House Fires – Firefighting in Thick Smoke
The vast majority of life losses through fire occur in our homes every year where young children and elderly persons are most at risk. The ‘house’ fire is predominantly the most common and basic building fire a firefighter can encounter.
It is generally small by nature compared to commercial and industrial premises, requiring less resources, but often the challenges can be extreme as this is where we are most likely to undertake search and rescue (S&R) operations. Therefore a firefighter’s potential for exposure to high risk is increased and since the early 1990s it has been demonstrated in the US, where lightweight construction has become commonplace, that the ratio of firefighters (to the number of fires) killed by ‘structural collapse’ in residential buildings has actually increased.
Working in thick smoke, even in small compartments, a firefighter can easily become disoriented and even lost where the ability to work safely in such conditions relies on regular and realistic training. It is also dependent on crews working and remaining in close touch with each other. Where smoke levels are within reason it is sufficient for firefighters to remain in visual contact with each other. This old maxim should guide us:
‘Go in together, stay together, protect your escape routes at all times, take enough water, and come out together.’
Now there alone is a one hour evening classroom session for firefighters, based on the above statement! Take that maxim and debate amongst each other exactly what it means to you.
‘GO IN TOGETHER – COME OUT TOGETHER’
When analysing why firefighters get killed or injured at house fires we can see a common pattern of command and tactical errors occurring over and again. It’s not so much about the quantity of water at the nozzle, any particular extinguishing technique, or anything more than basic tactical actions.
We so often fail to learn from past fire experience and implement the lessons of tragedy into our own operational approaches. Where crews are deployed to the interior for S&R:·
- The commander’s 360o view of the fire building is a critical and primary strategic action giving vital information
- View the sides and rear, as well as the frontage of the building, noting relevant features
- Try and locate the fire compartment/s during the 360 and form a deployment plan
- Important – smoke issuing from an opening does not always denote a fire’s location!· Don’t deploy into the building from the front if there is a safer access point elsewhere, depending on fire location and wind direction/speed- this is CRITICAL!· Are sufficient resources on-scene to deploy safely and effectively?· Has an adequate firefighting water supply been located and connected?·
- Prior to deployment, communicate and brief the crew/s (face to face where possible) exactly what their role is – be very clear and ensure the brief is understood – this is also critical· Is the flow-rate being deployed to the interior adequate to deal with the involved fire load?· If the fire rapidly increases in size due to fire related ventilation or further fuel load involvement, is the deployed flow-rate adequate to meet this increasing heat release?·
- Monitor all interior crews location and air-supplies, and establish effective communication with them at the earliest opportunity· Where crews are to work beyond or above the fire for search and rescue, assign a protection hose-line with responsibility to protect their escape route at all times· Never ventilate or make openings without anticipating the potential impact on fire spread and flow-path direction and ensure the interior crews are aware and support such an action·
- As soon as possible have relief crews ready to deploy, to relieve interior crews in good time· Anticipate bad outcomes, rapid fire spread, lost or trapped firefighters and prepare actions and assignments ahead of such events
WORKING IN SMOKE
The ability for firefighters to work and search safely and effectively in smoke and heat is something that demands regular and thorough training, learning to work blindly using ‘touch and feel’ techniques. When doing so, firefighters should remain in close contact with a wall, where possible, as well as each other.
Searching a house for unconscious victims must be undertaken with controlled haste, ensuring that no area is left untouched before moving on to the next room in a structured search pattern. Should firefighters take a hose-line with them when searching? Many instructors or SOPs recommend that they should.
- A hose-line is cumbersome and slows the search beyond and above the fire compartment
- For searching or entering the fire compartment itself, a hose-line in support is highly recommended
- In some cases where the fire location is unknown, it is important to protect escape routes by siting additional crews with hose-lines at the stairs or at critical junction points in the house, to protect other firefighters and possible victims
- The greatest use of fire containment actions should be made whilst search is underway. At every opportunity, close all doors that may feed air into the fire compartment
- If passing the fire compartment to search beyond or above the fire, close all doors leading to into it where possible
- If crews are working in the fire compartment, assign a door control firefighter/crew to reduce the fire’s heat release rate progressing towards flashover – partial closing, inserting a tool to prevent full closure. This support team may be equipped with a secondary safety hose-line.
THE RISK PROFILE OF A HOUSE FIRE
Based on your country or area, the average house has a lot in common but within a range of variable possibilities in both construction and size. These could typically be brick built, or timber framed with exterior cladding, demonstrating room sizes between 10-100m2. They may have multiple or split interior levels with some having basements. In some cases the basement at the front of the building is the ground level to the rear. They may also be detached from surrounding properties or attached with common roof voids between all properties. Each particular structural design presents its own challenges and risks in terms of fire spread.
Typical compartment size
10-100m2
Typical fire load (80% fractile)
870 MJ/m2
Typical HRRPUA*
250 kW/m2
Design fire growth rate
Medium t2
A typical *HRRPUA – Heat release rate per unit area (m2) – for ventilation controlled post flashover fire.
CHANGING LEVELS
Whenever a team of firefighters working internally are planning to change levels, that is go up or down stairs from the access level, there are some critical rules of engagement they must first consider: ·
- Has the fire been located?·
- Has the fire been isolated from their position and confined behind a closed door/s?·
- Is there a wind impact assessment?·
- Is there water being applied to the fire?·
- Is firefighting water-flow off the fire appliance tank or has it been augmented?·
- Has a hose-line been located between them and the fire?·
- What is the reason to change levels?
If the fire is a basement fire then the protocols for following such a situation should be pre-planned and documented through SOP, ensuring extreme caution and coordination between fire attack and venting actions. If the fire is on an upper floor the strict protocols should exist for such an operation.
However, if firefighters are moving with intention to go above a confirmed fire floor for search and rescue purposes, then again strict protocols should be followed. Failing to follow these protocols can expose firefighters to increased hazards.
Article written by Paul Grimwood from Euro Firefighter 2