Aerial Application of Water Enhancer Study
Water enhancers (commonly referred to as gels) have been limited in their operational use in recent years. As such, their effectiveness has not been thoroughly evaluated through field testing. Consequently, wildland fire agencies in Colorado do not have access to information about the availability, use, and effectiveness of water enhancers. The Center of Excellence for Advanced Technology Aerial Firefighting (CoE), with support from the Division of Fire Prevention and Control’s (DFPC’s) Aviation Unit and the Bureau of Land Management (BLM), is conducting a study during the 2017 wildland fire season to evaluate the effectiveness of water enhancers on wildfires by using single engine air tankers (SEATs) to test three products.
|State-contracted SEAT T-831 drops sunset orange (left)
and brilliant blue (right) FireIce HVO-F®.
Water enhancers are polymer products added to water to improve fire‑suppression characteristics. They have been used for aerial suppression in parts of the United States and Australia during recent fire seasons. Water enhancers contain thickeners that improve aerial application performance by minimizing drift and evaporation and increasing adherence to fuels. These products are also known as gels because they form gel-like slurry when mixed with water.
- Observe and evaluate drops (i.e., perform operational data collection) of water enhancers on wildfires and record the following observations:
- Did the water enhancer stop or slow the forward advance of the fire?
- Did the water enhancer reduce fire intensity to a sufficient level for ground crews to manage the fire?
- Did the water enhancer persist on the surface fuels long enough to prevent hotspots from redeveloping or the fire from burning through the drop?
- Determine whether water enhancers delivered from a SEAT are effective on wildfires in Colorado. Effectiveness will be viewed in terms of how effective the products were in achieving the desired suppression objectives (e.g., reduction of fire intensity or burn area, coverage of suppressants on the ground, alignment of intended and actual drop areas).
- Collect as much data as possible regarding the effectiveness of water enhancers used during initial attack and on emerging fires.
- Share lessons learned from the evaluations with interested parties, including cooperators and researchers.
- Test and evaluate newly developed ground-based mixing/batching equipment to assess the efficiency of the mixing and loading processes and the ability of the equipment to reduce response times.
Overview of Project
Prior to this study, Colorado loaded only long-term retardant (LTR) in SEATs. LTRs are chemical concentrates mixed with water that alter fuels so that they do not support combustion. Retardant is dropped adjacent to or ahead of the fire to create a chemically induced fire break at its perimeter. This deprives the fire of fuel, thus retarding the fire’s spread. After the water in the mixture evaporates, residual chemical on fuels continues to reduce the fire’s ability to generate heat, which is particularly useful in fighting high-intensity fires with a distant and indirect attack. LTR is most commonly used because of its long-lasting effect on fires.
Water enhancers are available as wet or dry concentrates. They contain polymers or other thickeners that aid plain water in its adherence to fuels, allow buildup of a thick and protective wet layer, and minimize the effects of wind drift during aerial application. Water enhancers modify fire behavior or extinguish fires by absorbing the energy (i.e., heat) being released by the fire because they have increased film thickness. In other words, their molecular bonds slow water evaporation by creating a thermal protective coating. SEAT drops of water enhancers are mainly used in direct attack to slow or halt the fire’s rate of spread long enough for ground resources to access the fireline and mop up or supplement the knockdown process. If ground resources cannot access the fire edge due to terrain or other access issues, the fire may rekindle over time.
In this study, the CoE will evaluate the use and effectiveness of three water enhancers: FireIce HVO-F®, BlazeTamer 380®, and Thermo-Gel 200L®. All of these products are approved by the U.S. Forest Service (USFS) for use in SEATs.
FireIce HVO-F® is a highly refined, cross-lined polyacrylate copolymer. FireIce is a dry powder that weighs approximately 8.45 pounds (lbs) per gallon when mixed with water. The mixing ratiois between 0.12 and 0.18 lb of powder per gallon of water. FireIce is available uncolored and in one-part and two-part orange and blue fugitive colorants. The colorants were developed to be tied to the effectiveness of the product: when a pilot can no longer see the line, then it is no longer effective. This product will be loaded at the State-managed Fort Collins SEAT base.
BlazeTamer 380® is a polymeric-elastomer-based water enhancer designed for deployment by aircraft to suppress wildfires. It contains a mix of polymers, surfactants, water, and other ingredients. BlazeTamer 380® is a liquid concentrate that weighs approximately the same as water. The mixing ratio is .65% concentrate for each gallon mixed. This product will be loaded at the BLM-managed Rifle SEAT base.
Thermo-Gel 200L® is a hydrophilic polymer based in mineral oil. It is packaged in a liquid concentrate form that, when added to water, transforms into a heat-absorbing gel. The water-filled gel particles adhere directly to the burning material and, in doing so, aid in the quick extinguishment of fire. It has a mixing rate between .5% and 3% of each gallon mixed. This water enhancer will be loaded at the BLM-managed Craig SEAT base.
SEATs loaded with water enhancers will respond to fires on State and private land, as well as to fires under the jurisdiction of BLM, the National Park Service, and USFS. Mixing will be at the recommended ratios in the USFS Qualified Products List for each product on all drops. For the first load on each fire, State and Federally contracted SEATs will respond to the incident with water enhancer unless the ordering unit clearly specifies the need for LTR instead.
Decisions regarding where, when, and how to apply a particular aerial retardant or suppressant are typically under the discretion of the Incident Commander, so if at any time the Incident Commander or the Air Tactical Group Supervisor feels that the enhancers are not performing as desired, the Incident Commander can immediately order that the SEATs be loaded with retardant.
An Interagency Information Bulletin was prepared and has been issued to provide increased awareness and information about the study to all impacted agencies.
The use and effectiveness of these products will be evaluated by ground firefighters, SEAT Base Managers and/or SEAT Managers, and the aerial supervision community through robust data collection forms.
Ground Data Collection
Ground firefighters will be reporting on:
- Drop direct suppression effectiveness
- Location and drop placement
- Fire behavior before and after drops
- Environmental conditions (e.g., humidity, temperature, wind speeds)
- Fuel types where drops occurred
- Product holding times
SEAT Base Managers and/or SEAT Managers will be reporting on:
- Issues with storage, mixing, and loading onto the aircraft, including time, complexity, physical labor requirements, and efficiency of vendor-provided mixing equipment
- Ease of mixing to specified viscosity, including any issues with the aircraft tank‑level‑indication systems, physical labor requirements, and quality control considerations
- Ease of spill cleanup (routine or accident)
- Safety considerations (e.g., personal protective equipment requirements, slippery surface conditions, hazmat issues)
- Ease of storage (e.g., ability to pre-mix, shelf life)
Aerial Data Collection
The aerial supervision community and SEAT Pilots will be reporting on:
- Accuracy (i.e., comparison of intended target and actual drop)
- Coverage levels relative to fuel types
- Immediate effects on fire behavior
- Colorant visibility (for identifying drops from the air)
In addition, SEAT Pilots will record their observations and impressions as to the performance of the water enhancers. When available, the DFPC Multi-Mission Aircraft will also record images and videos before, during, and after drops.
Analyzing the Data
After the 2017 fire season, CoE staff will analyze the information recorded by personnel on the fires and produce two reports:
- A preliminary report on the use of water enhancers during the 2017 fire season, including how many fires the water enhancers were used on, the locations of the fires, how much water enhancer was used, cost, fuel types, etc.
- A final report on the use and effectiveness of each enhancer with recommendations for future use on fires in Colorado and beyond, including:
- Should we keep using water enhancers?
- When should we use them over LTR?
- Cost (broken down by product) versus LTR
- Effectiveness of each product (i.e., evaluation standards)
Participating agencies hope to achieve the following goals during this project:
- Raise the awareness of firefighters, aviators, fire management officers, aviation managers, agency officials, media, and the research community on the effectiveness of aircraft-delivered water enhancers at combating wildland fires
- Gather data on the use of water enhancers that can be used for training to improve aerial fire suppression operations knowledge and awareness
- Evaluate the effectiveness of suppression drops (e.g., accuracy, drop heights, air speed)
- Increase firefighter knowledge and safety
- Determine if the methodology used during this evaluation will allow future users to successfully evaluate the effectiveness of next-generation water enhancers
- Verify past research on aerial suppression water enhancers
- Provide feedback to the manufacturers on the systems used to mix and load the products
 The aerial supervision community includes Lead Plane Pilots, Air Tactical Group Supervisors, Aerial Supervision Modules, and Mission Sensor Operators on the Multi-Mission Aircraft