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Course 736 - Introduction to Process Safety Management

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Process Hazard Analysis (PHA)

What is a PHA?

The employer must perform an initial process hazard analysis (hazard evaluation) on all processes covered by the PSM standard.
A PHA is required on all processes covered by the PSM standard.

A PHA is required by OSHA for any industrial process that makes use of hazardous chemicals. It identifies and analyzes data to provide information that will assist employers and employees in making decisions for improving safety and reducing the consequences of unwanted or unplanned releases of hazardous chemicals. Its purpose is to identify the significance of scenarios that could result in fires, explosions, chemical spills and the release of toxic fumes or chemicals.

  • It analyzes potential causes and consequences of fires, explosions, releases of toxic or flammable chemicals, and major spills of hazardous chemicals.
  • It focuses on equipment, instrumentation, utilities, human actions (routine and non-routine), and external factors that might affect the process.

1. A _____ is an organized and systematic process to identify and analyze the significance of potential hazards when handling hazardous chemicals.

a. Job Hazard Analysis (JHA)
b. Process Hazard Analysis (PHA)
c. Change Analysis (CA)
d. Potential Hazard Analysis (PHA)

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Steps in the PHA Process

The process hazard analysis must be <u>updated and revalidated</u> at least every five years.
The PHA process.
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The employer must perform an initial PHA on all processes involving highly hazardous chemicals covered by the PSM standard. Use the following steps in conducting the PHA process:

  1. set a priority order for analyses;
  2. conduct analyses according to a required schedule;
  3. use an appropriate method to determine and evaluate process hazards;
  4. address process hazards, previous incidents with catastrophic potential, engineering and administrative controls applicable to the hazards, consequences of failure of controls, facility siting, human factors, and a qualitative evaluation of possible safety and health effects of failure of controls on employees;
  5. perform the PHA using a team with expertise in:
    • engineering and process operations,
    • the process being evaluated, and
    • the PHA methods used;
  6. establish formal procedures to: promptly address findings and recommendations, assure recommendations are resolved and documented, document actions taken, schedule for completing actions, and communicate actions taken to affected employees;
  7. update and revalidate PHAs at least every 5 years; and
  8. retain PHAs and updates for the life of the process.

2. PHA team members should have expertise in _____.

a. safety management systems
b. the OSHA 191.119 standard
c. engineering and process operations
d. job hazard analysis and planning

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Prioritizing PHAs

The employer must perform an initial process hazard analysis (hazard evaluation) on all processes covered by the PSM standard.
Processes that affect the most employees are top priority.

First, employers must determine and document the priority order for conducting process hazard analyses. Priority should be given to processes with the potential of adversely affecting the largest number of employees. Other considerations include:

  • the extent of the process hazards;
  • the number of potentially affected employees;
  • the age of the process; and
  • the operating history of the process.

Together, these factors would suggest a ranking order using either a weighting factor system or a systematic ranking method.

The use of a preliminary hazard analysis will assist an employer in determining which process should be of the highest priority for hazard analysis resulting in the greatest improvement in safety at the facility occurring first.

3. PHA priority should be given first to processes _____.

a. that are most complex
b. that affect the most employees
c. with the highest cost
d. with the least complexity

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Methods for Conducting the PHA

PHA and Probability
Icarus-ORM Academy

The employer should use one or more of the following methods to determine the nature and probability of errors in the process being analyzed:

  • What-if Study - asking what-if questions during review of an uncomplicated processes;
  • Checklist - a what-if study of a more complicated process using a checklist;
  • What-if/Checklist - a team of specialists develops specific questions and achieves consensus on recommendations;
  • Hazard and Operability Study (HAZOP) - a formally structured method to analyze possible deviations in design conditions;
  • Failure Mode and Effects Analysis (FMEA) - a systematic study of component failures. This review starts with a diagram of the operation, and includes all components that could fail and conceivably affect the safety of the operation;
  • Fault Tree Analysis - either a qualitative or a quantitative model of all the undesirable outcomes, such as a toxic gas release or explosion, that could result from a specific initiating event; or
  • An appropriate equivalent method.

Different methods for various parts of the process may be used. For example, a process involving a series of unit operations of varying sizes, complexities, and ages may use different methods and team members for each operation. Then the conclusions can be integrated into one final study and evaluation.

An expanded discussion of these methods of analysis is contained in OSHA Publication 3133, Process Safety Management Guidelines for Compliance.

4. Which PHA method is a systematic study of component failures using a diagram of an operation?

a. What-if Study
b. Hazard and Operability Study (HAZOP)
c. Fault Tree Analysis
d. Failure mode and Effects Analysis (FMEA)

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Deciding Methods to Use in a PHA

The employer must perform an initial process hazard analysis (hazard evaluation) on all processes covered by the PSM standard.
The PHA method must be appropriate to the complexity of the process.

The process hazard analysis method selected must be appropriate to the complexity of the process and must identify, evaluate, and control the hazards involved in the process.

The selection will be influenced by many factors including how much is known about the process.

  • Is it a process that has been operated for a long period of time with little or no innovation and extensive experience has been generated with its use?
  • Is it a new process or one that has been changed frequently by the inclusion of innovation features?

Also, the size and complexity of the process will influence the decision as to the appropriate PHA method to use.

It's appropriate to use different methods and team members for various parts of the process. The the conclusions of the different methods and teams can be integrated into one final study and evaluation.

5. The process hazard analysis method selected must be appropriate to the _____.

a. expertise required by the process
b. complexity of the process
c. number of steps in the process
d. duration of the process

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Minimum PHA Method Requirements

The PHA must analyze the hazards of a process
The PHA must analyze the hazards of a process.

No matter which PHA method you use, it must meet the following minimum requirements to be effective. Each method must:

  • address the hazards of the process;
  • identify any previous incident that had a potential for catastrophic consequences in the workplace;
  • determine engineering and administrative controls applicable to the hazards and their interrelationships, such as appropriate application of detection methods to provide early warning of releases (acceptable detection methods might include process monitoring and control instrumentation with alarms, and detection hardware such as hydrocarbon sensors);
  • identify the consequences of failure of engineering and administrative controls;
  • address facility siting;
  • address human factors; and
  • conduct a qualitative evaluation of a range of the possible safety and health effects on employees in the workplace if there is a failure of controls.

6. It is a minimum requirement for the PHA to identify any previous incident that _____.

a. resulted in an injury or illness
b. had a potential for catastrophic consequences
c. could have resulted in serious injuries
d. caused property damage and/or injuries

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The PHA Team

Teams need expertise in engineering and process operations.
Teams need expertise in engineering and process operations.

OSHA believes that the process hazard analysis is best performed by a team with expertise in engineering and process operations. The team conducting the PHA needs to understand the method that is going to be used. The PHA team should include:

  • at least one employee who has experience with and knowledge of the process being evaluated; and
  • one member (preferably the team leader) knowledgeable in the specific PSM analysis methods and proper implementation of methods being used in the evaluation.

Click the button to see a list of areas for which other full or part-time team members may need to provide expertise.

  • Process technology
  • Process design
  • Operating procedures and practices
  • Alarms
  • Emergency procedures
  • Instrumentation
  • Maintenance procedures
  • Routine and non-routine tasks
  • How tasks are authorized
  • Procurement of parts and supplies
  • Safety and health
  • Any other relevant subjects

The ideal team will have an intimate knowledge of the standards, codes, specifications, and regulations applicable to the process being studied. The selected team members need to be compatible and the team leader needs to be able to manage the team and the PHA study.

The team needs to be able to work together while benefiting from the expertise of others on the team or outside the team to resolve issues and to forge a consensus on the findings of the study and recommendations.

7. One member of the PHA team (preferably the team leader) should be knowledgeable in _____.

a. elimination, substitution, and engineering controls
b. the basic principles of management
c. specific PSM analysis methods
d. occupational safety and health

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Employer Response to PHA Team Findings

The employer must perform an initial process hazard analysis (hazard evaluation) on all processes covered by the PSM standard.
Communicate actions to affected employees.

In response to the PHA Team's findings and recommendations, the employer must establish a system to:

  • address promptly the team's findings and recommendations
  • ensure that the recommendations are resolved in a timely manner and that the resolutions are documented;
  • document what actions are to be taken;
  • develop a written schedule of when these actions are to be completed;
  • complete actions as soon as possible; and
  • communicate the actions to operating, maintenance, and other affected employees.

8. In response to the PHA team's findings and recommendations, the employer must _____.

a. complete actions within six months
b. reach consensus on actions to be taken
c. communicate actions to all affected employees
d. submit recommendations for OSHA approval within 30 days

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Update and Revalidate every 5 years.
Update and revalidate the PHA every 5 years.

Review and Revalidation

At least every five years after the completion of the initial process hazard analysis, the process hazard analysis must be updated and revalidated by a team meeting the standard's requirements to ensure that the hazard analysis is consistent with the current process.

Employers must keep on file and make available to OSHA, upon request, process hazard analyses and updates or revalidation for each process covered by the PSM standard, as well as the documented resolution of recommendations, for the life of the process.

9. The employer's PHA update and revalidation documents must be ____.

a. reviewed at least every 2 years
b. completed annually and as needed thereafter
c. reviewed as needed or requested by OSHA
d. kept on file for the life of the process

Check your Work

Read the material in each section to find the correct answer to each quiz question. After answering all the questions, click on the "Check Quiz Answers" button to grade your quiz and see your score. You will receive a message if you forgot to answer one of the questions. After clicking the button, the questions you missed will be listed below. You can correct any missed questions and check your answers again.

Video

Video

This CSB Safety Video details a 2010 hot work accident at DuPont Buffalo.

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