66
December
2014
HYDROCARBON
ENGINEERING
HF engineers analyse emergency escape and rescue, an
issue that first gained prominence after the 1988 Piper Alpha
tragedy (in which a North Sea platform caught fire and
exploded, killing 167 workers). ‘Whenever you are dealing with
hydrocarbons, there is always the possibility of a fire or
explosion’, said Hollaway. ‘If it happens on an offshore
platform, are there enough lifeboats for all the crew? Is there
more than one way to reach them if access is cut off in a
certain direction? Are there pathways that lead to a blind trap
instead of an emergency exit?’
Span of control is a HF term that refers to the ability to
handle different tasks simultaneously. Generally, an individual
can keep track of up to seven unique items. A supervisor, for
instance, can oversee up to seven staff; after that, the facility
needs another level of supervision to remain effective. In
addition, there is a permit to work form (PTW) that must be
issued whenever an operator is doing a hazardous operation
such as hot tapping or working in a confined space where
oxygen supply might be limited. For a supervisor, every PTW is
an additional responsibility and impedes their span of control
by adding to their cognitive load; as such, PTWs need to be
limited in order to maintain safety.
Automation, in which certain processes are placed under
computer control, can be both a blessing, and a curse. HF
engineers know that human behaviour is superior for some
tasks, and automation is better under some circumstances.
Operators have to decide which is appropriate for any given
task. One can have positive automation bias, in which
something works too well; circumstances have arisen when
pilots have drowsed off, only to fly over their destination.
Or, one can have negative automation bias in which an
overly fussy system is turned off. ‘I investigated a situation
where there were two valves that automatically controlled the
pressure as a fluid flowed from point A to point B’, recalled
Hollaway. ‘If the flow were too high or too low, one or the
other would automatically shut down. During start up,
however, the automated valves would jump back and forth,
making it difficult to balance. An old hand said, ‘Let’s do this the
tried and true way’, so they opened the block and bled and
turned the valves manually until they balanced, then closed off
the block and bleed’.
The ad hoc workaround functioned well until, one night at
3 am, someone was told to turn a manual valve a little less, and
they turned it a little more, and there was an explosion. ‘The
point is, they should have field verified the automated valve
process in the first place’, said Hollaway. ‘And even if they did
not, the operator should have documented there was a
problem so that it could be fixed.’
Proper alarm management strategy is key when an
emergency arises. Accident investigators have delineated it as a
factor in numerous tragedies, including the Three Mile Island
nuclear meltdown and the Air France crash in the Atlantic
Ocean near Brazil. The problem becomes acute when a score of
alarms go off simultaneously and the operators have no idea
where to start in terms of dealing with them. Studies show that
people generally react in two ways; the first is that they freeze
due to cognitive overload. The second is that they react to the
alarm that is easiest to address, instead of the most critical.
One solution is to design an alarm system so that the problems
are identified in descending order of criticality.
Problems
Some operators take a parochial attitude toward HFE, said
Hollaway. ‘Operators say, ‘We have been doing it this way since
Spindletop (a prolific oilfield discovered in Texas in 1901), and we
are not about to change’. These same people could find
themselves in a difficult position if there is a mishap or explosion
and they learn that human error was to blame’.
While HFs are typically incorporated into elements of a plant
design through applicable codes and standards, a broad look at
the HF issues associated with the entire plant layout is often
overlooked. Whether due to time, cost or resource constraints,
companies often fail to reap the benefits of this broader HFE
examination.
Yet, according to Hollaway, the sector can fix the problem
through relatively simple, inexpensive human factor measures
that pay for themselves. ‘Through a human factors analysis, for
instance, you might reduce the time it takes to do a task. If it
used to take three workers 10 hours to change out a valve, and
you show them how to do it with three people in 5 hours, you
have just made a 50% savings. It is the same with safety training,
only the returns are much greater’.
At this point, there are great opportunities to enhance the
engagement of HFE reviews in final designs, said Hollaway.
‘Adding HFE to a project will cost around US$ 300 000 - 500 000
on a US$ 2 billion project, which is a very small percentage of
overall cost, but a huge eventual savings in increased safety,
operability and maintainability’.
Some jurisdictions have advanced programs. ‘Norway and
the North Sea are leading in HFE’, said Hollaway. ‘Brazil is also
very advanced. I taught at Petrobras University for three years. A
lot of their corporate social responsibility is focused on the
safety of their people. The US is improving and awareness is
growing, but there remain important opportunities for enhanced
application of HFE, such as the development of API RP54’.
The AFPM notes that its membership is advancing HF safety
proactively on several fronts. ‘Here are a few examples of a
strong COO program’, said Swett. ‘It enhances the organisations’
process safety culture with the expectation that every employee
performs each duty with alertness and a proper sense of pride
and accountability. There are better incident investigation
reports that go beyond ‘human error’ to address the real
underlying issue. This improves the organisation opportunity to
learn from the incident and decreases the chance of having the
same incident twice. Process safety awareness increases
throughout the organisation and specifically at the operator
level. It reinforces the value that safety and processes safety are
everyone’s responsibilities’.
Conclusion
How can North American firms further improve HF performance?
Hollaway believes that more cooperation between industry and
government is needed to establish consistent standards and
guidance.
‘When you look at states with higher standards, you see
higher injury rates, but low fatalities. When you look at states
with lower standards, you see lower injury rates, but higher
fatalities. There is a clear association between better standards
and lower fatalities. In my personal opinion, I think the oil and gas
industry should work more closely together to establish uniform
HF standards and requirements’.
