Guidance Home
Choosing Tool Lanyards & Tethers
Personel Injury The Real Cost
Tool Tethering Taking Appropriate Action
Dropped Objects
Tool Lanyard Safety
Dropped Object Prevention
Dynamic Static Dropped Tools
Tools At Height Risk Assessment
Can You Mitigate Against Dropped Tools
Guidance Objectives
Dropped Objects Awareness, Legal Duty and Responsibility
Dropped Tools Checklist and Controls
Supervising Work Activity Involving Tools at Height
Why You Should Tether Tools for Working at Height
Using Hand Tools at Height Safely
Before Work Begins
Height Safety For Tools & Equipment
Fallen Object Risk Assessment
Operator Considerations For Tool Safety When Working At Height
Managing Work to Control & Mitigate Falling Objects
The Prevention Of Dropped Tools & Objects While Working At Height
Examples Of Dropped Objects
Working At Height: How To Reduce The Risk Of Dropped Tools
Dropped Object Risk Assessment
Dropped Objects Are You Breaking The Law Without Knowing?
Dropped Objects What Can Be Done
Dropped Objects Mitigation Controls
Dropped Objects Case Studies
Examples Of Dropped Objects
Guidance for the prevention of dropped tools and objects when working at height
Fallen tools can often cause harm to people, damage to machinery or create costs associated with lost production time. The following graph shows the likely-hood of injury or death from falling objects, relative to the mass and height from which a fall takes place
(*
Graph Courtesy of Shell)
| Example 1 |
Standard Bolt (¾ x 3½) |
| Weight |
220 grams |
| Dropped Distance |
11M (3 floors) |
23M (6 floors) |
| Impact Velocity |
31mph (50kph) |
50mph (80kph) |
| Impact Force |
23.7kgs |
49.5kgs |
| Resulting Injury |
Hospitalised (Recordable) |
Fatality |
A bolt dropped from 23 metres is equivalent of being dropped from the 6th floor of a building. The velocity attained is 50mph / 80kph on impact. The bolt achieves a mass impact weight of 49.5kgs at this point, resulting in a fatal injury even if struck on the head whilst wearing a hard hat.
| Example 2 |
Screw Driver |
| Weight |
500 grams |
| Dropped Distance |
10M (3 floors) |
14M (4 floors) |
| Impact Velocity |
31mph (50kph) |
38mph (61kph) |
| Impact Force |
49kgs |
73.5kgs |
| Resulting Injury |
Hospitalised (Recordable) |
Fatality |
A screw driver dropped from 14 metres is equivalent of being dropped from the 4th floor of a building. The velocity attained is 38mph / 61kph on impact. The screw driver achieves a mass impact weight of 73.5kgs at this point, resulting in a fatal injury even if struck on the head whilst wearing a hard hat.
| Example 3 |
Claw Hammer |
| Weight |
2kgs |
| Dropped Distance |
4M (1 floors) |
6M (2 floors) |
| Impact Velocity |
20mph (31kph) |
24mph (39kph) |
| Impact Force |
78kgs |
117kgs |
| Resulting Injury |
Hospitalised (Recordable) |
Fatality |
A claw hammer dropped from 6 metres is equivalent of being dropped from the 2nd floor of a building. The velocity attained is 24mph / 39kph on impact. The claw hammer achieves a mass impact weight of 117kgs at this point, resulting in a fatal injury even if struck on the head whilst wearing a hard hat.
| Example 4 |
Sledge Hammer |
| Weight |
5kgs |
| Dropped Distance |
1M |
3M (1 floor) |
| Impact Velocity |
10mph (16kph) |
17mph (27kph) |
| Impact Force |
49kgs |
147kgs |
| Resulting Injury |
Hospitalised (Recordable) |
Fatality |
A sledge hammer dropped from 3 metres is equivalent of being dropped from the 1st floor of a building. The velocity attained is 17mph / 27kph on impact. The sledge hammer achieves a mass impact weight of 147kgs at this point, resulting in a fatal injury even if struck on the head whilst wearing a hard hat.
This is a guide only and in fact even a light-weight object dropped from a considerable height may turn out to be fatal.
Author: N. S. Beardmore October 2011
