1. Avoiding Injury Through Human-Capable Design
USACHPPM Ergonomics Program
Avoiding Injury Through Human-Capable Design
Author
Don Goddard, M.S., RPT
US Army Center for Health Promotion & Preventive Medicine
Presenter
Mark Geiger, M.S.E., CIH, CSP
Chief of Naval Operations N09FB
Safety Liaison Office, Arlington, VA

2. Ergonomics and materials handling
A key area for acquisition planning
Human Systems Integration (HSI) is a part of acquisition requirements (DoD5000.2)
Source of many mishaps and occupational illnesses
Potential approach to improving safety and reducing manpower
New acquisition project for improved ordnance loading initiated. Someone thought about the airplane, someone thought about the bomb, but there was not the connection between the two. Note the cart below does not have simple lift device that would eliminate this posture. The four airmen are using a device called the “hernia bar”.

3. ERGONOMICS AFFECTS THE NAVY Other Services Likely to be Similarly Impacted
Exposure 9%
Ergonomic
37%
Hearing 4%
All Others
15%
Falling
Objects 2%
Vehicle
Accidents 3%
Slips
16%
Falls
10%
Mental
Stress
FECA FY99:
Ergonomic injuries and illnesses*
Represent the single largest source of claims and costs to the Navy
Roughly $90 million annually or one-third of all recent claims
If left unchecked, the Navy’s annual cost is
Projected to increase to $111 million by FY 2009.
* Analyzing the Navy’s Safety Data by CNA, December 2001

4. What is Human-Capable Design?
Creating products that expose users to less mechanical stress in order to:
Decrease risk of operator injury
Increase operator performance (efficiency)
Allow operators to safely and comfortably interact with products longer
Helicopter seating is a key issue in performance and mission duration because of a combination of vibration and seat design relative to operator dimensions.

5. How is this accomplished now?
System Safety reviews:
Conducted during design phase of the product development cycle
Strive to identify and mitigate injury risks before products are deployed
Alternative is expensive retro-fits

6. System Safety and Human Systems Integration (HSI)
Both require risk identification
System safety has focused on risks to systems
Human Systems Integration focus on design for user

7. How is this accomplished now?
System Safety reviews tend to rely upon standardized System Safety methods and techniques
Tendency to focus on equipment failure
Considers risk of injury to human
May not optimize design to avoid features that compromise human performance

8. System Safety Methods & Techniques
Methods & Techniques Employed
Preliminary Hazard Analysis
Failure Mode and Effect Analysis
Fault Tree Analysis
Management Oversight & Risk Tree
Energy Trace and Barrier Analysis

9. System Safety Methods & Techniques
Struggle to Capture the “Human Side”
Analyses are not structured in a way that obligates users to consider long term effects on human operators
Tend to be “product-oriented” at the expense of the human system component
Deficiencies force users to make assumptions about injury risk

10. System Safety Methods & Techniques
Typical Product Specification
Product-Oriented Description
Hand Winch
Lift capacity: 1.1 tons
Rope capacity: 85 ft
Operating force requirements: 54 lbs
“Human-Capability” Questions
Is the user population able to generate 54 lbs?
What is the injury risk for weaker operators?
How does this affect the potential for failure?

11. System Safety Methods & Techniques
Limitations of Approach
System Safety tools dependent upon assessor’s knowledge of human capabilities
Assessment tools don’t provide references that fill knowledge gaps
Less knowledgeable assessors must develop inferences about product injury risks that are sometimes based upon faulty assumptions

12. System Safety Methods & Techniques
Weakness of Approach
People performing System Safety reviews tend to have limited knowledge of human capabilities
Commonly used tools do not always fill the gaps in knowledge

13. System Safety Methods & Techniques
Evidence of Weakness of Approach
Authors concluded that designers often fail to foresee the health risks in the activities associated with the intended use of their products
Advocated a task-based risk assessment approach using a hazard list that includes ergonomics
Raafat H & Simpson P.
Integrating safety during the machine design stage.
Raafat H & Simpson P. Integrating safety during the machine design stage.

14. System Safety Methods & Techniques
Evidence of Weakness of Approach
Study found an average of 5 Human Factors design problems in each product reviewed
Domains included physical & cognitive workload
Recommended adhering to a “user-centered” design approach
Susan G. Hutchins,
Analysis of human factors case studies of complex military systems: Surely we can do better.
Hutchins SG. Analysis of human factors case studies of complex military systems.

15. System Safety Methods & Techniques
Evidence of Weakness of Approach
Authors advocate “cradle to grave” integration of safety and design that includes:
Implementing Ergonomics Pro-actively
Developing Better Contract Specifications
Educating Purchasers
Christensen WC & Manuele FA. Safety Through Design. National Safety Council, 1999
Christensen WC & Manuele FA. Safety Through Design. National Safety Council, 1999

16. Common System Design Errors
Excessive Muscular Exertion
Manual Material Handling Demands
Pushing-Pulling Demands
Grasp & Finger Force Demands
pinch grip
push big.jpg 1000 x 714 pixels - 450k www02.clf.navy.mil/.../ page%203/push%20big.jpg

17. Common System Design Errors
Example: Excessive MMH Demands
Army Mobile Analysis System
Original
Current
402 lb
275 lb
313 lb
200 lb
100 lb
65 lb
715 lb
640 lb
Note: Max Allowable Weight for 4 person team:
All Male Team – 305 lbs; Mixed Team – 154 lbs
MIL-STD-1472F -- DoD Design Criteria Standard: Human Engineering

18. Common System Design Errors
Example: Excessive Pull Demands
Drink Can Pulling Force Demands
Explain that the X-axis is Percentiles distribution.
Force Required To Open Can 4.6 lbs
Average Maximum Force Capacity (lbs): Female, Male

19. Common System Design Errors
Excessive Extrinsic Load
Load Carriage
Head Supported Mass*
The head is about the size and weight of a bowling ball
The head is about the size and weight of a bowling ball

20. Common System Design Errors
Example: Excessive Load Carriage
Heavy Army Field Infantry Load
Soldiers Expected to Carry Heavy Equipment Load

21. Common System Design Errors
Example: Excessive Load Carriage
Position
Ave
FL1 FL
%BW
AML2
AML
EAML3
EAML
Rifleman
63 lb
36%
95.7
55%
127.3
71%
M240B Ammo Bearer
69 lb
37%
117 lb
62%
144 lb
80%
1FL = Fighting Load
2AML = Approach March Load
3EAML = Emergency Approach March Load
Many new acquisitions are conceived as “add-ons” to this “baseline” load

22. Common System Design Errors
Example: Excessive Load Carriage
Military Headgear Design
Wearing heavy gear of long durations may elevate the risk of cervical injury
Asymmetrically distributed load can cause fatigue and increase cervical injury risk

23. Common System Design Errors
Excessive Metabolic Demand
Regional Fatigue
Overusing smaller muscles within a specific region of the body
Systemic Fatigue
Overusing larger muscles from multiple body regions
Activity stresses heart & lungs
Heat stress may contribute to overall metabolic load

24. Common System Design Errors
Example: Excessive Metabolic Demand
Many DoD personnel perform jobs with high cardiopulmonary demands
Demands increase further during deployed military operations
Have been associated with increased musculoskeletal injury risk (MIR)
MIR ↑ 7.6 times for personnel constructing deployed bases
Identifying the physical demands of Army Reserve personnel during deployable medical systems training.
Mil Med 1997 Aug;162(8): (ISSN: )
Dybel GJ; Seymour CJ
Physical Therapy Department, University of Massachusetts/Lowell 01854, USA.
The purpose of this investigation was to (1) assess the physical demands of soldiers involved in Deployable Medical Systems (DEPMEDS) activities, and (2) evaluate the incidence of musculoskeletal injuries among reserve military personnel involved in these tasks. The primary study group consisted of 190 soldiers participating in a 2-week annual field training exercise. Information regarding the DEPMEDS construction was obtained by performance of an ergonomic analysis, administration of a physical exertion questionnaire, and collection of injury data reported during daily sick call. The neck, shoulders, and low back were the most frequently reported sites of musculoskeletal injury. Soldiers involved in DEPMEDS construction were 7.6 times more likely to sustain a musculoskeletal injury than soldiers not involved in this aspect of the field training exercise. Current methods of DEPMEDS construction that utilize medical personnel for erecting and dismantling equipment may reduce the unit's mission readiness. Comment In: Comment In: RefSource:Mil Med Oct; 162(10):632/PMID:

25. Common System Design Errors
Dimensional Incompatibility
Sizing
Human-Machine Couplings
Control Points (handles)
Other Couplings (i.e., seatpans)
Wearables (headgear & clothes)
Accesses (doors/hatches & portals)
Reaches (arms & legs)

26. Common System Design Errors
Example: Human-Machine Coupling
Photos courtesy of Gerry Miller

27. Common System Design Errors
Example: Human-Machine Coupling
Photos courtesy of Gerry Miller

28. Military Vehicle with Retrofitted Ladder
Step-off distance in various military vehicle is in the range of 4 to 6 feet.
The ladder is a retrofit!
Imagine doing this in a vulnerable combat situation with a 80 pound pack!
Photo courtesy of Trailormate

29. Common System Design Errors
Example: Human-Machine Coupling
This is a first design of what device?
Computer Mouse

30. Common System Design Errors
Example: Human-Machine Coupling
Hand-Tool Size Mismatch
Handles get smaller, but hand does not
Smaller handles are difficult to use by normal-sized hands

31. Do we need different size operators to use each task or tool?

32. Common System Design Errors
Example: Size of Wearables
Product Size Mismatch
Wrong-sized apparel frustrates users

33. Common System Design Errors
Example: Access Dimensions
Wrong-sized Opening
Head may strike handle while trying to exit vehicle

34. Common System Design Errors
Example: Access Dimensions Problem
Inadequate Clearance
Pilots Killed Ejecting From F104A
Cause: Bad Seat Design
Detail: pilot’s knees would not clear the forward canopy edge due to the fact that the parachute placement positioned the pilot too far forward
Solution: The model DQ-7 seat was replaced with a redesigned GQ-H7 seat that allowed clearance
Problem #1 F104A Seats
The new Martin-Baker Starfighter seat unexpectedly experienced some initial problems, however, and several German Luftwaffe pilots were killed in Starfighter ejections using M-B Mk.DQ-7 seat. An investigation team was quickly brought into determine the source of the seat failure and found that frequently the pilot’s knees would not clear the forward canopy edge due to the fact that the parachute placement positioned the pilot too far forward. The seat was subsequently modified to address this problem and from then on the Martin-Baker Mk. GQ-7F seat performed quite well in Starfighter emergencies experienced by the German Luftwaffe.
Problem #2: F104 Visors
mid-1950's
Problems with Martin-Baker seats
During ejection seat drill at Aalborg Air Base in July 1972 it was discovered that the upper ejection handle of the Mk.DQ-7 ejection seat got stuck on the rear of the HGU-2A/P-D visor housing when pulled forward. Several measures were tried to remedy the situation, initially by changing the ejection handle but it was not fully satisfactory. Two ALSE guys at Aalborg Air Base developed a longer visor housing that went all the way to the rear end of the ramshorn visor housing extensions. Initial testing of a metal sheet prototype looked promising so Gentex made a new protoype in plastic. This was tested in June 1977 and performed so well that the solutions had finally been found. The wheels of acquisition spun slowly but surely and the first production examples were received for approval in November Next summer the modification programme was initiated. Even if only the F-104 pilots had experienced problems it was decided that the modification should apply to helmets used on the F-100 also as this type was equipped with Martin-Baker seats as well.
F105D “Sample” Cockpit

35. Common System Design Errors
Example: Poor Workstation Design
Excessive Reach Requirement
Bike Design Causes Headaches
Cause: Bicycle “Workstation” Design
Detail: Chronic extended neck posturing shortens muscle in back of neck, increases pressure on suboccipital nerve, and may cause headaches & disc disease
Solution: Ride a bicycle that allows upright spinal posture
Problem #1 F104A Seats
The new Martin-Baker Starfighter seat unexpectedly experienced some initial problems, however, and several German Luftwaffe pilots were killed in Starfighter ejections using M-B Mk.DQ-7 seat. An investigation team was quickly brought into determine the source of the seat failure and found that frequently the pilot’s knees would not clear the forward canopy edge due to the fact that the parachute placement positioned the pilot too far forward. The seat was subsequently modified to address this problem and from then on the Martin-Baker Mk. GQ-7F seat performed quite well in Starfighter emergencies experienced by the German Luftwaffe.
Problem #2: F104 Visors
mid-1950's
Problems with Martin-Baker seats
During ejection seat drill at Aalborg Air Base in July 1972 it was discovered that the upper ejection handle of the Mk.DQ-7 ejection seat got stuck on the rear of the HGU-2A/P-D visor housing when pulled forward. Several measures were tried to remedy the situation, initially by changing the ejection handle but it was not fully satisfactory. Two ALSE guys at Aalborg Air Base developed a longer visor housing that went all the way to the rear end of the ramshorn visor housing extensions. Initial testing of a metal sheet prototype looked promising so Gentex made a new protoype in plastic. This was tested in June 1977 and performed so well that the solutions had finally been found. The wheels of acquisition spun slowly but surely and the first production examples were received for approval in November Next summer the modification programme was initiated. Even if only the F-104 pilots had experienced problems it was decided that the modification should apply to helmets used on the F-100 also as this type was equipped with Martin-Baker seats as well.
Shortened muscles compress nerve

36. Common System Design Errors Avoided by New Approach
springdalebicycle.com/ Why_Recumbant.htm
Kreuzotter Carbon. Vollgefedertes schnelles Liegerad. Für Touren mit viel Gepäck (auch auf nichtasphaltierten Wegen), für Alltags-Benutzung und Rennen. Unkommerzielles Projekt. Geändert: (FAQ für Fahreleistungs-/Geschwindigkeitsrechner erweitert)
Problem #1 F104A Seats
The new Martin-Baker Starfighter seat unexpectedly experienced some initial problems, however, and several German Luftwaffe pilots were killed in Starfighter ejections using M-B Mk.DQ-7 seat. An investigation team was quickly brought into determine the source of the seat failure and found that frequently the pilot’s knees would not clear the forward canopy edge due to the fact that the parachute placement positioned the pilot too far forward. The seat was subsequently modified to address this problem and from then on the Martin-Baker Mk. GQ-7F seat performed quite well in Starfighter emergencies experienced by the German Luftwaffe.
Problem #2: F104 Visors
mid-1950's
Problems with Martin-Baker seats
During ejection seat drill at Aalborg Air Base in July 1972 it was discovered that the upper ejection handle of the Mk.DQ-7 ejection seat got stuck on the rear of the HGU-2A/P-D visor housing when pulled forward. Several measures were tried to remedy the situation, initially by changing the ejection handle but it was not fully satisfactory. Two ALSE guys at Aalborg Air Base developed a longer visor housing that went all the way to the rear end of the ramshorn visor housing extensions. Initial testing of a metal sheet prototype looked promising so Gentex made a new protoype in plastic. This was tested in June 1977 and performed so well that the solutions had finally been found. The wheels of acquisition spun slowly but surely and the first production examples were received for approval in November Next summer the modification programme was initiated. Even if only the F-104 pilots had experienced problems it was decided that the modification should apply to helmets used on the F-100 also as this type was equipped with Martin-Baker seats as well.
Shortened muscles compress nerve

37. Common System Design Errors
Example: Poor Workstation Design
Excessive Reach Requirement
$5 solution
Difficult pinning papers located beyond reach envelope

38. Common System Design Errors
Extrinsic Mechanical Energy Exposure
Hand Arm Vibration (HAV)
Whole Body Vibration (WBV)
Jolt
hot_work_welding.html

39. Common System Design Errors
Example: Excessive HAV Exposure
Manual Soil Plate Compactor
Exposure Characteristics
Acceleration: 7.3 m/s2
Exposure Limit: 120 min/day
Compactor Transfers Vibration to Operator’s Hands
Mitigation efforts (equipment redesign, equipment substitution, process redesign) unknown –
See this afternoon’s presentation by Nancy Estrada

40. Common System Design Errors
Example: Excessive WBV Exposure
Heavy Construction Equipment
Exposure Limits
Paved Road: 30 min
Gravel Road: 105 min
Cross-Country: 410 min
Vehicle Transfers WBV Through Body Contact Points
Mitigation efforts (equipment redesign, equipment substitution, process redesign) unknown
See this afternoon’s presentation by LT Harrer

41. Typical Life Cycle Costs in Acquisition
Commit to Human Systems Integration
Implement Human Systems Integration efforts throughout the product’s entire lifespan
This can be the disposal end
-They may include unexpected hazards
-May use outdated technology
-The tail (lifetime costs) are much bigger than the head (initial design and purchase costs).
- Safety and health professionals have often been attacking the beast from the wrong end!
60-70% Operations, Maintenance & Disposal
20-30% Procurement
10% R&D
70% of costs committed in preliminary designs
Concept Refinement
Technology Development
Operations & Support
Production & Deployment
System Development & Demonstration

42. Requirements for Life-cycle Safety
DODI Operation of the Defense Acquisition System May 12, 2003
3.9.2 Sustainment
Effective sustainment of weapon systems begins with the design and development of reliable and maintainable systems through the continuous application of a robust systems engineering methodology. As a part of this process, the PM shall employ human factors engineering to design systems that require minimal manpower; provide effective training; can be operated and maintained by users; and are suitable (habitable and safe with minimal environmental and occupational health hazards) and survivable (for both the crew and equipment).
DODI Operation of the Defense Acquisition System May 12, 2003
3.9.2 Sustainment
Effective sustainment of weapon systems begins with the design and development of reliable and maintainable systems through the continuous application of a robust systems engineering methodology. As a part of this process, the PM shall employ human factors engineering to design systems that require minimal manpower; provide effective training; can be operated and maintained by users; and are suitable (habitable and safe with minimal environmental and occupational health hazards) and survivable (for both the crew and equipment).

43. Requirements for Life-cycle Safety
Practice = Theory
DODI Operation of the Defense Acquisition System May 12, 2003
3.9.2 Sustainment
The PM shall employ human factors engineering to design systems that require minimal manpower; provide effective training; can be operated and maintained by users; and are suitable (habitable and safe with minimal environmental and occupational health hazards) and survivable (for both the crew and equipment).
                              
Fall protection >5 Ft
U.S. Navy Photo by Photographer's Mate 2nd Class Bradley J. Sapp (RELEASED) For more information go to:

44. How Can The Process Be Improved?
Educate Key Players in Ergonomics
Increase acuity of recognition of job demand/worker physical capacity mismatches
Improve problem-solving skills relevant to mitigating potential health risks due to mismatches between job demands & worker physical capacity

45. How Can The Process Be Improved?
Develop Better Risk Assessment Tools
Based on Human Capability and Exposure Tolerance Limits for these Common Problem Areas:
Excessive Muscular Exertion
Extrinsic External Load
Excessive Metabolic Demand
Dimensional Incompatibility
Extrinsic Mechanical Energy Exposure

46. How Can The Process Be Improved?
Develop Better Risk Assessment Tools
Design engineers can use them to guide decisions during early product development

47. How Can The Process Be Improved?
Stop Buying High-Risk Products
Purchase of high-risk products is reduced through awareness education and risk assessment
Decision-makers are provided an assessment tool that identifies high risk product characteristics that should be considered before purchase

48. Examples

49. Procurement of Heavy Vehicle
Risk Analysis Reveals Following:
Vehicle operation exposes personnel to whole body vibration
Purchase decision should consider injury risk based upon existing standards

50. Procurement of Heavy Vehicle
Vehicle maintenance exposes personnel to ergonomics hazards
Purchase decision should apply an assessment tool that considers ergonomics injuries

51. No injuries since inception
Navy Ergonomics
Facility Maintenance
Manual Process Annual Cost K
Improved Process Annual Cost K
Annual Cost Difference (Savings) K
Tool Purchase Price (5 units) K
Return on investment (10 yr. service life)
Cost Savings K
Break Even Point Days
Task: Workers maneuver on the side rails of roll off dumpsters while man handling heavy tarps to cover their load. Knee injuries were a particular concern due to contact with the truck body and twisting to pull the tarp cover. Other injuries included cuts, puncture wounds, sprains, and strains.
Workers risk back and shoulder injury from repeatedly pulling the heavy tarp to cover the load and knee injury from crawling along the metal side rails. Additionally, a worker can easily fall due to the unsure footings.
Pushing or pulling on an uneven, slippery, or sloped surface can result in a sudden increase in the force needed to move or stop an object. The increase in force alone can tear muscles or strain tendons enough to cause an injury.
Injuries: The safety specialist commented that at least three lost workday injuries occur each year due to this task.
Resolution: System operated from the ground, virtually eliminates risk of injury. Automatic system lifts tarp and then worker pulls tarp over frame and load from rear of the truck photo. The workers are pleased with the equipment and have experienced no lost workday injuries since implementation.
Considerations: A connection ring added to the back bumper makes tarp easier to guide back into the roller. The tarp system stores between the cab and the dump body. On some vehicles, the engine exhaust required relocation to accommodate the rolling mechanism.
Additionally, side flaps tangles easily when wound and may need modification to ease use. Recommendation: modify a prototype truck before fleet installation.
No injuries since inception

52. Savings $250,000 per shipyard period, $2,500,000 lifecycle
TYPICAL AIRCRAFT CARRIER DEEP TANK REFURBISHING OPERATION COST AVOIDANCE ASSOCIATED WITH IMPROVED ACCESS
Present
Proposed
Savings
Number of entries/ personnel
Work time (hours)
Cost ($60/hr)
Work time 42 88
$21.2K 55
$13.3 32
$7.9K
Life cycle savings projected to be in the range of $2 to $5 million per carrier
Savings $250,000 per shipyard period, $2,500,000 lifecycle

53. This Training Protective equipment Complex procedures Not this!
System Safety protects USERs Those often unable to influence system design (Also protects the taxpayers)
Identifies risks in prior systems
Requires that controls be built into the design
Minimizes later work-around
Training
Protective equipment
Complex procedures
Reduces maintenance and disposal costs
This
Not this!

54. Resources

55. Service Ergonomics Programs
DOD Ergonomics Working Group
Air Force Occupational and Ergonomics Program
Crew System Ergonomics Information Analysis Center

56. Service Ergonomics Programs
Navy- Acquisition Website
Ergonomics program
OPNAVINST Chapter 23 Ergonomics
NAVSEAINST A Date 20 May 2005 Subject HUMAN SYSTEMS INTEGRATION (HSI) POLICY IN ACQUISITION AND MODERNIZATION

57. Service Ergonomics Programs
Army Ergonomics Overview
US Army Center for Health Promotion and Preventive Medicine
Health Hazard Assessment Program
Manprint Program

58. Example of Common Task Design Criteria
welding/ergonomics.html

59. Field Tools Most are simple
Angle measure
Scale
Gauge for pulling stress
length__moisture.html

60. Contact Information
Don Goddard, M.S., RPT
US Army Center for Health Promotion & Preventive Medicine
Mark Geiger, M.S.E., CIH, CSP
Chief of Naval Operations N09FB
Safety Liaison Office, Arlington, VA