64
December
2014
HYDROCARBON
ENGINEERING
in this emergency situation, possibly impacting incident response
effectiveness.’
The operator’s confusion over which button to push was a
classic example of human machine interface (HMI) issues, one of
the principle focuses of human factors engineering (HFE). ‘HFE is a
multi disciplinary science that integrates the human operator
into a mechanical system’, said Hollaway, the Human Factors
Engineering Manager for ABS Consulting, Inc., a Houston based
firm.
When a petrochemical plant or refinery is being built or
modified, design engineers ensure that the facility operates as
efficiently as possible. HF Engineers, on the other hand, are plant
safety experts who determine potential HMI danger spots.
The origins of HFE date back almost a century, to the early
1920s. At the time, biplanes began carrying mail around the
country. In the space of five years, over 100 pilots were killed.
Cognitive scientists were brought in to investigate the situation,
and they learned that pilots would fly into bad weather and not
know which way was up. They would suffer gravitational illusions
and think they were flying level, when they were not. Plane
manufacturers began to put gauges into the planes so they
would know altitude, direction and orientation. This resulted in
improved safety which exists today; the same basic HFE concepts
integrated into a plane in 1930 still exists in a Boeing 737.
Currently, there are approximately 10 000 HF engineers
worldwide. Most of them are usability engineers; they work with
software firms, for instance, to see how a client would burrow
down through their software applications.
Hollaway is an ergonomic HF engineer. Ergonomic engineers
must go through rigorous training and experience in order to
qualify. Hollaway, for instance, has a Master of Science degree in
Human Factors and Aerospace System Safety from the Embry
Riddle Aeronautical University, in Florida. He is also certified as an
Associate in Claims (AIC) and an Associate in Risk Management
(ARM) from the Insurance Institute of America. For many years
prior to his current position, he was the Third Party Administrator
for the HOVENSA refinery in St. Croix, USVI, investigating and
adjusting occupational injuries and losses from fires and
explosions.
In addition to HMI, HF engineers examine ways in which
human physical and mental limitations affect operations, staff
levels of training, and conduct of operations (COO), i.e., the way
that a company runs its processes. ‘Our members believe that
safety is everyone’s responsibility throughout the entire
organisation and therefore topics that help promote safe
operation like conduct of operations, operational discipline,
human factors and human reliability are discussed at a variety of
committee meetings, workshops, and conferences’, said Lara
Swett, the American Fuel & Petrochemicals Manufacturers
(AFPM) Director of Health and Safety Programs. ‘A COO program,
for instance, reduces operational risk, helps promote a strong
safety culture, and ensures that all employees perform their
duties safely and consistently. The result is an organisation that
has safety as a core value, less incidents occurring, improved
safety performance, and most importantly every employee and
contractor going home safely every day’.
HF analysis can occur before, during or after a plant has been
commissioned. There are two main stages to designing a plant;
FEED, which lasts approximately one to three years, and then
another 18 months to two years for detailed design. Subsequently,
design changes are also made during the times the plant is being
constructed, and later modified to correct operational issues.
Ideally, HFE is incorporated right from the beginning, when it
is relatively inexpensive to classify and verify safety and optimise
operations and maintenance. Hollaway was recently consulting
on a project where an operator had three associated valves that
were set into an offshore processing facility; a 5000 psi, a
7500 psi and a 10 000 psi. ‘If you were to open the 5000, then the
10 000, there would be no problem, but if you opened the 10 000
first, there would be a serious problem. I noticed this in the
design stage and recommended they interlock them so that the
10 000 could not be operated incorrectly’.
Usually, however, HF engineers are called in during the
construction phase, when the plant is already taking shape. They
look at a number of basic factors to ensure safety. As an example,
HF engineers have several classifications for valve and instrument
criticality, and appropriate access. Valve criticality 1 level involves
ensuring that, in an emergency, an operator can get to a valve
instantly. Criticality 2 level is for valves that must be accessed
frequently, such as every day to test samples. Criticality 3 level is
for valves that might be used once a year for maintenance
purposes. Appropriate access can vary from being right on the
main control panel, to a scaffold, to a ladder; HF engineers verify
that the access is appropriate to the function.
The location of emergency buttons is also a priority. ‘Manual
alarm call (MAC) is a button that sets off a loud warning sound
that alerts everyone to evacuate an area when there is danger’,
said Hollaway. ‘We were investigating a situation where a human
error possibly led to an explosion. Prior to the explosion, the
control room operator heard a rumbling and knew there was
going to be an explosion, but he did not hit the emergency stop
button before he ran away. When asked, he said that the MAC
was not on the way out, it was in the direction of the hazardous
event’.
In an emergency situation, the MAC should be located near
an exit, noted Hollaway. ‘Even then, the location of the MAC is
very important, because when people are caught in an
emergency, their spatial perception contracts to the point where
it seems they are looking through a toilet roll, they only see what
is immediately in front of them’.
Standardisation is very important. HF engineers have a saying
for valves; lefty loosey, righty tighty’, said Hollaway. ‘It means
that valves should open by turning to the left, and close by
turning to the right. Rotary switches increase clockwise, and
decrease counter clockwise. A lever increases when you push it
away from you, and decreases when you pull it towards you.
Standardisations change from region to region, however. In
North America, for instance, a light switch turns on when one
flicks the switch up, and off when the switch is flicked down. In
the UK, however, the opposite is true; if a facility is to be run by
British operators, HF engineers and designers must account for
population stereotypes.
The design of worker access, such as scaffolding and ladders,
can make significant difference in safety. ‘There are a lot of
injuries due to the force of gravity’, said Hollaway. ‘You may think
that it is easy to lift a 20 lb object, but not if it is 4 ft beyond the
access point. For every worker killed, there are far more injured.
There were 127 fatalities in the offshore Gulf of Mexico from
2003 - 2010 (Bureau of Labor Statistics), but there were 1400
career ending injuries’.
