Linking PSM, NFPA, and ISA/IEC 61511 for fired equipment

Many facilities rely on prescriptive applications to manage fired equipment, which may not always be sufficient.

By Chris Neff July 10, 2022
Image courtesy: Brett Sayles


Learning Objectives

  • Understand OSHA’s thinking about steam boilers and the process safety management (PSM) standard 29 CFR 1910.119.
  • Learn about OSHA violations related to  process safety management (PSM) at one site.
  • Learn why PSM-covered facilities should execute the standard risk assessment process for fired equipment.

In 2012, one of the steam boilers at the Wynnewood Refinery in Oklahoma exploded during a turnaround operation, resulting in the death of two workers. It was discovered that the boiler in question had a history of “hard starts.” As a result, the Occupational Safety and Health Administration (OSHA) cited Wynnewood Refining Company with multiple violations related to the process safety management (PSM) standard 29 CFR 1910.119.

The incident at Wynnewood impacted the families of those harmed, the corporation’s reputation and bottom line; in the aftermath, OSHA penalized the facility for 50 alleged PSM violations. It also set an important new precedent for how facilities evaluate and implement PSM applicability regarding interconnectivity and proximity for fired equipment.

PSM Implications

Wynnewood argued that although the fired equipment (a boiler, in this case) was connected to a PSM-covered process through steam piping, it did not contain a PSM-covered flammable material. OSHA contended the boiler was integral to a covered process and therefore within PSM scope.

In October 2020, the 10th Circuit Court of Appeals agreed and ruled on behalf of OSHA that the boundary of a PSM process can extend beyond vessels and piping that contain hazardous chemicals. This ruling determined that fired equipment and utilities may be drawn into a site’s PSM-covered processes independent of the presence of regulated materials within the equipment.

Linking NFPA, ISA/IEC 61511, and PSM

The Wynnewood case helped solidify that fired equipment should be evaluated for applicability to the PSM standard. Many facilities rely on prescriptive applications, such as codes provided by the NFPA, to manage fired equipment, which may not always be sufficient.

PSM-covered facilities should execute the standard risk assessment process for fired equipment, like how they do for the other equipment in their facility, to determine if it should be included from a risk-based approach, in the PSM program. Gaps found through the risk assessment process may need to be closed through the application of ISA/IEC 61511. Further, OSHA considers ISA/IEC 61511 as RAGAGEP (Recognized and Generally Acceptable Good Engineering Practice) for safety instrumented systems (SIS). Integrating NFPA, ISA/IEC 61511, and PSM for fired equipment together may create a safer facility.

The three most applied codes for fired equipment in the process industry include National Fire Prevention Association (NFPA) 85 for Boiler and Combustion Systems, NFPA 86 for Ovens and Furnaces, and NFPA 87 for Fluid Heaters. These NFPA codes include an equivalency provision that permits alternative approved methods to achieve compliance. This provision is not intended to serve as a waiver of compliance. Instead, it requires that a level of safety is provided via performance-based requirements that are at least equivalent to the prescriptive-based NFPA requirements.
Per NFPA 851, utilizing the equivalency provision, an alternative design to meet the requirements of the code can be accomplished where all the following are provided:

  1. Approval of the Authority Having Jurisdiction (AHJ)
  2. A documented hazard analysis that addresses all the requirements of the code
  3. A documented life-cycle system safety analysis that addresses all requirements of the code and incorporates the appropriate application-based safety integrity level (SIL) for safety instrumented systems (SIS).

All three above-mentioned NFPA codes reference ISA/IEC 61511 as a recognized methodology for achieving equivalency. Likewise, OSHA recognizes ISA/IEC 61511 as RAGAGEP for SIS as part of PSM covered processes.

A safer solution

Almost 10 years later, the legal battle and controversy surrounding the Wynnewood incident provides operating facilities a major takeaway lesson – apply a risk-based approach to fired equipment. For those pieces of equipment that present a risk, use the same principles as for other high-risk units and evaluate whether fired equipment should be included in a formal PSM program.

When applying the equivalency provision, owners should adhere to the safety lifecycle, including risk analysis such as a process hazard analysis (PHA) as well as SIL selection, and SIL verification, in addition to aligning with NFPA. Applying PSM to fired equipment is a more proactive approach to your facility’s compliance, operations, and maintenance objectives.

Chris Neff, PMP, senior director fired equipment, aeSolutions. Edited by Chris Vavra, web content manager, Control Engineering, CFE Media and Technology,


Keywords: process safety management, process safety


What codes and standards compliances do you follow at your facility?


1NFPA 85, Boiler and Combustion Systems Hazards Code, National Fire Protection Association, 2019, Annex A, A4.11

Original content can be found at Control Engineering.

Author Bio: Chris Neff, PMP, senior director fired equipment, aeSolutions.