Friday Notes

by Paul Grimwood,

There is one thing that all firefighters should be aware of and it’s this;

‘If you make an opening in a fire involved building, on or above the fire floor, it’s almost certain that the fire will head towards the opening you’ve made’.

This single aspect of practical fire dynamics (flow-paths) is something firefighters have sometimes failed to grasp during operations and it is something that has led to many firefighters losing their lives.

Fire, smoke and heat movements are driven by air and gas density and pressure differentials between the warm interior conditions and cooler external conditions of a fire building. If you are on, or above, the fire floor and you create a vent opening from an interior location to relieve visibility or localised heat building up, you are likely placing yourself in the dragon’s mouth! Within a few short seconds the local temperature is likely to rise to untenable levels.

At one fire we had, two firefighters advancing a hose-line into a smoky apartment fire but they were unable to locate the fire. The conditions were reported as cool to warm by two other firefighters who were assisting the hose-line advance from behind. On reaching the second level they decided to open some windows to clear the smoke to assist in locating the fire (see rules 1 and 4). This action caused rapid fire development to head up from below them, towards the openings they were making. Two of these firefighters tragically lost their lives.

At another fire in a basement of a bar, difficult conditions were being experienced by crews attempting to reach and extinguish the fire. A command decision was communicated to the firefighters in the basement that the street level windows were going to be tactically vented, to relieve conditions (see rules 1 and 4). This led to an escalation of the fire as hot smoke headed past the firefighters in the basement, rising up the access stair and out into the street. Conditions were severe and two firefighters were exposed to untenable conditions, causing them to evacuate immediately. In the process, they parted from each other and although still in voice contact, one of them became lost on the way out and tragically lost his life.

Here is another example; firefighters were advancing a hose-line into the ground floor of a house and despite flowing water, they were unable to have any effect on the hidden and shielded fire. They decided to break the windows behind them to gain some relief from the heat and heavy smoke conditions (see rules 1 and 4). The fire headed straight for those windows and firefighters ended up having to climb out of the windows to escape the fire.

Two firefighters were taking an uncharged hose-line down into a basement fire from the A-side. The wind was heading towards the rear (C-side) (see rule 3). As windows failed on the C-side they were calling the line to be charged. The rapid-fire development caused their hose-line to melt before they had water and they became trapped for some minutes in the basement, both eventually tragically losing their lives.

4 Golden rules:

1. Don’t create an opening that places firefighters between the fire and the opening you are making.
2. The open door you have entered by is an opening and the fire will be heading that way soon enough without effective door control or suppression.
3. If you can enter a fire building with the wind at your back that is likely far safer than entering towards the wind. However, this equates to PPV and you MAY need to consider making an opening on the other side of the fire, to release the pressurised fire conditions.
4. If you make an opening in a fire involved building on or above the fire floor, it’s almost certain that the fire will head towards the opening you’ve made.