Reduce Hidden Process-Safety Costs
EP Editorial Staff | September 15, 2016
Today’s technology means end users no longer must accept every cost associated with validation, verification, and documentation of process-safety equipment and shutdown systems.
Special to Maintenance Technology
The process of validating and verifying the good function of installed process-safety systems and equipment is driven as a mandatory effort governed by end users and regulatory stipulations across industry. At stake is the protection of people; the environment, property, and equipment; and the economics of preventing unscheduled downtime and lost production. The importance of this validation verification is to ensure that if and when equipment goes to a safe state, good function is established.
An expensive problem for end users, according to a white paper, written by Phil Millette, P.Eng, MEI, and principal industry consultant for Honeywell Process Solutions, Houston, has been the hidden costs associated with many practices for confirming and documenting the fact that safety instrumented systems (SIS) are installed and functioning as advertised. Such costs include the actual time to do the work using manual processes and disconnected information sources, not to mention longer planned, and more-frequent unplanned, shutdowns that reduce the operation’s revenue opportunity.
A key reason for these hidden costs is that, until recently, there were no automated mechanisms to support this critical activity—or formalized approach in industry to conducting it. In his white paper, Millette outlines principles and approaches of a recently introduced capability to perform this function in an automated way—one that results in structured information and shared knowledge, a provable safety state, and benefits from lower costs and greater revenue opportunity.
Structuring and automating
As the author explains, while the requirements for timeliness and documentation of the completed validation and verification effort are generally expected, the actual mechanisms aren’t stipulated—and authorities aren’t especially clear on how to perform the task. Thus, with the proliferation of different systems and different generations of technology installed at sites, there’s been widespread adoption of homegrown tools that involve time-consuming manual inspection of results from manpower-intensive tests. In the process, regular cycles of validation and verification and labor-intensive manual work, whether needed or not, have helped generate the previously referenced
For example, in the case of process-safety equipment that has been observed to function well on actual process demand, the test-interval timer can be reset, leading to available discount on the otherwise fixed-test interval. Yet, this benefit can’t be captured without the necessary structured documentation of proven good function.
The general result from “own-built” approaches, Millette laments, has been the emergence of countless tools that are used with little consistency throughout industry. Consider variations, from one person to the next, in the manual review of results, which can then lead to variability in the quality of the analysis itself. Even worse, “Due to the drudgery of observing long lists of events from logs, Sequence of Event Recorders, Safety Historian functionality of SIS/ESD systems or even of consolidated process and safety-event journals,” Millette writes, “the task of such review has often been handed to more junior engineers. This may result in a less experienced or critical eye taken to manual review of event journals.”
A structured approach to this task, he continues, can provide significant savings by better targeting a site’s validation and verification efforts. For example, where verification is an immediate pre-startup, critical-path activity in planned shutdowns, it’s possible to shorten the duration of such events. Reduced downtime, expressed as less deferred or lost production, can be a significant benefit as well.
When an unplanned shutdown of part or all of a process area occurs, the urgent action is to understand the cause and quickly see if the cause can reoccur. If, for example, it is momentary (high or low value to process variation reaching a critical point) or a latched failure (equipment-repair needed), engineers need determine the prospects or the timing of a restart—immediately following confirmation through observation and engineering conclusions, or after additional time due to other process-area effects and verifying a safe-starting point. The question, according to Millette, then becomes, “Can we check the actual cause; did everything happen as it should with the expected effects and with expected timing?”
Manually checking the Sequence of Events or other related event logs might then be conducted. But that checking may not flag what is not in the log as “missing events” unless the engineer has expert knowledge of the specific sequences. Moreover, related causes, logical relationships to other effects, or sub-shutdown levels, may not show up in a manual analysis—or, at least, they’ll take considerable time to discover and may require expert eyes.
The ability to receive an automated analysis of how the shutdown occurred and whether all resultant elements performed as expected can provide some critical time saving and relief to detailed searches across multiple systems. Millette references a number of ways this type of automated validation, verification, and documentation directly supports the process-safety management function. Among them:
A stored reference cause and effect, with all relevant event signatures, timings, and relationships, acts as the documented, “as-expected” base.
Events captured from Level 2 control or safety system event journals form the basis of the as-is case to be validated.
The automated analysis then carries out the needed, sequential comparison between the set of logical relationships stored, the event signatures with those observed from the captured event journals. MT
Phil Millette, P.Eng, MEI, is principal industry consultant for Honeywell Advanced Solutions, Houston, part of Honeywell Process Solutions (HPS). For more information on referenced capabilities of the company’s Process Safety Analyzer (PSA), visit honeywellprocess.com.