Please Wait...


This page provides descriptions of subjects of topical interest. Click on the links below to go to a hot topic.

Damage Mechanism Review (DMR)
Hierarchy of Controls Analysis (HCA)
Safeguards Protection Analysis (SPA)
Combustible Dust Hazard Analysis (DHA)
SIMOP Studies
PHA Analytics
Human and Psychological Factors in the Performance of PHA
Competency Management for Process Safety
Cyber Security Vulnerability Analysis (CSVA)
Environmental Impact Identification (ENVID)

Previous Hot Topics:

Changes to EPA's RMP Rule
Revisions to OSHA’s PSM Standard

Damage Mechanism Review (DMR)

The Division of Occupational Safety and Health within the California Department of Industrial Relations has proposed amendments to current process safety management (PSM) regulations for petroleum refineries in California. The amendments include requirements for conducting damage mechanism reviews (DMRs).

Damage mechanisms are mechanical, chemical, physical or other processes that result in equipment or material degradation, for example, brittle fracture, stress-corrosion cracking, and low temperature metal embrittlement.

Damage mechanisms may cause the failure of process equipment resulting in loss of containment or impaired operability of equipment. They may cause damage to equipment and materials that contain process fluids such as piping, pumps, and valves; equipment and materials that provide safeguards against process incidents such as fireproofing, dikes, and deluge systems; and equipment and materials in utilities and support systems whose failure may impact on or result in a process safety incident. Damage mechanisms can arise internally or externally such as from internal or external corrosion.

Damage mechanisms should be addressed in PHA studies. However, the occurrence of incidents involving damage mechanisms has demonstrated that sometimes they are overlooked. Indeed, it is not common for PHA teams to identify specific damage mechanisms as a cause of equipment failure.

A damage mechanism review (DMR) is used to:

  • Identify the damage mechanisms that are possible for processes.
  • Determine that the materials of construction are appropriate and resistant to potential damage mechanisms.
  • Ensure methods to prevent the occurrence of damage mechanisms or mitigate damage that may occur have been considered.
  • Identify operating parameters that affect damage mechanisms.
  • Ensure previous experience with damage mechanisms for the process has been considered
  • Identify applicable standards, codes and practices.

DMRs should be performed by a team of individuals whose expertise covers the possible damage mechanisms for the process. They are performed prior to the performance of a PHA study to identify those damage mechanisms that are believed possible for a process. This information is provided to the PHA team for consideration during a study.

For information about performing DMRs, please contact Primatech.

Hierarchy of Controls Analysis (HCA)

Various types of controls are used in process safety management to manage the risks of catastrophic events in processes involving toxic, flammable, explosive, and reactivity hazards. Controls can be prioritized in a hierarchy according to their type:

Inherent safety approaches are preferred over other measures and emergency response is a last resort.

This hierarchy should be addressed in the design and review of new processes, process units, and facilities. Also, the hierarchy should be considered when developing recommendations for risk reduction in PHA studies and management of change (MOC) reviews, and when developing corrective measures resulting from incident investigations.

The Division of Occupational Safety and Health within the California Department of Industrial Relations in amendments to current process safety management (PSM) regulations for petroleum refineries in California has proposed requirements for performing HCAs.

For information about performing HCAs, please contact Primatech.

Safeguards Protection Analysis (SPA)

Safeguards protect processes from process safety incidents. They are critically important. Consequently, every effort must be exerted to ensure they are functional, effective, and adequate.

Unfortunately, many process safety incidents have occurred in processes that were not adequately protected by safeguards or other controls. Needed safeguards were not present or those that were present were insufficient, unreliable or disabled.

A safeguards protection analysis (SPA) should be performed before a PHA study and updated after the PHA study. An SPA should address:

  • Identification of process safeguards including safety critical equipment and safety critical actions.
  • Performance of a hierarchy of controls analysis (HCA) that identifies the position of each designated safeguard in the hierarchy and justifies use of the designated safeguards in protecting against the hazards of the process based on their position in the hierarchy.
  • Preparation of a Safety Requirements Specification (SRS) for each safeguard. An SRS documents the functional and integrity requirements for a safeguard.
  • Validation that safeguards adequately protect against the hazards of the process, have a specified integrity level, have been installed correctly, are functional, etc.

Once the SPA has been performed, the PHA team can focus on the qualification of safeguards for specific hazard scenarios. Qualification of safeguards addresses whether safeguards are appropriate for each hazard scenario in a PHA study.

Information developed in a PHA study may necessitate revisions to the SPA and SRSs. For example, it may be determined that a redundant power supply is needed to support the integrity required for an emergency shutdown system. SPAs should be updated during MOC reviews and when developing recommendations from incident investigations.

The Division of Occupational Safety and Health within the California Department of Industrial Relations in amendments to current process safety management (PSM) regulations for petroleum refineries in California has proposed requirements for performing SPAs.

You may be interested in:

For information about performing SPAs, please contact Primatech.

Combustible Dust Hazard Analysis (DHA)

Many facilities manufacture materials in the form of powders and some facilities generate powders through handling and processing solid materials. Such facilities may be subject to combustible dust hazards. A combustible dust is a finely-divided particulate solid that presents a flash-fire hazard or explosion hazard when suspended in air, or another oxidizing medium, over a range of concentrations. A wide variety of industries pose combustible dust hazards from various materials including chemicals, metals, wood, plastics, rubber, coal, flour, sugar, and paper.

In 2008, the U.S. Occupational Safety and Health Administration (OSHA) reissued its combustible dust National Emphasis Program (NEP), CPL 03-00-008, and OSHA has been engaged in rule making on a combustible dust standard. In 2015, the National Fire Protection Association (NFPA) published NFPA 652, Standard on the Fundamentals of Combustible Dust (2016 edition). The standard requires a dust hazard analysis (DHA) which is a systematic review to identify and evaluate the potential fire, flash fire, or explosion hazards associated with the presence of one or more combustible particulate solids in a process or facility.

The purpose of a DHA is to identify hazards and document how those hazards are being managed. The hazards addressed by NFPA 652 are fire, deflagration, and explosion hazards of combustible dusts. The results of the DHA are documented, including any necessary action items requiring change to process materials, the physical process, process operations, or facilities associated with the process.

For information about performing DHA, please contact Primatech.

SIMOP Studies

Simultaneous operations (SIMOPs) are situations in processes where two or more operations or activities occur at the same time and place. They may interfere or clash with each other and may involve risks that are not identified when each activity is considered by itself. Thus, they can increase the risks of the activities or create new risks.

Simultaneous operations often involve work in the same area by multiple contractors and subcontractors or multi-disciplinary workers whose work may overlap and/or interact. For example, construction activities near active equipment such as crane lifts over a storage tank containing a toxic material may result in a release from dropped objects. Similarly, a maintenance activity near another process operation such as hot work in the vicinity of a tank truck unloading a flammable material may result in a fire.

A number of major process industry accidents have involved simultaneous operations.

The situations addressed by SIMOP studies usually are not considered during process hazards analysis (PHA) studies which focus attention on individual process operation. Furthermore, PHA teams may not recognize the importance of examining how simultaneous operations may interfere with each other. Moreover, it is difficult to do so within the constraints of a regular PHA study.

A SIMOP review identifies possible interactions between activities that may adversely impact people, property, or the environment. SIMOP reviews are an important adjunct to the performance of PHA studies such as hazard and operability (HAZOP) studies.

For information about performing SIMOP studies, please contact Primatech.

PHA Analytics

PHA studies largely are performed to comply with government regulations and industry good practices. However, they contain a wealth of information that can be mined for a variety of other purposes. For example, critical equipment and human actions can be identified, process risk profiles can be developed, insights into incident causality can be obtained, the relative contributions of safeguards to risk reduction can be determined, and the impacts of bypassing safeguards can be determined.

Many companies have performed large numbers of PHA studies for their processes. They contain data on hazard scenarios that can occur for the processes. These data can be mined to provide knowledge-based tools to facilitate the performance of further PHA studies.

PHA studies require the investment of considerable resources. Consequently, the effort to utilize the information they contain for as many beneficial purposes as possible is well warranted.

You may be interested in:

For assistance with PHA analytics, please contact Primatech.

Human and Psychological Factors in the Performance of PHA

People perform PHA studies and, therefore, such studies are subject to various possible human failures. Studies are difficult and time-consuming activities that place significant demands on participants which increases the chance that errors will be made. Many human factors influence human failures during PHA studies.

Human factors such as willingness to rely on the unsubstantiated opinions of others; groupthink; underestimation of the frequencies of low-probability, high-consequence events; and allowing a false sense of accomplishment to distract from implementing study results must be recognized and addressed. Human factors issues during the preparation, conduct, recording, documentation, and follow-up of studies can influence their quality markedly.

Furthermore, PHA often is viewed as an objective engineering analysis. However, in reality, PHA is based largely on subjective judgments by team members. Recent research has identified various psychological factors that influence the decisions made by PHA teams. In particular, cognitive biases influence human decision making and people largely are unaware that they do so.

Competent PHA facilitators must understand the impact of human and psychological factors on PHA studies because they can seriously impact the quality of study results. Hazard scenarios may be missed, risks estimated incorrectly, and important recommendations omitted.

You may be interested in:

For assistance with human and psychological factors in the performance of PHA, please contact Primatech.

Competency Management for Process Safety

The ability of people to perform tasks according to expectations, or the competency of personnel, is crucial to every organization because of the role it plays in ensuring tasks are carried out satisfactorily and safely. Competency implies appropriate qualifications, training, skills, physical and mental capabilities, knowledge, understanding, behavior and attitudes as well as the ability to perform tasks according to defined performance standards.

Competency should be managed, otherwise poor performance and accidents may result. Indeed accidents have occurred when competencies other than knowledge and experience were absent. Competency management is particularly important when an organization relies heavily on the skills, knowledge and capabilities of its personnel, such as in the process industries. The importance of competency is compounded in the face of the re-engineering, downsizing, and multi-tasking that can occur in the process industries. Personnel are often expected to take on a wider range of tasks with less supervision thus increasing the need to manage competency effectively.

Competency management should be part of an organization’s overall management system. It should apply to personnel from the top to the bottom of the organization and include contractors and others who perform work within the organization.

You may be interested in:

For assistance with competency management for process safety, please contact Primatech.

Cyber Security Vulnerability Analysis (CSVA)

Manufacturing and process plants use computer systems to control manufacturing processes, store information, and manage value chain activities. All these computer systems can be attacked by cyber means and used to cause harm. Cyber attacks can result in the manipulation of control systems, loss of control, process shutdown and other impacts. Hazardous materials may be released, products may be contaminated, production may be interrupted, and equipment may be damaged.

Increasingly, manufacturing and process control computer systems are connected to business, commercial and enterprise networks that in turn are connected to the Internet. Process control systems may also contain computers with connections to the Internet, or modems for remote access. These connections with the outside world provide the means for attackers to penetrate the systems and cause harm. Also, the potential exists for manipulation of control systems by people acting from inside a company.

Cyber security vulnerability analysis identifies ways specific threats can be realized (called cyber threat scenarios) in a similar way to identifying hazard scenarios in a process hazard analysis (PHA). A threat scenario is a specific sequence of events that has an undesirable consequence resulting from the realization of a threat. It is the security equivalent of a hazard scenario.

You may be interested in:

For information about performing CSVA studies, please contact Primatech.

Environmental Impact Identification (ENVID)

ENVID studies are used to identify environmental impacts posed by processes or facilities. They parallel HAZID studies that identify the hazards posed by processes or facilities. ENVID studies are performed to comply with environmental regulations, best available technology for environmental emissions control, and company objectives.

ENVID studies help to determine how the process design may be altered to eliminate or mitigate possible environmental impacts. Safeguards are identified that address these impacts and recommendations are made so that they are kept as low as reasonably practicable.

As with HAZID studies, ENVID studies first should be performed during early process design when design changes can be made with minimal cost impacts. ENVID studies also are important when process changes are made that may pose environmental impacts. These studies should address all stages in the life of a process from commissioning, through operation, to decommissioning, and cover all modes of process operation.

For information about performing ENVID studies, please contact Primatech.

Changes to the Environmental Protection Agency's (EPA's) Risk Management Program (RMP) Rule

EPA has finalized amendments to its RMP regulation in response to Executive Order 13650. Primatech has created a series of PT Notes on this subject which can be accessed by clicking here.

Revisions to the Occupational Safety and Health Administration’s (OSHA’s) Process Safety Management Standard

OSHA has solicited comments on possible changes. Primatech has created a series of PT Notes on this subject which can be accessed by clicking here.