Posted on March 23rd, 2022

Wildfires are an unfortunate reality in California and the Western United States. Larger and more destructive wildfires year-round result in 6,870 wildland fires that burn an excess of 1.5 million acres on average each year. To battle these blazes, the California Department of Forestry and Fire Protection (CAL FIRE) is responsible for the fire protection and stewardship of over 31 million acres of California’s privately-owned wildlands.

Amid intense wildfire challenges in September 2017 and again in July 2018, the Global SuperTanker B747-400 (“The Spirit of John Muir”) was activated by CAL FIRE to fight quickly spreading fires in Northern California, including the Ponderosa Fire located 10 miles east of Lake Oroville. The Global SuperTanker, representing the world’s largest aerial firefighting tanker, serves the nation and the world by providing air assistance to fight large scale, extreme fires effectively and efficiently.

The aircraft is the latest and largest in aerial firefighting and can drop nearly 18,600 gallons (approximately 155,000 pounds) of fire retardant or water across 150 feet, 1.8 miles to assist with fire-fighting efforts on the ground. In 2017, CAL FIRE estimated 17 million gallons of retardant was used across the state during 12,000 plane hours. In 2018, CAL FIRE activated and deployed Global SuperTanker again to battle fires in Northern California.

The SuperTanker has the unique capability to be anywhere in the world in 24 hours or less with one fuel stop. In addition, the tanker, based in Colorado Springs, is approved to battles fires in other extreme settings such as marine environments where ship or oil platform fires are common.

Retrofitting a Boeing 747-400 to Support Aerial Firefighting Efforts

The successful missions in the U.S. and elsewhere around the globe would not have been possible without Global SuperTanker’s meticulous planning that began many years in advance. In fact, according to Global SuperTanker VP of Maintenance Scott Olson, planning first started in the early 2000s and involved testing steel tanks in the middle of the desert. Years later, in 2015, the Global SuperTanker Services management team decided to put the concept back together making a configuration capable of meeting demanding performance requirements.

The company’s in-depth research to determine how to retrofit a Boeing 747-400 to meet aerial firefighting requirements led company executives to Victaulic. Global SuperTanker wanted to learn more about the capabilities of Victaulic’s grooved mechanical systems for mission-critical environments.

Specifically, this process involved finding the best pipe joining and coupling solutions to support Global SuperTanker’s patented system capable of delivering single drop in 13.2 seconds or multiple payload drops totaling nearly 18,600 gallons of water, fire retardant, or suppressant at speeds reaching 150 knots. The fluids can be released at variable rates from the plane’s pressurized tanks, producing a tailored response to the firefighting need. This unique ability allows it to make as many as six drops in a single flight. Global SuperTanker’s independent system has left and right-hand side tanks that can do multiple drops from either side or a full drop.

Through conversations with Victaulic, Global SuperTanker became convinced that Victaulic’s Style 77 flexible coupling (6-inch and 10-inch) and Style 07 Zero-Flex Rigid couplings (10-inch and 16-inch) were the ideal solutions to reliably withstand the high shock load and movement that occur in aerial fire containment environments. For Global Supertanker, this involves carrying and discharging large volumes of liquids—resulting in a rapid high-pressure change from 0 to 50 PSI if required—over a couple miles.

Meeting Rigorous Certification Standards

Once Global SuperTanker decided to install Victaulic products, the challenges to get the aerial tanker in the air were still significant. The company had to convince the U.S. Forest Service and other interested parties by completing rigorous testing procedures. According to Olson, Global SuperTanker was fully prepared for certification because the company had developed, and successfully demonstrated, Acceptance Test Procedures (ATP) that were approved by the FAA. The ATP included demonstrating the ability for the Victaulic solutions to meet compliance with applicable pressure and motion performance standards for specific durations without failure. Global SuperTanker was able to perform at 1.5 times the mandatory pressure limit performance required.

Victaulic couplings provide significant pressure restraint and end load capability to withstand pipe movement from internal and external sources, as proven through third-party cade based seismic qualification testing. This allows piping assembled with Victaulic couplings to differentially flex and move.  The strategic use of rigid and flexible couplings provided design and performance advantages not available with traditional joining methods. In terms of the discharge, the system has left and right-hand side tanks to accommodate multiple drops from either side or a full drop. Because of these inherent advantages, the risk of any piping system failures is significantly reduced – preventing nonconformities that could potentially lead to the hazardous discharge of liquids inside the aircraft.

It ultimately took Global SuperTanker 55 days for U.S. Forest Service and CAL FIRE initial certification. Global SuperTanker credits Victaulic’s performance as a critical piece of making certification happen. “Victaulic solutions were critical to the success of the complex tank system,” commented Olson. He added, “To date, Global SuperTanker has completed well over 400 drops with no Victaulic failures.”

Saving time is money

Beyond durability and flexibility advantages, Global SuperTanker was confident Victaulic’s grooved mechanical piping would provide benefits during the installation phase. Global SuperTanker realized the benefits of using Victaulic couplings went beyond their performance capabilities as their ease of installation made pipe joining in the confined spaces of the aircraft much easier, faster and safer.

In addition, ongoing maintenance advantages include the ability to quickly unbolt the couplings to clean the piping that slides into the plane in sections. Because of the corrosive nature of the fire suppression chemicals, Global SuperTanker needs to flush the system and periodically disassemble it for inspection. Victaulic couplings provide ease of maintenance and the ability for Global SuperTanker to clean and remove abrasive fire-retardant substances, ultimately supporting the life of the system and protecting the very costly investment of the aircraft. Without this capability, Global SuperTanker also would face a much more time-intensive installation process, increasing the amount of time required for the tanker to be deployed for its next mission.

The Benefits of Unique Solutions for Unique Challenges

The project provides another example of why Victaulic is the partner of choice in extreme conditions: proving that a mechanical grooved piping system can be installed in aerial tankers to support reliable performance against the world’s toughest firefighting challenges. According to Olson, “Ultimately, Global Supertanker helps save lives and natural resources. Victaulic is a significant part of that effort and, in fact, we could not do what we do without Victaulic.”