Our Services > Forensic Engineering
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Forensic EngineeringWe provide an in depth and detailed analysis of engineering failures, accidents, safety incidents and contractual issues. Using the latest state of the art analytical techniques we are able to provide comprehensive assessments and determinations and have managed multiple disciplines in a wide range of contexts. We work with metallurgists, other engineers and lawyers to provide a holistic and comprehensive service that compliments our project management services. We work in both legal and safety environments and our practitioners have a fundamental understanding of dispute resolution and safety processes.Services & CapabilitiesSafety / Accident Investigations
Insurance & Litigation Claims
Dispute Resolution, Industrial Projects
Detailed Examples of our Forensic Engineering Services
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| Failure of a crankshaft journal bearing |
This is a photograph of a crankshaft journal bearing removed from a large industrial stationary engine used to generate electrical power and process heat (co-generation). The bearing shows advanced damage from acid attack, which has eaten away the top layers of the bearing shell. Acid compounds in lube oil derive from sulphur and other contaminants which are carried in with the fuel and if the oil is not changed regularly, these acid compounds can accumulate and cause damage to engine components such as this crankshaft journal bearing.
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Cavitation in a
cylinder liner |
This photograph shows Cavitation on the coolant side of a cylinder liner. Cavitation in this context is caused by the repeated collapse of vapour (gas) bubbles in the coolant fluid. During engine operation, water vapour bubbles continuously form and collapse on the sides of the liner. As the bubbles collapse, extremely high pressures-as high as 15,000 atmospheres, can occur momentarily, eroding the material. The problem can be mitigated to some extent by applying a thicker chrome layer over the surface of the liner at the time of manufacturer and good management of the engine coolant.
Factory Fires
Often the cause of industrial factory fires is related to mechanical failures which lead to a release of flammable material such as hydraulic oil, building panel foam, or even edible products such as milk powder. Prosolve Ltd has investigated industrial factory fires which have succumbed to these causes. Examples of such fires are shown below.
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| Milkpowder Factory Fire |
Ordinary milk powder is quite flammable. During the milkpowder manufacturing process, milkpowder can combust spontaneously due to runaway exothermic reactions and explode within the drier. Milk powder driers are required to be installed with explosion doors to vent such explosions to atmosphere, however occasionally these not sufficient to contain the explosion and more serious fires develop in other parts of the plant. Prosolve Ltd has assisted in the remediation of one such fire, and this included managing the implementation of measures to prevent a recurrence.
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Paper Machine Fire
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The fire damage to this ceiling was caused by an oil fire directly below it. The oil fire started due to the rupture of an oil filled rubber sleeve and adjacent hydraulic lines in turn due to a catastrophic shaft and bearing failure that occurred nearby.
Leaky Buildings
Leaky Building Syndrome (LBS) is often caused by a number of different factors, conspiring together over time to cause a problem that can be expensive to fix. The report “Accidents Failures, Mistakes and leaky Buildings” discusses these factors and can be downloaded here. Registered building surveyors are normally called upon to troubleshoot and repair Leaky Building homes. The failure of building type components can also lead to failures in industrial processes. After one such failure, Prosolve was engaged to analyse the performance of ceiling cladding screws and determine why the screws were failing and dropping into industrial machinery below.
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Analysis of weathertite cladding fixing
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With the assistance of a roofing specialist and a metallurgist, we discovered several factors that contributed to the problem, and illustrated our findings in this drawing. The friction weld joining the hardened tip to the screw shank weakened the screw and predisposed it to fail. The cladding lap joints were deliberately designed to fit clumsily in order to prevent the osmotic migration of moisture. This resulted in a joint depth too long for the screw shank which had a different helical pitch to its cutting tip. This meant that when penetrating the cladding lap joints the threads on the screw shank stripped before the tip fully penetrated the purlin. This prevented the screw shank from being able to properly grip the purlin and over time the screws loosened and fell into machinery below. The report also investigated why industry controls did not prevent this problem from occurring. This investigation was carried out before the Leaky Building Syndrome was publicized, and exemplifies how even the simplest of problems can require the management and technical co-ordination of several engineering disciplines to solve it.
Process Plant Failures
A fertilizer plant in New Zealand shut down for six weeks due to the mechanical failure of a titanium lined reactor. The cause of the reactor failure was a weld failure of the titanium liner. Andrew McGregor was engaged indirectly by the insurers to help determine the cause of failure and also to assist in the monitoring of the remediation works. The photographs depicted below show the reactor under repair.
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Titanium lined reactors involve specialized technology and in order to determine the cause of this failure, Prosolve’s international network of consultants and associates was able to locate a retired expert who was able to assist. His assistance was sourced through the Corrosion and Protection Centre of Industrial Services (CAPCIS), University of Manchester, UK.
Bearing & Shaft Failures
The comprehensive failure analysis of bearings and shafts often requires a detailed assessment of their design details, particularly at the mechanical interfaces and also the lubrication philosophy assumed in this design. A metallurgical analysis of the failure sites, though helpful, may only highlight consequential causes and a detailed understanding of the plant history may be necessary to comprehensively determine the cause of failure. An example of one bearing and shaft failure analysis undertaken by Prosolve is shown below.
This shaft failed because it seized inside its bearing as a result of poor lubrication due to water contamination. Operational process water leaked past the shaft seal into the bearing grease because of a worn shaft surface at the seal line. Prior to catastrophic failure, the bearing was changed several times without the causal mechanisms being properly understood.  |
These two photos show a bearing that was replaced before the shaft shown above failed catastrophically. They show signs of lubrication failure, as evidenced by flaking or ‘spalling’ at the ball line and cracking of the bearing shell.
The Prosolve Philosophy
Recent work in the international accident safety field shows that accidents and engineering failures normally have several contributing causes. At first glance there may appear to be a single root or primary cause which may be sufficient in satisfying immediate questions at hand. More in depth investigation however can often reveal several latent failures or defects existing in an engineering organisation or system for some time before the failure occurred. Collectively these hidden factors can be as significant as the more obvious failures that occur immediately prior to the failure and which are often mistakenly considered as the 'root cause'.These latent failures can arise from a combination of defective organisational cultures and systems, task related risks, together with mistakes, lapses and violations on the parts of individuals. These causal factors can lie dormant within an organisation and can be distinguished from factors occurring at the time of failure which are termed ‘active’ factors.
Active factors by their nature are more visible than latent ones and are also easier to comprehend. A simple example of an active factor would be the failure of an individual to operate a machine safely, which in turn caused an accident. A simple example of a latent factor would be poor or insufficient training being made available to the operator prior to the accident. A more complex example of a latent factor would be if machine operator training appeared sufficiently comprehensive but failed to address an aspect of machine control that was only one of many factors involved in the accident.
In assessing legal responsibility for a loss, the test is typically whether the loss was a reasonably foreseeable consequence of an earlier failure. There is often a temptation to limit the attribution of the loss to a single, obvious and proximate ‘active’ failure. However that sort of superficial approach can mask or overlook latent failures that, while initially appearing more remote, may be more powerful and dominant causes of the loss. The proximate failure may have simply been the opportunity for the latent failures to reveal themselves.
An understanding of these latent factors may be necessary in order to correctly identify effective recommendations so that recurrences can be prevented. They may also present a client, insurer, lawyer or Court with the tools or information needed to more properly attribute legal responsibility.
In order to address these types of considerations, engineering failure reports must be comprehensive and technically robust. If they are also succinct, open and easy to understand, parties are more able to contribute to their findings or accept them. In many cases, this leads to out of court settlements and cost effective management of legal fees and technical expertise.
This is the philosophy of Prosolve Ltd and exemplifies the nature of reporting that we feel passionate about providing.