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IT'S HURRICANE SEASON: Are your tank farms ready?

Articles & Insights Jun 09 2020

a weekly blog series by John Carroll, Associate Managing Director, Regulatory Compliance


Every year during hurricane season I have a couple articles I like to repost due to the important reminders they detail. On Wednesday June 3, I was sent the Tropical Storm Cristobal briefing report by the National Weather Service. In the report it notes there may be impact to land as early as Sunday in the gulf. Since the estimated landfall area is full of petrochemical facilities and bulk storage facilities, the below is a vital review. Adding to this conversation, the Houston Chronicle published the following story on June 4.

Gulf chemical plants unprepared for increasing flood risk from climate change: report
Hurricane season is similar to a slot machine –unpredictable in nature. You never know what is going to happen weather-wise during this time of year. However, it’s always wise to prepare for a potential hurricane, and that goes for oil companies with tank farms too. Furthermore, there are tools and methodologies to assist with post hurricane damages.

Prior to a hurricane, companies should ask themselves:

  • If secondary containment floods, what is the required amount of product to keep the tank from floating away?
  • If there are strong winds, how much wind force should be considered acting on the tanks, and how much more product is required to keep the tank from moving?
  • Are old tanks more susceptible to damage than tanks built to newer codes?
  • Are small tanks with higher aspect ratios more likely to overturn than big tanks?
  • What could be the effect of moving water on tanks located at my facility due to rainwater drain-off after flooding?
  • If there is not enough oil to fill tanks, what alternatives do I have to be reasonably safe?

Sadly, not everyone asks these questions in advance, or prepares plans before a hurricane hits that will help mitigate against potential hurricane-related issues. What happens when you don’t prepare? The minute a hurricane or other major tropical depression is on the horizon, people refer to a generic pre-storm planning checklist to secure operations, rather than following a pre-determined, individualized plan. While this approach is not necessarily wrong, with a well-thought out preplan in place a more desirable outcome is likely.

What does industry do to help prepare when a weather-related event is imminent? The practice used by most within industry is to anchor tanks and ancillary piping at the same time one starts filling the tanks with water. This practice prevents the tank from floating offsite and/or impacting other objects, minimizing the risk of a spill in the event the anchored tank is impacted by another object. Implementing these preventative measures makes perfect sense and is standard industry practice. However, there is a precise science to the practice as well. As mentioned, there are a significant number of variables to account for that will ensure tanks are properly secured.

Due to the large number of spills generated by flooding events post Katrina and Rita, the Environmental Protecting Agency’s (EPA) Regional Response Team (RRT) - Region-6 published the following set of guidelines that provide even further guidance and details. Flood Preparedness Recommended Best Practices


The hurricane has passed, flooding has subsided around storage tanks and now it’s time to assess operations. Most people will focus on the easily noticeable damage flood lines to assess damage levels, blown down items or damaged items. However, one thing that is not always obvious is tank settling. Similar to how a water-logged car’s electrical system can be hidden from view, settling can be hidden, subsequently obscuring critical failure points looming in the future.

A lightbulb moment: Large trees that have been living near the tanks for hundreds of years have fallen on their sides, but there’s no evidence of wind damage in the immediate area. Why did the trees fall over? In reality, the ground where the trees stood has been saturated for days because of flooding (standing water), which, due to the weight of the trees, loosened the area around their roots and weakened the root structure. Remember, pre-storm procedures instructed one to fill tanks with water; these tanks are incredibly heavy now, and a similar event is possible here too. It may not be as visible; however, it may be enough to cause critical stress fractures or other issues with the tanks.

September 14, 2017 Article

“The AP has identified at least 34 above ground fuel storage tanks and tank batteries that failed during Harvey and released more than 600,000 gallons (2.2 million liters) combined of crude oil, gasoline and other chemicals.

Two storage tanks failed in the (name removed for blog) case. Initial indications suggested the massive tanks floated off their foundations as floodwaters swamped the company’s tank farm, (name removed) said. That’s what happened at tank farms in Louisiana during Hurricane Katrina, when numerous storage tank failures spilled millions of gallons of fuel into floodwaters.”

If in doubt, or if there is any indication that the surrounding areas may have been overly saturated allowing for sub-surface ground disturbances, part of one’s post recovery efforts should be commencing an API 653 Section 12 and Appendix B methodology for evaluating storage tanks for out–of–plane settlement study or similarly applicable evaluation.

Do not forget, industry also has Underground Storage Tanks (UST) too. Though not part of today’s discussion, here is a great guidance tool published by the EPA with similar pre-and-post event considerations: UST Flood Guide.

Not necessarily related to today’s discussion; however, FEMA prepared the “Ready Business Hurricane Toolkit”, which contains a wealth of helpful information, contacts and suggestions to better prepare your business for hurricane season and what to do after a hurricane hits.


Witt O’Brien’s develops pre-hurricane checklists, hurricane manuals/plans and tank risk-assessment reports to help prepare one’s operations. Our subject matter experts (SME) cover a wide spectrum of engineering competencies, emergency response, and environmental planning; giving us a unique capability in managing one’s needs with a wide angle.


Witt O’Brien’s SMEs perform the full suite of API 653 tank settlement calculations depending on the damage conditions and future operational needs. We specialize in saving clients millions of dollars by avoiding misdiagnosed tank settlements, unnecessary jacking expenditures and lost time. Tank jacking is a major repair, and there is the inherent risk that the cure could be worse than the settlement. In addition to the standard API 653 calculations, we have improved methods of analysis to minimize the use of jacking to only the instances where it is truly appropriate.


Witt O’Brien’s surveying capabilities cover all sizes of containments from a single tank to hundreds of acres. We offer various 3D modeling solutions that have amazing accuracy of photogrammetric modeling paired with the capturing ability of drones that are supported by GNSS Integrated Network Rover (GPS/cellular) field equipment, and boots-on-the-ground data truthers allows us to offer cutting-edge dike surveys designed to save time and money to our customers throughout the United States. We have experience with many types of dike arrangements and low-cost repair strategies including shared containment.


We are here to help solve your compliance questions and challenges. Need some compliance assistance, or just have a question? Please contact us today.