(142b) The Meaning of “Should”

When implementing the performance-based Process Safety Management (PSM) Standard (OSHA 1910.119), industry needs to comply with applicable recognized and generally accepted good engineering practices (RAGAGEP) for their facility. While this may seem like a simple task, determining what is applicable and how it affects the design, construction, inspection/testing, and operations, can be a significant effort. This paper aims to provide guidance on interpreting the “should” vs. “shall” debate, particularly how to deal with “should” provisions, why this matters, and share lessons learned from AcuTech’s extensive onsite observations where the impacts of these interpretations are seen in process safety programs

“Should” vs. “Shall”. Provisions in laws and regulations as well as in RAGAGEP are worded using the verbs “shall,” “should,” or equivalent terms such as “must” or “may.” Historically, these verbs have been interpreted to indicate whether the provisions are intended to be mandatory or not. The long-standing informal industry practice has been that “shall” or equivalent verbs create mandatory requirements, while the use of “should” or equivalent verbs are generally not mandatory requirements. However, this context has never been codified anywhere and it has evolved over time as a general practice. In the PSM Standard and the RMP Rule, as well as in state process safety regulations, RAGAGEPs are specifically described as reference documents in both the Process Safety Information element for design and construction requirements, and the Mechanical Integrity element for inspection, testing, and preventive maintenance requirements. Internal company/site process safety procedures generally use the same conventions. The Standards Developing Organizations (SDO) that create and maintain these RAGAGEPs also distinguish between “should” and “shall” in the same manner.

In their 2016 enforcement memo to its field offices on the definition of a RAGAGEP, OSHA stated that “should” provisions are acceptable and preferred practices but are not mandatory as written. However, they are not completely optional. As there have been no court rulings establishing case law for the OSHA definitions of these terms thus far, industry looks to OSHA written guidance on this topic, including 2016 OSHA enforcement memo, as well as the OSHA Field Operations Manual. In the American Heritage Dictionary of the English Language the verb “should” has several meanings, contexts, and usages, including the following:

“1. Obligation, duty, necessity.”
“Usage: Should, in indicating obligation or necessity, is somewhat weaker than ought and appreciably weaker than must and have to.”

While this definition clearly establishes a difference between “should” and stronger terms such as “must,” it does not indicate that “should” means a complete absence of obligation or necessity. Rather, it indicates that “should” carries a weaker connotation than terms such as “must” (and “shall”). Therefore, this general English language definition is consistent with the OSHA definition in its 2016 enforcement memo that the “should” provisions in RAGAGEPs are not completely optional and that some form of risk reduction is still required.

Additionally, the OSHA Field Operations Manual, Chapter 4, Section I.A.1 contains the following statement with respect to how the wording of industry standards should be interpreted when determining if a violation has occurred:

“Only the mandatory provisions, i.e., those containing the word “shall” or other mandatory language of standards incorporated by reference, are adopted as standards under the Act.”

The Field Operations Manual does not currently offer a corresponding definition or interpretation of “should” or equivalent language. However, the definition of “shall” implies that the use of any language other than “shall" or its equivalents indicates that flexibility is acceptable in interpreting non-shall provisions.

Examples of Important “Should” Provisions. Based on an extensive sample of onsite observations, it is apparent that the typical practice with respect to the “should” provisions has been to treat them as optional, i.e., these provisions can be totally ignored if desired. This is not OSHA’s intent nor does it comport with the general language definition. In many cases, the “should” provisions of relevant RAGAGEPs contain important conditions, precautions, or design or operational specifications to control or reduce the process safety risk. Therefore, completely ignoring these provisions will likely result in a significant increase in the process safety risk. Some examples of RAGAGEP “should” provisions and their importance are:

As-received pop tests of relief valves. API-576, 4^th Ed. states that as-received pop tests (ARPT) on relief valves should be performed as a first task when the valve enters the shop before any disassembly, cleaning, or parts replacement. The importance of the ARPT is that it is the only way to determine whether the relief valve would have lifted at the correct set pressure and performed adequately to an overpressure event while it was still installed in the process. Therefore, not performing ARPTs will not allow a facility to know if their relief valves were functional prior to maintenance.

Facility siting. API-752, 3^Rd Ed. and API-753, 1^st Ed. state that buildings with no personnel assigned but occupied by individuals for a short duration may be included or excluded in a building siting evaluation on a case-by-case basis. The basis for the building’s inclusion or exclusion should consider the number and frequency of visitors and the cumulative level of occupancy among all visitors. These buildings include, but are not limited to: smoking shelters, weather shelters, dock attendant stations, loading rack personnel stations, and restroom buildings. The a priori exclusion of these types of structures without first closely examining the actual timing, duration, and number of personnel who use or occupy these structures, as well as the actual nature of the usage of them could understate the facility siting risk.

Implementation Lessons Learned. Facility process safety procedures should include written guidance with criteria and/or various options for addressing the key “should” provisions of relevant RAGAGEPs. What are the key “should” provisions? This will require some analysis and prioritization by companies/facilities. For example, API-570 4^th Ed. Addendum 3, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, and API-520, 7^th Ed. REV, Sizing, Selection, and Installation of Pressure-relieving Devices, currently contain 235 and 218 “should” provisions respectively. Is it necessary that every “should” provision in these RAGAGEPs be addressed in facility process safety procedures? Clearly, some of the provisions address routine issues or provide guidance regarding documentation or other administrative matters. Incorporating every “should” provision into internal procedures is not practical nor is it necessary. The analysis and prioritization of which “should” provisions from RAGAGEPs deserve attention should account for the following factors:

• The most important issue to weigh is what is the risk if the “should” provision is ignored? Has the issue been examined in facility Process Hazard Analysis (PHA)?
• Does the “should” provision address broad or systemic process safety issues? The ARPT example described above regarding carbon steel is an example of a broad issue given the large number of relief valves in process units and the reliance on them as an important process safety risk reduction measure (as confirmed by the significant credits afforded to them in PHAs and LOPAs).
• Has a “should” provision, or the lack of what it recommends, been a contributor to a process safety incident or near miss at the facility or anywhere else?

This written internal guidance should describe the risk of not addressing these provisions as part of the action statements in the procedures, or as part of caution or warning statements (where more emphasis is warranted for specific risks). Other possible evaluation criteria to weigh: difficulty of implementation, redundancy with other safeguards or process safety program provisions and activities, and cost.

Internal Procedures. The topic of “should” vs. “shall” language also applies to internal procedures as well as to RAGAGEPs. Facilities should carefully determine which provisions of internal process safety procedures should be worded using “should” or equivalent language. As with RAGAGEPs, the use of “shall” language in internal provisions imposes mandatory requirements. The same factors described above with respect to evaluating RAGAGEP “should” provisions also applies to the provisions of internal procedures. Therefore, simply changing all the “shalls” to “shoulds” and then treating them as optional is not a viable approach to this issue. A prominent example of the importance of internal procedure provisions is the vibration monitoring of rotating equipment, which provides for the monitoring of equipment health far in advance of any failure. Currently, there is no consensus RAGAGEP that requires vibration monitoring. Based on hundreds of audits and evaluations, industry internal procedures governing the preventive maintenance of rotating equipment nearly universally require vibration monitoring using “shall” language. Changing this requirement to a “should” provision and then treating it as optional would result in a measurable increase in the process safety risk, as well as a decrease in the reliability of the rotating equipment.