Machinery related hazards continue to result in hundreds of deaths and thousands of serious injuries each year. In 2019, 2,963 deaths occurred in the construction, transportation and warehousing, agriculture, forestry, fishing and hunting, and manufacturing industries in the United States¹. Additionally, serious injuries continue to pose a major challenge to these industries and in 2018 6,200 non-fatal amputations occurred in the US, with 58% of these involving machinery².

Adopting a lifecycle based approach to identifying, mitigating, and maintaining protections against machinery hazards is critical to lowering the fatality and accident rates. This approach must start with the accurate understanding of the hazards posed by the operation of the equipment. International standards such as ISO 12100 Safety of machinery — General principles for design — Risk assessment and risk reduction provide best practices and guidelines for conducting machinery risk assessments consistently.

In general, two types of hazard assessments are conducted for machinery applications:

• Equipment-Based Machine Hazard Analysis
• Task-Based Machine Hazard Analysis (Job Safety Analysis)

Equipment-Based hazard analysis focuses on the physical hazards of the machinery application, considering the mechanical, electrical, and chemical (if applicable) sources of hazards in the application requiring safeguarding. The risk assessment focuses on providing adequate guarding and other means of protection between the operators and the equipment. The most common methodologies for this type of risk assessment are Hazard and Operability Studies (HAZOP) or Failure Mode and Effects Analysis (FMEA).

Task-Based hazard analysis focuses on the specific steps that will be taken by each group that interacts with the machine (e.g., operators, maintenance technicians). For each group all of the tasks completed are documented and are reviewed to determine if any hazards are present. Where hazards are identified strategies for risk mitigation are documented including changes to operating/ maintenance procedures and additional guarding.

Both machine risk assessment types have strengths and weaknesses, and accurately identifying all of the potential risks for an application requires that the most appropriate methodology. As such, understanding which applications are best addressed by an equipment focused risk assessment and which require a task-based approach is a key step when developing policies and procedures for machine risk assessments within an organization.

To learn more about the types of machine risk assessments as well as how these risk assessments feed into the machine safety lifecycles from ISO 13849 Safety Of Machinery - Safety-Related Parts Of Control Systems - Part 1: General Principles For Design and IEC 62061 Safety Of Machinery - Functional Safety Of Safety-Related Electrical, Electronic And Programmable Electronic Control Systems please join us on our upcoming webinar:

1.  U.S. Department of Labor, Bureau of Labor Statistics, Census of Fatal Occupational Injuries, 2019
2. Bureau of Labor Statistics, U.S. Department of Labor, The Economics Daily, Machinery involved in 58 percent of work-related amputations in 2018