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Build it Better: Construction Ergonomics

Work design tips,

recommendations, and best practices

Edison Electric Institute Occupational Safety & Health Committee Conference, Fall 2016

Carolyn M. Sommerich, PhD, CPEThe Ohio State University

College of Medicine - School of Health and Rehabilitation Sciences

College of Engineering - Department of Integrated Systems Engineering

Discussion Points

• Ergonomics - what’s that?

• Construction ergonomics

– Worker health and safety statistics

– Know your workers

– Injury risk factors

– Interventions - work design tips, recommendations, & best practices to reduce risk factor exposure

What is Human Factors/ Ergonomics?

• Human factors/ergonomics is a body of information about human abilities, limitations, behaviors, and other human characteristics that are relevant to design.

• Human factors engineering is the application of human factors information to the design of tools, machines, systems, tasks, jobs, and environments for productive, safe, comfortable human use.

modified from Chapanis (1996)

Key premise of HF/E

• A key goal, when applying ergonomics principles, is to design systems and tasks well within the capacity of the humans that will use them…

If ( task requirements ≥ human capacity )

Then adverse outcomes are more

likely to occur,

such as… reduced productivity, increased injuries, reduced quality, increased turnover, etc…

Potential benefits of applying HF/E principles

• increase safety

• improve system performance

• increase reliability

• improve maintainability

• improve the working environment

• increase human comfort

• increase ease of use

• increase user acceptance

• increase aesthetic appearance

• reduce turnover

• increase compliance

• increase economy of production

• reduce errors

• reduce personnel requirements

• reduce training requirements

• reduce fatigue and physical stress

• reduce boredom and monotony

• reduce losses of time and equipment

Adopted and modified from Chapanis, A. (1996). Human Factors in Systems Engineering. New York: John Wiley & Sons, Inc.

Example…

Design Problem Case 1:

• Symptom: Shrek performers at Universal Orlando had issues with shoulder, neck, and lower back pains. Costs: 21 first aid cases, 26 recordable injuries, 622 light duty days, and 49 restricted/lost work days from June 2004 to March 2006 with a direct cost of over $80,000.

• Root cause: issues identified were weight of the costume, body positioning in the costume, ventilation, and visibility.

• Intervention: Redesign costume - cost $1700 labor and materials

– Weight reduction: redesign harness with lighter materials; eliminate unnecessary layers (10 lb savings)

– Improve body posture: separate head from the body to allow movement and balance weight inline with the spine (also aids neck mobility and visibility)

– Improve ventilation: add opening at back of the head to allow for air flow assisted by a battery powered pancake fan. The separation of the head (and added mobility to move the neck) increased visibility.

• Intervention: Redesign costume - cost $1700 labor and materials

– Weight reduction: redesign harness with lighter materials; eliminate unnecessary layers (10 lb savings)

– Improve body posture: separate head from the body to allow movement and balance weight inline with the spine (also aids neck mobility and visibility)

– Improve ventilation: add opening at back of the head to allow for air flow assisted by a battery powered pancake fan. The separation of the head (and added mobility to move the neck) increased visibility.

• Outcome: 0 injuries & 0 lost time after March 2006 implementation

Relevance to construction?

Occupational safety: & ergonomics:Recognize - Evaluate - Control

• Recognize– Workplace hazards

• Evaluate hazard exposure and risk – What concentration, for how long, and how often

• Control hazard (hierarchy)

– Eliminate/remove hazard/risk factor

– Engineering controls• Make changes to workplace, equipment, task, methods,

product design, etc.

– Administrative controls• Reduce exposure duration

• PPE, training

Approach to

Occupational safety & ergonomics:Recognize - Evaluate - Control

• Evaluate hazard exposure and risk– What concentration, for how long, and how often

• PPE, training

Approach to

• PPE, training

Approach to

• PPE, training

Approach to

Work System Components

Methods

OrganizationEnvironment

Workers

Tools and Equipment

Product, performance,…

Worker health outcomes

Physical ergonomics -some useful characteristics to

know about people…

• How they are affected by environmental conditions

• Fatigue/endurance limits

• Anthropometric characteristics

• Muscular strength

• Sense capabilities (hearing, touch, sight)

• Dexterity

know about people…• How they are affected by environmental conditions

• Dexterity

• And how these vary across a work force…

• Dexterity

• And how they change with age…

Ergonomics -some useful characteristics to

• Dexterity

• And how they change with age…

• And how personality, cognitive, and psychosocial factors interact with all of these

Psychosocial perceptions - some examples

for construction employees

Sloan Center on Aging & Work: Talent Pressures and the Aging Workforce: Responsive Action Steps for the Construction Sector, 2010

Who works in construction?

9.3% of workers in

construction are

female; about

200,000 women work

in production

(laborers, trades, etc.)

29% of workers in construction

are Hispanic/Latino.

Mean age of construction workers is

42.6 years of age; 14.5% are over 55.

Recognizing differences in characteristics

Men & Women & Body Size

Source: KHE Kroemer et al, 1997, Engineering Physiology: Bases of Human Factors/Ergonomics.

Height

Hand Length

Forward Grip Reach

Overhead Grip Reach

Forward

Overhead

Ethnicity & Body Size

Source: Centers for Disease Control, National Health Statistics Reports, 2008

Average height

Recognizing differences in characteristicsAccommodating differences in body size

Example in practice:

• Drywall stilts, to allow shorter employees to get closer to work without use of ladder

Recognizing differences in characteristicsAccommodating differences in body size & shape

• PFAS designed for women

•Provide gloves in multiple sizes

Men & Women & Strength

Female Body Strength, Compared to Males

Men & Women & Strength & Aging

* Compared to a 24 year-old male

Recognizing differences in characteristicsAccommodating differences in strength

• Use powered vacuum lift for heavy lifting

Before

Vision & Aging

• Beginning in mid-40’s for many adults, normal effects of aging include…

– Need for more light to see well

– Difficulty with near vision (presbyopia)

– Glare sensitivity increases

– Changes in color perception

– Reduced tear production

Recognizing differences in characteristicsAccommodating differences in visual capabilities

• Provide additional sources of light

Recognizing differences in characteristicsPersonal health

BMI = 703 x weight (lbs)(ht (in))2

25<BMI<29.9 30≤BMI

Weight statistics are similar to population as a whole: 69.2% of US adult pop. is overweight

(CDC, Health, US, 2012).

Obesity and smoking are risk factors for occupational injury

Energy requirements for task performance increase with weight. Smoking decreases endurance and physical performance.

Work System Components

Methods

OrganizationEnvironment

Workers

Tools and Equipment

Product, performance,…

Worker health outcomes

Worker capabilities and limitations Systems view of work - components and interactions •Recognize•Evaluate•Control

Recognizing workplace hazards

• Injury statistics

• Research studies

• Assessment tools

• Safety experts

• Employee insights

2014 BLS Injury statistics

Non-fatal

2012 BLS Injury statistics

Non-fatal

20142014

Recognize through Research:Relevant to slips, trips, falls in construction

From the literature, concerning Personal Fall Arrest System (PFAS) usage:• Some workers are not supplied with PFAS (Cattledge et

al. , 1996)

• Work environment does not allow the use of PFAS (Cattledge et al., 1996)

• e.g. no tie-off point

• From workers’ perspectives it reduces productivity and makes them uncomfortable (Sa, 2005)

• Lack of fall protection training and company’s enforcement (Janiack, 1998; Johnson et al. , 1998)

Recognize through Research:Relevant to slips, trips, falls in construction

Recognize through Research:Musculoskeletal injuries due to overexertion

and other causes

Identified risk factors:Excessive force

Excessive repetitionAwkward postures

Lack of restVibration

Recognize through Assessment Tools:Musculoskeletal injuries due to overexertion

and other causes

Identified risk factors:Excessive force

Excessive repetitionAwkward postures

Lack of restVibration

Evaluation methods include tools such as:•NIOSH Lifting Equation•ACGIH TLVs for lifting and hands•Checklist tools (QEC, etc.)…..

Vibration

Vibration - recognition of adverse effects on health

• Hand-arm vibration is associated with:– Vibration White Finger (VWF) / Hand-Arm

Vibration Syndrome (HAVS)• Prevalence higher with…

– increased age,

– exposure to higher levels of hand-arm vibration (HAV),

– exposure to colder climate in those exposed to HAV Burstrom et al. 2010

– Carpal Tunnel Syndrome (CTS)

• Whole-body vibration is associated with:– Circulatory, bowel, respiratory, muscular and back

disorders

– Fatigue, insomnia, stomach problems, headache, …

Vibration - recognition of effects on grip strength

Vibration

Images from http://resource.isvr.soton.ac.uk/HRV/VIBGUIDE.htm

WBV relevant frequencies: 0.5 to 80 Hz

HAV relevant frequencies: 5 to 1500 Hz

Hand-Arm VibrationEvaluation

• Vibration total value

• Daily vibration exposure, A(8)

– When using one tool:

– When using more then one tool:

EU Guide to good practice on Hand-Arm Vibration, v7.7, 2006

T=daily exposure duration;

T0 = 8 hrs

• Example:

grinder chipper

vibration emission, m/s2 7 16

use, hr/day 2.5 0.25

A(8), each tool 3.9 2.8

=7*sqrt(2.5/8) =16*sqrt(0.25/8)

A(8), total exposure 4.8

• Example:

grinder chipper

A(8), each tool 3.9 2.8

=7*sqrt(2.5/8) =16*sqrt(0.25/8)

• Example:

grinder chipper

A(8), each tool 3.9 2.8

=7*sqrt(2.5/8) =16*sqrt(0.25/8)

Vibration - Evaluation tools

• Hand-arm vibration

– Look it up

• Tool databases

– Measure it

– Factors that can affect HAV

• Type of tool, tool condition, materials, etc.

Vibration - controls for HAV• Substitute – mechanization, automation

• Equipment selection –

– Right tool for the job

– Procurement policy

• Check tool’s vibration emission value and assessment method

• Check that tool’s exhaust does not blow on hands

• Tool maintenance

• Review work methods

• Work schedule (job rotation, piece rate, …)

• Training

• Worker input

• Use caution: Rubber or other resilient materials wrapped around tool handle can actually amplify vibration

Vibration - controls for HAV• Anti-vibration Gloves

• Hewitt et al.’s conclusions about AV gloves:– Unreliable devices for controlling vibration exposure

– Generally cannot reduce vibration exposure from low-frequency tools

– Can somewhat reduce frequency-weighted vibration transmission to palm of hand from powered hand tools, but not to fingers

– Often adverse “ergonomics” response occurs when wearing AV gloves

Controls for other risk factors in Construction

National Institute for Occupational Safety & Health, 2007

Available as pdf or webpages

Controls to reduce force

Kneeling Creeper with Chest

Support

Mechanical LiftsAfterBefore

Pneumatic Drywall Finishing

Powered Caulking Guns

Before After

Before

Skid Plate for Hose Pulling

Before

Controls to reduce awkward postures

Stand-Up Screw Gun

Rebar-Tying Tool

Before

Overhead drilling: Inverted drill press

Before

Offset Tool Handles

Upright Snips

AfterBefore

Controls to reduce slip, trip, fall hazards

• Worker & management engagement

• Housekeeping• Staging locations• Clear, designated walkways• Cords and hoses• Lighting• Use appropriate, intact devices for elevating workers• …

• For work ≥ 6’, appropriate safety devices and measuresDuty to have fall protection. - 1926.501

• Work shoes with non-skid soles

Diagram by Karn G. Bulsuk (http://www.bulsuk.com)

Handtool Selection Tips

General suggestions:• Use a tool rather than the hand.• Use a fixture rather than a hand.• Use a power tool if possible, if force exertion is required

repeatedly or for extended duration, but address the added weight.

• Use tools appropriate for right and left handers.

• Tool handles should be:o non-slipo non-sweato shock attenuatingo temperature insulated

• Tool handle shape and size:o Span (7.5-8.5 cm)o No digital profiling (no finger ridges)o Long, to avoid digging into palmo Try T-bar in place of screwdrivero Cylinder dia: 3-5 cm.

• Tool properties:o To reduce force

• Minimize weight• Center of mass: for power tool it should be over the hand; for

striking tool it should be near head• Provide auxiliary handle for heavy tools, awkward positions• Provide articulating arms, balancers

• To reduce awkward postures• Bend tool handle• Change orientation of part• Provide arm rests

• To reduce temperature extremes• Control direction of power tool exhaust • Insulate handle• Provide gloves

Intervention resources Construction ergonomics

• Ohio BWC

– Ergonomics Best Practices for the Construction Industry

– Safety Grant Program

• NIOSH

– Constructionhttp://www.cdc.gov/niosh/construction/

– Highway work zone safety - construction equipment visibilityhttp://www.cdc.gov/niosh/topics/highwayworkzones/BAD/

– Simple Solutions for Construction Workershttp://www.cdc.gov/niosh/docs/2007-122/

• CPWR - Center for Construction Research and Traininghttp://www.cpwrconstructionsolutions.org/

Intervention resources Vibration

• US Army Public Health Command Vibration Pocket Guidehttp://phc.amedd.army.mil/PHC%20Resource%20Library/VIBRATION_POCKET_GUIDE_06_17_2013.pdf

• University of Southamptom Institute of Sound and Vibration Research– Good practice guides for HAV and WBV

http://resource.isvr.soton.ac.uk/HRV/VIBGUIDE/HAV%20Good%20practice%20Guide%20V7.7%20English%20260506.pdf

http://resource.isvr.soton.ac.uk/HRV/VIBGUIDE/2008_11_08%20WBV_Good_practice_Guide%20v6.7h%20English.pdf

• UK Health & Safety Executive - Vibration at work– Explanation, exposure calculator, exposure limits guide, case study-based solutions guide

http://www.hse.gov.uk/vibration/

• Various powered handtool databases– NIOSH - http://wwwn.cdc.gov/niosh-sound-vibration/

• usage hint - pass mouse/cursor over column headers to read definitions

– Umea Universitat - http://www.vibration.db.umu.se/HavSok.aspx?lang=en

Intervention resources Ergonomics at OSU

• Faculty & Labs

– Engineering Laboratory for Human Factors/Ergonomics/Safety

– Orthopaedics Ergonomics Laboratory

– Spine Research Institute

– Institute for Ergonomics

• Students

– Capstone

– Internships/co-op

– Research practicum, thesis, dissertation

www.ise.osu.edu

Concluding points

• Ergonomics applied in construction - good timing as construction workforce becomes more diverse

• Analyze work as a system of interacting parts, in hazard analysis and in intervention ideation

• Useful information on HAV and WBV is available on the web, through reliable sources

Thank you!

Carolyn Sommerich

Engineering Laboratory for Human Factors/Ergonomics/Safety

The Ohio State University

Email: sommerich.1@osu.edu

Call: 614-292-9965

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