Drastic reduction in maintenance cost, achieving unity uptime, reduction in overtime
from 5000 to 2000 hours at BPCL refi nery are few of the accomplishments of
PLN Murthy, CHMM, Maintenance Head BPCL.
In an exclusive interview with CEW
he shares his opinion on critical role of instrumentation to ensure uninterrupted plant
operations and personnel and plant safety. Excerpts from the interview.
Please apprise us about the safety practices
in context to the chemical industry in the
country. How have the safety practices
changed over the years, typically in the
Like all the other standards, safety
standards and practices are evolving and
modified with time. The working conditions,
awareness of health hazards especially in
abnormal conditions like plant or unit start up
and shutdown, made the safety regulations
more and more detailed and specific. After
every incident - like BHOPAL tragedy and
Jaipur incident - the safety regulations were
revised. On the other hand, in earlier days
the chemical plants were located away from
populated locations. But over the time, the
townships have come around old plants and
with cities growing the units are surrounded
by dense inhabitant.
Again the environmental criteria have
been constantly demanding less pollutants
release both in atmosphere and liquid
effluent. It is possible for new units to be
designed according to new guidelines.
However continuous efforts are needed to
modify the existing units to suit the revised
safety guidelines. Not only CAPEX, but
also space and technical limitations come
in way to run or modify the units safely.
We at BPCL follow all the statutory
guidelines, of PESSO for safety. Like all the
other Oil Companies, we are guided by Oil
India Safety Directorate (OISD) standards.
We have continuous Internal Safety Audits,
biannual external audits (like DNV), and
surprise audits from OISD. There is an
external audit once in 3 years by OISD. We
dilute / mitigate all the points raised in the
above audits, in timely manner, so that the
same stand for scrutiny by next audit team.
What are the major considerations that
need to be factored in at the time of design,
keeping in mind upgrading to future
technologies to ensure plant performance
At the time of design, various factors are
considered and factored in to the plant design
and selection. The first factor is selection of a
process technology, which gives an optimum
performance and process safety.
Simply putting a renowned process licensor
can fulfill such a requirement. But the
catch lies in bringing different (Technique)
licensors on to a common level for comparison
purpose. Many a time, performance criteria
are fulfilled by all licensors. There will be
variations in requirement of utilities, both in
quality and quantity. Sometimes the criteria
is on space requirement, in other cases it
will be maintenance factors and ease of
operation. In all cases process safety is
ensured, but the risk factors and levels
vary. Some of these cannot be quantified,
which makes it complicated to compare two
All the above factors are for only process
selection. At design stage, many more
considerations come into play, such as
area availability for the plant or unit. If the
space available is limited then, one has to
go vertically (up) for construction. If inter
equipment distances and free spaces are
limited, it is more difficult and less safe for
maintenance working. Sometimes, due to
space constraint, a particular equipment
selection may become different and that may
lead to non-optimum performance or more
prone to maintenance.
The other factor at design stage is capital,
as any investment is considered, based on
return on capital (except in case of safety
requirements). The limitation on capital will
tell on quality and finish of the work done.
Capital limitation leads to cut corners in many
a place, which will leave tell tale on every
aspect of the unit. Sometimes additional
facilities (in each individual equipment and
also overall) may be dropped which may not
be possible to add later. This may curtail the
optimum utilisation of the equipment or any
Actually, once a process technology or
equipment is selected, later on the upgrading
is only dependent on the OEM. The
technology may be improved at a regular interval, but to adopt the new technology and
make a new hardware changes, it may take
few years as the factors such as procurement
of technology, time for approvals and
preparing for a hardware change and next
available opportunity (of plant turnaround)
may take some time. A meaningful up
gradation happens say after 10 to 12 years.
As mentioned above, process safety is assured
all the time. The plant safety conditions can be
and shall be upgraded at the earliest without
any time limits (upper or lower).
From the maintenance perspective, what
are the major parameters that one needs to
look out for to ensure safe and uninterrupted
For ensuring both safety and uninterrupted
plant operation, the prime parameters
are quality, quality and quality. Quality
in work, quality of selected equipment,
quality (reputed) vendor, quality in design
are important for achieving safety and
uninterrupted plant operations.
Quality at design stage ensures reliable
equipment specifications such as correct
metallurgies. Suitable API specifications
increase the availability of equipment with high
efficiency. Where as quality in work reduces,
frequent failures and avoids rework. Rework
cost, or say cost of poor quality of work, is the
single most avoidable cost of maintenance.
Rework (failure) causes interruption in
plant operation and has many folds cost
implication. Apart from the cost aspect, it
gives rise to avoidable efforts from operator
for isolating, handing over, commissioning of
the equipment, and maintenance efforts for
attending the equipment.
The equipment like pump is to be installed
with proper care. Any piping stress,
alignment, foundation, anomalies will have
impact on performance of bearings, seals
and result in interruptions in availability of
equipment. The availability of spares is
another major factor to deliver the quality
work, so that mean time between failures
can be increased (and hence, more availability of plants). Purchasing spares
from OEM, other material from standard
manufacturers (not from traders) through
third party inspection will increase the
quality of spares.
Instrumentation plays a critical role to
ensure uninterrupted and safe plant
performance and avoid unprecedented
downtimes. What is the lifespan of
Instruments typically in refineries and how
frequently these need to be upgraded?
The instrumentation in plant performance
is like central nervous system to the
human body. The instrumentation in safe
plant performance is broadly categorised
into three categories.
One is for safe start up and one is for
safe shutdown. Though the popular belief
is to avoid spurious trips, in terms of
safety of the plant, spurious trip is still
acceptable rather not tripping the plant,
when required, as it is unsafe and not at
all acceptable. In that case, the damage/
loss to both the plants and human cannot
The third category of Instrument is used
while plant is running. This category is
considered to be very important for
uninterrupted and safe plant performance.
Under this category, the indications/
controllers are more found.
The transmitters, barriers, relays and SOV
form major part in the nervous system
apart from cables, terminals, terminations,
electronic cards and JBs. The strength of
the chain is determined by the weakest link.
In this case of requirement of uninterrupted
plant running (in terms of instrumentation),
all the above have to provide robust,
Hence the quality, which we talked earlier,
is of utmost important. The quality of each
instrument, the quality of installation,
quality of design of logic, the Proven Track
Record (PTR) of equipment and use of standard software is essential. The SOV
considered being the last control element
(assuming the shutdown valve is designed
fail safe), which has to trip when required,
shall be reliable.
At BPCL the SOV is designed (as a default
practice, as is in many other refineries) to be
¬ON (energised) condition while the plant is
running. The ¬DC power is supplied through
battery back up so that even in power failure
conditions the control is possible.
The other regular troublemaker is ¬relay .
By design the relay is ¬ON while plant is
running. The relay through DC power is in
energised condition, so that in all situations,
logic will have control on the safety of
the plant. We had experienced that the
other key contribution to interruptions is
(high pressure) tube fittings. We have
restricted vendor list for all the above, SOV,
relay and tube fittings. This along with
dedicated teamwork, I believe, has given
us the uninterrupted and safe running of
our units with a 100 per cent up time.
Apart from above, all those instruments,
which form part of interlocks, say vibration
switches, bearing temperature elements etc.
give raise to unwanted trips. These can be
regularised at design stage, in consultation
with OEM, may be made 2 out of 3 logic, or
2 out of 2 or making 2 or 3 separate groups.
Yes, when we talk about the uninterrupted
performance of equipment (instruments),
there comes a question of Ąhow long?Č
That is the life span of instruments. Now
a days the Meantime Between Failures
(MTBF) of instrument, is very high, as the
electronics life as well as quality of material
However, the reliability of RT type of
thermocouples and vibration probe life is
still uncertain. Hence we change them in single equipments like compressors, at
All other instruments, as we ensure quality
of material and quality of work and check
at every turnaround, we did not find
necessary of changing yet. We do upgrade
the DCS software, and man machine
interface, (operation stations) at 8 to 10
May we have your comment on forward
thinking in CAPEX considering the
real economic life and changes in
The point in your question, though has
a vast implications and coverage, I will
answer in Maintenance perspective.
Normally at design stage, some margins
are included for quality improvements.
But if the product or feed specifications
change then, material of construction
need to be looked into.
That is where CAPEX in maintenance come
into the lime light. If the severity of the
damage, is manageable, i.e., if the wetted
parts repair is less costly and less frequent
that is advisable to continue, without any
changes (no capital cost). If otherwise,
spend CAPEX to increase the reliable and
uninterrupted plant running, by upgrading
the wetted parts to higher metallurgy.
The forward thinking in CAPEX, it is always
¬postpone CAPEX, if not possible reduce
the CAPEX to bare minimum. In any case,
without full economic calculations no
CAPEX shall be taken up.