Discuss the methods of demolition. Mention the hazards and risks involved in demolition works.

Demolition is the process of dismantling, tearing down, or removing structures, buildings, or infrastructure to make way for new construction, renovation, or redevelopment projects. Several methods of demolition are employed, depending on factors such as the type of structure, site conditions, and environmental considerations. Some common methods of demolition include:

1. Mechanical Demolition: Mechanical demolition involves using heavy machinery, such as excavators, bulldozers, cranes, and wrecking balls, to dismantle structures and remove debris. This method is suitable for large-scale demolition projects and structures made of concrete, steel, or masonry.

2. Implosion: Implosion demolition involves strategically placing explosives within a structure to cause it to collapse inward onto itself. This method is used for tall buildings or structures in densely populated areas where space is limited. Implosion requires careful planning, engineering, and coordination to ensure safety and minimize collateral damage.

3. Deconstruction: Deconstruction is a selective demolition method that involves dismantling structures piece by piece to salvage reusable materials, such as lumber, bricks, metals, and fixtures, for recycling or reuse. Deconstruction is labor-intensive but environmentally friendly, as it reduces waste and conserves resources.

4. High-reach Demolition: High-reach demolition involves using specialized equipment, such as high-reach excavators or cranes equipped with demolition attachments, to dismantle tall structures or structures with limited access. High-reach demolition equipment allows operators to work at heights safely and efficiently.

Hazards and Risks Involved in Demolition Works:

1. Structural Collapse: Demolition works carry the risk of structural collapse, especially when removing load-bearing elements or using explosive demolition methods. Structural instability can lead to unexpected collapses, endangering workers and nearby structures.

2. Falling Debris: Demolition activities generate dust, debris, and falling objects that pose hazards to workers and bystanders. Proper safety measures, such as barricades, safety nets, and personal protective equipment, are essential to prevent injuries from falling debris.

3. Hazardous Materials: Demolition works may involve handling hazardous materials, such as asbestos, lead-based paint, PCBs, and chemical contaminants, which pose health risks if released into the environment. Proper identification, handling, and disposal of hazardous materials are necessary to protect worker health and prevent environmental contamination.

4. Equipment Hazards: Operating heavy machinery and demolition equipment poses risks of accidents, collisions, and equipment failures. Workers must be trained and certified to operate machinery safely, and equipment must be inspected and maintained regularly to prevent malfunctions.

5. Environmental Impacts: Demolition activities can have adverse environmental impacts, such as air and water pollution, soil erosion, and habitat destruction. Proper waste management, pollution prevention measures, and environmental controls are essential to minimize environmental risks and comply with regulations.

Overall, demolition works require careful planning, coordination, and execution to mitigate hazards and risks effectively, protect worker safety, and minimize environmental impacts. Compliance with safety regulations, site-specific risk assessments, and proper training of personnel are essential for safe and successful demolition projects.