Many many years ago, when I was a young
tradesman, I found myself working with a team designing smoke alarms for long
distance passenger trains. You see, traditional smoke alarms can’t be used
because the fumes from the train engine, even if too faint to be sensed by
people, would set the alarms off. Finally, a solution was found, a sensor
designed and manufactured and then installed in four carriages, each
representing a different type in common use. It remained only to test them. A
young engineer was given the task, and a smoke grenade, and sent off to the station
yard where the newly modified carriages were parked alongside platform 4.
Unfortunately, there was also another set of very similar carriages parked at
platform 3, being readied for passengers, and indeed, some passengers had
arrived early and already embarked. Obviously, this story does not have a happy
ending, the grenade was placed in a carriage entrance and set off, and when the
hapless passengers and staff ran screaming from the train, the engineer’s
stomach turned to water.
It may be an extreme example, but the story is
a demonstration of the pitfalls of Testing and Commissioning, and the potential
for a simple T&C process to impact on a much wider scale than just the item
being commissioned. Not all T&C losses are due to a gormless graduate equipped
with explosive ordinance though; most arise when there is the initial application
of energy to complex and expensive machinery, sometimes with unexpected and catastrophic
results.
In a standard Contract Works policy, Machinery Breakdown,
or Derangement is generally an exclusion. Testing and
Commissioning is usually available as an endorsement, which effectively removes
the policy Machinery Breakdown exclusions during the commissioning period.
Underwriters will often want the T&C period well-defined, perhaps to the extent
of nominating specific dates and specific commissioning processes, and it will
generally carry a large deductible, to reflect the increased risk to plant
during the commissioning period. And quite an increased risk it is too. The
installation of complex plant and equipment is fraught with dangers. For
starters, the machine may very well have left the factory with an inherent
defect, which doesn’t manifest until some load is introduced, or the
installation process may include a careless moment, or a fitting that is not
quite right. The fact is that most machines are never more at risk than those
moments when they are first switched on, or first experience load conditions,
except as they near the end of their working life, when wear and tear starts to
contribute to breakdowns.
This increased rate of breakdown at infancy and
again at the end of the working life of a machine can be expressed graphically
in what engineers commonly refer to as The
Bathtub Curve, and I have included just such a graph below for you. The
horizontal axis represents the age of the machine, the vertical, the failure
rate for like machines. In terms of the infancy of the machine, it can be seen
that the potential failure rate is extremely high at very early stages, then
falls as the machine overcomes what may be referred to as teething problems and
settles into a steady and efficient working life. If the curve was applied to,
say, a refrigeration sealed unit compressor, the yellow section would span
about 5 months, the green about 15 years. For a large electric motor running a
relatively constant load, it would more likely be 1 month and 30 years.
As I
mentioned before, there are a number of factors which contribute to the
increased failure rate of an infant machine and below are a few examples, from
my own personal experiences, that might highlight those factors.
The Factory Fitted Fault: Commissioning of an air compressor
in a medium sized workshop, installed, and power supplied. On start up, the
compressor ran for a few seconds and then the cylinder head, about the size of
a small suitcase, fragmented and exploded across the workshop. The largest
piece slammed into an overhead crane cab and, unfortunately, a smaller piece
travelled about 40 metres and sliced through tendons in the elbow of a workshop
employee. Subsequent investigations revealed that an internal valve plate had
been fitted back to front, although how it escaped quality control has never
been adequately explained.
The Careless apprentice: A very large Diesel powered generator set was being installed in a
remote town. During erection, an apprentice was given the task of fitting
lagging to the exhaust manifold, to quieten the engine a little. To make it
easier to get access, he removed the governor linkages, attached the lagging,
and then reattached the linkages – upside down. When the engine was started for
the first time, because of the wrong linkage position, it immediately ran to
full speed. By the time the kill switch was activated, the engine had almost
self destructed, and had to be replaced.
Who Needs Instructions: A large freezer installation was
finally finished, and although it was late on a Friday, it was decided to give
it a quick test. The control panel was energized and the compressors operated
and everything cooled down nicely. It was knockoff time so the plant was then
shut down and everybody left the site, for the weekend, overlooking the fact
that the control panel still had power to it. In that control panel was a
timer, in that timer was a small plastic pin, attached to that small plastic
pin was a tag, which read for factory
testing only, remove before commissioning. As nobody had read the
instructions, the pin remained in place, allowing the defrost heaters to run
all weekend, melting the insulated sandwich panel forming the walls of the
freezer rooms.
You Forgot WHAT?: A ball mill was erected at a gold mine and had been tested without load.
It was then loaded with dead weight and the bearing deflection calculated, and
the bearings set up accordingly. The Mill had a capacity of 50 Tonne and so 50
Tonne of deadweight was used. The test engineers overlooked however, that the
mill still hadn’t had its liner installed, which weighs another 10 Tonne, so
their calculations were out by that amount. When it was commissioned with a
full load, the bearings failed and the repairs took 4 months, triggering a
major Advanced Loss of Profits claim.
Is it any
wonder then, that Insurers and reinsurers exercise great caution when endorsing
a policy for T&C? Brokers and their clients are well advised to ensure a T&C
endorsement is given consideration for every Contract Works policy written where
the works include anything where mechanical, hydraulic or electrical forces are
applied. They should also have a thorough understanding of the T&C process
and how timelines will impact on policy response and premium. In some cases, an
independent pre-construction survey may be invaluable in getting the right
cover.
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