Patrick Swan Investigates Mechanical Failures in Africa

July/August 2010 – Number 20
Forensic
Tribologist
Patrick Swan Investigates Mechanical
Failures in Africa
By Dave Scott
I
Patrick Swan
Photos courtesy
of Patrick Swan
t’s all too easy to cast
blame when a serious
mechanical failure occurs. This is even more
true when there are deficiencies in the application
of root cause analysis, a discipline that tries to identify
and correct root causes of
problems rather than treating their symptoms. While
RCA shortfalls can exist anywhere, they are aggravated
by a number of factors found
in emerging economies, especially in the emerging
markets of Africa.
This reporter witnessed a
real-life example once in a
Botswana truck workshop.
A new truck was consuming
excessive engine oil. Prior to
stripping the engine to find
the cause, a visiting service
manager asked for a spare
dipstick from the parts warehouse to be compared to the
Reproduced with permission. © 2010, LNG Publishing Company Inc.
dipstick already in the engine. He discovered that the
wrong dipstick was installed.
The installed stick was too
short, leading to the engine
being overfilled every time
the oil level was checked,
only to blow out the excess
oil on each trip. The correct
length dipstick solved the
problem without a costly and
fruitless engine teardown.
Such incidents are no surprise to Patrick Swan, chief
executive officer of Aswan
Consulting Cc, a failure analysis practice based in Cape
Town, South Africa.
“Business in Africa varies from ‘very sophisticated’
with good maintenance practices at the top to an attitude
of ‘run-to-failure’ with limited maintenance at the bottom,” he said. Swan has been
professionally examining vehicle failures in Africa for 15
years and has seen a variety
of challenges to good maintenance practices.
“Generally, tribology is not
an African priority,” he said,
citing the following points:
• If something wears out or
fails, there’s a tendency to
fall back on the capital expenditure budget. CAPEX
is something that a financial director can understand, but it seems to escape financial people that
aging equipment requires
increased and not reduced
maintenance budgets.
• Most lubricators are illiterate individuals with
low skills and little education. The disparaging term
“grease monkey” is loosely
applied as a job description.
• Although equipment is
supplied with maintenance
L’n’G | Europe – Middle East – Africa | July/August 2010 | 1
2 | L’n’G | Europe – Middle East – Africa | July/August 2010
Reproduced with permission. © 2010, LNG Publishing Company Inc.
FORENSIC TRIBOLOGIST
Exhibit 1. Aswan Consulting concluded that the bearing shown above – taken from a fruit chilling plant –
failed because of inadvertent use of incompatible greases.
manuals, these manuals are
often kept under lock and
key by the engineer, causing those who perform the
tasks to work in ignorance.
• There is a common misconception that “oil is oil,” and
“grease is grease,” which,
together with illiterate lubricators, leads to application errors. To overcome
this, most plants minimize
the number of lubricant
grades used, sometimes excessively to the detriment
of plant and machinery.
Swan keeps a ball bearing
from one of his investigations
as an example of damage that
can be done by employing the
wrong lubricant. The failed
bearing, seen in Exhibit 1,
came from a Western Cape
fruit chilling plant. Purity FGbranded specialty grease supplied by Petro-Canada was in
service, meeting both foodgrade and cold temperature
requirements. This grease has
an aluminum complex thickener, which is incompatible
with most other grease thickeners. The failure materialized approximately one week
after another grease had been
applied, Swan said. The real
cause of this failure was inadequate skills training, he said.
“The technician did not know
that different greases could
not be added or applied.”
Swan is by no means the
only industry insider who
considers education a key to
proper maintenance. “The
South African Institute on
Tribology has recently seen
an increase in training requirements for lubricant endusers,” said John Fitton, the association’s president. “This is a
great sign that the issues have
been identified and that training is sought to address these
needs from artisan through to
engineering level.”
But Fitton added, “As production pressures increase
and the drive to reduce costs
increases, operating condi-
tions have typically changed
over time. Therefore just
because a lubricant always
‘worked’ in the past, it may
not be an appropriate lubricant for the present. For example, South Africa is relatively well industrialized,
and the role that lubricants
and greases play in keeping
industry moving is big. But
procurement costs are typically ‘optimized’ to such an
extent that lubricant performance is compromised.”
Unwelcome Truth
Attitude can play a major role in forensic investigations, Swan said. Nobody
likes to be “found out,” so in
many cases critical evidence
has been cleaned and the lubricant disposed in waste systems. This means that Aswan
Consulting is often called in
when there has been an effort at masking the cascade
of events leading to failure,
and the general attitude of
all involved is both hostile
and not readily forthcoming
with essential facts.
The truth can sometimes
be very unpalatable, Swan
explained, especially when
there is big money at stake
– money that can far exceed
mechanical failure costs due
to precedence and consequential damages. Exhibit 2 comes
from a case that offers an example of an attitude of denial prevailing prior to forensic
investigation. A new crown
wheel and pinion were fitted when reconditioning a
bus differential. About two
weeks later and after running
for just 1,550 kilometers, abnormal differential wear was
noted, and the crown wheel
and pinion were removed for
inspection.
Unfortunately,
nobody
thought to save a sample of
the oil that was drained when
the differential was removed.
When the bus owners saw
the gear wear, they immediately returned the differen-
Exhibit 2. This crown wheel (at left) and pinion were taken from the differential drive of a bus just two weeks
after installation. The wear that is visible was caused by the differential being filled with engine oil rather than
gear oil.
Reproduced with permission. © 2010, LNG Publishing Company Inc.
L’n’G | Europe – Middle East – Africa | July/August 2010 | 3
FORENSIC TRIBOLOGIST
tial to the supplier demanding replacement under the
warranty. Fortunately for the
supplier, Swan was present
when the differential arrived
and advised that the cause
of failure was incorrect oil.
Based on the smell and feel
of the remaining oil film, he
deduced that the bus operator had most likely installed
engine oil instead of gear oil.
This conclusion was supported by other evidence:
• The gears were positioned
to mesh correctly;
• A lack of heat discoloration indicated there had
been plenty of oil;
• At a micro scale, the wear
was adhesive.
As Swan recounted, the
bus owner responded angrily that he had just commissioned a computerized lubricant dispensing system, and
it was totally impossible for
any technician to access an
incorrect lubricant. Further,
the owner said, each technician had a personal identification number so that any
errors could easily be traced.
Two days later, the owner
called Aswan Consulting requesting a report. The reason for his change of heart?
He learned that the contractor who had installed the new
dispensing system had crossed
the lines for gear and crankcase oils. The gear oil was an
API GL-5 85W-140 fluid, the
crankcase oil ACEA E3 15W40. Approximately 30 engines
had been filled with gear oil
and 17 differentials with engine oil during normal servicing since the system was
commissioned. This costly
blunder resulted in some engines and differentials being
reconditioned.
Exhibit 3. This valve plate (left) and piston (right) were part of a hydraulic pump on an excavator.
The wear occurred because the unit was not properly cleaned at the time of reconditioning.
Swan thus often operates
in a grudge atmosphere and
must provide facts which can
withstand legal scrutiny. He
has made many court appearances on behalf of clients as
an expert witness.
The Curse of
Contamination
Ambient
temperature
ranges and dust levels in
Sub-Saharan Africa are typically more extreme than
other parts of the world and
must be taken into account.
Add to this the fact that fuel
specs in Africa vary from ultra low-sulfur diesel (which
is 0.005 percent or less sulfur
by mass) to very high sulfur
(over 1 percent) to bio-diesel
that is frequently used to top
up fuel tanks, and the impact
is severe on both engine service intervals and lubricant
additive packages.
Everyone expects maximum service life from machinery. However, as filtration experts point out, this is
only achievable when excluding particles above 6 micron.
Swan has found contaminants to be a major problem in
many cases. Exhibit 3 shows
the failed main hydraulic
piston-pumps on an excavator. The farmer-owner, who
4 | L’n’G | Europe – Middle East – Africa | July/August 2010
also operated a quarry from
his farm, replaced the pumps
with reconditioned units.
These units failed after
about two days of operation,
Swan said, and the farmer
filed a claim against the pump
reconditioner. The reconditioner refused the claim and
enlisted Aswan. The photos
show the pump-suction and
delivery plate plus a piston –
both heavily scored by metal
debris in the fluid.
When a hydraulic pump
fails it leaves a significant
volume of wear-metal debris
throughout the system. Systems such as on this excavator
are large and very complex. It
is imperative, Swan said, that
the entire system be removed
and cleaned, pipe by pipe and
valve by valve, after such a
failure, and not as this farmer did — simply by changing
the oil and filters with the reconditioned pumps. This case
was a very expensive lesson
for the farmer because dirt
does not lubricate; downtime
alone was around two and a
half weeks.
Looking for Answers
The subject of lubricants
and greases and their application tends to get treated as
a minor operational issue by
company management. But
when there is a serious failure
that leads to a plant shutdown,
vehicle downtime, or costly
equipment replacement, then
lubes rocket to the top agenda item in a boardroom. And
that’s when Aswan Consulting’s 15-year fact-finding reputation is severely scrutinized
and judged.
U.S. Army General David
Petraeus, who oversees Coalition forces in Iraq, made
the following comment on
leadership in the March issue of Fortune magazine:
“We also work very hard on
[being] first with the truth.
That’s a powerful admonition: First of all we’re going
to tell the truth. We’re not
going to put lipstick on pigs.
We’re going to be absolutely
forthright and brutally honest – not just with ourselves
and with our subordinates
and our superiors – but with
the press. The credibility of
leaders is of enormous importance.”
Patrick Swan’s forensic
findings for tribology failures in Africa have never
attempted to “put lipstick
on pigs.” Even if harsh facts
around maintenance are uncomfortable, it’s worth finding out the truth. ❖
Reproduced with permission. © 2010, LNG Publishing Company Inc.