Oak stool workshop risk assessment
A school workshop is preparing a batch of 20 oak stools. Each stool has four 600 mm legs, a 350 mm × 350 mm seat and two cross rails. Students will cut oak on a circular saw, drill 8 mm mortises with a pillar drill, and round over edges with a handheld router. The workshop has one portable extracted circular saw, a pillar drill with a chuck guard, and a router table with a 32 mm extraction port connected to a 100 mm dust extractor via an adaptor. Two students in the group have mild asthma. A risk assessment from last year lists 'wood dust - low risk' and does not mention the router. During a trial, a router bit broke and a piece of carbide flew across the workshop. The technician found the bit had been used on MDF and was missing one flute. The class has 6 lessons of 50 minutes before the stools are due for a community cafe.
1. Identify the significant hazards in this workshop activity and rank them by risk. Justify your ranking using likelihood and severity.
Read the worked answer
Rank by risk = likelihood × severity:
- Router bit breakage / flying carbide (high). A damaged bit missing a flute has already failed in trial. Severity is high (eye injury, cuts); likelihood is moderate if damaged bits remain in use. This is the top risk because the consequence is serious and the cause is known.
- Oak dust exposure (high). Two students have asthma. Fine oak dust is a respiratory sensitiser; the 32 mm router port necked to a 100 mm extractor via an adaptor will reduce airflow and leave dust. Severity can be high for asthmatics; likelihood is high without effective extraction.
- Circular saw kickback or contact (medium-high). Portable saw, 600 mm oak, possible binding. Severity high, likelihood medium with guarding and push sticks.
- Pillar drill entanglement (medium). Chuck guard helps, but loose clothing and 8 mm bits can snag. Severity medium-high, likelihood low if guarded.
- Noise and manual handling (medium/low). Router noise, lifting 20 stools.
The old assessment's 'wood dust - low risk' is not credible given the asthma and the router.
2. Recommend control measures for the two highest risks, following the hierarchy of control. Explain why PPE alone is not sufficient.
Read the worked answer
Router bit breakage: Use the hierarchy of control.
- Eliminate/substitute: Do not use damaged bits. Inspect every bit before use for missing flutes, cracks or overheating; discard damaged bits. Use the correct bit for oak, sharp and rated for the router speed. If possible, use a bearing-guided round-over bit in a router table with a guard.
- Engineering: Enclose the bit with a guard, use a push stick and feather board, set the correct feed direction, and ensure the workpiece is clamped. Check the collet and tighten to the correct torque.
- Administrative: Train students, supervise one at a time, and have a pre-use check sheet.
- PPE: Face shield and safety glasses are last, not first.
Dust:
- Engineering: Replace the 32 mm port and 100 mm adaptor with a properly sized 100 mm hood or a high-volume low-pressure extractor. A 32 mm port on a 100 mm extractor creates a bottleneck and reduces capture. Use an air filter and wet-wipe surfaces.
- Substitution: Use hand tools or pre-machined components for asthmatic students; avoid routing oak where possible.
- Administrative: Schedule dust-producing work when asthmatic students are not present, or provide remote extraction.
- PPE: Fit-tested FFP2/FFP3 masks for those who must be present; but PPE alone is not sufficient because it relies on correct fitting and wear.
Why not PPE alone: PPE does not remove the hazard, can fail, and does not protect others in the room. The hierarchy requires engineering controls first.
3. The technician says the risk assessment only needs updating after an accident. Evaluate this statement.
Read the worked answer
The statement is wrong. A risk assessment is a living document. It should be reviewed:
- Before the activity, especially when the process, materials, tools or people change. Here, the router was not in the old assessment, and two students have asthma - both are changes.
- After an accident or near miss; the broken bit is a near miss that should trigger an immediate review.
- When new information appears (e.g. a bit used on MDF, missing flute).
- Periodically, e.g. annually, even if nothing has changed.
Waiting for an accident is reactive and unsafe. The technician's view may reflect habit, but the school's legal and ethical duty is to assess before harm. The assessment should record who is at risk (including asthmatics), the controls, and the review date. The broken bit should be removed from service and the router checked before the next lesson.