Technical Equipment: Restore or Replace?
- Published on October 26, 2007
Clearly, equipment in Category #1 will be replaced. Theoretically, almost any damage can be restored, but where many or most components need to be replaced, it becomes uneconomical to restore the equipment.
On the other hand, Category #2 equipment, which merely needs a thorough internal and external cleaning, and perhaps the replacement of a few minor parts, is restorable.
Not very long ago this was not true. However, about 13 years ago, a group of engineers got together and formed a company with the sole purpose of restoring contaminated equipment. Since this was a new venture, all know-how, procedures and chemicals had to be developed from scratch.
During the ensuing 12 year period, technical equipment restoration has developed from these humble beginnings into a fully scientific and repeatable process, completely reliable, and recognized and approved by insurance companies and equipment manufacturers alike.
Thousands of successful case histories worldwide, in which all categories of electrical and mechanical equipment have been decontaminated and put back into service, attest to the viability of this new industry.
As might be imagined, the cost savings compared to replacement are impressive, not only because new equipment is not needed, but also because restoration is (almost always) much faster, and personnel re-training, software replacement, etc., are not required.
No matter what type of equipment is being restored, the basic procedures remain the same:
1. Disassembly of the equipment to the extent necessary to expose all contaminated/corroded surfaces for treatment.
2. Decontamination, using procedures and chemicals which will selectively remove the offending contaminant with minimal or zero effect on the underlying good material.
3. Removal of all traces of restoration chemicals, and also complete and thorough drying to eliminate all residual moisture.
4. Re-assembly, testing, recertification and return to service. This step includes the replacement of any parts damaged by the event, or during restoration.
Proper restoration requires the services of professional restoration technicians, and also equipment field service technicians from the manufacturer or a third-party service provider. Equipment technicians are best qualified to direct and assist in the proper disassembly and re-assembly of the equipment, and, most importantly, to perform the final check-out and re-commissioning of the entire system.
Most types of damage of which we are speaking are covered by insurance.
When disaster strikes, it is to the insurer’s benefit to mobilize a technical team to return the insured to operation as quickly as possible.
Because of their special expertise, field service technicians familiar with the equipment are a critical part of the restoration procedure and also the cost.
Several common types of damage are amenable to restoration rather than replacement:
1. Soot and other debris carried into the equipment can be conductive and/or hygroscopic, and should be removed.
2. Any fire in which plastic materials have been consumed creates hot hydrogen chloride gas, which condenses on and in the equipment, in the presence of moisture, to form hydrochloric acid. This corrosive acid immediately attacks metal. Since the corrosion process does not use up the HCl, it will continue until the metal is totally consumed.
3. Operating or powered electrical or electronic equipment which has been invaded by water (from flood, leakage, or firefighters’ hoses) immediately develops short circuits and galvanic corrosion and will require major repairs after decontamination. However, contrary to popular belief, unpowered equipment is not permanently damaged by water. If the water is clean, thorough drying may be all that is required before powering-up. In most cases, however, the water brings with it debris and dissolved or suspended solids, which remain after evaporation and must be removed by restoration if equipment function is to be maintained and guaranteed.
4. A certain amount of dust is ever-present and does not negatively affect the operation of electronic equipment unless it collects moisture. It is a different story when a device is covered by an eighth of an inch of industrial dust. Not only will this dust impede the operation of mechanical sub-systems, (tape and disk drives, contacts, switches, potentiometers, etc.) but also it can change the heat-dissipation in a fully-electronic system, causing it to malfunction or even catch fire.
5. Other contamination often found in an industrial environment (cutting oil vapors, sulfur gases, chemical residues, and the like) can result in the degradation of any number of plastics and metals commonly found in electronic and other equipment. Thus, restoration may become necessary even though no “disaster” has occurred.
There are only four things to remember when equipment has become contaminated:
1. Shut off all power
2. Initiate drying procedures
3. Reduce atmospheric relative humidity to 40% or less (this retards the progress of corrosion)
4. Call a restoration company
In addition to properly trained and qualified technicians, the most essential ingredients in a superior restoration job are the chemicals. These have been developed over the years exclusively for technical restoration, and must fulfill sometimes contradictory requirements:
- They must remove the contaminant completely, but not any other material.
- They must remove a broad spectrum of contaminants, and at the same time be compatible with the great number of materials which are used in electronics.
- They should be biodegradable and easily disposable.
Experienced restoration companies will have on hand a number of different chemicals for the specialized cleaning of copper, zinc, iron, aluminum, silver, plastics and all other materials found in electronic or electro-mechanical devices.
They should all be water-based to facilitate disposal, and also because water is a highly effective solvent for corrosive acidic residue.
In the past, cleaning of electronic circuit boards was most often accomplished with fluorocarbon compounds.
Specifically, Freon TF113, which is liquid at room temperature, was used with high-pressure spray equipment to dislodge contamination without leaving a residue.
The high density of liquid Freon also provided a “scrubbing” action to assist in the cleaning process.
Freon has always had one major drawback, however. It is a poor solvent for aggressive chemical substances such as chlorides, sulfates and nitrates, which often are found in contaminated equipment. Even after the addition of isopropyl alcohol to the Freon to improve solubility, it still was not as effective as aqueous cleaning. It remained popular primarily because of the fear of technical people that water would damage their equipment.
Technical equipment restoration has developed from these humble beginnings into a fully scientific and repeatable process, completely reliable, and recognized and approved by insurance companies and equipment manufacturers alike.
Nowadays, we find that Freon in any form is being banned throughout the world because of its destructive effect on the Earth’s ozone layer. As restoration experts, we have no problem whatsoever with this, because we have known all along that water-based cleaning is technically superior.
The actual decontamination consists of a combination of mechanical and chemical procedures.
After selecting the appropriate cleaning agent, the contamination is removed by spraying with pre-heated cleaning fluid in a spray booth by brushing, by rubbing, by immersion or by a combination of these measures.
Sometimes service technicians who have no expertise in restoration attempt to clean electronic modules by using an ultrasonic bath. This is not recommended since the internal bonding of the leads in an IC may loosen and render the IC inoperable.
Ultrasonic cleaning, however, is quite useful in decontaminating many electro-mechanical components.
After aqueous cleaning, drying becomes crucial. For circuit boards and small modules, vacuum ovens and convection ovens with constant temperatures are used. Drying time should last about 12 hours to guarantee absolute dryness.
Larger objects such as control cabinets and machinery are encapsulated in a tent-like structure under which one or more special purpose heater/dryers (a dehumidifier which works at elevated temperatures) will be placed. Equipment must not be energized until it has become completely dry.
In conclusion, since the advent of scientific restoration, the replacement of contaminated equipment which is restorable is no longer technically or economically defensible. Knowledgeable equipment manufacturers and service providers are now aware of this, and no longer demand that contaminated equipment must be replaced.
Indeed, astute field service managers may now look forward to an entirely new source of revenue by providing their service technicians to assist in and become part of the restoration team.
Max Klepp is the President of Relectronic Service Corporation, an affiliate of Siemens Relectronics specializing in the restoration of electronic, mechanical and medical equipment after water or fire damage or other contamination.
Michael Woelfel is a consulting engineer with Relectronic Service Corporation, USA. He was previously associated with a number of U.S. corporations in research, technical service and engineering management.
This article adapted from Vol. 4 #4.