Included
in this appendix is information on how to conduct a “what-if” hazard
analysis. In particular, a form (Figure
C-1) is included, and this form should be completed for each written report. The purpose of this exercise is to teach you
how to conduct a “what-if” risk assessment and also to ensure that we are aware
of any safety concerns you may have about the experiments. Safety concerns that arise during the course
of the experiment should be immediately brought to the attention of one of the
TAs and the Technical Instructors.
The
reference for the attached material is:
Handbook of Occupational Safety and Health, Second
Edition, edited by Lou Diberardinis, “Chapter 6 Risk Assessment Techniques,”
Thomas M. Dougherty, pp. 127-178, John Wiley and Sons, 1999.
A. What-If Analysis
Overview
What
–If Analysis is a structured brainstorming method of determining what things
can go wrong and judging the likelihood and consequences of those situations
occurring. The answers to these
questions form the basis for making judgments regarding the acceptability of
those risks and determining a recommended course of action for those risks
judged to be unacceptable. An
experienced review team can effectively and productively discern major issues
concerning a process or system. Lead by
an energetic and focused facilitator, each member of the review team
participates in assessing what can go wrong based on their past experiences and
knowledge of similar situations.
Using
an operating procedure and/or Piping and Instrument Diagram (P&ID), the
team reviews the operation or process step utilizing a form similar to one
illustrated in Figure C-1. Team members
usually include operating and maintenance personnel, design and/or operating
engineers, specific skills as needed (chemist, structural engineer, radiation
expert, etc.) and a safety representative.
At each step in the procedure or process, What-If questions are asked
and answers generated. To minimize the
chances that potential problems are not overlooked, moving to recommendations
is held until all of the potential hazards are identified.
The
review team then makes judgments regarding the likelihood and severity of the
“What-If” answers. If the risk
indicated by those judgments is unacceptable then a recommendation is made by
the team for further action. The
completed analysis is then summarized and prioritized, and responsibilities are
assigned.
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Division: |
Desc.
of Operation: |
By:
Date: |
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What If? |
Answer |
Likeli- hood |
Conse- quences |
Recommendations |
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Figure C-1. What-If
Analysis Form
B. Getting Started – What’s Needed
The
first steps in performing an effective analysis include picking the boundaries
of the review, involving the right individuals, and to have the right
information. The boundaries of the
review may be a single piece of equipment, a collection of related equipment or
an entire facility. A narrow focus
results in an analysis that is more detailed and explicit in defining the
hazards and specific recommended controls.
As the review boundaries expand to include the equipment involved in a
large complex process or even an entire facility the findings and
recommendations become more overview in nature. The boundaries can include the steps in the construction of the
system under review, the steps involved in the operation of the equipment or
facility or the steps required to maintain the equipment or facility. A clear definition of the boundaries of the
analysis starts the review off in an effective manner.
Assembling
an experienced, knowledgeable team is probably the single most important
element in conducting a successful What-If analysis. Individuals experienced in the design, operation, and servicing
of similar equipment or facilities is essential. Their knowledge of design standards, regulatory codes, past and
potential operational errors as well as maintenance difficulties brings a
practical reality to the review. On the
other hand, including new designers and new operators in the review team mix is
an excellent learning opportunity for subjects that are not taught in design
school or in operating classes.
The
next most important step is gathering the needed information. One important way to gather information on
an existing process or piece of equipment is for each review team member to
visit and walk through the operation.
Videotapes of the operation or maintenance procedures or still
photographs are important and often under utilized excellent sources of
information. Additionally, design
documents, operational procedures, or maintenance procedures are essential
information for the review team. If
these documents are not available, the first recommendation for the review team
becomes clear. Develop the supporting
documentation! Effective reviews cannot
be conducted without up-to-date reliable documentation. An experienced team can provide an overview
analysis, but nuances to specific issues such as interlocks, pressure relief
valves, or code requirements are not likely to be found.
C. Conducting the Review – How’s it Done?
Now
that the team has had an opportunity to review the information package, the
next step is conducting the analysis.
Generally, an experienced hazards review facilitator will lead the group
through a series of “What-If” questions.
A focused, energetic and knowledgeable facilitator can keep the review
moving productively and effectively. A
scribe is usually assigned to take notes of the review. Recent advances in software as well as
laptop computers can provide on-line data collection possibilities by the
scribe. That is, as hazards are
identified, judgments made, and responsibilities assigned, the scribe can input
the data and agreements live!
Scheduling more than four hours at a time can result in the team members
losing energy and eager to finish the analysis rather than probing deeper. Generally, in a well-designed system or
well-operated system, the participants in the review will need to work hard to
find major issues. It is the job of the
facilitator to keep the effort moving productively.
1. Developing the “What-If” Questions –
Using the documents available and knowledge of the review team, “What-If”
questions can be formulated around human errors, process upsets, and equipment
failures. These errors and failures can
be considered during normal production operations, during construction, during
maintenance activities, as well as during de-bugging situations. The questions could address any of the
following situations:
·
Failure to follow procedures or procedures followed
incorrectly
·
Procedures incorrect or latest procedures not used
·
Operator inattentive or operator not trained
·
Procedures modified due to upset
·
Process conditions upsets
·
Equipment failure
·
Instrumentation miscalibrated
·
De-bugging errors
·
Utility failures such as power, steam, gas
·
External influences such as weather, vandalism,
fire
·
Combination of events such as multiple equipment
failures
Experienced personnel are knowledgeable
of past failures and likely sources of errors.
That experience should be used to generate “What-If” questions.
For example, consider a chemical manufacturing process
which includes the charging of a granular-like material from a 55-gallon drum
to a 1000-gallon mix vessel containing a highly caustic liquid. Some typical questions that could be
generated are shown in Figure C-2 for illustration purposes.
As the “What-If” questions are being
generated, the facilitator should ensure that each member of the team has an
opportunity to input potential errors or failures. Determining the answer to each question as it is generated
creates the danger of closing too soon on all possible upsets. The facilitator needs to assess if the team
has really looked at all of the possibilities before going to the next step of
answering the questions. Break up the
analysis into smaller pieces if there is danger of just developing questions
and not gaining the value of having them fresh in mind to answer those
questions.
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Division: Chemical Ops |
Desc.
of Operation: Manufacturing B
Mix/Drum Charging Operations – Page 2 of 4 |
By: Review Team Date 9/97 |
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What If? |
Answer |
Likeli-
hood |
Conse-
quences |
Recommendations |
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1. Granular powder is not freely flowing? 2. Drum is mislabeled? 3. Wrong powder in the drum? 4. Drum hoist is not used? 5. Two drums are added? 6. Drum is misweighed? 7. Drum hoist fails? 8. Drum is corroded? 9. Ventilation at mixing tank is not
operating? 10.Granular
powder becomes dusty? 11.Powder
gets on operator’s skin? 12.Tank
liquid level too high? |
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Figure C-2.
Example of Completed Step No. 1 What-If Analysis
Form
2. Determining
the Answers – After being assured that the review team has exhausted the
most credible “What-If” scenarios, the facilitator then has the team answer the
question, What would be the result of
that situation occurring? For example,
consider the following answers illustrated in Figure C-3 to the “What-If”
questions in our previous example.
|
Division: Chemical Ops |
Desc.
of Operation: Manufacturing B
Mix/Drum Charging Operations – Page 2 of 4 |
By: Review Team Date 9/97 |
|
What If? |
Answer |
Likeli-
hood |
Conse-
quences |
Recommendations |
|
1. Granular powder is not freely flowing? 2. Drum is mislabeled? 3. Wrong powder in the drum? 4. Drum hoist is not used? 5. Two drums are added? 6. Drum is misweighed? 7. Drum hoist fails? 8. Drum is corroded? 9. Ventilation at Mix Tank is not operating? 10.Granular
powder becomes dusty? 11.Powder
gets on operator’s skin? 12.Tank
liquid level too high? |
1. Back injury potential when breaking up
clumps 2. Quality issue only 3. If wet, could cause exotherm 4. Back injury potential 5. Quality issue only 6. Quality issue only 7. Leg, foot, back, arm injury 8. Iron contamination as well as drum failure
& injury 9. Dusting & potential operator exposure 10.Same
as above 11.Possible
burn 12.Possible
caustic splash as well as quality issue |
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Figure C-3.
Example of Completed Step Nos. 1 & 2 What-If
Analysis Form
If done correctly, reviewing the
potential equipment failures and human errors can point out the potentials for
not only safety and health improvements but also the opportunity to minimize
operating and quality problems.
Including the operators and trades personnel in the review can bring a
practical reality to the conclusions that will be reached.
3. Assessing
the Risk & Making Recommendations – Not having considered the answers
to the “What-If” questions, the next task is to make judgments regarding the likelihood
and severity of that situation. In
other words what is the risk. The
review team needs to make judgments regarding the level of risk and it’s
acceptability. For example, consider
the following risk judgments and recommendations to the answers in our example
as illustrated in Figure C-4.
|
Division: Chemical Ops |
Desc.
of Operation: Manufacturing B
Mix/Drum Charging Operations – Page 2 of 4 |
By: Review Team Date 9/97 |
|
What If? |
Answer |
Likeli-
hood |
Conse-
quences |
Recommendations |
|
1. Granular powder is not freely flowing? 2. Drum is mislabeled? 3. Wrong powder in the drum? 4. Drum hoist is not used? 5. Two drums are added? 6. Drum is misweighed? 7. Drum hoist fails? 8. Drum is corroded? 9. Ventilation at mixing tank is not operating? 10.Granular
powder becomes dusty? 11.Powder
gets on operator’s skin? 12.Tank
liquid level too high? |
1. Back injury potential when breaking up
clumps 2. Quality issue only 3. If wet, could cause exotherm 4. Back injury potential 5. Quality issue only 6. Quality issue only 7. Leg, foot, back, arm injury 8. Iron contamination as well as drum failure
& injury 9. Dusting & potential operator exposure 10.Same
as above 11.Possible
burn 12.Possible
caustic splash as well as quality issue |
Quite Possible Remote Unlikely Possible Remote Possible Remote Remote Unlikely Unlikely Quite Possible Remote |
Serious Serious Minor Serious Minor Serious Serious Serious Minor Minor Serious Very Serious |
Design
delumping equipment Contact
vendor Include
inspection in procedure Train
personnel & ensure use None Require
2nd check on weight Ensure
hoist on PM program None Include
vent check in SOP None
beyond existing procedure Use
dust suit & gloves Use
goggles and apron |
Figure C-4.
Example of Completed What-If Analysis Form
D. Reporting the Results – To Whom & How?
The
hard work of conducting the analysis has been competed. The important work of reporting the results
still remains. The make up of the
organization generally determines to whom and how the results get
reported. Usually, the department or
plant manager is the customer of the review.
The leader of the review team will generate a cover memo that details
the scope of the review as well as the major findings and recommendations. In some organizations, the report recommendations
will also include who has been assigned the responsibility to follow up and
time frame. In other cases, a separate
staff or function will review the recommendations and determine the actions
required. A periodic report is then
generated to summarize the present status of each of the recommendations. Those organizations that have a well
developed hazard review program require follow-up assignments every three to
five years based on the associated hazard levels.
E. “What-If” Summary – Pros and Cons
The
What-If Analysis technique is simple to use and has been effectively applied to
a variety of processes. It can be
useful with mechanical systems such as production machines, with simple task
analysis such as assembly jobs, as well as with reviewing tasks in chemical
processing. No specialized tools or
techniques are needed. Individuals with
little hazard analysis training can participate in a full and meaningful way. It can be applied at any time of interest
such as during construction, during debugging, during operations, or during
maintenance. The results of the
analysis are immediately available and usually can be applied quickly. This is especially true if the review team
members also operate or maintain the system being assessed.
On
the other hand, the technique does rely heavily on the experience and intuition
of the review team. It is somewhat more
subjective than other methods, such as Hazard and Operability Analysis (HAZOP),
which require a more formal and systematized approach. If all of the appropriate What-If questions
are not asked, this technique can be incomplete and miss some hazard
potentials. It may be appropriate to
assign those more dangerous portions of the system to a more rigorous review
such as HAZOP.