Fire Management Tech Tips Logo of USDA Technology & Development Program
March 2000
5100 0051 1302—SDTDC



LIQUID TANK BAFFLES
Ralph Taylor, Assistant Fire Program Leader
Eric Shilling, Mechanical Engineering Technician
Mike Dunn, Field Sponsor-San Bernardino National Forest

BACKGROUND
If traditional baffles break in a tank carrying liquid, the tank must be either replaced or repaired, often at considerable expense. Traditional baffles used to control water surge, are generally welded inside the tank and, over a period of time, can breakdown or fail. The vehicle operator and crew are subject to a very serious safety hazard when baffles become ineffective and water surge is not minimized.

Recently, a demonstration was conducted at San Dimas Technology and Development Center on an effective and unique baffling system. Unlike traditional baffles, the Trail Creek baffle system uses a number of polyethylene strips formed into spheres. The number of spheres depends on the size of the tank. Once these strips are placed in the tank, they serve the same purpose as traditional baffles.

THE PRODUCT
The Trail Creek baffling strips are made of a polyethylene material, and are available in different sizes depending on tank size. The strips, held together by polyethylene or stainless steel rivets, form a sphere when final assembly is completed. (Figure 1).

This baffling system is a free-floating unit that works in tanks of all sizes and shapes and does not attach to the tank. The baffles, when placed in the tank, displace approximately 1 to 2 percent of the tank’s volume. The opening of the tank must be a minimum of 3 inches in diameter for placement and removal of baffles. The baffles are installed by simply squeezing their sides, which causes the baffle to collapse into a rectangular shape. To remove, simply grasp a baffle and pull it through the tank fill-hole opening. The baffle collapses as it is removed.

DEMONSTRATION
The first demonstration was accomplished with a small-scale model that showed the water surge with and without baffles (Figure 2).

 Figure 1a–View of Trail Creek baffles.
 
 Figure 1b–View of Trail Creek baffles.
Figure 1–Two views of Trail Creek baffles.


It is apparent, when looking at figure 2, the middle cylinder contains no baffles. While moving the model rapidly from side-to-side the water surge in the middle cylinder was significant. The two outside cylinders had very little water surge due to the baffles.

The second demonstration was conducted with two 500-gallon tanks—one tank contained baffles, and one tank did not. The tanks were placed in the bed of a 1-ton pickup truck and tied down to prevent tank movement.

Figure 2–Small-scale model.
Figure 2–Small-scale model.


The tanks were filled with water and food coloring was added to make the water more visible. The vehicle was driven at high rates of speed while making sharp turns and sudden stops. The vehicle operator noted that the vehicle’s operation, with the unbaffled tank, was unstable and nearly uncontrollable. During sudden stops the severe water surge caused the forward movement of the truck to continue (Figure 3).

Figure 3–Movement of water in test tanks without baffles.
Figure 3–Movement of water in test tanks without baffles.


With baffles inserted the vehicle’s operation was a different story. The vehicle operator noted a significant reduction in vehicle movement due to water surge while driving the same course at the same speeds. No additional forward movement of the truck was noted during sudden stops. (Figure 4.)

Figure 4–No water movement in tanks with baffles inserted.
Figure 4–No water movement in tanks with baffles inserted.


Using a stopwatch, it was observed that it took 20 to 30 seconds for the water to settle in the tank without baffles. It took 6 to 10 seconds for the water to settle in the tank with baffles.

CONCLUSION
Proper tank baffling is essential for the safe operation of fleet vehicles that carry liquid. The Trail Creek baffling system provides a safe and cost effective alternative to expensive tank replacement and baffle repairs. For more information on the Trail Creek baffle system contact:

Jim Spickelmire
Trail Creek Inc.
617 Cunningham
P.O. Box 66
Grangeville, ID 83530

Web site: http://www.trailcreekinc.com

About the Authors…
Ralph Taylor
Ralph joined the San Dimas Technology and Development Center in October 1996 as the Fire Program Assistant. He is project leader for Fire Chemical Technical Services, Hi-Tech Fire Simulator, and National Wildfire Coordination Group (NWCG) Working Team publications.
Ralph is a qualified Type I Safety Officer and Type II Operations Section Chief and is currently assigned to a National Type I Incident Management Team. He is a graduate from Lassen Community College with a degree in Forest Management.

Phone: (909) 599-1267 x 234
Fax: (909) 592-2309

Eric Shilling
Eric has a Bachelor of Science in Engineering Technology from California State Polytechnic University at Pomona, and has been at the Center since 1992. Eric’s skill and experience with field and laboratory testing/evaluation is relied upon in a variety of projects.

Phone: (909) 599-1267 x 290
Fax: (909) 592-2309

Mike Dunn
Mike went to work for the Forest Service after graduation from high school. His FS career was interrupted by a tour of duty with the U.S. Marine Corp at Camp Pendelton, CA. After the Marines, Mike rejoined the Forest Service and has worked on Hotshot crews, engines, prevention, and resources. Currently, Mike is a dispatch captain on the dispatch floor at FICC on the San Bernardino NF.

Phone: (909) 599-1267 x 223
Fax: (909) 592-2309

Library Card
Taylor, Ralph; Shilling, Eric; Dunn, Mike, ed. 2000. Liquid tank baffles. Tech Tips. 0051-1302-SDTDC. San Dimas Technology and Development Center. San Dimas, CA: U.S. Department of Agriculture, Forest Service, San Dimas Technology and Development Center. 4 p.

Demonstration of a free floating type of baffle system for tanks that haul liquid. Baffles made of polyethylene material; size varies depending on tank size. Presents test results and dealer information.

Keywords: tank baffles, water surge


TD logo
For Additional Information Contact:
Fire Management Program Leader
San Dimas Technology and Development Center
444 East Bonita Avenue, San Dimas CA 91773-3198
Phone 909-599-1267; TDD: 909-599-2357; FAX: 909-592-2309
E-mail: mailroom_wo_sdtdc@fs.fed.us

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