Table 7. MOC “Technical Basis of Change” attributes.
What is to be changed?
This is a narrative description of the object of the change. For example:
This change replaces all the rubber seals on this pump with neoprene seals.
This serves the same function as the keyword “Description”, but overcomes its vagueness. After all, there can be “descriptions” of many things. What this attribute tries to elicit is a clear identification of the object of the change, i.e. the “what”.
What is to be achieved by the change?
This is a narrative description of the intended results. For example:
This pump will be less susceptible to leaking and therefore more reliable. This will reduce maintenance costs and reduce unplanned outages.
This serves the same function as the keyword “Justification”, but overcomes its vagueness.
This attribute is sometimes improperly left blank on MOC forms—the implication is that it should be obvious why the change is being made. Often a change is implemented months after it was proposed, and the initiator may no longer be involved, prompting others to ask, “why are we doing this change?”
Why will the change achieve the intended goal?
This is a narrative description of why the proposed change approach will achieve the intended goal. For example:
Neoprene is well-known to be more _________ than rubber in this service.
A particular change may be effected in a variety of different ways. Is the approach that is chosen for the change likely to achieve the intended goal?
This is actually a second aspect of the “justification” notion: not only is it necessary to justify why the change is needed (previous point), but also why the proposed approach is likely to be successful.
Change Impact Pre-Screening
A change can have many impacts: process safety impacts, environmental impacts, financial impacts, customer impacts, and so on. The motivation for a disciplined and reliable MOC process can be attributed to the desire for avoiding undesirable impacts. A great deal of effort is often expended in carefully analyzing the impacts of a proposed change, normally during the Impact Analysis state.
However, the Impact Analysis state (see Figure 1) occurs much later in the MOC lifecycle. It appropriately follows the Change Design state since much of the information needed to conduct a proper impact analysis is unavailable until someone has documented it, either in redline form or in a new document.
Deferring any thought about change impact until the Impact Analysis state is problematic, since anyone looking at or working on the MOC can benefit from some knowledge of the potential impacts, right up front. This appears like a circular argument where it’s desirable to know the impacts during Initiation, yet the MOC has to be initiated in order to put into motion the process that will cause the impacts to be analyzed.
The solution to this dilemma is to recognize that information often exists at several levels of detail. For instance, it’s common to provide a rough-order-of-magnitude, “ROM”, cost at the start of a project, say, $10,000 ± 100%. Later, as the project details become more refined, costs are stated with greater accuracy, say, $12,500±20%.
The same logic can be used to characterize MOC impacts during Initiation. A preliminary assessment can be made of process safety, environmental, and other impacts, during the Initiation state. It’s understood that a more refined analysis will occur later on. The preliminary assessment of impacts can be termed “Change Impact Pre-Screening”. One presentation of this is shown in Table 8. MOC change impact pre-screening attributes.Table 8.
This notion of progressively more refined assessment is also promoted in Guidelines for Risk-Based Process Safety : “[Hazard Identification and Risk Analysis] HIRA reviews may be performed at any state in a project’s life cycle.. In general, the earlier that a hazard is identified, the more cost-effectively it can be eliminated or managed”. Early hazard identification, which might be termed “pre-screening”, is less detailed, less costly, but also less certain. Highly detailed risk analysis, which might be termed “impact analysis” is more detailed and costly, but also much more certain.