Dr. Lu Yuan, CSPSoutheastern Louisiana University

1. Ergonomics in general2. Ergonomic issues in petrochemical

industry3. Solutions and future challenges

Derived from two Greek words:◦ “Ergon” means “work;”◦ “nomos” means “law.”

Ergonomics = The Science of work◦ The science of fitting workplace conditions and

job demands to the capabilities of employees (U.S. Dept. of Health and Human Services)

◦ The scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance (International Ergonomics Association)

Use neutral postures Reduce excessive force/motions Keep everything in easy reach Work at proper heights Minimize pressure points Maintain a comfortable environment Exercise and stretch

Precision work, such as writing or electronic assembly - 5 cm above elbow height; elbow support is needed.

Light work, such as assembly-line or mechanical jobs - about 5-10 cm below elbow height.

Heavy work, demanding downward forces - from 20-40 cm below elbow height.

This design is satisfactory for me – therefore, it will be satisfactory for everybody else.

This design is satisfactory for the average person – it will, therefore, be satisfactory for everyone.

The variability of human beings is so great that it cannot possibly be catered for in any design – but since people are wonderfully adaptable it doesn’t matter anyway.

Ergonomics is expensive and since products are actually purchased on appearance and styling, ergonomic considerations may conveniently be ignored.

Avoid manual lifting when possible Lift in “power zone” (knee-to-shoulder

height) Be in good physical shape Lift the load with a smooth body motion

(avoid jerking) Get a good grip Keep the load close to the body Do not twist or bend sideways Get help for large or heavy loads

Injuries and disorders of the muscles, nerves, tendons, ligaments, joints, cartilage, and spinal disc, etc.

Other common names include: cumulative trauma disorders, repetitive strain injuries, and overuse disorders, etc.

Typical examples include: carpal tunnel syndrome, disc herniation, low back pain, tendonitis, and osteoarthritis, etc.

Repetitive motions Forceful exertion Awkward postures Contact stress Temperature extremes Vibration

According to Parks and Schulz (1998), 56% of low back injuries and 73% of head, neck and face injuries are associated with industrial valve handwheel actuation.

According to Humantech, Inc. (2004), 88% of surveyed operators indicated work-related MSDs and discomfort attributed to industrial valve handwheel actuation at a major petroleum facility.

Operator and maintenance errors account for 41% of incidences (CMA, 1994).

PSM Standard 1910.199 (e)(3)(vi) requires that “The process hazard analysis shall address: Human Factors.”

Human factors consider:◦ Basic ergonomics◦ Operator-machine interface◦ Aspects of a safety culture

Physical ergonomics:◦ Control room: glare, cluttered display, color,

alarm, etc.◦ Work access: valve location, workstation, etc.

Macroergonomics:◦ Fatigue management◦ Shift work◦ Deadlines

Purpose of scaffold building/erecting: To provide work platforms on building, industrial and other sites, for temporary structures such as stages and catwalks, and for the purpose of painting, repairing, seating, disguising building facades, etc.

https://actsttcom.ipage.com/images/slideshow/scaffolding.jpg

Lifting/carrying heavy and bulky materials Awkward postures Repetitive motions Improper work-rest scheduling

Helpers: Manual lifting and carrying of scaffolding parts and materials

Manually moving/transporting the scaffolding materials while on the scaffolds greatly increases the risk of falling from heights due to the stability issues.

According to the scaffolding material weight sheet provided by the contractor, many materials weigh more than 25 lbs and some more than 51 lbs which is the safe limit as suggested by National Institute of Occupational Safety and Health (NIOSH).

Awkward postures including elevating arms and twisting trunk are used in order to reach the materials.

Often the existing structure at the facility provided a very limited access for scaffold builders.

For example, one of the workers kneeled on the scaffold plank with a severe flexion of trunk to hammer screws into the scaffold planks.

In another crew, the leadman had to squeeze in and out through a very small opening which caused him to crawl.

Scaffold builders are required to repetitively hammer the cuplocks to stabilize the scaffolds.

It has been observed that some workers used their hands as hammers to fasten the pieces.

The conversation with field personnel revealed that some of the scaffold builders took lunch break at 1:30 pm. Because of this, workers might end up working a relatively longer period of time without break.

Scaffold hoist pulley system Ergonomics training provided to all field

personnel Proper work-rest scheduling Workplace stretching program

http://www.cbmscaffold.com/Pages/ScaffoldHoistPulley.aspx

http://www.betamaxhoist.com/scaffolding/

All field personnel including scaffold builders, superintendents/foremen, and field managers, should receive ergonomic training to better understand ergonomic hazards and utilize ergonomic principles during scaffold building/erecting.

Participatory ergonomics approach could also be used to maximize the active involvement of workers in implementing ergonomic knowledge, procedures and changes with the intention of improving working conditions, safety, productivity, quality, morale and/or comfort.

The ergonomic research and field studies suggested that workers should take 5-10 minutes of break every 2 hours, especially for those who are doing heavy construction work.

If the time for lunch could not be changed, workers should be provided with 3 breaks in the morning.

It was learned from one of the superintendents that the scaffold builders exercise an approximately 10-minute pre-job stretching in the morning.

It would be necessary to examine how the stretching proceeds to make sure that they are appropriate.

It is recommended that a second during-the-job stretching be implemented as needed, especially for those who are exerting high forces.

For the best results, worksite stretching sessions shall be included as mandatory component of a comprehensive ergonomics program, along with pre-job safety/ergonomics planning (e.g., pre-shift huddles, toolbox safety talks).

Control room◦ Multiple Display Layout◦ Alarm◦ Situation Awareness

Frequency of use. Most frequently used displays should be adjacent to the primary visual area (PVA).

Importance of use. Important information, even if not frequently used, should be displayed within the PVA.

Display relatedness or sequence of use. Related or sequentially used displays should be close together.

Consistency. Displays should always be consistently laid out with the same item positioned in the same spatial location. This minimizes load on memory and attention.

Organizational grouping. All displays within a group should be functionally related.

Stimulus-response compatibility. Displays should be close to their associated controls.

Clutter avoidance. There should ideally be a minimum visual angle between all displays.

Should be at least 15 dB above the background noise, preferably 30 dB to guarantee it will be heard.

Must not be above the noise level that can damage hearing.

Should not be startling. Alarm should rise in intensity.

Should not interfere with critical speech communication.

Should be informative (e.g. voice telling one what to do)

Must not be confusable. No more than 5-6 alarms that must be distinguished (absolute judgment).

Designers, researchers, and users often employ the cognitive concept of situation awareness to characterize users’ awareness of the meaning of dynamic changes in their environment.

Implications:◦ Designing easy-to-interpret displays of dynamic

systems◦ Tool for accident analysis◦ Important for training (especially for attentional

skills)

Adjusting the workplace (shape, location, and orientation of the workplace)

Adjusting the worker position relative to the workplace (change in seat height, use of platforms or step-up stools)

Adjusting the work piece (lift tables, parts bin for easier access)

Adjusting the tool (adjustable-length hand tool)

Besides lack of sleep, we can be out of synchrony with our body’s natural rhythms of temperature and arousal.

Most of us perform worse in the early morning hours and better in the late afternoon/early evening.

Sleep latency refers to sleepiness: How long it takes to fall asleep in a comfortable situation.

The best plan may be to rotate shifts slowly (every 14-21 days), or to rotate by delaying rather than advancing the shift.

Definition of roles and responsibilities Utilization of skills Opportunity for continuous improvement Support from managers and co-workers

Technology advancement Human-centered participatory design Identification of Performance Shaping

Factors (PSFs) More accurate human reliability analysis Generational transition “Let other people do it!”