Collapsed Structures- PN 302

Question 1

What are the NATURAL causes of collapse?

Answer 1

• Earthquake
• Hurricane
• Lightning
• Flooding
• Subsidence

Question 2

What are the HUMAN causes of collapse?

Answer 2

• Premises is under renovation
• Accidental impact
• Arson
• Terrorism induced (vehicular impact,explosion)
• Accidental gas explosion

Question 3

What are the elements of structure?

Answer 3

Beam : spans an opening,can withstand
load placed upon it
Column: carries weight via compressive
force to elements below
Floor : divides building,helps Support walls
Wall : load bearing or not,separates area and
provides Shelter
Protected Shaft:enclosed space between floors,
increased strength + fire resistance
Gallery : floor spanning high ceiling room, adds
space and helps support high wall.

Question 4

What are the types of construction?

Answer 4

Framed. :typically steel or reinforced
concrete, frame bears load.
Commonly modern buildings,
greater resistance to collapse.

Unframed :Walls will be load bearing, also referred
to traditional or masonry construction.
If load bearing walls columns or
beams fail, result is extensive
collapse + large area of debris.

Question 5

What are the 3 categories of collapse?

Answer 5

• Internal
• External
• Total

Question 6

Name the 4 types of Internal collapse

Answer 6

-Pancake: failure of load bearing walls or an
upper floor.one collapse causes
subsequent collapses via shock
loading.
-Lean to : where a supporting wall fails
and a beam fails at one end,
forming triangle shaped void
- “V”. : Floor fails in centre, but not at ends
- Tent : Floor beams fail near outer walls but
remain supported in centre.

Question 7

Name the 3 types of external collapse

Answer 7

-90° collapse:MOST DANGEROUS- wall
falls outward for a distance at.
least equal to its height.
-Curtain :Part of the wall comes straight
down, debris piles up near base.
-Inward/ :horizontal crack in middle
Outward causes one section to collapse
inward, one outward

Question 8

Who should the OIC request at any dangerous structure / collapse?

Answer 8

Local authority Dangerous Structures engineer.

Question 9

Pending the arrival of a Dangerous Structures Engineer, what control ,ensures can be implemented?

Answer 9

Cordons put in place

Question 10

Depending on the scale and causes of collapse, what procedures may need to be instigated by the IC?

Answer 10

• Major Incident procedure
• Terrorist related Incidents
• HAZMATS
• Civil Disturbance
• Fires involving Radiation

Question 11

Why is scene preservation an important consideration?

Answer 11

The majority of collapses will be subject to an investigation by the Police and HSE.

Question 12

What unusual pressures, particularly in the early stages of the incident, may crews face?

Answer 12

Extreme Pressure to act through public expectation.

Question 13

Why is it important to remove Good Samaritans from the scene as quickly as possible?

Answer 13

Any remaining parts of the structure may be structurally unsafe, and uncoordinated actions by non emergency service personnel could lead to further collapse.

Question 14

What hazards may be encountered at collapsed structure incidents?

Answer 14

• obstructed/restricted access
• restricted visibility (smoke,dust)
• unstable underfoot conditions
• falling objects
• overhanging hazards
• airborne particulates/irrespirable atmosphere
• secondary collapse
• weight and position of casualties
• bulk and weight of debris
• explosive / flammable atmosphere
• poor lighting
• biological hazards
• exposed / damaged utilities
• asbestos
• sharp/protruding objects
• further acts of terror (if this was the initial cause)

Question 15

What would the OIC consider requesting and providing at an early stage of the incident?

Answer 15

Request.
USAR tactical advisor (UA)
Dangerous Structures Engineer

Provide.
RVP
Dedicated USAR RVP if required.

Question 16

What would be an OIC’s Early considerations?

Answer 16

-Positioning of appliances/RVP To minimise 
  vibration
-correct level of PPE Required
-creation of zones / cordons
-Isolation of Utilities

Question 17

What considerations should staff committed to the structure make?

Answer 17

-Avoid forcing doors or windows, they may
be supporting load.
-Staff should remain as close to walls as
possible to avoid undue strain on floors.
- Utilities may not be isolated.

Question 18

What Tactical considerations should an OIC make?

Answer 18

Incidents of this nature:

• are usually protracted
• attract a large attendance
• require close Inter-agency working

Question 19

What capability does the brigade have to deal with collapsed structures, and what resources provide the staff and equipment?

Answer 19

Capability- USAR (part of new dimension)
Resources- Dedicated FRU’s, plus 5
Modules

Question 20

What are the 5 USAR Modules?

Answer 20

1-Structural Collapse
2-Major Transport
3-Breaching and Breaking
4-Multi Purpose Vehicle 
5-Timber

Question 21

In what way should operations be carried out and what order should rescues be undertaken

Answer 21

Operations should be systematic, co-ordinated and based on up to date information.
Rescues should be easiest first moving on to more complex.

Question 22

What are the ‘6 stages of rescue’?

Answer 22

R - Reconnaissance and survey
E - Elimination of utilities
P - Primary surface search and rescue
E - Exploration of voids and spaces
A - Access by selected debris removal
T - Terminate by general debris removal

*stages will overlap, but all must be completed.
This is a protracted process.

Question 23

What control measures must be implemented by the OIC to ensure crew safety?

Answer 23

-Dedicated safety officers
-An evacuation signal must be established
and communicated
-Minimum staff committed to risk area at any time
-Emergency team must remain available

Question 24

What resources can the IC consider at the R stage

Answer 24

TIC
Interrogation of plans
Interview of witnesses