Maintaining plant safety depends on rigorous Management of Change (MOC) of all process changes. I won’t bore you with the drawn-out legalese definition of a process change given by the Center for Chemical Process Safety of the American Institute of Chemical Engineers, New York City. Suffice it to say that it includes virtually any change in a manufacturing operation.
Hopefully, the impact of the change will be fully understood during scope development. Woe to the project engineer when it’s not. So, here, we’ll identify some of the problems with MOC and suggest some ways to make the process easier to follow.
To understand MOC, let’s consider its steps: preparation, approval, implementation, start-up and completion. They apply to both normal and emergency projects.
During preparation, you’ll need to identify those items that must be completed to meet production’s goals. Items are divided between critical and noncritical. Critical items are training, and process and instrumentation drawings (P&ID). Noncritical ones include training of people once they’re back from vacation and as-built drawings. Don’t forget about noncritical items; these should have a deadline like everything else.
Generally, the approval process varies little — only the names change on the MOC form. Reviews should take place at each step in process: the design review of the first P&ID; the hazard and operability (HAZOP) study at the completion of detailed engineering; an environmental impact review; a review of changes in training requirements and workloads, etc. For instance, if your project involves bringing in a new feedstock and you’ll use an existing dock, will there be enough room for your trucks?
Implementation is your reward for putting up with the abuse you can expect during the approval process. At this step, you order equipment, revise your schedule and hire contractors. This step has remained the same since the first Pharaoh built a pyramid.
Start-up has become a little more complicated since then, doubly so because of standards developed by OSHA and ISO. The first step is a pre-start-up safety review (PSSR). This differs from a HAZOP in that it focuses on whether the process can operate with the new changes instead of looking for potential faults in safety and operability. In addition, a PSSR should catch any unforeseen problems that could crop up between design and construction. Commissioning is the next step, followed by process testing, training and hand-over to operations.
By the last step, completion, it’s crucial to have all documentation done and in its final form. Changes should be locked out after completion approval.
Now, let’s consider some of the challenges you can expect to face in meeting OSHA’s MOC requirements. First, you must get responsible parties to sign the forms. In the early days, engineers trudged like a bunch of door-to-door salesmen from department to department for signatures. Today, at least, you can use a computer-based template. Second, a safe, reliable fast track for MOC of emergency work must exist. For 24-hour plant operation, a sufficient number of adequately experienced people should be available at all times, on standby, to review and sign MOC forms. I suggest a standby list of personnel based on equipment that may prompt emergency work; local people are preferred — even retirees. A vendor under a special contract might meet your requirements. Also, it’s prudent for emergency MOC forms to require the signature of at least one more reviewer than the number usually required on normal forms. Don’t forget an equipment review within a few days of implementation. And remember, emergency changes never should become permanent solutions! You should develop a suitable long-term fix typically within 90 to 120 days. One of the greatest challenges to meeting requirements is organizing MOCs for large projects. The best approach is to assign an umbrella MOC with subordinate MOCs based on units (or equipment) and services.
Treat the post-implementation review of an emergency change as a HAZOP study. Any fault in the change must be corrected and the revised change inspected after implementation — and modified, if necessary, until it passes review.
Too many engineers regard every problem as unique. I assure you that most aren’t. I suggest creating a checklist for specific equipment. For example, for a valve replacement, it would include checking: the dimensions, API information, seal rating, face connection and material of construction. This is a simple and effective way to spot mistakes. During one emergency change, the correct valve of the right material was installed but inspection by a keen operator a day later showed the valve had the wrong pressure rating. Treat MOC as a process and you can avoid these problems.
Dirk Willard is a Chemical Processing contributing editor. You can e-mail him at firstname.lastname@example.org.