FMEA of Door and conclusions
If Cavemen had done an FMEA of the door when it was invented, this would possibly be the outcome.
| Item | Potential Failure mode | Potential Effects of failure | Severity Rating | Potential Causes | Occurence rating |
| Open door | Person behind door gets door in face | Â – Broken neck – Death – Bleeding nose |
5-6 | Â – Two persons trying to pass the same door – Door placed to open into corridor – -“- onto esplanade – Badly placed painting on back of door |
4 |
| Open door | Hidden vicious monster on other side | Â – Death – Loss of limb – Loss of head |
10 | Â – Door opens into wilderness – Glass not yet invented, so other side of door can not be inspected |
4 |
| Close door | Limbs get stuck between door and doorway | Â – Loss of limb – Broken fingers/toes – broken nails – Bloodshed |
7 | Â – Person is angry and slams door shut – Annoying salesman sticks foot into door – Forgot person behind you |
5 |
| Run through door | Other side opens into chasm Other side opens up on multistory building Other side opens up into ocean |
 – Falling off high cliff – Death – Drowning – Bludgeoning – Cuts and bruises |
10 | Â – Earth activity causes earthquake and resulting chasm on other side of door – Balcony fell down – Global warming caused ocean to rise – Person was in a rush, running through the door, falling off. |
2 |
| … | … | … | … | … | … |
Conclusion
If the cavemen would have been engineers, they would never have invented the door, or at least not used it.