Element 11 Excavation confined spaces Flashcards
Outline the control measures needed to reduce risks during excavaion works
Provide good access such as ladders access or other safe methods of getting in and out of teh excavation, ladders should beincluded in the inspection and extend above the top of the excavation by atleast 1m.
Fence of the excavtion in public areas to prevent pedestrians and vehicles falling into them. Where children may get onto the site take precautions such as back filling or securley covering them.
A competent person must supervise the installation, alteration or removal of excavtion support, people working in excavtions should be given clear instructions on how to work safely.
A competent person muyst inspect excavtions nd support systems at the start of each shift before work begins, after any eventlikely to have affected the strength of stabilty of the excavtion. After any fall of rock, earth or other material.
A risk assessment and study and if required radar use to located or confirm site clear of EXB.
Provision of suitable lighting, during darkness the edges of an excavion should be illuminated especially where they are adjacent to public throughfares.
Barriers to prevent vehicles getting to close and causing the sides to collapse or where excavations are over 2m deep edge protection should be put in place to prevent falls or materials falling in. Where the fal is less than 2m but additional hazards such as water or reinfocing bars are projecting upwards the same standard of fall protection should be provided.
Signs should be present around the perimeter warning o fthe excavtaions presence.
Ventilation should be provided where fumes or gases may be present, exhaust fumes from plant or near by generators can accumulate and pose serious hazards. Excavtions must be kept free form toxic or explosive gases, the gases involved could be natural like methane, the workers in an excavtion should be instructed in escape and resuce procedures
Crossing points should be provided at pre-determined points placed along the excavation to allow safe crossing from one side to nother, these should be adequate in strength an have hand rials and edge protection.
Spoil should not be stored within 1.5m of the edge, however if the depth exceeds 1.5m the spoil needs to be at a distance that equals the depth of the excavation.
Workers are undertaking repair work in a sewer chamber that is 3m deep, outline the issues that should be considered to ensure that emergency arrangemens are adequate
Issues to be considered are build up of poisonousgas, fumes or vapour. The access could be through a resticted space such as a manhole and escape or rescue in a emergency will be more difficult. There could be water in the sewer and biological agents from vermin and waste.
Identify hazards that may be encountered by workers driving sheet piles into a river bed and the water pumped out
- Drowning
- Flooding of teh cofferdam
- Unstable soil
- Collisions with shipping
- Weather and strong tides
- Hoisting of people, materials and equipment
- noise
- vibration
- crushing
- collision with plant
- Biological hazards like wiels deseise
Identify the statutory requirements for inspection of excavations under CDM
A competent person must inspect excavataions and the support systems;
- At the start of each shift, before work begins
- After any event likely to have affected the strength or stability of teh excavation
- After any accidental fall of rock, earth or othe rmaterial
A written report should be made after most inspections, work should be stopped if the inspection shows the excavation to be unsafe
Although an excavation must be inspected at the start of every shift, only one report of such inspections is required every seven days
identify hazards associated with work in confined spaces
- Exposure ot toxic, explosive and oxygen-deficient atmospheres
- Heat
- Water
- Free-flowing solids
- Restricted space
Identify examples of confimned space found on a construction site
- Trenches
- Sewers
- Chambers
- Tanks
- Pits
- Cellars
- Manholes
- Excavations
- Tunnels
