Safety Instrumented Systems

Take safety up a notch

There’s still room to improve industry’s good safety performance, says Editor in Chief Mark Rosenzweig in his monthly column. Mechanical integrity programs generally need more attention.

By Mark Rosenzweig, editor in chief

The stakes are just too high to give safety anything less than top priority, as the recent explosion at BP’s Texas City, Texas,  refinery unfortunately underscores. Despite that tragedy, the chemical industry’s safety record remains exemplary.

This performance stems in no small measure from the detailed methodologies put into place to identify and address potential hazards. Indeed, a great deal of effort has gone into systematizing our approach to safety, both through cooperative efforts within industry, such as the development of the American National Standards Institute (ANSI) S84 standard on safety instrumented systems (SISs), and government mandates, like the Process Safety Management (PSM) Standard of the U.S. Occupational Safety and Health Administration (OSHA).

Chemical companies devote considerable resources to comply with these standards. However, many could improve their safety programs if they better understood some of the nuances of the standards.
For instance, the revised ANSI S84 standard, adopted last September, allows the “grandfathering” of installed SISs. “However, making a claim that an existing system meets the intent of the grandfather clause should not be taken lightly,” cautions Angela Summers in ”Can you safely ‘grandfather’ your SIS?,” p. 42. She provides guidance for determining whether an existing SIS actually can be grandfathered.

The mechanical integrity (MI) element of the PSM standard probably raises even more issues. “PSM audits by OSHA have consistently demonstrated that MI accounts for a large number of citations at most facilities,” notes Mike Hazzan in “Repair your mechanical integrity program,” p. 30. He has found widespread problems in how chemical companies handle MI.

For instance, firms often do not include in their programs much equipment that clearly impacts MI. One reason is confusion over what specific equipment the PSM standard actually covers. For example, he says, many companies don’t realize that the mechanical portions of instrumentation fall within a MI program for piping systems or that “pumps” also includes non-rotating machinery like eductors.

Another problem, Hazzan notes, is too narrow an interpretation of what an MI program should involve. Some equipment <em dash>— he lists ten broad types including fire-protection equipment and ventilation systems in buildings designated as safe havens or assembly points during emergency evacuations <em dash>— aren’t explicitly called out in the standard. So, a company probably wouldn’t be cited for not including them. “However, adding them (either formally or informally) certainly will improve the MI program and process safety,” he stresses.

Plants also create difficulties for themselves by not properly appreciating the role that staff outside of the maintenance group play in the MI program. “Many personnel may not realize that their jobs involve a portion of a regulated MI program,” he adds.

From PSM audits and related work he has done, Hazzan also pinpoints a number of weaknesses in the nitty-gritty elements of many MI programs, including:

• lack of a consolidated listing of MI-covered equipment;
• an incomplete roster of maintenance procedures and, often, absence of approved welding procedures;
• no definition of the skills that maintenance technicians must demonstrate before they are considered fully qualified and technicians with expired welding and other certifications;
• overdue inspection, testing and preventive maintenance;
• inadequate follow-up on deficiencies identified; and
• no monitoring of the shelf lives of some spare parts and materials.

So, despite all the efforts that the chemical industry makes, it’s safe to say there’s significant room for improvement.

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