A proactive approach, coupled with properly planned and implemented safety and risk management systems can help you comply with local, state and federal PSM regulations, as well as minimize loss of life, environmental impact, equipment damage, citations and litigation.
ioMosaic pioneered many of the current risk assessment techniques for processes that handle hazardous chemicals.
Our experts support every aspect to ensure that your facility runs safely and efficiently.
Expertise to help you minimize your exposure to fire, injury, property damage, and litigation.
Integrating best practices with cost-effective solutions to address program deficiencies.
Helping manage risk with facility siting studies, assessments and recommendations.
Senior knowledgeable engineers facilitate PHAs or DHAs in nearly all sectors of the process and processing industries.
Decades of experience leading incident investigations for process industry companies.
We prepare expert opinion reports and provide expert testimony for process incident cases.
Experienced engineers who have performed LOPAs on a wide range of facilities and terminals.
Our experts are at the forefront of pipeline Process Safety Management proficiency.
Proven track record of performing QRAs for facilities, pipelines and transportation routes.
Well versed in assisting global companies with their sustainability reporting communications.
The chemical company of a large integrated energy company was developing a corporate standard for LOPA, which incorporated a risk ranking matrix. The company was interested in obtaining an independent review of the design of the risk matrix, and in benchmarking the underlying risk tolerability criteria with generally accepted industry norms.
A major pulp and paper manufacturing company in Mississippi determined that its process safety management (PSM) program had to do more than merely follow OSHA regulations; they wanted it to also be effective in preventing accidents.
If your facility uses, stores, manufactures, handles, or moves flammable or highly hazardous chemicals on site above the threshold quantity (TQ), OSHA does require PSM implementation. Learn the facts about process safety management.
During the development of the QRA, it is critical to properly locate all structures/buildings present in a process facility. Read this white paper for a risk-based approach focused on identifying which occupied buildings in a process facility could be impacted by hazardous dispersions due to toxic and flammable releases.
Even before the adoption of ISA-S84.013 as a national standard, safety instrumented systems (SIS) were used to mitigate the risks of process hazards. With the establishment of the standard, there is now a framework for defining Safety Integrity Levels (SIL) for such systems and the associated reliability requirements. However, the standard does not address the topic of how to determine what SIL category is needed to fill the independent layers of protection (IPL) gap. It assumes (section 4.2.2) that this analysis is performed prior to applying the principles of the standard.
The IPL gap is usually addressed during a Process Hazard Analysis (PHA) or in a separate exercise such as Layer of Protection Analysis (LOPA) or Fault Tree Analysis (FTA). All of these involve some type of risk assessment (typically risk ranking) against established tolerability criteria. Needless to say, the quality of the IPL gap analysis is very critical to the overall risk mitigation benefit and implementation cost.
As part of the IPL gap analysis for existing plants, it is necessary to determine the SIL credit afforded by the current SIS IPLs. During the PHA, the tendency is to err on the conservative side to avoid overstating the credit. By using FTA, it may be possible to incorporate factors such as functional testing, and to allow the proper credit for existing IPLs.
FTA also has application in establishing the SIL credit for the design of new SISs that are required to address recommendations from PHAs or that are associated with new or modified plant projects. FTA is one of the evaluation techniques for which ISA has developed guidelines4 to be used for determining the SIL for Safety Instrumented Functions (SIF).
Because ANSI/ISA-S84.01 is a performance based standard, it provides the designer some flexibility as to how the required reliability is achieved. Section 6.2.3 of the standard states that the desired SIL shall be met through a combination of fifteen design considerations that include: separation, redundancy, failure rates and failure modes, and functional testing interval to mention a few. Furthermore, Appendix B.15.2 states, “The functional test interval should be selected to achieve the Safety Integrity Level (SIL).”
The use of functional testing to improve the reliability of interlocks and SISs is a well-established concept. Some examples of how functional test intervals can be adjusted to obtain equivalent SIL reliability are presented below. Fault tree analysis can be used to quantify the effect of adopting a certain functional testing interval on system reliability. Coupling this with cost-benefit analysis allows the designer to compare initial hardware cost against the ongoing maintenance expense of the additional functional testing. Furthermore, with voting SISs, FTA can provide insight on how to set the functional testing interval to obtain the required SIL reliability.
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