Safety of Machinery Flashcards
What is the purpose of ISO12100:2010?
- Framework and guidance for decision making during machine design.
- Design machines that are safe for their intended use.
- Type A standard covers
- basic terminology and
concepts of safety of
machinery
- principles and
methodology for
achieving safety in
design.
- risk assessment and
risk reduction
Define machinery / machine.
Assembly, fitted with / intended to be fitted with a drive system, consisting of linked parts of components, at least one of which moves, and which are joined together for a specific application.
Define hazard.
Source of harm (physical injury or damage to health).
Define risk.
Combination of the probability of occurrence of harm and the severity of that harm.
Define limit.
Bounds in which machine operates. / Designed limits such as space limit, pressure limit, load moment limit, etc.
Define emergency stop.
-Avert arising or reduce existing hazards to persons, damage to machinery or to work in progress, and
-be initiated by a single human action.
What are the 4 steps of risk assessment?
1) Determine machinery limits.
2) Identify hazards.
3) Estimate risks.
4) Evaluate risks.
Elaborate on the first step of risk assessment (determining machinery limits).
This step informs the intended operation / use of machinery.
Consider the entire machine life cycle.
Limits include use limits, space limits, time limits, and other
Elaborate on the second step of risk assessment (identify hazards).
Hazards may arise from inherent dangers associated with intended operation.
Hazards may also arise from unintended operation or misuse of machinery.
In this step, consider the entire machine life cycle, what happens when the machine does not operate as intended, and what happens when operator misuses the machine.
Elaborate on the third step of risk assessment (estimate risks).
Risk depends on the severity of harm and the probability of occurrence.
Severity: slight, serious, or death; extent (number of people involved).
Probability of occurrence: exposure (time exposed / frequency of exposure) and likelihood of occurrence (expected, possible, unusual, or unlikely).
Qualitative or quantitative: used standards, based on data; refer to sources, state uncertainty.
Elaborate on the fourth step of risk assessment (risk evaluation).
Iterative process.
Determine is risk reduction is necessary.
Assess adequacy of risk reduction.
Check if additional hazards were introduced during risk reduction (if so, iterate risk evaluation).
How can risks associated with hazards be reduced?
Eliminate hazards.
Reduce the severity of harm.
Reduce the probability of occurrence.
What steps can be applied in sequence to reduce risks?
1) Design for inherent safety.
2) Include safeguards.
3) Provide information for use.
What does designing for inherent safety entail?
Hint: MEEPCMA
Mechanical safety
- limit forces, masses, velocities
- limit emissions (noise, radiation)
- consider mechanical stresses and material properties (safety factors)
- avoid sharp edges
Ergonomics
- accessibility
- ease of handling
- ease of operation
- comfort
- visibility
Electrical hazards
- short circuit
- shock
- water exposure
Pneumatic and hydraulic hazards
- safe rated pressures
- vessels comply with design codes
- automatically depressurize when off
Control systems
- provide specific operating modes (normal start-up, restart after e-stop, remove workpiece, etc.)
- prevent accidental generation of unexpected start command
- maintain stop commands to prevent unexpected restart (e.g. after interrupted power supply)
- limit movements of machine parts to within safe parameters
- display faults clearly
Manual controls
- accessible
- visible
- marked
- safely operated
Automation
- limits exposure to hazards
- e.g. low temperatures in biobank
What does including safeguards entail?
Types include:
- access prevention
- containment
- special characteristics (insulating, noise dampening, etc.)
Examples include:
- fixed or mobile guards
- enclosures
- light curtains
What does risk reduction by providing information entail?
Convey information about residual risks to user.
Texts, words, signs, signals, symbols, or diagrams.
Located in/on machine, in documents, on packaging
Unambiguous, clear and visible
Signals and warning devices in case of hazardous events.
What does the documentation of risk analysis and reduction include?
Description of machinery (intended operation, limits)
Relevant assumptions (loads, strengths, safety factors)
Hazardous events.
Risk assessment (include data and sources).
Risk reduction
Residual risks.
