Demolition and Dismantling

Introduction

CDM applies to all demolition and dismantling work, irrespective of notification to HSE. Demolition and dismantling is;

The deliberate pulling down, destruction or taking apart of a structure, or a substantial part of the structure. It includes dismantling for re-erection or re-use. Demolition does not include such operations as making openings for doors, windows, services, or removing non-structural elements such as cladding, roof tiles or scaffolding. Such operations may, however, form part of demolition or dismantling work when carried out alongside other activities.

Demolition and dismantling of structures is seen as a 'reverse construction' process.

Most of the accidents that take place during dismantling and demolition of structures arise from premature collapse of the building or structure. Dismantling and demolition operations should be planned to the same detail as any other construction operation. The operations should have appropriate drawings and specifications detailing the structure and materials to be encountered. In premises such as hospitals, factories and other buildings where chemicals have been used or stored, hazards associated with flammable substances and substances hazardous to health, including radioactive substances, may be known to the owner. However the structure may have lain idle for a number of years or may have changed hands. In this case there may be no alternative but to retain the services of a competent analyst to report on the hazards remaining in the structure.

A method for dismantling or demolishing the structure should be devised to ensure that there is at least one possible safe method of carrying out the operation. In most instances, structures should be demolished in the reverse order to their erection.

The Designer's method for dismantling or demolishing the structure does not dictate a particular method but allows safety hazards to be identified. It is for the Contractor to choose a particular method for dismantling or demolishing the structure.

Identify and Describe

• Relevant structural calculations and assumptions and imposed loading affecting the stability of the structure including any identified structural weaknesses.
• Temporary Support. These may include:
• bracing
• temporary restraints
• anchorages
• false work
• Unusual or special stability arrangements
• Materials to be encountered. These may include:
• Flammable material and gases
• Asbestos
• Lead
• Radioactive substances
• Biological substances

The Pre-construction Information should require the Contractors to prepare a Method Statement detailing how the work will be carried out.

Protecting the Public

Demolition processes are frequently carried out near highways or other areas open to the public. Precautions taken to protect the health and safety of the public should be similar to those for employees on site. Wherever possible the site should be completely fenced.

Legislation

The Construction (Design and Management) Regulations 2015 require that a competent person supervises the work, that precautions must be taken to prevent fire, explosions or flooding and that the overloading and collapse of buildings be prevented.

This legislation also covers all aspects of scaffolding, ladders, working platforms, and gangways together with work on or near fragile materials.

In addition to the above the HSE provides guidance on Health and Safety in Demolition Work in the form of Guidance Note GS 29 / 1,3 & 4 obtainable from HSE Books.