Safety & ergonomics
Design & Manufacture · National 5 · mrkellydt.co.uk
What you're learning in this topic
Learning intention WALT
We are learning about safety & ergonomics, specifically to:
understand
- how ergonomics makes products safe, comfortable and easy to use
- how safety has influenced the design of a product
be able to
- use anthropometric data and choose the right percentile
Success criteria WILF
- I can describe how ergonomics makes products safe, comfortable and easy to use
- I can use anthropometric data and choose the right percentile
- I can describe how safety has influenced the design of a product
Ergonomics
Improving the interaction between people and products so they are safe, comfortable and easy to use.
- Anthropometrics: human body measurements (height, reach, grip, hand width).
- Physiology: strength, effort, movement, posture, fatigue and strain.
- Psychology: how the product looks, feels, sounds, smells and tastes affects how a user perceives and uses it.
Link specific body parts to specific parts of the product: "the handle diameter suits the grip of a 50th percentile adult hand".
Anthropometric data and percentiles
Body sizes follow a bell curve. Designers usually design for the 5th–95th percentile range (90% of users).
- Reach: design for the 5th percentile so small users can reach (shelves, emergency stop buttons).
- Clearance: design for the 95th percentile so large users fit (doorways, leg room).
- Comfort/average: 50th percentile, or make it adjustable.
UK standing height (mm): men 5th 1625 / 50th 1740 / 95th 1855; women 1505 / 1610 / 1710.
Safety
- Rounded edges and corners; guards over moving parts and finger traps; stable wide bases.
- Non-slip textures and secure grips; electrical insulation; non-toxic materials and finishes.
- Warning labels where a risk cannot be removed; clear instructions; emergency stops.
Key terms
| Anthropometrics | The study of human body measurements used to size products. |
|---|---|
| Physiology | Strength, effort, movement and strain required to use a product. |
| Psychology (ergonomics) | How a product's look, feel, sound, smell or taste affects the user. |
| Percentile for reach | 5th percentile, so smaller users can reach. |
| Percentile for clearance | 95th percentile, so larger users fit through or under. |
Quick check
1. Which percentile should be used for the height of a doorway?
- 5th
- 50th
- 95th
- 1st
Show answer
2. Which percentile is used to position an emergency stop button?
- 99th
- 50th
- 95th
- 5th
Show answer
3. "The force needed to squeeze the trigger is low so the user does not tire" is an example of…
- Physiology
- Anthropometrics
- Psychology
- Aesthetics
Show answer
4. A bright red, clearly labelled off switch reassures the user. This is…
- Anthropometrics
- Psychology
- Physiology
- Function only
Show answer
5. Which feature mainly improves safety?
- Brand logo on the casing
- Glossy, easy-clean finish
- Guard over moving blades
- Extra storage compartment
Show answer
Exam-style questions
1. Describe how ergonomics has influenced the design of a product such as a cross trainer. (4 marks)
Show marking guidance
- Anthropometrics: handle diameter suits grip of users; footrest length/width; reach to handles; adjustability (body part + product part + impact = 1)
- Physiology: force needed to operate is variable; posture is upright and comfortable
- Psychology: looks simple and safe to operate; sounds smooth; feels robust
- Max 3 marks for any one area at Higher when all three are required
2. Describe how the design of a product has been influenced by safety issues. (4 marks)
Show marking guidance
- Stable wide base / secured to ground
- Covers over moving parts to prevent finger traps
- Non-slip pattern on foot rests
- Rubber grips for secure hold
- Electrical insulation / emergency stop
- 1 mark per valid description
Printable worksheet
An I do, we do, you do worksheet for this topic, with a separate answer sheet.