Ergonomics 1 Midterm: Vibration and Vestibular Sense

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Questions and Answers

What is the definition of vibration in the context of ergonomics?

The acceleration of an object in a specific direction

The transfer of vibration from a tool to a worker's hand and arm

The mechanical oscillations of an object about an equilibrium point (correct)

The movement of a tool in a circular motion

What type of industries are most exposed to vibration?

Software development and finance

Food manufacturing and healthcare

Education and tourism

Construction, logging, and equipment repair (correct)

What is the unit of measurement for acceleration?

Hertz (Hz)

Meters per second (correct)

Pounds per square inch

Velocity per unit time

What is the safe vibration level for an 8-hour exposure to hand-arm vibration?

Below 3.5m2 Signup and view all the answers

What is a characteristic of vibration as a vector quantity?

It has both magnitude and direction Signup and view all the answers

What is an example of a tool that can cause high vibration?

Impact wrench Signup and view all the answers

What is the maximum vibration dose value that workers should not exceed to avoid health risks?

17.0 m/s1.75 Signup and view all the answers

At what vibration dose value should workplaces consider implementing controls?

8.5 m/s1.75 Signup and view all the answers

What is the basis for measuring worker exposure to whole-body vibration?

ISO 2631-1:1997 Signup and view all the answers

Where are measurements of vibration exposure typically taken?

At the human/vibration interface Signup and view all the answers

What is one way to reduce exposure to whole-body vibration in the workplace?

Purchasing vehicles and equipment with lower manufacturer-reported vibration emission values Signup and view all the answers

Why is it important to control exposure to whole-body vibration in the workplace?

To prevent injuries Signup and view all the answers

What is one of the ways to reduce vibration exposure through engineering controls?

Providing a suitable seat for the vehicle Signup and view all the answers

What is a key consideration when selecting a seat for vibrating vehicles or mobile equipment?

The seat's performance in reducing vibration exposure Signup and view all the answers

What is an example of an administrative control to reduce vibration exposure?

Providing alternate tasks for the worker to perform Signup and view all the answers

What is a potential drawback of using suspension seats to reduce vibration exposure?

They can increase the amount of vibration transmitted to the operator Signup and view all the answers

Why is it important to maintain the vehicle, mobile equipment, or machinery in good condition?

To reduce vibration exposure Signup and view all the answers

What is one of the ways to reduce vibration exposure through dampening or isolation?

Dampening or isolating the source of the vibration Signup and view all the answers

What is the primary purpose of defining the population in anthropometric design?

To identify the target users for a design Signup and view all the answers

What is the purpose of measuring hand breadth in anthropometry?

To design hand tools and gear Signup and view all the answers

What is the unit of measurement for nude body weight in anthropometry?

Kilograms Signup and view all the answers

What is the purpose of the Range Principle in anthropometric design?

To allow for adjustments in position, size, intensity, and duration of a product or system Signup and view all the answers

How much should be added to standing height or seated knee height to accommodate clothing, according to the anthropometric design principle?

2.5 cm or 1.0 in Signup and view all the answers

What is the typical range of population used in anthropometric design?

From 5th percentile female to 95th percentile male Signup and view all the answers

What is the primary goal of the Design for Extreme Principle?

To accommodate the largest percent of the population group Signup and view all the answers

What is the focus of the Design for the Average Principle?

Designing for the 50th percentile of the population Signup and view all the answers

What is the acceptable percentile range for the Clearance Load Tolerance?

95th-100th percentile Signup and view all the answers

Why is designing for the average person not suitable in most cases?

Because there is no average person Signup and view all the answers

What is the rule of thumb for designing to accommodate different population groups?

Design so the tall can fit and the small can reach Signup and view all the answers

What is an example of a Design for the Average Principle in use?

Self-serve checkout counter Signup and view all the answers

Study Notes

Vibration in Ergonomics

Vibration refers to the mechanical oscillations of an object about an equilibrium point, resulting in exposure to shaking or oscillations.
Equipment that causes high vibration includes impact wrenches, carpet strippers, floor polishers, chain saws, percussive tools, and jack hammers.
Acceleration is the amount of velocity in speed or direction per unit time, measured in hertz (hz) or meters per second.
A vibration level below 3.5m2 is considered safe for an 8-hour exposure to hand-arm vibration.
Vibration dose value is an alternate measure of vibration exposure, with a recommended limit of 17.0 m/s1.75 to avoid health risks.

Industries Exposed to Vibration

Construction
Logging
Equipment and machinery repair
Ship yards
Automobile manufacturing and repair
Foundries
Building and maintenance of roads and railways
Mines and quarries

Controlling Vibration Exposure

Consider purchasing vehicles and equipment with lower manufacturer-reported vibration emission values.
Measures can be taken to control exposure and prevent injury by separating vibrating machinery from the work area, redesigning tasks, and using suitable seats.
Maintain surfaces in good condition, select appropriate tires, and ensure proper vehicle maintenance.
Dampen or isolate the source of vibration or the work surface.

Workplace Exposure Limits

Whole-body vibration exposure should be assessed or measured based on ISO Standards: 2631-1:1997.
Exposure limits and estimates have been characterized in ISO 2631-1 for whole-body vibration.

Anthropometry

Anthropometry is used to accommodate a range of body sizes and types.
Critical dimensions include hand breadth, weight, and standing height.
Design principles include:

Accommodate Range Principle
- Allow for adjustments in position, size, intensity, and duration of product or system to accommodate unexpected circumstances and maximize use on the body.
Adjust for Clothing
- Add 2.5 cm or 1.0 in for standing height or seated knee height to reflect the presence of a heel.
- Add 0.8 cm or 0.3 in for breadth due to bulk of clothing.
Design for Extreme Principle
- Accommodate the largest percent of the population group where adjustability is costly or not feasible.
- Use 95th-100 percentile for clearance, load tolerance, and girth.
Design for the Average Principle
- Design for the 50th percentile, acceptable for short-term use, but excludes 50% of the population.
Examples of anthropometric design principles in use: car seats, desk height, keyboard support, and footrest.

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Description

Test your understanding of vibration and its effects on the human body in the context of ergonomics. Learn about the mechanical oscillations of an object and how it relates to occupational health and safety. This quiz covers the basics of vibration and its impact on the vestibular sense.