With the challenges posed by fighting wildland fires, agencies are always on the look out for technologies that will make more effective use of their resources. Class A foam has helped make better use of those limited resources, and now water-enhancing gel products are emerging.

During the recent California fires, these products were used to protect structures, provide wet lines to back up firing operations and suppress fire. The gels were delivered by ground engines, water tenders, helicopters and fixed-wing water scooping air tankers.

As in the early days of foam, gel had problems with ground applications such as the ability to proportion the product, which limited its use and popularity. Until recently, the only way to deliver a finished gel solution was via an end-of-line self-educting nozzle with a backpack or small handheld container of the concentrate. The second generation end-of-line type systems have fixed some of the problems of the first nozzles, making them more reliable and more versatile.

The first Type 3 wildland engines equipped with gel proportioning systems recently have come into service. The engines will service the Southwest interface areas.

The California Department of Forestry and Fire Prevention has been using gel products for the last several years. Recently, CAL FIRE put into service two prototype engines that were retrofitted to proportion 132 gpm of gel on the engine. Also, in August, the U.S. Forest Service Region V took delivery of an engine equipped with combination gel and Class A foam proportioning systems.

It is not as critical to have the same accuracy with Class A foam as with the gel products. The accuracy necessary with the gel solution can have a considerably different viscosity from a 2% to a 2.2% solution. The ability to change the viscosity of the finished solution is needed for different applications. For example, a viscous solution is needed for structure protection while a medium-viscosity solution is preferred for suppression or putting down wet lines. The gelled water needs to be thick enough to cling to the fuel but thin enough to allow for some penetration.

Wayne Hepper is a product manager with FireDos.

The 2008 Focus on Foam is sponsored by: