When Completing A Risk Assessment – How Do I Prioritise Risk Reduction Measures?




ANSI B11.0 – 2015 Safety of Machinery. B11.0 from the American National Standards Institute provides the particularly useful ‘Hazard Control Hierarchy’ shown in the table below.

Risk Assessment


You will be performing risk assessments every day. As we go about our daily lives, we identify hazards and the risks associated. Without realising it, we complete a dynamic risk assessment every time we cross the street as we check whether cars are coming and make the decision to proceed or not.



Stop lights are a welcome risk reduction measure. When it comes to the workplace, risk assessments suddenly appear to be more complex. However, useful risk assessment guidance is available for machinery safety via the use of available standards documentation.



It’s worth remembering that when it is not possible to eliminate risk through design, Engineering Controls including interlocks become the “preferred” method of risk reduction as they can greatly reduce the probability of harm occurring. Training, Lockout Tagout (LOTO), and Personal Protective Equipment (PPE) are lower in the hierarchy as they rely on people remembering and following procedures.

The Hazard Control Hierarchy (B11.0 Table 2)


Risk Reduction Measures


Influence on Risk Factors


Elimination or Substitution

  • Eliminate pinch points (increase clearance)
  • Intrinsically safe (energy containment)
  • Automated material handling (robots, conveyors, etc.)
  • Redesign the process to eliminate or reduce human interaction
  • Reduced energy
  • Substitute less hazardous chemicals
  • Impact on overall risk (elimination) by affecting severity and probability of harm
  • May affect the severity of harm, frequency of exposure to the hazard under consideration, and/or the possibility of avoiding or limiting harm depending on which method of substitution is applied

Design Out



Devices and



  • Barriers 
  • Interlocks 
  • Presence sensing devices (light curtains, safety mats, area scanners, etc.)
  • Two hand control and two hand trip devices
  • Greatest impact on the probability of harm (Occurrence of hazardous events under certain circumstances)
  • Minimal if any impact on the severity of harm

Engineering Controls

Awareness Devices

  • Lights, beacons, and strobes
  • Computer warmings
  • Signs and labels
  • Beepers, horns, and sirens

  • Potential impact on the probability of harm (avoidance) 
  • No impact on the severity of harm


Administrative Controls

Training and Procedures

  • Safe work procedure
  • Safety equipment inspections
  • Training
  • Lockout/Tagout*
  • Potential impact on the probability of harm (avoidance and/or exposure)
  • No impact on severity of harm

Administrative Controls

Personal Protective Equipment (PPE)

  • Safety glasses and face shields
  • Ear plugs 
  • Gloves 
  • Protective footwear
  • Respirators
  • Potential impact on the probability of harm (avoidance)
  • No impact on severity of harm

Administrative Controls

*Lockout / Tagout is lower in the hierarchy as it is an administrative control, however it may be required depending on the situation and applicable regulation.
Fortress offers training on machinery safety standards specific to the United States which can be delivered at a customer’s facility. 


Products Mentioned in this Article


Heavy duty guard locking with PROFlsafe and CIP safety


Mechanical Trapped Key