Whenever a primary attack line is stretched, a backup line must also be stretched. Hose lines should be stretched one at a time — there cannot be a backup line unless the primary line is already in place. It is critical that the crew manning the backup line helps the primary line to get into service before trying to advance the backup line into the fire area.
The backup line is a safety net for the crew on the initial attack line. This safety net has two main functions:
1. It provides protection of the primary way out for the initial attack crew.
2. In the event that the volume of fire overwhelms the initial line, the backup line can move up to provide additional fire flow.
In many structures it is possible for the fire to “wrap around” the initial attack line. Having a backup line in place will prevent this wrap around from occurring. Obviously the crew operating the backup line must be sure that they are not creating an opposing hand line situation. If the backup line believes that they are creating an opposing hand line situation, they should radio the primary line and both lines should back out to a safe place and reconsider the attack.
A more likely scenario is that a room darkened down by the initial line flares up again, threatening the way out. With a backup line in place, the chances that the first line will be overcome are diminished.
It is hard to come up with hard and fast rules about where the backup line should be placed. However, if the objective is to provide protection and additional fire flow to the primary attack line, the backup line officer should be positioned in a place that allows him/her to meet the objective.
Progress of crews and fire
Typically there are many companies working to get into the immediate fire area — the primary line, the first truck, the rescue squad conducting the search, and the backup line. Someone has to sit back and keep an eye on the progress of both the fire crews and the fire. In most cases, the backup line should be positioned to do both.
Given a small, single-family dwelling, the backup line might sit outside the main entranceway. In a garden apartment, they may position on the fire floor landing, or maybe even on the landing below. The position of the backup line is driven by the conditions present, the position of the primary line, the layout of the structure, and the actions of the other operating companies.
The stretching of a backup line should not be a function of rote behavior. Just because a primary attack line is stretched and just because it is more often than not able to control the fire, the attack priorities of Life Safety, Incident Stabilization and Property Conservation remain the same.
The primary attack line’s first purpose is to protect search efforts. It usually does this by putting the fire out. It may be that the primary attack line is not actually attacking the fire because of the needs of the search or that the fire was outside. The officer leading the backup line must then redirect his/her efforts to making an initial attack on the fire.
Judgement calls
If it appears that the primary line is making good headway on the fire and it is not likely that their primary way out will be compromised, then the back up line can be used to protect search efforts or to control horizontal or vertical extension elsewhere in the structure. Adjusting the placement of the backup line is a judgment call on the part of the unit officer leading the backup line into the structure.
However, if the primary attack line commits to an interior position in an IDLH environment, the backup line must support their efforts unless:
1. The IDLH resolves.
2. There is a concurrent search effort requiring hand line support.
If the backup line ever finds due cause to not immediately support the primary line, they must notify the primary line and advise command. It is unacceptable for the primary line to think they have support when that support that has been committed elsewhere.
