Machinery Hazard Zones
Context & Use
In the process of risk assessing the hazard zone required for plant and equipment, considerations needs to account for:
- context and use
- the major hazard(s) present
- operational factors
- materials handling
A primary consideration for a hazard zone is the use and context of the plant or equipment. Context focuses on the location of the plant or equipment. Answering this simple question should then allow for the generation of more complex questions that the risk assessment should help resolve ie. Where is it located? Is the space used by teachers, students or a technician? What are the access and egress points?
The purpose of the plant and equipment will be heavily influenced by the material it will process and by whom it will be processed. This is particularly relevant to the preparation of full materials such as hollow section and bar steel, timber boards and sheet based products. Further material requirements are discussed later in this article.
"Put simply, if the control doesn't exist, you can't assess it."
- Andrew Nicholls
Major Hazards
Once the risk assessment has identified the critical hazards (unguarded blades, electrical points, spinning parts etc), appropriate distances should be allocated to ensure anyone but the operator is in proximity of the hazard. A typical distance should be slightly longer than the average human reach or arm length, approximately 700-800mm. Applying vigilant thinking, the hazard area should be linearly measured longitudinally, laterally and vertically out from the extremities of the hazard.
Operational Factors
Operational factors account for any movement of the plant or equipment eg. travel of a blade, swing of an out-rigger table. These areas need to be used to adjust the original hazard areas. Again, the distances need to be measured in a longitudinal, lateral and vertical linear fashion out from the extremities of the moving part.
Materials Handling
Lastly, the manual handling and processing of materials needs to be considered. This should include stock material delivered from suppliers and work produced by students. The hazardous work zone should account for a major proportion of the material's stock length. For example, if the school commonly orders 5.7m timbers which it pre-cuts to 2.5m lengths, then a suggested hazard zone would be 5.7m on one side of the saw and 2.5m on the other.
In the case of a thicknesser, consideration needs to be given to the length of the board to be processed. If the common processing length is 2m then the hazard zone should be 2m for the board and 0.8m entry and exit points.
A table of common stock lengths is provided below as a guide. Your local supplier of materials will be able to provide a more accurate list of measurements. Naturally, a cost to benefit analysis should be conducted to assess whether it is more economical to have the material pre-cut by a supplier. Although this may increase the cost of your materials, it can assist reduce the need for large hazard zones.
Common Material Dimensions (nominal)
| Material | Description | Dimensions (mm) | ||
| Width/Diameter | Height/Thickness | Depth/Length | ||
| Timber | 5700 | |||
| Board | Linear boards | 140 190 240 290 | 12/19 | 5700 |
| MDF | Panel | 1200 | 3 6 9 12 16 18 25 32 | 2400 |
| Whiteboard | Panel | 450 600 1200 | 16 | 2400 36000 |
| Structural | Panel | 1200 | 6/9/12/15/18/25 | 2400 36000 |
| Metal - Steel | ||||
| Flat Bar | 20-300 | 5-25 | 6000 | |
| Round Section | 6-65 | 6000 | ||
| Square Section | 10 12 16 20 25 32 40 | 10 12 16 20 25 32 40 | 6000 | |
| Channel Section | 75-380 | 75-380 | 1200 1800 | |
| Unequal Angles | 65x50 | 50x100 | 9000 1200 1500 | |
| Sheet - Hot Rolled | 900/1200/1500/1800 | 1.6-6 | 1800 2400 3600 6000 | |
| Sheet - Galvanised | 900 1200 1500 1800 | 0.25-6 | 1800 2400 3600 6000 | |
| Sheet - Painted (Colourbond) | 900 1200 1500 1800 | 0.55-0.95 | 1800 2400 3600 6000 | |
In addition to the physical size of materials, consideration should also be given to the by-products created by the various manufacturing processes ie. welding, cutting, grinding, milling etc. In such cases, additional engineering controls may help reduce the need for hazard zones that could occupy valuable workshop space.
Marking Out
Once the hazard zones have been identified, the hazardous areas around machinery should be identified with black and yellow chevron tape. Safety zones for through traffic should additionally be marked with plain yellow tape. Above all, ensure floor markings are keep simple and easy to follow. Suppliers of safety products will be able to provide additional information about how to prepare surfaces for their tapes and signs.
Clearways
Last but not least, clear ways need to be provided to ensure users of the space do not venture into hazard zones. The desired clear way between hazard zones should be approximately 800mm. However, this specification does vary between Australian states / territories so be sure to check the respective code of practice or compliance code in your area.
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