is to completely remove the soot, acids, and dirt before they inflict any damage further down the road. The most effective method is to disassemble the equipment, scrub and clean all the affected parts in specially formulated detergents, neutralize the chloride if needed, then if applicable, thoroughly rinse them in distilled or demineralized water, or an organic solvent such as ether. The secret is to dry them thoroughly at an elevated temperature with well circulated air for extended periods of time in order to remove any remaining moisture. Such work should only be handled by trained professionals using specialized equipment.
The procedures involved in dealing with moisture-exposed equipment are very similar to those employed for treating smoke and water related contamination. The disassembly of the equipment, thorough cleaning, and proper drying are the keys. Again, the work should only be handled by trained professionals using specialized equipment.
As risk management and insurance professionals, we should all keep equipment restoration top of mind whenever we are involved in a commercial or industrial loss. Millions of dollars can be saved for all parties involved.
Danny Fung is President & Senior Technical Consultant of Newtron Group, a restoration and consulting firm. He is a veteran engineer with 30 years of experience specializing in equipment restoration and technology.