Construction Site Safety Ergonomics
Construction Site Safety Ergonomics
Course Objective At the end of this course, learners should know: ● ● ● ●
The definition of ergonomics The 5 common ergonomic hazards The main injuries Practical ways to avoid injuries
Definition ● Study of the relationship between people and their working environment, especially the equipment they use (dictionary.com) ● Study of the physical abilities and limitations of the human body in relation to work tasks; tools, equipment, and materials; and the job environment. 5 Common Ergonomic Hazards1 1. Repetition – same tasks using the same muscles, e.g. shoveling, painting 2. High Force – high muscle engagement, e.g. heavy lifting, gripping, pushing items 3. Awkward postures – holding body in a poor position, e.g. overhead work, reaching, bending, twisting, squatting 4. Contact stress – object is pushing into soft body tissues, e.g. knees on hard flooring, forearm on sharp corners, hand tools pressing into palms 5. Hand-Arm Vibration, e.g. from power tools
Main injuries Among construction workers, injuries are common in the following areas of the body: ● Lower back (Disc herniation) ● Knee (Bursitis and tendinitis) ● Shoulder (Tendinitis, Rotator cuff tear) ● Hands and wrists (Tendinitis, Carpal tunnel syndrome) ● These injuries are referred to as musculoskeletal disorder (MSD) ● They start with minor discomfort – different from injuries from slips, falls, cuts, or electrocution which are immediately painful! ● Good ergonomics prevents injuries and helps to work more efficiently 1
Washington University School of Medicine in St. Louis, Toolbox Talks on Ergonomics, https://oshr.wustl.edu/for-employers/toolbox-talks-on-ergonomics/
Construction Site Safety Ergonomics How to prevent musculoskeletal disorder: ● ●
Recognize hazards in your tasks – What is uncomfortable or difficult? Try solutions that make tasks easier
Reaching2 ● ● ●
Reaching involves shoulders, low back, arms and hands Reaching with elbow extended risks straining the shoulder and low back Shoulder is very mobile – prone to injury!
Keep your reach close! Try to keep hands below your head and arms close to your body ● When working overhead o Elevate yourself or move ladder to get closer to the work area o Keep work areas clear of obstacles so ladders / equipment can be moved easily o Limit time for overhead work without a break o Use telescope extensions where possible ● Remind colleagues of their positioning ●
Table 1 Examples for Reaching
Trade Carpenter Drywall Floor Layer Sheet Metal Worker
2
Reaching (Awkward Posture) Hazards Operating a screwdriver overhead with the arm fully extended and the wrist bent. Spreading adhesive using a hand trowel with the arm fully extended out to the side and the wrist bent. Prepping duct parts on the floor while bending (the back) and reaching to work on them.
Washington University School of Medicine in St. Louis, Toolbox Talks on Ergonomics – Keep Reach Close: https://oshr.wustl.edu/wp-content/uploads/2020/04/TBT2_Keep-Reach-Close_TBT_5-21-14.pdf
Construction Site Safety Ergonomics
Positioning3 Get closer to the task o Green Zone: keep usual work tasks as far out as your wrists o Orange Zone: keep occasional work tasks as far as your fingertips o Red Zone: limit time you reach beyond your fingertips! ● Prop up your tasks off of the floor o Use a raised surface, cart, H-frame scaffold, saw horses to prep materials near waist height o Avoids kneeling (which can hurt the knee) and bending over (which puts stress on the lower back) ●
Table 2 Examples for Positioning
Trade Carpenter Drywall
Floor Layer
Sheet Metal Worker
3
Awkward Posture Hazards Leaning over the side of a scissor lift to reach and operating a screw gun with the arm fully extended (reaching in the red zone past the fingertips). Spreading mortar overhead on a wall with the H-frame scaffold one foot away from the wall due to buckets on the floor below (reach in the red zone, past the fingertips). Prepping duct parts on the floor while bending the back and reaching to work on them.
Potential Solution Before starting to install the line of screws to the side of the lift, move the lift to recenter it for the next 2 lines of screws to be installed. Pre-plan this task by removing all objects in the path of the H-frame scaffold. Having an open path allows you to work closer to the task. Pre-plan this task by setting up a waist-height workstation on extra materials, a cart, or saw horses.
Washington University School of Medicine in St. Louis, Toolbox Talks on Ergonomics – Positioning: https://oshr.wustl.edu/wp-content/uploads/2020/04/TBT3_Positioning_TBT_5-21-14.pdf
Construction Site Safety Ergonomics
Moving Materials4 ● ●
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Work smart! DOLE weight lifting standards (1412.07): o Male workers: no more than 50kgs o Female workers: no more than 25kgs o Handle heavier loads in teams by mechanical means. Lifting, Holding, handling, materials o Don’t reach more than 10 inches away from your body when you pick up or set down a load. o Don’t twist your body under load. o Lift with your legs, not your back. Keep your back as straight as possible. o Lift the load using a solid two-handed grip. Use moving assist when handling heavy loads! o Wheeled cart to reduce carrying, take less trips o Keep floor clear of obstacles to move freely and avoid trip hazards Work in a team! Stretch and warm-up before working.
Table 3 Examples for Moving Materials with Assist
4
Trade Carpenter Drywall
Hazards Carrying a big sheet of drywall without an assist.
Floor Layer
Transferring multiple cartons of ceramic tile from a staging area to the installation area.
Sheet Metal Worker
Lifting a large, round duct piece overhead without an assist.
Potential Solutions 1. Work with a partner to lift drywall 2. Consider the use of a drywall lift device. 1. Prepare! Deliver pallets of materials close to the work area to reduce moving them. 2. Use a rolling dolly cart to transfer the boxes and reducing carrying. 1. Work with a partner when lifting large, heavy, or bulky objects. 2. Use a duct lift to position the duct piece overhead and hold it
Washington University School of Medicine in St. Louis, Toolbox Talks on Ergonomics – Move Materials with Assist: https://oshr.wustl.edu/wp-content/uploads/2020/04/TBT4_Move-Materials-with-Assist_TBT_5-21-14.pdf
Construction Site Safety Ergonomics in place while the worker installs it.
Selecting Hand Tools5 ● ●
The right tools for the job protect your hands, wrists and elbows! Does the tool: ● Fit the task? Use chisel instead of screwdriver when chiseling! ● Allow for a good grip? 🡪 Make sure handles of pliers are not too wide or narrow; and that handles have non-slip grip. ● Keep your wrist in a straight posture? A bent wrist has less grip strength. Some tools have offset handle, to keep the wrist straight! ● Feel comfortable? Tool should not cut or press into the hand, and it should not feel too heavy. ● Take less effort than other tools for the task? Pick a tool with a long handle to get better leverage. ● Work effectively? A sharpened, greased, and well maintained tool makes the job easier!
Working with Power Tools6 According to the Philippine Department of Labor and Employment’s (DOLE) OSH Standards, power tools “refer to any hand or portable tools which are driven pneumatically, or by electricity, mechanical means, or explosive charge” ● Examples include: o sledge hammer o jack hammer o drilling machines o soil compactors o chainsaws ●
Washington University School of Medicine in St. Louis, Toolbox Talks on Ergonomics – Manual Tools: https://oshr.wustl.edu/wp-content/uploads/2020/04/TBT5_Manual-Tools_TBT_5-21-14.pdf 5
6Washington
University School of Medicine in St. Louis, Toolbox Talks on Ergonomics – Power Tools:https://oshr.wustl.edu/wp-content/uploads/2020/04/TBT6_Power-Tools_TBT_5-21-14.pdf
Construction Site Safety Ergonomics ● ● ●
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Power tools generate vibrations that can damage blood vessels and nerves in hands when used over a long period of time The higher the vibration level, the shorter the time it should be used Indicators for injuries or hand-arm-vibration-syndrome (HAVS): o Numbness and tingling in the fingers o Discoloring of fingertips o Loss of grip strength Injury prevention: o Use “reduced vibration power tools” o Use certified full-fingered anti-vibration gloves o Use a grip as light as light as possible on power tools to reduce vibration exposure o Don’t use power tools over an extended period of time o Check vibration information for each tool and use a vibration exposure calculator to compute safe working time o Maintain tools – blunt, un-aligned tools will vibrate more
The information have been obtained from the following sources: NIOSH Simple Solutions: Ergonomics for Construction Workers, 2007, https://www.cdc.gov/niosh/docs/2007-122/ ● Washington University School of Medicine in St. Louis: Toolbox Talks on Ergonomics, https://oshr.wustl.edu/for-employers/toolbox-talks-onergonomics/ ●