Limitations of the What-If/Checklist Analysis

DOE-HDBK-1100-2004

PREPARING FOR THE ANALYSIS.

For a what-if/checklist analysis, the PrHA team leader

assembles a qualified team and, if the process is large, divides it into functions, physical areas,

or tasks to provide some order to the review. The important aspects of preparing for a what-if

analysis, which also apply to the what-if/checklist analysis, are discussed in Section 4.2 and are

not repeated here.

For the checklist portion of the analysis, the PrHA team leader obtains or develops an

appropriate checklist for the team to use. This list need not be as detailed as those used for a

standard checklist analysis. Rather than focusing on a specific list of design or operating

features, the checklist used here should focus on general hazardous characteristics of the

process.

DEVELOPING WHAT-IF QUESTIONS.

Section 4.2 describes the approach the PrHA team uses to

develop questions about potential accident scenarios.

USING A CHECKLIST TO COVER THE GAPS.

After the team members have identified all of the

questions in a particular area or step of the process, they apply the previously-obtained or

prepared checklist. The team considers each checklist item to determine whether any other

potential accident scenarios exist. If so, these scenarios are added to the what-if list and

evaluated in the same way. The checklist is reviewed for each area or step in the process.

EVALUATING THE QUESTIONS.

After developing questions involving potential accident

scenarios, the PrHA team considers each one; qualitatively determines the possible effects of the

potential accident; and lists existing safety levels to prevent, mitigate, or contain the effects of

the accident. The team then evaluates the significance of each accident and determines whether

a safety improvement should be recommended. This process is repeated for each area or step of

the process or activity. The evaluation may be performed by specific team members outside the

team meeting but must be subsequently reviewed by the team.

DOCUMENTING THE RESULTS.

The results of a what-if/checklist analysis are documented like

the results for a what-if analysis (see Section 4.2). The what-if/checklist analysis method

usually generates a table of potential accident scenarios, consequences, safety levels, and action

items. The results may also include a completed checklist or a narrative. The PrHA team may

also document the completion of the checklist to help illustrate the completeness of the analysis.

For compliance with the PSM Rule, detailed explanations of the analysis action items and

recommendations should be provided to management for review, and transmitted to those

responsible for their resolution.

4.3.3 Limitations of the What-If/Checklist Analysis

Combining the what-if and checklist analysis methods emphasizes their main positive features

(i.e., the creativity of what-if analysis and the experience-based thoroughness of a checklist

analysis) while at the same time compensating for their shortcomings when used separately. For