September-October 2008 Issue

Handline Selection

Reprinted from the March 2000 Issue of Fire Nuggets

Stretching and operating the first handline at a serious fire is the key to saving lives and constitutes the very essence of the fire department's mission. The effectiveness of the first handline as a lifesaving tool is dependent upon several factors.

Simply put, it requires stretching the correct diameter (size) hose to the correct location in the correct amount as quickly and efficiently as possible.

We will concern ourselves here with the first factor—selecting a handline of the correct size.

Handline selection decisions occur on two levels. First-level decisions are strategic in nature and concern what sizes and amounts of attack and supply hose to carry on each engine apparatus. Decisions at this level require an understanding of community risk characteristics including predominant building types, occupancy hazards, height and area considerations, lot sizes, set backs, and hydrant spacing. These factors must be measured against average response times (which impact fire growth) and engine company staffing levels (larger handlines are more difficult to stretch and operate with fewer firefighters). Existing hosebed capacity may also be a consideration. In general, fire departments equip each engine apparatus with at least two sizes of attack hose: Smaller, more maneuverable 1¾-inch or 2-inch hose for fires involving automobiles and residential occupancies and at least one 2½-inch handline for use when larger flows are needed. (The omission of 1½-inch and 3-inch hose was intentional and will be explained below.)

Second level handline selection is based on a size-up of the fire problem once the engine company arrives "at the box." Tactical handline selection is influenced by one or more of the following factors: Fire department standard operating procedures; the nature of the fire occupancy; the amount of fire encountered; the length of the handline stretch; staffing levels; and the practical flow limitation imposed by each of the available handline options.

With the widespread adoption of 1½-inch hose by municipal fire departments after World War II, fireground tactics changed markedly. No longer was larger, heavier 2½-inch hose required for every fire. Coupled with improvements in turnout clothing and the availability of self-contained breathing masks, fire departments everywhere gained the ability to attack residential fires quickly and efficiently from the interior.

But the residential fire environment of the 1940's, '50's, '60's, and '70's was much tamer than it is today. The 60-90 gallons- per-minute (gpm) flows typical of 1½-inch hose are now woefully inadequate. A minimum flow of 150 gpm is far safer.

While many residential fires can be extinguished with only 90 gpm and certainly the skill and tenacity of an experienced nozzleman should never be underestimated, 1½-inch hose offers no flow reserve for contingencies. In addition, the friction loss in 1½-inch hose can be significant, requiring a high pump discharge pressure (PDP) and severely restricting handline length.

The use of 1¾-inch hose, pioneered by the New York City Fire Department in the late 1960's, overcame many of these limitations. Not only is the practical flow limit much higher (about 200 gpm versus 125 gpm for 1½-inch), the friction loss per length is much more reasonable.

Consider the following example: A 150-foot, pre-connected, 1½-inch handline with a 100 psi combination nozzle flowing 125 gpm will require a PDP of almost 160 psi. The same flow with the same nozzle through 150 feet of 1¾-inch hose will require a PDP of only 135 psi. At the same PDP used in the first example (160 psi), the 1¾-inch handline will deliver 165 gpm—a 24 percent increase in flow volume.

A more recent introduction is the 2-inch handline. While the practical flow limitation of 2-inch hose is over 200 gpm, in reality there is a significant amount of "unused capacity." It has been suggested that actual fireground flows from 1¾-inch hose average a paltry 110 gpm or less. The reason is that as flow increases, so does nozzle reaction. Particularly for fire departments that employ 100 psi combination nozzles, reaction forces will exceed levels that can be safely and effectively controlled by a single firefighter at flows of only 130-140 gpm. The difference between potential and actual flows is even more dramatic with 2-inch hose. Since the upper-end flows through a 2-inch hose produce rather substantial nozzle reaction forces and make the line difficult to bend, the nozzleman usually ends up screaming for less pressure or the nozzle is partially closed in order to maintain control. As a result, 2-inch handlines often end up delivering less than 50% of their potential capacity. In practical terms, 1¾-inch hose is just as effective, plus it costs less and is easier to handle.

While 150 gpm is adequate for most residential fires, commercial building fires demand a minimum flow per handline of at least 250 gpm. Characterized by large floor areas, high ceilings, and heavy fire loads, fires in commercial buildings require high-volume streams with long reach and superior penetrating power. In order to deliver 250 gpm without excessive friction loss per length, the use of 2½-inch hose is a must.

In addition to fires in commercial buildings, the 2½-inch handline is ideal for large outside fires, heavy fire conditions on arrival (regardless of the occupancy), vacant buildings, buildings under construction, defensive operations, and exposure protection. Although the size and weight of 2½-inch hose make it rather intimidating, with proper training, the right nozzle, and the use of modern, lightweight hose, it can be a highly effective handline, even for understaffed fire departments. Incident commanders must understand the benefit of a single, well-placed 2½-inch handline and should never hesitate to pair together engine companies to ensure its mobility and fire extinguishing prowess.

Although a few firefighting manuals indicate the use of 3-inch hose as a handline, and some fire departments utilize it as a pre-connected "blitz" or "bomb" line, it is too heavy and too large to be used effectively in the majority of fireground situations. Since 2½-inch hose can deliver well over 300 gpm and is smaller and more manageable, the use of 3-inch hose is an unnecessary waste of hosebed capacity and firefighter resources.

It is incumbent upon each fire department to evaluate its hose and nozzle systems using calibrated-flow and pressure-measuring devices to determine actual performance. Feedback from engine company firefighters on issues such as nozzle reaction and stream performance must also be considered when making strategic decisions on what sizes of hose to carry on each engine. This in turn will lead to more informed tactical decisions and ultimately, faster fire control and increased safety on the fireground.