The CoE is happy to present the final report of our 3-year Aerial Application of Water Enhancer study.  Please feel free to share this and to contact Aviation Project Manager This email address is being protected from spambots. You need JavaScript enabled to view it. with comments or questions.  The report suggests a number of follow-up actions that the CoE will consider.  We want to share our thanks for all those agencies and partners who assisted with this report over the last 3 years.  Read The Aerial Agent Test Report.

The following is an excerpt of fromthe report.

Purpose

The Center of Excellence for Advanced Technology Aerial Firefighting (CoE), with support from the Colorado Division of Fire Prevention and Control (DFPC’s) Aviation Unit and the Bureau of Land Management (BLM), conducted a study during the 2017–2019 wildland fire seasons to evaluate the effectiveness of water enhancers on wildfires by using single engine air tankers (SEATs) to test three products.

This report documents the results of the CoE study as well as key observations and recommendations for the effective use of water enhancers.

Introduction

The most common firefighting agents used in aerial firefighting in the United States are water and long-term retardant (LTR). Prior to this study, Colorado loaded only LTR in SEATs. LTRs are chemical concentrates mixed with water that alter fuels so that they do not support combustion.

Water enhancers are polymer products added to water to improve its fire-suppression characteristics. Plain water dropped from aircraft without the addition of water enhancers is actually a very inefficient suppressant. When it converts to steam, it has a great capacity to absorb and carry away heat. However, it also has a strong surface tension that causes it to bead up and roll off most fuels before it can absorb its full heat capacity. In essence, much of the water runs off the fuel. Typically, the terms polymer and elastomer are used to refer to firefighting gels—we use the term polymers to describe "super-absorbent polymers.” The cross-linking process allows them to absorb and retain a very large amount of water and builds viscosity and thickening without altering the other properties of the water.

The term elastomers is used to describe polymers that impart what is called “viscoelasticity,” or viscosity and elasticity together. This consistency is typically called rubbery; because they are lightly cross-linked they do not absorb as much water when mixed. In addition to building viscosity, they also add the elasticity so are referred to as elastomers.  Read The Aerial Agent Test Report.

Introduction

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 continuing the study during the 2019 wildland fire season to evaluate the effectiveness of water enhancers on wildfires by using single engine air tankers (SEATs) to test three products.

Water enhancers are polymer products added to water to improve fire‑suppression characteristics. The products 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. While they have been used for aerial suppression in parts of the United States and Australia during recent fire seasons, the majority of previous research investigating the suppressants has focused on direct application in protecting exposed flammable surfaces in the form of structures and wood piles.These studies have used a variety of techniques to investigate how suppressants can extinguish non-spreading (i.e., static) fires or prevent/delay the ignition of flammable surfaces exposed to heat sources. There have been several studies that have been conducted on direct ground-based application in vegetative fuels for the suppression of spreading fires. These studies were limited in their size and repeatability and provided more of a demonstration of a method, rather than a comparison of suppressants or techniques.