Excavating: Working with hydraulic excavators and backhoe loaders
You can dig an excavation with a hand shovel or a machine. Use a hand shovel improperly and you risk blisters. Use a machine improperly and you risk a life. Too many workers are injured or killed because they are not properly trained or supervised and don’t follow safe practices when they use mechanical equipment for excavation work. Most accidents happen for three reasons.
1: Entering the excavator’s swing area
Workers need to be aware of the excavator’s swing area and blind spots. Always maintain at least 3 feet of unimpaired clearance between the excavator’s rotating superstructure and adjacent objects. Keep workers outside the area by marking it with rope, tape, or a similar barrier if necessary.
- Require the operator to lower the boom to a safe position with the bucket on the ground and turn off the excavator before getting off.
- Require the operator to keep the bucket as close to the ground as possible when workers are attaching loads.
- Do not allow workers to stand under a suspended load, the boom, arm, or bucket.
2: Using quick-coupling devices improperly
After-market “quick-coupling” devices make it easy for workers to quickly change buckets or replace other attachments. However, a number of workers have been killed when the coupling devices have not been locked properly and the buckets have detached. Manufacturers of quick couplers recognized the hazard and newer devices have locks that prevent buckets from detaching unintentionally, but not all users may be aware of the problem. Retroﬁt locking pins are available for older equipment.
- Follow the manufacturer’s instructions for using positive locks on quick-disconnect equipment.
- Securely latch attachments such as quick-disconnect buckets before beginning work.
- Make frequent visual inspections of quick-disconnect systems — especially after changing attachments.
3: Using unsafe rigging methods to drag a trench shield
Using an excavator to drag a shield through a trench can put tremendous forces on rigging components. For example, the force required to drag a 10,000-pound trench shield through a narrow trench will increase dramatically with resistance from the trench walls or from plowing of the front of the shield. Know the sling’s rated capacities and never exceed them. The whiplash effect of a broken or improperly rigged sling can kill anyone in its path.
- Follow the instructions in the operator’s manual when using an excavator to lift or move an object.
- “Lift and drag” to move a trench shield horizontally in a trench; avoid “plowing” with the front of the shield. Plowing significantly increases the tension on the slings.
- Some manufacturers of trench shields warn workers to stay out of the “box” while it is being moved. Always check the manufacturers’ requirements.
- Never use damaged chains, frayed cables, slings, straps, or ropes.
- Use an appropriate lifting shackle for attaching cables or slings.
- Never stand in line with or next to a sling that is under tension.