Sealing Sense
When Packing Fails: Emergency Preparedness
Turning unexpected failures into controlled, manageable events.
Drew Dixey | Fluid Sealing Association member, A.W. Chesterton Company
| IMAGE 1: Packed stuffing box load characteristics (Images courtesy of A.W. Chesterton Co.)
In facilities that rely on pumps and valves to move and control critical media, mechanical packing remains a widely used sealing solution. It is a technology that has existed for well over a century and is used across industries from water treatment to power generation. Whether installed in a centrifugal pump or rising stem valve, packing is a vital component to maintain plant operations and equipment reliability.
When packing fails, the consequences can escalate quickly, leading to:
- Unplanned downtime
- Safety risks
- Environmental exposure
- Costly repairs
Preparedness is what defines facility operations. Knowing how to respond, what temporary actions are acceptable and how to prevent recurrence can lead to long-term success, saving both time and money.
The Reality of Packing Failures
Mechanical packing typically follows recognizable patterns across both pumps and valves:
- Acceptable leakage can no longer be controlled through normal gland follower adjustments.
- The stuffing box temperature increases dramatically compared to the baseline readings taken when the packing was first installed.
- Packing extrusion can be seen from the entry of the stuffing box.
In pumps, failures are often tied to premature wear from overtightening, sleeve/shaft wear, burning due to dry running, loss of flush (solid embedment) and chemical incompatibility. In valves, leakage can be caused by worn, aged or improperly tightened packing, typically resulting from thermal cycling, excessive stem friction, excessive extrusion gap or stem clearance, and incorrect material selection.
In both cases, root causes are frequently preventable. Improper installation, incorrect gland load and improper material selection for the application are among the most common contributors. Overtightening is a universal issue leading to heat buildup, excessive friction and wear of the stems and shafts in both pumps and valves. That said, failures are inevitable, but being unprepared is not.
| IMAGE 2: Temporary vs. permanent packing repairs (Image courtesy of the author with AI assistance)
Immediate Response & Containment
When excessive leakage or failure occurs, the priority is always safety. Operators should immediately follow established plant protocols and safety procedures. If conditions allow continued operation, initial corrective actions taken should be to control the failure. Careful adjustment of the gland follower is often the first line of response; however, this must be done incrementally to allow the increased gland load to settle in the packing set. Adjusting too quickly can lead to overadjustment, which can accelerate failure by increasing friction and heat. In pumps, restoring acceptable leakage or flush is equally important, as dry running can quickly destroy the packing. One of the most common mistakes in both pumps and valves is reacting too aggressively. Quick, forceful adjustments often turn a manageable issue into a severe failure.
Once the situation is stabilized, operators must then consider balancing uptime with long-term equipment health. Not all leakage requires immediate shutdown; in fact, a small, controlled amount of leakage is often necessary for packing performance, specifically in pumps.
The key question operators must ask is: Can the equipment safely remain in service temporarily? For pumps, controlled leakage may be maintained with incremental gland adjustments until a scheduled maintenance shutdown. For valves, minor leakage around the stem may be tolerable in noncritical applications, allowing time to plan repairs. These decisions often come with tradeoffs. Running compromised packing for too long can damage shafts, sleeves or valve stems, leading to additional repairs. What may be a short-term gain in uptime can become a long-term loss.
Temporary repairs for both pumps and valves should be documented clearly per piece of equipment. Common trends with adjustment timelines can be established to better plan in the future. Permanent repairs typically involve a full repack, along with inspection of the shaft or sleeve for scoring or wear. Worn or pitted stems will prevent effective sealing even with new packing. Additionally, underlying issues such as shaft misalignment, improper selection of packing and unforeseen upset conditions must be addressed. Even the best packing materials will fail prematurely when all factors have not been evaluated. When in doubt, document the condition of the equipment and removed packing with thorough pictures and reporting, then share these details with the packing OEM for analysis and review.
| IMAGE 3-5: 3. Packing cutting tool (Image courtesy of the Fluid Sealing Association), 4. Tamping tool (Image courtesy of A.W. Chesterton Co.), 5. Packing extractors (Image courtesy of A.W. Chesterton Co.)
Stocking Critical Components
Preparedness starts with on-hand inventory. Having the right materials on hand is critical to fast and effective response. Facilities with strategic inventory recover from failures significantly faster. Each site should consider maintaining the following essential items.
Essential packing materials:
- Stock common sizes and styles for equipment.
- Have spare cut ring sets on hand for a quicker maintenance turnaround.
- Use preassembled packing kits for critical valves.
Packing-specific hardware:
- Tamping tools
- Packing extractors
- Packing knives and calibrated cut ring tools
- Anti-seize (where applicable)
Equipment-specific spares:
- Lantern rings
- Glands
- Replacement studs, nuts and fasteners
- Shaft sleeve repair kits (for pumps) or spare stems/sleeves
Carrying inventory has a cost, but downtime costs far more. Consider this inventory as insurance and protection against unplanned outages. It is best to start with prioritizing critical pumps and valves that could affect continuous operation and adjust inventory levels based on failure history and usage trends.
| IMAGE 6: General stuffing box arrangement (Image courtesy of the Fluid Sealing Association)
Driving Continuous Improvement
After maintenance has been performed, analysis is essential to capture long-term value. Thorough documentation of adjustments, maintenance practices, operating parameters and materials used allows teams to evaluate if the correct packing was selected and installation procedures were properly followed, as well as whether or not operating conditions exceeded design limits. For equipment that presents recurring issues, it is critical to move beyond repeated fixes and instead identify the underlying cause. Consistent documentation enables trend analysis, supports better decision-making and drives continuous improvement in reliability
Drew Dixey is a design engineer with A.W. Chesterton Company and currently serves as chair of the Fluid Sealing Association’s mechanical packing division. He may be reached at drew.dixey@chesterton.com.
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