Published 3/3/2022

Know Your Tank Liner Options

Experiencing tank trouble? Curtis Goad of GOAD Company, supplier linings, plating tanks and critical containment, discusses tank lining options.

Curtis Goad, GOAD Company

While a “bag” liner will provide fast relief in a true emergency, they are a temporary remedy, as they have well-documented weaknesses and are nearly impossible to repair. Staying with “bag” liners may trap you into a never-ending cycle of future liner replacements, their inevitable downtimes, and a higher total cost of ownership.

The three 21^st century breakthroughs (each one employs patented technologies performed by AWS certified plastic welders) are described, in detail, below:

A “box” liner is shop fabricated and can be dropped into your tank without much, if any, preparation of your existing tank. These box liners are faster to install than an on-site “stick-built” liner and are far superior in quality and longevity. Welded-in-place liners only have interior joining welds, which are weaker than bends and machine butt-welds and can fail with expansion/contraction. A hard chrome plating client in early 2004 dropped two factory pieces, which were then field spliced, into his 18-¹/₂' deep tank creating a PVDF Rigid “box” liner. As of today, almost 18 years later, the PVDF “box” liner is still running strong. The only downside was the need for the client to empty the tank and get good internal measurements for the pre-fabricated, two-piece (must fit) drop-in. Box liners 10' deep and under can be pre-fabricated in one piece.

In 2013, this same client had another hard chrome tank (lead-lined), that he did not want to empty for the “must-fit” measurements, so a Plasticized PVC (PVC-P) “liner-ing” was installed. (Definition: “Liner-ing”: A liner is loose and not bonded. A lining is bonded to its substrate. A liner-ing is mostly not bonded but is anchored on the perimeters, which prevents it from floating in the tank, if cut, as a “bag” liner may). This system goes right over the prior lining (lead, titanium, fiberglass, other plastic), saving the time and cost of stripping off the old lining, disposing it as hazardous waste, blasting and priming/gluing. New substrate and mechanical anchors in the vertical and bottom corners hold the “liner-ing” in place for the infused welding and long-term service. Now in 2022 (almost 9 years later), the PVC-P sheet material has degraded as the Teflon skirt was compromised over time. The client is open to another perimeter anchored “liner-ing” approach, but this time wants to use the unaffected proven PVDF plastic. While not done before, this “liner-ing” with the true “silver bullet” plastic (PVDF) will be pursued — stay tuned!

Last, but not least, bonded lining solutions with drastically reduced field welding are the best approach, especially if you have outlets, weirs, sumps or divider walls. Bonded linings can be either PVC-P or PVDF as both materials are great for high-quality dielectric (radio frequency) welding into large panels. Two very large, 15' deep and 115' long tanks (8,830 square feet) joined together for counterflow rinsing, were PVC-P lined and 2,340 linear feet of field welding was avoided! The 960 linear feet of interior joining welds, done in the field, was performed with patented infused welding technology (hand seam strip welding is eliminated). A 71% reduction of field welding was realized and the client met their hoped-for start-up date. Both dielectric and infused welds are guaranteed not to fail for the life of the lining.

The word “client” may sound unusual as used in this context, but it has significance. The term “customer” references a purchaser of goods or services and is commonly used in our industry. A client, however, relies on the expertise of a provider (i.e., accountant, architect…) who has a moral obligation (fiduciary duty) to put the client’s interest ahead of his own. A client expects and gets more than the benefit of a transaction; and often works with the expert innovator to try new approaches that advance the shared goal of continual improvement. In doing so, the client should not be taken advantage of as a “guinea pig.” The provider must have a track record of long-term satisfaction in this relationship and be worthy of this “leader” * definition: “A leader makes something happen that would not have otherwise happened.” Thanks to many clients, like Logan Plating of Chapmanville, W.V., referenced in #1 and #2 above, our industry moves forward in this century.

* Dr. Lisa Lang, from www.velocityschedulingsystems.com, The Two Laws of Leadership: https://www.velocityschedulingsystem.com/blog/job-shop-leadership/