Chemical Engineering October 2016 - 54

A final statement
Creating a safe working environment,
with respect to CPI facilities,
requires three key elements. Those
key elements include processing
systems that are properly:
* designed and engineered for safety
and integrity in accordance with
appropriate industry standards
* constructed and installed for safety
and integrity in accordance with
appropriate industry standards
* maintained and operated for
safety and production efficiency in
accordance with well-defined and
thoroughly vetted and adhered to
procedures
Adhering to the safe design, engineering,
and construction elements
imposed by industry consensus
standards is essential. But, beyond
that, the two most vulnerable elements
in the life of a process unit is
in its maintenance and operation, the
final bullet point above.
Reports from the U.S. Chemical
Safety and Hazard Investigation
Board, known simply as the Chemical
Safety Board (www.csb.gov), are
evidence that no matter how safe
process systems are built a flawed
design, poor maintenance, or inappropriate
operation can negate that
integrated safety. The potential for
mitigating such potential disasters
comes in the form of holding hazard
and operability (HAZOP) reviews of
the design drawings as design of a
process system progresses. This is
followed up with a pre-startup safety
review (PSSR) as construction takes
place. Such reviews should be an
integral part of the design and construction
process. That means the
HAZOP reviews should be ongoing
during design, not after the fact when
design is complete. And the same
with the PSSR. This should be an ongoing
review during construction, not
at the time commissioning begins.
The vast majority of CPI disasters
stem, not from poorly manufactured
equipment or components used in
the construction of a CPI facility, but
from small design flaws that were
wrongly considered unlikely to be an
issue, or not noticed at all, to insufficient
maintenance procedures, or
maintenance procedures that may
54
have been sufficient, but were not
adhered to. In short, it takes more
than code compliance and high integrity
equipment and components
to make a CPI facility safe.
The situation is analogous to a
new automobile. A car can be built
in compliance with all of the safety
regulations, and possess all the bells
and whistles that advanced technology
can provide, but when not operated
or maintained properly it can
change in an instant from a transportation
vehicle to a weapon.
A final clarification
Often heard in passing, and even in
earnest discussions, are statements
to the effect that when a code, such
as the piping codes we have been
discussing in this article, have been
codified by a jurisdictional government
or by inclusion in a performance
contract, that everything in
the code is a compliance requirement
and becomes an essential
requisite to be adhered to. Those
are my words, but they capture the
intent of the varied, but similar statements
that have been uttered over
the years, and they are misleading to
say the least.
A code or standard contains both
requirements and recommendations.
And unless they are adopted
by a jurisdictional government or
written into a performance contract,
as mentioned earlier, they are
merely guidelines at best. But when
adopted by any fashion, statements
regarded as requirements have to
be complied with and recommendations
are just that, recommendations
or suggestions. This applies to government
regulations as well. It's all in
the wording.
What that means is this, the words
" shall, " " should, " and " may " are used
to lend sense and purpose to a
statement. When a statement of action
is preceded by the term " shall " it
is indicating a required action. When
a statement of action is preceded by
either of the terms " should " or " may "
it is indicating a recommendation or
suggestion, leaving the recommendation
or suggestion to the engineer's
or constructor's discretion.
Following are examples of such
statements taken from the Code of
Federal Regulation (CFR):
Example 1, from CFR Title 21:
Food and Drugs, Part 211-Current
Good Manufacturing Practice for
Finished Pharmaceuticals, Subpart
D-Equipment, §211.63 Equipment
design, size, and location, in which
it states the following: " Equipment
used in the manufacture, processing,
packing, or holding of a drug
product shall be of appropriate design,
adequate size, and suitably located
to facilitate operations for its
intended use and for its cleaning and
maintenance. "
When an action is preceded by
the term " shall, " as in the above
sentence, the action that follows is
an imperative requirement. As with
many government regulations the
stated required actions that follow the
" shall " are often intentionally vague
for a reason. Such stated actions
serve as a cautionary statement in
which the government is stating the
broad essential parameters of " ...
appropriate design, adequate size,
and suitably located..., " but allowing
industry, in the form of an industry
code or standard, the opportunity
to determine the specific values for
those essential requirements.
Example 2, from (CFR) Title 21:
Food and Drugs, Part 211-Current
Good Manufacturing Practice
for Finished Pharmaceuticals, Subpart
D-Equipment, §211.68(a) Automatic,
mechanical, and electronic
equipment, in which it states the following:
" Automatic, mechanical, or
electronic equipment or other types
of equipment, including computers,
or related systems that will perform a
function satisfactorily, may be used
in the manufacture, processing,
packing, and holding of a drug product.
If such equipment is so used,
it shall be routinely calibrated, inspected,
or checked according to a
written program designed to assure
proper performance. Written records
of those calibration checks and inspections
shall be maintained. "
In the above paragraph there are
three declarative actions. The first,
preceded by the term " may, " makes
the following action a recommendation
or suggestion. The following
two actions, preceded by the term
" shall, " makes each of those actions
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Chemical Engineering October 2016

Table of Contents for the Digital Edition of Chemical Engineering October 2016
