2.5 Personal Protective Equipment
D.M. Donner
Personal protective equipment (PPE) is protective clothing or equipment that protects the wearer against injury. PPE is the last line of defense from injury when all other options have been exhausted. Before selecting PPE for protection, the hazard must be evaluated for possible controls. The hierarchy of controls for hazards are: elimination, substitution, engineering controls, administrative controls, and then PPE.
Consider workers who operate rotating equipment such as manual lathes and milling machines. One of the hazards associated with the operation of this equipment is the creation of hot and sharp metal chips caused by the cutting process. Can this hazard be eliminated from the process? If so, use that method. If not, proceed to substitution. Can another process be used that has fewer hazards? Has a new process been created that may be used in place of the current process? 3D printing and other additive methods do not have the same hazards. Next is engineering controls; can we isolate the worker from the hazards? CNC lathe and milling centers do this by creating an enclosure around the cutting operation, which solves the problem. However, this is not feasible for small quantities or repair operations. Administrative controls are processes tailored to reduce injuries. These are often referred to as best practices, and they vary from shop to shop. Using rough cutting passes on the mill, which sends the chips away from the operator, is a good best practice if possible.
Finally, we get to PPE. For the hazards that have progressed through our efforts at mitigation without a solution, we must find equipment or clothing to protect the operator. The list of PPE for manual lathes and mills includes:
- Machine shields to intercept chips coming off the cutter
- Face shields
- Eye protection
- Cotton clothing to protect the skin
Let’s take a look at PPE commonly used in the machining industry.
Clothing and Accessories
What you wear in a machine shop impacts your safety. Long sleeves and loose-fitting clothes such as “hoodies” can get caught in the rotating assemblies of equipment and pull you into the rotating mechanisms.
In the image above, a shirt sleeve was caught in the knurling of a part being turned on the lathe. The garment quickly wrapped around the part, and the lathe’s powerful motor tore the shirt off the operator as he braced himself against the machine.
To prevent getting caught in the rotating assemblies of machines, roll sleeves above the elbow, and do not wear gloves while operating equipment. Remove jewelry from around your neck, wrists, and hands. Tie long hair up and away from the front of your body.
Synthetic materials such as nylon and polyester will melt when in contact with hot metal chips formed during the cutting processes. Cotton is a better choice when selecting work clothes for the machinist. A close-fitting neck will also aid in preventing hot chips from contacting your neck a