6 Steps to Machine Safety Risk Assessment

Occupational health and safety legislation requires (amongst other things) persons who supply machinery to, so far as is practicable, ensure that persons properly using the machinery are not exposed to hazards. As part of this obligation suppliers are required to provide adequate information in respect of any dangers associated with the machinery, the proper maintenance of the machinery and how to correctly use the machinery.

The reality, unfortunately, is that with a lot of older machines, the safety systems don’t comply with the current Australian OH&S Regulations or the Australian Standard AS4024.1-2006 Safeguarding of Machinery. In such cases it is the responsibility of the employer to insure the hazards and risks are reviewed.

“An employer must, so far as is reasonably practicable, identify all hazards to health and safety associated with the installation, commissioning, decommissioning, dismantling, erection and use of plant and the systems of work associated with that plant.” 3.5.23 (2) Occupational Health and Safety Regulations 2007 S.R. No. 54/2007

Step 1 Identify Hazards

All hazards with in the plant must be identified in respect with the uses and maintenance of the machinery. These hazards include but not limited to crushing, cutting, shearing, puncturing, abrasion (or burns), and tearing (or stretching)

The common situations which result in injury to persons are:

• Coming into contact or entanglement with a machine. This could include a person being drawn into a machine or being drawn into a position where they might sustain further injury.
• Being caught between a machine and material being used in the machine to manufacture a product.
• Coming into contact or entanglement with material being used in the machine to manufacture a product.
• Being caught between a machine or machine part and a fixed structure such as a wall, column or fixed machine.
• Being struck by parts of the machine during failure or break-up of the machine.
• Being struck by material ejected from the machine.
• Being struck as a result of a release of potential energy.

Step 2 Risk Prioritisation

Assessing the risks associated with each hazard is a way of identifying which hazards need to be controlled and which to tackle first.

Assess the severity, frequency and probability and add the score of each associated with the category to determine the risk level.

For risk levels:

< 4 Low Risk – Modification should be considered for employee safety
5 – 7 Medium Risk – Modifications should be undertaken for employee safety
8 – 10 High Risk – Immediate modification must be undertaken for employee safety
>10 Extreme Risk – Do not use until modification has been undertaken

Step 3 Categorise Risk

Once hazards have been identified and prioritised, the risk must be categorised to determine the control measures required this is done by

• assess the severity of possible injury
• assess the frequency or time spent in the hazardous area
• assesses the possibility of avoiding the danger

This process may involve some subjective judgements. Make your "best estimate" and have another person, knowledgeable about the hazard and work practices, carry out a check assessment. This will ensure a somewhat systematic estimate.

Severity of injury
S1: Minor Injury
S2: Severe or Loss Time Injury or Death of Person

Frequency of Exposure and/or Duration
F1: Seldom Up to Often (Less than once a day)
F2: Frequently Up to Continuous (Once a day or more than 5 min each time)

Possibility of Avoiding the Danger
P1: Possible under certain conditions or easily avoid danger (I.E. slow moving machines)
P2: Scarcely Possible

Category B

Safety related parts, of the machine control system and/or their protective equipment as well as their components, shall be designed, constructed, selected, assembled and combined in accordence with the relevant standards so that they will withstand any expected influence.

This Category has no special measures but form the base of other categories

Category 1

The requirements of categories B applied together with the uses of well tried safety components and safety principles.

Normally single channel from safety devices to control isolation device. Safety circuits must be hard wired. The occurrence of a fault can lead to the loss of safety function but the probability of occurrence is lower than category B

Category 2

The requirements of category 1 and the use of well tried safety components and safety principles.

The safety functions must be checked at the time of machine start up and periodically by the machine control system. The occurrence of a fault can lead to the loss of safety function between the checks. The loss of safety function is detected by check.

Category 3

The requirements of category 2 and the use of well tried safety components and safety principles.

The system shall be designed so that a single fault will be detected, but an accumulation of faults can lead to a loss of safety. Requires dual circuits from the safety device through to dual isolation and a 1:1 ratio of safety monitoring relays and safety devices is not required

Category 4

The requirements of category 3 and the use of well tried safety components and safety principles.

The system shall be designed so that a single fault will be detected and an accumulation of faults will not lead to a loss of safety. Requires dual circuits from the safety device through to dual isolation and a 1:1 ratio safety monitoring relays and safety devices is required.

Step 4 Decide on Control Measures

An employer must ensure that any risk associated with machinery is eliminated so far as is reasonably practicable.

If it is not reasonably practicable to eliminate a risk associated with plant, an employer must reduce that risk so far as is reasonably practicable, by:

• Substituting the machinery with one that has a lower level of risk
• Use of Engineering Controls
• Eliminate access to the danger

If an employer uses guarding as a measure to control risk, the employer must ensure

• The guarding will prevent access to the danger point
• Guarding can not be by-passing or disabled easily, whether deliberately or by accident
• If access to the area of the machine that requires guarding is not necessary during operation, maintenance or cleaning the guarding must be a permanently fixed physical barrier or
• If access to the machine is necessary during operation, maintenance or cleaning of the plant, the guarding is to be an interlocked physical barrier that allows access to the area being guarded
• if it is not reasonably practicable to use guarding referred to above, the guarding used is a physical barrier that can only be altered or removed by the use of tools
• if it is not reasonably practicable to use guarding referred above, a presence-sensing safeguarding system is used that eliminates any risk arising from the area of the plant requiring guarding while a person or any part of a person is in the area being guarded.
• If safety has been breached all hazardous energy sources include: electrical, mechanical, hydraulic, pneumatic, chemical, thermal, potential, stored, and others must be isolated.

Step 5 Implement Control Measures

When implementing the safety system ensuring:

• Ensuring that equipment is selected and installed on the basis of the risk factors of the area and the category of the machinery and the suitability of the equipment for those risks;
• Following manufacturer's or supplier's advice about the suitability of electrical equipment for the installation and method of use intended;
• Implementing a maintenance regime which considers the use of the equipment and the manufacturer's instructions regarding repair, cleaning, maintenance, etc.

Step 6 Monitor and Review

Whenever a change in work environment occurs, or whenever there is a change in the type of equipment used, moving of the machine to a new area or any modification are made to the machine, you must review the relevant parts of the risk assessment.

A practical way to do this is when you have an electrical contractor at your workplace doing some electrical work or maintenance. Get them to review your risk assessment while they are there.

Records of monitoring, review, maintenance, inspections and tests should be kept and made available for inspection at your workplace.

If you implement these above steps you will reduce the risk of injury with in your plant. In order to find out more about risk assessment or machine safety or require someone to conduct a risk assessment in your plant, talk to Mobile Electrics to organise a meeting.

Note: all care has been taken in preparing this article, however the responsibility remains with the person conducting the risk assessment to read all the relevant OH&S regulations and Australian Standards.