Let’s start Part 2 of this article with a short recap of Part 1 (May 30, 2022, see link below). As discussed, industrial equipment can often sit idle at a new site for months while construction progress slows. On-site storage protection that’s needed for 3 to 12 months at a construction site requires a preventive maintenance (PM) program. At best-in-class (BiC) performers, on-site storage preservation with oil mist is standard practice, and its cost is included in the initial budget for projects.
Only in dire circumstances would best-in-class performers revert to the conventional ways of temporary storage protection. Part 1 then highlighted those circumstances, and listed strategies and recommendations strictly for short-term preservation using conventional, old, non-optimized protection methods. (As noted, these described plans and methods are for plants located in northern, dry climates.)
Here in Part 2, our discussion focuses on additional storage-preservation issues, including how they are addressed in industry standards.
This article is based on a chapter in the author’s book
“Optimized Equipment Lubrication, 2nd Edition, 2021;”
De Gruyter, Berlin/Boston, (ISBN 978-3-11-074934-2).
Additional chapters will be highlighted on this website in the future.
STORAGE PRESERVATION MENTIONED IN INDUSTRY STANDARDS
A number of equipment standards and industry guidelines exist on the topic of storage protection. Among them are references in API documents:
- API-RP-686 3.2.1 states: “When more than ten pieces of equipment are to be stored for a period
of longer than six months from time of shipment, oil-mist protection should be considered.”
- API-RP-686 3.2.2 notes: Oil mist should be used to protect the bearing housings, seals areas, and
process end of equipment.
- API-RP-686 3.2.3–3.2.16 state the full API recommendations.
The manpower needs for storage and preservation would be much higher for vapor-phase-inhibitor application (e.g.,preparation for storage and preparation for installation and commissioning) as opposed to oil-mist preservation. The latter would leave the equipment, including any machine used in the petrochemical, oil refining, and mining industries, ready for installation and startup.
Documented accounts are available where oil mist has, in past decades, provided reliable protection for idle and standby equipment at many facilities. Project executives seeking on-time commissioning and high future operating reliability are encouraged to provide the same well-proven protection for current projects and its new equipment during storage.
To date, no facility has ever published the embarrassing statistics of early bearing and mechanical seal failures encountered when trying to omit equipment storage preservation. However, infant mortality, defined as failures within 30 days of startup, is exactly what has been observed by large and small companies that temporarily idled plants or units with inadequate or no effort spent on storage protection (i.e., mothballing).
One 2013 incident involved a facility that had initially “saved” a few dollars by not using the best equipment protection. Those in charge later tried to obtain advice on “what could we do now” from consultants. Risk-reduction strategies that would cost the facility millions in undoing the damage were then mapped out. Whenever machines were installed with in-place spares, one of the two units was to be dismantled by contract personnel. Company retirees were asked to supervise the machine dismantling and reassembling tasks. Decisions relating to work on a second machine were made with the full knowledge gained from the first dismantling and reassembling.
This situation would have been less costly if the Reliability Professionals at the facility had aimed for the implementation of best-available technology. Reliability Pros who don’t see this as their role have no business calling themselves Reliability Professionals. At all times, they would do well to remind themselves of the principles of equipment-storage preservation:
- Operating machinery must be protected from the elements. Painting, plating, sheltering, use
of corrosion resistant materials of construction and many other means are available to achieve
the desired protection.
- A similar set of protection requirements applies to not yet commissioned or temporarily
- Storage preservation makes economic sense. However, the quest for safety and reliability must
be first, saving money should be considered a close second.
- Early in the chain of decision-making, management deserves to be thoroughly briefed on the best-
- Bring in competent advisers early in the process. Regrettably, competent advisers are often brought
in after the damage is done. On average, incompetent opinionators are often involved initially. They are
holding on to their jobs by always supporting the boss. Opinionators are rarely asked to explain why BiC
competitors have made it corporate policy to budget and include oil-mist preservation in their projects.
- Follow these principles for both new (i.e., not yet commissioned) and mothballed (i.e., previously operating,
but now shutdown or inactive) machines.
- The work processes or procedures chosen for the preservation or corrosion-inhibiting of fully assembled,
but inactive (e.g., mothballed) process machinery will logically depend on the type of equipment, expected
length of inactivity, geographic and environmental factors, and the amount of time allocated to restore the
equipment to service.
The basic and primary requirement of storage preservation is exclusion of water from those metal parts that would form corrosion by-products. Rust is one by-product of corrosion that could find its way into bearings and seals. A secondary requirement might be the exclusion of sand or similar abrasives from close-tolerance bearings or sealing surfaces. All or any of the storage-preservation strategies must aim at satisfying these requirements.
Machinery preservation during pre-construction, storage, or long-term deactivation (i.e., mothballing) will affect machinery’s infant mortality at the startup of the plant or process unit. Many times, machinery arrives at the plant site long before it is ready to be installed at a permanent location. Unless that equipment is properly preserved, scheduled commissioning dates may be jeopardized, and the risk of failure would increase.
♦ PROTECTION OF MECHANICAL-SEAL COMPONENTS IN NON-OPERATING FLUID MACHINES
Protection of liquid or dry-gas types of mechanical seals in pumps that are stored or mothballed for prolonged periods of time deserves attention. The precautionary recommendations of at least one mechanical seal manufacturer are provided below as a general guide.
The guidelines for mechanical-seal and bearing storage are straightforward. When possible, remove the mechanical seal from the pump. Mechanical seals are assembled and tested in a clean-room environment. Left unprotected in the field, both internal and external contaminants, such as airborne dust, can accumulate in the critical sealing areas, causing leakage or damage to the seal upon startup. This may equally be true for liquid and dry-gas seals.
The seal should be labeled to identify its materials of construction, then packaged and stored in a controlled environment. Note that a consumer-type vacuum-sealing apparatus can be used to preserve and protect the seal. If the seal has been in operation previously or has been in contact with fluids, it should be returned to the manufacturer for inspection and/or repair.
Bearings in storage in a warehouse should remain wrapped in their factory plastic, wax paper, or vacuum pack. They must be laid flat, not be standing on edge.
♦ REGARDING PUMPS AND FLUID MACHINES WHERE NO FLUID IS PRESENT
When possible, process fluid is drained before applying the storage or protective treatment. In that case, the guidelines are:
- Valve off the pump and drain the fluid from the pump casing.
- Remove the seal’s environmental controls and plug the ports.
- Drain all other fluids, including the barrier fluid, from the seal.
- Clean the seal chamber(s) with a solvent that’s compatible with the seal’s materials to remove
all possible residues. Next, verify that all fluid/solvent has been drained from both the pump and
seal. Rotate the shaft by hand during this process.
- Plug all seal ports.
- Mask the opening between the shaft or seal sleeve and the gland to protect the seal from
- Tag the equipment with the date of storage.
♦ REGARDING PUMPS AND FLUID MACHINES WHERE FLUID IS PRESENT
In these instances, the recommended general guidelines are as follows:
- Remove the seal’s environmental controls.
- Plug all seal ports.
- Securely mask the opening between the shaft or seal sleeve and the gland to protect the
seal from environmental contamination.
- Tag the equipment with the date of storage.TRR
ABOUT THE AUTHOR
Heinz Bloch’s long professional career included assignments as Exxon Chemical’s Regional Machinery Specialist for the United States. A recognized subject-matter-expert on plant equipment and failure avoidance, he is the author of numerous books and articles, and continues to present at technical conferences around the world. Bloch holds B.S. and M.S. degrees in Mechanical Engineering and is an ASME Life Fellow. These days, he’s based near Houston, TX.
Tags: reliability, availability, maintenance, RAM, electric motors, bearings, pumps, mechanical seals, lubrication, lubricants, oil mist