Exercise 1
Prepare a checklist for the safe of use suspended access equipment, such as a window- cleaning cradle.
Answer 1
• Condition of cables. • Condition of pulleys.
• Safety of platform boards (SWL). • Presence of guardrails.
• Presence of barriers below work area. • Presence of signs.
• Communication arrangements. • Emergency arrangements. • Use of PPE as harness.
Exercise 2
Outline the circumstances in which it would be inappropriate to carry out work at height from a ladder.
Exercise 2
• Inappropriate task (e.g.: where two hands are needed or where the work area is large. • The equipment or materials to be used are heavy and awkward.
• Work at excessive height.
• Work of a long duration where use of ladders will lead to ergonomic body problems. • The ladders cannot be secured or made stable.
• The ladder cannot be protected from vehicles. • Adverse weather conditions.
Exercise 3
In relation to safe access for construction work above ground level:
-Identify the means of a labeled sketch, the component parts of an independent tied scaffold.
-Outline the precautions that should be taken when using a ladder as means of access to the scaffold.
Answer 3
The following are the main components of independent tied scaffold: • Upright poles.
• Diagonal poles.
• Bracing (transverse & longitudinal). • Sole plates & base plates.
• Working platform. • Guard rails }
• Toe board. } For edge protection. • Ledger & transoms.
• Tie to the structure.
The working platform should include: 3 boards --- for footing.
4 boards--- for footing & storing materials. 5 boards --- for general work.
6 boards--- for masonry work. Types of independent tied scaffold:
• Light duty: where one platform is used at anyone time e.g.: for painting. • General purpose: where up to 4 platforms can be used. Example for general
maintenance.
• Heavy duty: where 2 general purpose and two light duty platforms are used. Example for masonry work.
The precautions that should be taken when using a ladder as a means of access to the scaffold:
• Ensuring suitability of the ladder (regarding type, length, free from damage, etc.). • Securing the ladder.
• Use of the ladder on a firm and level ground.
• Safe position of the ladder (e.g.: away from traffic routes). • Correct height to base ratio of 4: 1
• Area at base to be kept clear of obstruction, mud, etc. • Platform at top to be kept clear of obstruction.
• Ensuring removal at the end of the day. Exercise 4
Outline FIVE factors that may contribute to the collapse of an independent tied scaffold.
Answer 4
The factors that may contribute to the collapse of an independent tied scaffold: • Incorrect design or assembly.
• Unstable foundations (unconsolidated ground, close proximity to excavations, inadequate sole plates & base plates).
• Unauthorized alteration (e.g.: removal of ties). • Overloading of platforms.
• Adverse weather conditions (as wind, rain, etc. (rain can affect base stability). • Collision by vehicles.
Exercise 5
Outline precautions that could be taken to prevent materials falling from a scaffold whilst work is being carried out.
Answer 5
Precautions that could be taken to prevent materials falling from a scaffold while work is being carried out.
• The close boarding of platforms.
• The provision of toe boards, brick guards, nets, etc.
Exercise 6
What are the main hazards associated with the use of ladders at work and how to avoid these hazards.
Answer 6
The main hazards associated with the use of ladders at work:
• Falling hazard: due to slipping or due to insecure ladder (on top and/ or base). • Falling materials over passers by (due to no guarding of area, no signs, etc.). • Electrical hazard: due to placing metallic ladders or wet wooden ladders near power
lines.
• Collision of ladders by vehicles: if the area is not guarded. • Weather hazards as heat, cold, etc.
How such hazards may be avoided:
• Before using ladder be sure it is free from slippery substances. • Guarding of the work area & the use of signs & markings.
• Make sure ladder is firmly secured (tied at top, secured at bottom or footed by a second person if no more than 3 meters height access is required).
• Ensure correct slope of ladder (750 angle) corresponding to a ratio of 4:1.
• Ensure that rungs are level and free from defects.
• Metallic ladders & wet wooden ladders to be away from power lines. • Ensure that ladders are regularly inspected & maintained.
• Use of the required PPE.
Exercise 7
Describe the features that you would look for in properly elected scaffolding.
Answer 7
The features that you should that look for in properly erected scaffolding are: Correct design with adequate load bearing capacity, adequate foundations, structures should be erected by competent persons, all working platform edges should be adequately protected. (by toe boards, net, handrails, etc.), safe stacking of all materials resting on platforms, no overloading of platforms, working platforms provided with safe means of access, and check inspection records to ensure regular inspection.
Exercise 8
What is meant by "independent scaffolding"?
Answer 8
Independent scaffolding: is a scaffolding independent of the structure to which access is required. It has many types:
• Independent tied scaffold: which are tied to the structure for stability (for example to a window) .
• Independent mobile towers: which are towers formed with scaffold tubes and mounted on wheels. They have single working platforms with hand rails and toe boards all around.
Exercise 9
Outline the precautions to be taken when contractors are carrying out work on a fragife roof.
Answer 9
• The use of roof ladders or crawling boards. As an absolute minimum, 2 ladders or boards are needed. (never step onto a fragile roof).
• The fragile area is to be covered and the cover should extend minimum of 1 meter up the roof.
Exercise 10
Describe the precautions necessary for the safe use of a mobile access tower.
Answer 10
Precautions for safe use of mobile towers:
• Erection should be in accordance with manufacturer's recommendation. • Erection, alteration &dismantling to be done by competent persons. • It should stand on a firm level base.
• Scaffold tubes to be free from defects e.g.: bent sections. • Proper bracing to prevent twisting and collapse.
• The ratio of the minimum base dimensions to the height should not exceed: 1:3 in external use & 1:3.5 in internal use.
• The maximal height of tree standing tower is 9.75 meters. • The maximal height of tied tower is 12 meters.
• A safe means of access to be provided on the narrowest side of the tower "as vertical ladder attached internally".
• Platforms should be properly supported and fully boarded.
• Toe boards &guard rails to be provided to prevent falls of workers and/ or materials. • Ladder or stepladders should not be placed on the platform to gain extra height for
working.
• Tie the mobile tower if:
The scaffold is likely to be exposed to strong winds. The tower base is too small for the height.
The tower is to be used for operations like: • Grit blasting.
• Heavy drilling. • Water jetting.
If necessary to lift materials & equipment up . • On using a mobife tower, make sure the castors are locked.
• Toe boards & guard rails are to be provided for a platform of more than 2 meter height. The guard rails should be 3 feet above the platform.
• Before moving tower, be sure no power lines, obstructions, holes in the ground, etc . • Push the tower from the base.
Exercise 11
Outline the precautions that may be needed when carrying out repairs of the flat roof of a building.
Answer 11
-Provision of safe access to the roof: by scaffolding and/or ladder. -Edge protection: to prevent falling of people and / or materials.
-Barriers around the area below the roof to prevent access to the area. -Netting under the roof is sometimes required.
-Means of transporting materials to and from the work area.
-Protecting workers from weather conditions as sun, rains, winds, etc.
-The proper positioning and the safe use of hazardous equipment as: bitumen boilers &gas cylinders.
-Special Measures for fragile roof. Never foot on fragile roof directly. Use roof ladder or crawling boards. (these are to be laid across the roof surface).
-Wearing the suitable PPE (harness is required in addition to other PPE items as helmet, gloves, safety shoes, overall, etc.).
Exercise 12
Woodwork on the exterior of a two-storey office building is to be repaired during July this year. Preparation work will be carried out from a mobile tower scaffold using below lamps, scrapers and an electrical hand-held sander.
1) Identify the measures that should be adopted in order to protect against the danger of people and / or materials falling from the scaffold.
2) Outline the practical measures to reduce the risk from electricity when using the portable sander.
3) List four other hazards arising from the preparation work and for each hazards, state the possible means of protection.
Answer 12
1) The measures required are:
• Erection of scaffold should be in accordance with the manufacturer's recommendation. • Erection of scaffold to be done by competent persons.
• Barriers (by tape for example), warning signs and flash light around the work area. • Scaffold should rest on firm level ground.
• Scaffold tubes to be free from defects.
• Proper bracing to prevent scaffolding collapse. • Castor wheels to be locked while working.
• To tie the mobile tower if there are winds or if using heavy materials or equipment. • To be of a safe height: not to exceed: 9.75 meter for mobile towers & 12 meters for
tied towers.
• Safe ratio of base dimensions to height: 1:3 in internal use & 1:3.5 in internal use. • Use of safe ladders; of sound rungs, with no slipping hazards and the ladder is to
properly secured .
•. Toe boards and guard rails to be adequate enough to prevent persons and materials falling.
• Close boarding of platform.
• Never move the tower while people and / or materials are still on platform. • Good housekeeping of materials on the platform.
2) The practical measures to reduce the risk from electricity:
• Use certified suitable sander free from any defects with CE quality mark. • Check the cable condition and connections.
• Use double insulated cable with impact proof cover/water proof cover. • Use low voltage (11 Qv).
• Fit protective device as residual current breaker (CB) or fuse. • If possible use battery powered equipment (to avoid electrical risk).
• Earthing: to connect the equipment to earth so that in fault conditions, earth will constitute the least resistant pathway for current.
• Regular inspection and maintenance of equipment. • Proper storage of the equipment.
• Use the proper PPE.
3)
Hazard Precautions
*Heat hazard: due to working under -Reduce time of exposure.
the Sun -Frequent rest breaks in a shady area.
-Wear suitable clothes and wear caps or helmets. -Sufficient fluid & salt intake.
*Manual handling hazard: due to -Mechanical handling (as by the aid offorklifts). lifting paint materials. -Team handling.
-Use of proper PPE (as cloth glove).
-Training workers about good kinetic handling techniques.
*Ergonomic hazards: due to -Proper work station design. awkward postures during painting. -Safe system of work.
-Workers training & supervision at work. -Task to be interrupted by rest breaks.
*Exposure to asbestos & or lead: -Identification & segregation of Asbestos materials. while removing old paints. -Use of appropriate PPE (respirator with dust
cartridge).
*Paint health hazards: as dermatitis, -Use of protective clothes and required PPE (as rubber asthma, effects on central nervous gloves, masks, etc.)
system, dizziness, etc. -Reducing time of exposure.
*Fire and explosion: due to hot work -Avoid hot work as cutting, grinding, welding, etc. close or ignition source close to painting. to painting.
-Exclusion of all ignition sources (including smoking) in painting area.
Exercise 13
Doing repainting work using tower scaffold, outline: 1. The likely hazards of this operation.
2. The required control measures to avoid risks from this operation.
Answer 13
Tower scaffolds are towers made with scaffold tubes and having a single working Platform accessible by a ladder. It is commonly used for painting and simple maintenance jogs on buildings. It can be used mobile as it is or ties to the building:
The likely hazards are:
• Health hazards due to exposure to paint: leading to dermatitis, asthma, effects on central nervous system, dizziness, etc. Also lead hazards due to removal of old paints. • Ergonomic hazards: due to awkward posture & movements during painting.
• Manual handling hazards: due to carrying heavy cans & other instrument. • Heat hazards: due to working under the Sun .
• Falling hazards: due to:
• The use of unsafe ladder.
• Improper boarding of the platform.
• Collapse of the tower due to many reasons (improperly erected tower, doing unauthorized alterations, use of defective scaffold tubes, or erection on non firm & non level ground).
• Collision with power line &other obstructions.
• Falling of materials (if toe boards &guard rails are inadequate).
The precautions:
• Erection of the tower scaffold should be in accordance with manufacturer's recommendations.
• Erection, alteration and dismantling of tower scaffold to be done by competent persons .
• Tower scaffold should stand on a firm level base. • Scaffold tubes to be free from defects.
• Proper bracing to prevent twisting & collapse.
• Base dimensions to height should not exceed: 1:3 in external use & 1:3.5 in internal use.
• The maximum height is: 9.75 meters for free mobile tower & 12 meters for tied tower. • Tower should never be moved while people or materials are still on the platform. • Platform should be properly supported & fully boarded.
• Toe board & guard rails to be provided to prevent falling of workers and / or materials. • To make sure that castors are locked.
• Before moving tower, be sure no power lines / obstructions or holes in the ground. • Training of painters about how to work safely.
• Use protective clothes and PPE during painting (as gloves, suitable overall, face shield, respirator).
• Good supervision of the painting process . • Good communication.
• Stand-by first aid and emergency services.
Waste
Exercise 1
Outline the issues that should be considered by an organization to ensure safe system of work on dealing with waste collection & disposal.
Answer 1
For collection of waste, consider the following:
• Risk assessment to identify the hazards associated with waste collection. • Collect waste at regular basis and avoid its accumulation.
• Use waste containers of sufficient number, of a suitable material and of adequate size and to be positioned in accessible locations with signs referring to it.
• Avoid overfilling of waste containers.
• Waste container to be easily opened and to be securely closed to avoid attraction of flies, insects, etc.
• Proper selection and training of workers dealing with waste collection. • Health surveillance for workers dealing with waste collection.
• Provision of required PPE for workers involved in waste collection.
For disposal of waste, consider the following:
• Use the method of disposal suitable for the waste type (as incineration for papers, etc. and composting for food waste).
• Assess the chemical and effective load of the waste. • Monitor the environment (pre and post disposal).
• Waste disposal work permit is required for some special wastes.
• Safe method for dealing with by-products of waste disposal (as dumping of ash resulting from incineration).
• Use of property trained personnel for waste disposal. • Health surveillance for disposal workers.
• Stand-by emergency equipment for events as fire, etc. • Use of the required PPE by disposal workers.
Regulations concerned with waste are:
• Waste Management Licensing Regulation 1994. • Special Waste Regulation 1996.
Control Measures
Exercise 1
While dealing with any question asking for "Control Measures": always remember the hierarchy of control measures:
Answer 1
• Elimination • Substitution.
• Engineering controls (including work permit) • Administrative Controls
o Reduced time of exposure. o Training.
o Safety signs.
o First aid and emergency measures. o Health surveillance.
o Use of PPE.
Exercise 2
The key items as how to deal with any hazard question:
Answer 2
According to the work activity performed: • If the work is outdoor, consider:
Weather hazards as heat, cold, rain. Bite by animals, snakes, insects, etc. • If work is at the roadside, consider:
Collision by vehicles.
• If the work is dealing with grass or other plants consider: insect bites. • If the work is dealing with water (as fro cleaning canals), consider:
Drowning hazard. Trench foot hazard.
Leptospirosis (Weil's disease)
• If the work is requiring manual handling (as lifting painting cans, cleaning material, etc, etc.) consider: manual handling hazard.
• If doing tasks as painting, floor cleaning, keyboard use, assembly work, etc., consider: Ergonomic hazard.
• If an equipment is used, consider: Equipment hazards (mechanical & non mechanical) • If the equipment used is petrol driven, consider:
Carbon monoxide hazards. Nitrogen oxides hazards.
• If the equipment used is electrically operated, consider: electrical hazards. • If a chemical is used (as a solvent), consider:
Health hazards as dermatitis, asthma, effects on central nervous system, dizziness, etc.
Safety hazards as fires, explosives, etc. • If the work is at height, consider:
Falling hazard of individuals. Falling hazard of materials.
• If there is a risk of infection (as on dealing with refuse, sludge, etc.) consider: biological hazards .
• If working in a confined space, consider:
Atmospheric hazards (as lack of oxygen or toxic frames). Entrapment.
Biological hazards. Equipment hazards. Manual handling hazards . • On doing repainting, consider:
Hazards due to removal of old paint: as lead exposure.
Hazards of painting (as health hazards, fire, explosion, manual handling, ergonomic and weather hazards).