Safeguarding - Working around Machinery

Note: This OSH Answers fact sheet is part of a series. Please see Safeguarding – General for more information.

The CSA Standard Z432-16 Safeguarding of machinery provides detailed guidance for the design, installation, use and maintenance of machinery.  The use of machinery in a workplace exposes workers using it, and people near it, to various hazards. CSA standard Z432-16 defines machinery as:

“an assembly of linked parts or components, at least one of which moves, with the appropriate machine actuators, control and energy circuits, etc. joined together for a specific application, in particular for the processing, treatment, moving, or packaging of material.”

Note: This OSH Answer fact sheet is based on CSA standard Z432-16 Safeguarding of machinery. Please refer to this standard in its entirety and any regulatory requirements that may apply for your jurisdiction.

Hazards associated with working near or on machinery vary depending on the exact machine used but can include exposure to:

• moving parts (e.g., risk of injuries from entanglement, friction, abrasion, cutting, severing, shearing, stabbing, puncturing, impact, crushing, drawing-in or trapping, etc.)
• energy (e.g., electrical, electromagnetic, magnetic, etc.)
• heat or cold
• noise
• vibration
• radiation
• gas or liquid under pressure (e.g., injuries from injection or ejection by hydraulic systems, pneumatic systems, compressed air, paint sprayers, etc.)
• psychosocial hazards (e.g., stress, job content, work organization, cognitive factors, etc.)

Because there are many different types of machines and processes, a risk assessment should be conducted for each machine or situation, and in some cases, before each use. It may be necessary to involve individuals with specialized or technical expertise (i.e., engineer, safety professional, manufacturer, etc).

Each piece of powered equipment should be assessed using the following process:

1. Understand how the machine is designed.
2. Understand how to use the machine safely.
3. Identify all tasks performed by and associated with the machine:
   • What hazards may occur from use and misuse of the machine?
   • What moving parts and corresponding safeguards are currently in place?
4. Identify who will be using the machine, and how often the machine will be used.
5. Determine what materials are used with the machine (e.g., sheet metal, wood, metalworking fluid, oil, etc.).
6. Estimate the risk of each hazard by considering the:
   • Severity of possible injuries and or incidents, and
   • Probability or likelihood of occurrence.
7. Eliminate the hazard(s) where possible.
8. Use protective measures to control the risk of each hazard including considering:
   • the design,
   • safeguarding and protective devices,
   • administrative controls, or
   • other measures.
9. Re-assess to estimate the new risk level.
10. Repeat the process if the risk level has not been eliminated or effectively controlled.

Severity of the injury can be determined by asking two main questions:

• What type of mechanical or other hazard is involved?
• What type(s) of injury could happen?

The probability of the injury should be determined by reviewing information about the machine’s operation such as:

• exposure to a machine that could cause the injury while working with or around the machine (e.g., entanglement, contact with blade, etc.)
• potential human behaviour while performing these tasks
• reports of machine breakdowns, etc.

These three factors can be combined to determine the probability of injury from a particular task. 

Determine a risk rating for each type of injury by assuming no protective measures have been installed on the machine.  This evaluation will help when determine if sufficient action has been taken to prevent injury. The CSA Standard Z432 provides additional details on the assessment process.

The following checklist will help identify hazards in your workplace. It is important to tailor the information to your workplace and add any additional items as necessary.