CITB Specialists Demolition Safety — Questions and Answers
Question 1: Before any demolition work begins on a structure, what must a specialist demolition contractor produce under UK regulations?
- A verbal plan discussed with the site foreman
- A written demolition method statement based on a structural survey (Correct answer)
- A list of available machinery
- An insurance certificate only
Correct answer: A written demolition method statement based on a structural survey
BS 6187 and CDM 2015 require that a written method statement is produced before demolition begins, based on a thorough structural survey of the building. This must detail the sequence of demolition, precautions, exclusion zones, and emergency procedures. The method statement must be prepared by a competent person.
Question 2: When demolishing a building that may contain asbestos, what must a specialist contractor do before any physical demolition work starts?
- Proceed with demolition and deal with asbestos if found
- Commission a Refurbishment and Demolition Asbestos Survey (Type 3) before work begins (Correct answer)
- Wear dust masks and carry on
- Only check areas that are visibly damaged
Correct answer: Commission a Refurbishment and Demolition Asbestos Survey (Type 3) before work begins
The Control of Asbestos Regulations 2012 require a Refurbishment and Demolition Survey before demolition begins. This is a destructive inspection that identifies all asbestos-containing materials (ACMs) so they can be removed by a licensed contractor before demolition proceeds. Proceeding without this survey is a criminal offence.
Question 3: What is the primary purpose of establishing an exclusion zone during specialist demolition operations?
- To prevent theft of materials
- To protect the public and workers from falling debris, dust, and structural collapse (Correct answer)
- To provide parking for demolition vehicles
- To store salvaged materials
Correct answer: To protect the public and workers from falling debris, dust, and structural collapse
Exclusion zones are established to prevent unauthorised persons from entering areas where they could be struck by falling debris, exposed to hazardous dust, or endangered by uncontrolled structural collapse. The size of the zone depends on the height of the structure and the demolition method being used.
Question 4: During the deliberate collapse of a structure using pre-weakening techniques, who must be in overall control of the operation?
- The crane operator
- The most experienced labourer on site
- A competent person appointed specifically to control the demolition sequence (Correct answer)
- The client's representative
Correct answer: A competent person appointed specifically to control the demolition sequence
Pre-weakening and deliberate collapse are among the highest-risk demolition techniques. A specifically appointed competent person must maintain overall control, ensuring the sequence proceeds as planned, all personnel are at safe distances, and the collapse direction is as engineered. This person must have specific demolition experience and qualifications.
Question 5: What is the correct approach to managing services (gas, electric, water) before specialist demolition of a building?
- Turn off at the mains and begin work
- Confirm disconnection with each utility provider and obtain written confirmation before work starts (Correct answer)
- Cap the services at the boundary and begin work
- Only disconnect electricity; gas and water are not hazardous
Correct answer: Confirm disconnection with each utility provider and obtain written confirmation before work starts
All services must be identified, disconnected, and capped at the boundary by the relevant utility companies. Written confirmation of disconnection must be obtained and kept on site. Simply turning off at the mains is insufficient — mains supplies can be inadvertently restored, and underground services may be pressurised.
Question 6: A specialist demolition supervisor notices that an adjacent occupied building shares a party wall with the structure being demolished. What additional measures are required?
- No additional measures if the demolition method statement has been approved
- A structural assessment of the party wall, temporary support measures, and a monitoring programme (Correct answer)
- Simply informing the neighbours by letter
- Demolishing the party wall first to speed up the process
Correct answer: A structural assessment of the party wall, temporary support measures, and a monitoring programme
Where a party wall or shared structure exists, a structural engineer must assess the wall's condition and the impact of demolition on the adjacent building. Temporary support (shoring, propping) may be required, and monitoring (crack gauges, survey points) must be established to detect movement. The Party Wall etc. Act 1996 also applies.
CITB Specialists Demolition Safety
Before any demolition work begins on a structure, what must a specialist demolition contractor produce under UK regulations?