1. Risk Assessment: A Practical Guide to Assessing Operational Risk
Chapter 6:
What-If Hazard Analysis

2. Risk Assessments: What-If Hazard Analysis
Objectives
Introduce What-If Analysis
Review Process Hazard Analyses Methods
Examine the Use of Techniques, their Strengthens and Limitations
Provide Guidance on the Use of What-If Analysis Techniques

3. Introduction
What-If Hazard Analysis is a well-established and widely used qualitative method for identifying and analyzing hazards, hazard scenarios, and existing and needed controls. Although originally developed for chemical and petrochemical process hazard studies, the What-If Hazard Analysis and its variations have become widely used in many other industries including energy, manufacturing, high-tech, food processing, transportation, and healthcare to mention a few. The method can be applied to a system, process, or operation or at a more specific focus such as a piece of equipment, procedure, or activity.

4. What-If Applications
operations that contain hazardous chemical processes
operations with large refrigeration and chiller systems containing ammonia such as meat packing, food processing and storage
non-routine activities such as equipment installations, repair, or decommission
‘Table top drills’ to develop emergency scenarios and necessary measures for preparedness, disaster recovery, and business continuity
Design Safety Reviews of new facilities, systems, and equipment
In operations where ‘Management of Change’ is considered
Analysis prior to selection and procurement of new technology, equipment, or materials

5. Process Hazard Analysis
A ‘process’ can be defined as a series of actions or steps taken to produce something or achieve a particular result. A process hazard analysis (PHA) is a set of organized and systematic assessments of the potential hazards associated with an industrial process. A PHA is directed toward analyzing potential causes and consequences of fires, explosions, releases of toxic or flammable chemicals, and focuses on equipment, instrumentation, utilities, human actions and external factors that may impact the process. In many cases, an additional benefit of conducting such an analysis is a more thorough understanding of the industrial process, leading to opportunities for improving process efficiency and cost reduction.

6. Mandated PHAs
OSHA 29 CFR Process Safety Management (PSM) of Highly Hazardous Chemicals standard, established in 1992, requires process hazard analyses for regulated industrial processes containing 10,000 pounds or more of a hazardous chemical for the purpose of protecting the employees working in and around such processes. EPA 40 CFR PART 68 Chemical Accident Prevention Provisions, Risk Management Plan (RMP) Rule issued in 1994 as a result of the Clean Air Act Amendments of 1990 mirror’s the OSHA Process Safety Management requirements for process hazard analyses in regulated facilities for the purpose of protecting the public and the environment from undesired consequences of explosions or releases.

7. Mandated PHAs
What-If Hazard Analysis is one of several process hazard analysis methodologies referred to in the OSHA Process Safety Management standard and EPA Risk Management Plan Rule as an acceptable method.

8. What-If Analysis and Related Methods
The primary objectives of the What-If methodology are to identify and analyze: 1) major hazards and hazard exposure scenarios in a system; 2) causes, deviations and weaknesses that can lead to major hazards; 3) control measures in the system; 4) and needed controls to achieve an acceptable risk level. Methods include:
Brainstorming
Checklist Analysis
What-If Hazard Analysis
What-If Checklist
Structured What-If Technique (SWIFT)
Hazard and Operability Study (HAZOP)

9. Brainstorming – Structured and Unstructured

10. Checklist Analysis

11. What-If Hazard Analysis

12. What-If Checklist

13. Structured What-if Technique (SWIFT)

14. Hazard and Operability Study (HAZOP)

15. Risk Scoring and Ranking
A shortcoming in traditional hazard analysis methods is that they do not include the extra step of estimating risk. Safety professionals are advised to include the risk assessment step in such methods to provide their organizations adequate decision-making information. Following a What-if analysis, an analysis should be made of each hazard’s likelihood of exposure scenario and its severity of consequences to estimate and rank risks for risk reduction.

16. Application of ‘What If’
The flexibility of the What-If Analysis approach can be applied to nearly any operation, process or activity, either existing or planned. It can be applied to routine and non-routine activities, maintenance and service work, installations and setup activities among others. From a design review standpoint, this method can be used to identify single failures and obvious hazards of proposed changes or new designs.

17. What-If Analysis

18. What-If Analysis

19. Conclusion
What-If Hazard Analysis is a relatively simple and flexible method of identifying and analyzing hazards in a process, activity or system. It can be applied to a wide range of circumstances in almost all industries. As one of the process hazard analysis methods listed in the OSHA Process Safety Management standard, the What-If method has become a commonly used technique, both in regulated and non-regulated operations.