PN302 Collapsed Structures

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 and 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 and 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/Outward: 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

Dangerous Structures Engineer.

Question 9

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

Answer 9

Cordoning off an area by the erection of barriers

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 are the 5 USAR modules?

Answer 17

• Module 1 – Structural collapse
• Module 2 - Major transport
• Module 3 – Breaching and Breaking
• Module 4 – Multi purpose vehicle (MPV)
• Module 5 – Timber

Question 18

What considerations should staff committed to the structure make?

Answer 18

• Constantly observe all safety precautions to protect themselves and others from injury
• Be aware of any changes in conditions that may cause additional threats to safety and alert all personnel to the danger

Question 19

What Tactical considerations should an OIC make?

Answer 19

• Carry out a DRA
• Formulate a plan, requesting DSE and UA
• Plan the ‘Six Stages of Rescue’
• Identify a suitable RVP
• Appoint safety officers
• Agree an evacuation signal
• Only the minimum amount of personnel necessary to carry out the task

Question 20

What are the ‘6 stages of rescue’?

Answer 20

• 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

Question 21

What resources can the IC consider at the R stage

Answer 21

TIC