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Cat 1 first responders should be able to describe basic collapse patterns. When referring to the collapse pattern, the rescuer should simply describe what they observe.
It is critical that Cat 1 rescuers understand that the collapse pattern will give more information on the possibility of survivable voids.
When describing structural collapse, use simple descriptive terms:
1. Give an estimated size of the building
2. Consider the building material that has collapsed:
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| Piles of brick work will be unlikely to present survivable voids, unless there are elements underneath that may provide survivable voids
for victims (such as motor vehicles). |
Timber and steel beams will manufacture survivable voids, which will be easily moved by light rescue crews to perform a rescue. |
Concrete panels are likely to present survivable voids if they are still connected to another element of a structure, but they will may present deeply entrapped victims. |
3. Consider the use of the building:
* House
* Factory
* Office block
* Church
4. Descibe the scale of the collapse:
* "Total" collapse means that the entire structure has been affected
* "Partial" collapse indicates that not all of the structure has been affected. If a partial collapse occurs, give an estimated percentage of the collapse area in relation to the entire building
5. Describe exactly what has collapsed:
* Wall collapse
* Roof collapse
* Awning collapse
* Total collapse
Other collapse such as:
| Pancake floor collapse |
Soft storey collapse |
Progressive collapse |
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Occurs when a floor or ceiling falls downwards, usually due to compressive failure of the load bearing walls or columns.
Small voids are created by strong supporting objects between the floors.
This type of collapse might not move victims horizontally at all. They may drop straight down. |
A soft storey is a building level that possesses reduced structural elements in comparison to other levels. For example, the ground floor of a multi-storey building may have more glass elements to "open up" lobbies or retail areas.
During an earthquake this storey becomes a weak point and the soft storey collapses when the rest of the structure above remains intact. |
A progressive (or chain reaction collapse) occurs when there is an initial failure of a single primary support member and a chain reaction of failures continues in a downward movement.
Many small voids are created. Victims may survive in areas of the floor away from the collapsed areas. |
Using combinations of the above options may be used to formulate the following example of a collapse pattern:
"We have a concrete tilt slab factory, 20m by 20m, with a total roof collapse"
Considering the factors presented will determine the probability of survivable voids and chance of live rescues. |
No-Go collapse areas
Any area on the structure collapse site that appears unsafe, or could be subject to further collapse, must be marked as a No-Go area.
No-Go areas may include standing walls that are unstable and could collapse.
Rescuers need to be able to identify areas that a collapsed wall could cover if further collapse occurs. Use cordon marking to identify these dangerous areas. | 
