Machine safety and safeguarding glossary

Machine safety

German: Maschinensicherheit

In machine safety, machine safety is the discipline of protecting people, assets and the environment from hazards created by machinery across its whole lifecycle, from design and commissioning to operation, maintenance and decommissioning.

Machine safety · Risk assessment

Safety culture

In machine safety, safety culture is the set of shared values, practices and behaviors in an organization that make safety an operational priority. It shows in how people report hazards, follow procedures and decide when safety and production goals conflict.

Machine safety · Human factors

Safety-first mindset

In machine safety, a safety-first mindset is a decision-making approach that considers hazards and controls before production convenience. It asks what could go wrong and which protective measures are needed before a task, change or restart goes ahead.

Machine safety · Human factors

Acceptable risk

In machine safety, acceptable risk is risk that has been reduced to a level accepted under the applicable criteria and context. Whether a risk is acceptable depends on legal requirements, the state of the art and the documented acceptance criteria, not on a single universal threshold.

Machine safety · Risk assessment

Administrative control

In occupational and machine safety, an administrative control is a policy, procedure, schedule, supervision practice or training measure used to reduce exposure to a hazard. It relies on people following it, so it ranks below elimination, substitution and engineering controls in the hierarchy of controls.

Machine safety · Human factors

Complementary protective measure

In machine safety, a complementary protective measure is a protective measure that is neither an inherently safe design measure nor a safeguard, such as an emergency stop. ISO 12100 places it in the second step of the three-step method, together with safeguarding.

Machine safety · Risk assessment

Engineering control

In occupational and machine safety, an engineering control is a physical or technical measure that reduces exposure to a hazard without relying mainly on individual behavior. Guards, interlocks, extraction systems and enclosures are typical examples.

Machine safety · Risk assessment

Harm

In machine safety, harm is physical injury or damage to health. It is the outcome that risk assessment tries to prevent, and its severity is one of the two elements of risk.

Machine safety · Risk assessment

Hazard

In machine safety, a hazard is a potential source of injury or damage to health. Hazards are usually classified by origin, such as mechanical or electrical, or by the nature of the potential harm, such as crushing or burns.

Machine safety · Risk assessment

Hazardous event

In machine safety, a hazardous event is an event that can cause harm. It can be of short duration, such as an unexpected start-up, or develop over a longer period, such as a gradual loss of guard integrity.

Machine safety · Risk assessment

Hazardous situation

In machine safety, a hazardous situation is a circumstance in which a person is exposed to at least one hazard. The exposure can lead to harm immediately or over time.

Machine safety · Risk assessment

Hierarchy of controls

In occupational and machine safety, the hierarchy of controls is the ordered preference for elimination, substitution, engineering controls, administrative controls and personal protective equipment. Measures higher in the order are generally more effective because they depend less on human behavior.

Machine safety · Risk assessment · USA

Inherently safe design measure

German: Inhärent sichere Konstruktionsmaßnahme

In machine safety, an inherently safe design measure is a design measure that eliminates a hazard or reduces risk without relying on guards, protective devices or user behavior, for example by changing the design or the operating characteristics of the machine. It is the first step of the three-step method.

Machine safety · Risk assessment

Intended use

In machine safety, intended use is the use of machinery in accordance with the information provided by the manufacturer, in particular the instructions for use. It defines the baseline for the risk assessment, together with reasonably foreseeable misuse.

Machine safety · Technical documentation · EU

Machine limits

In machine safety, machine limits are the use, space, time, environmental and other boundaries considered in risk assessment. Determining them is the first step of risk analysis under ISO 12100.

Machine safety · Risk assessment

Personal protective equipment (PPE)

In occupational and machine safety, personal protective equipment (PPE) is equipment worn by a person to reduce exposure to hazards, such as safety glasses, hearing protection, gloves or safety footwear. It is the last level of the hierarchy of controls.

Machine safety · Human factors

Reasonably foreseeable misuse

German: Vernünftigerweise vorhersehbare Fehlanwendung

In machine safety, reasonably foreseeable misuse is use of machinery in a way not intended by the manufacturer but which can result from readily predictable human behavior. Manufacturers must consider it in risk assessment, not only intended use.

Machine safety · Risk assessment · Human factors

Residual risk

German: Restrisiko

In machine safety, residual risk is the risk remaining after risk reduction measures have been implemented. The manufacturer must inform users about residual risks that are relevant to them.

Machine safety · Risk assessment · Technical documentation

Risk

In machine safety, risk is the combination of the probability of occurrence of harm and the severity of that harm. It is always related to a specific hazard and a hazardous situation.

Machine safety · Risk assessment

Risk acceptance justification

In machine safety, a risk acceptance justification is the documented rationale for accepting a residual risk, including the acceptance criteria, assumptions, approvals and evidence. It makes the decision to stop reducing risk reviewable.

Machine safety · Risk assessment · Technical documentation

Risk analysis

In machine safety, risk analysis is the process of determining the limits of the machinery, identifying hazards and estimating risk. Together with risk evaluation it forms the risk assessment.

Machine safety · Risk assessment

Risk assessment

German: Risikobeurteilung

In machine safety, risk assessment is the overall process comprising risk analysis and risk evaluation. It is carried out iteratively together with risk reduction until the remaining risk is judged acceptable.

Machine safety · Risk assessment · EU

Risk estimation

German: Risikoeinschätzung

In machine safety, risk estimation is the process of assigning values to the probability and severity components of risk. The values can be qualitative, semi-quantitative or quantitative.

Machine safety · Risk assessment

Risk evaluation

German: Risikobewertung

In machine safety, risk evaluation is the judgment, based on risk analysis, of whether risk reduction is required. It compares the estimated risk with the objectives of adequate risk reduction.

Machine safety · Risk assessment

Risk reduction

German: Risikominderung

In machine safety, risk reduction comprises the measures used to eliminate hazards or reduce the associated risks. For manufacturers, ISO 12100 structures it as the three-step method; users add their own measures, such as organization, training and PPE.

Machine safety · Risk assessment

Safeguard

German: Technische Schutzmaßnahme

In machine safety, a safeguard is a guard or protective device used to reduce risk. A guard is a physical barrier; a protective device, such as a light curtain or two-hand control, reduces risk alone or together with a guard.

Machine safety · Risk assessment

Safeguarding

In machine safety, safeguarding is the application of guards, protective devices and related measures to protect people from hazards that cannot reasonably be eliminated, or risks that cannot be sufficiently reduced, by inherently safe design measures. It is the second step of the three-step method.

Machine safety · Risk assessment · USA

Three-step method

In machine safety, the three-step method is the ISO 12100 order of risk reduction: first inherently safe design measures, then safeguarding and complementary protective measures, then information for use. Each step is applied only to the extent the previous one cannot reduce risk adequately.

Machine safety · Risk assessment · EU

Hazard identification

German: Gefährdungsermittlung

In machine safety under ISO 12100, hazard identification is the step of risk analysis in which all reasonably foreseeable hazards, hazardous situations and hazardous events are systematically identified across all phases of the machine's life and all tasks.

Machine safety · Risk assessment

Protective measure

German: Schutzmaßnahme

In machine safety under ISO 12100, a protective measure is a measure intended to achieve risk reduction. It can be implemented by the designer, through inherently safe design, safeguarding and complementary protective measures, and information for use, or by the user, through organization, safe working procedures, additional safeguards, personal protective equipment and training.

Machine safety · Risk assessment

Biological hazard

In machine safety, a biological hazard is a hazard arising from biological agents, such as bacteria, viruses, molds or fungi, or from materials contaminated with them.

Machine safety · Risk assessment · Maintenance

Bypass behavior

In machine safety, bypass behavior is the intentional defeat or avoidance of a protective measure, such as bridging an interlock switch or reaching around a guard. It is often driven by poor usability, nuisance trips or production pressure.

Machine safety · Human factors · Risk assessment

Chemical hazard

In machine safety, a chemical hazard is a hazard arising from exposure to hazardous substances, fumes, vapors, dusts or process media, for example by inhalation, skin contact or ingestion.

Machine safety · Risk assessment · Technical documentation

Crushing hazard

In machine safety, a crushing hazard is a mechanical hazard in which a body part can be compressed between moving parts, or between a moving part and a fixed object.

Machine safety · Risk assessment

Cutting hazard

In machine safety, a cutting hazard is a mechanical hazard created by a sharp edge, a blade or a cutting process that can cut or sever tissue.

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Drawing-in hazard

In machine safety, a drawing-in hazard is a mechanical hazard in which a person or body part can be pulled into moving parts, typically at in-running nips between rollers, belts and pulleys, or gears.

Machine safety · Risk assessment · Human factors

Ejection hazard

In machine safety, an ejection hazard is a hazard created when a workpiece, tool, fragment or process material is expelled from the machine, for example after a tool breaks or a clamp releases.

Machine safety · Risk assessment

Electrical hazard

In machine safety, an electrical hazard is a hazard arising from electrical energy, including electric shock, arc flash, burns or unintended energization of equipment.

Machine safety · Maintenance · Technical documentation

Entanglement hazard

In machine safety, an entanglement hazard is a mechanical hazard in which clothing, hair or body parts can be caught by rotating or moving parts, such as shafts, couplings, spindles or chucks.

Machine safety · Human factors

Ergonomic hazard

In machine safety, an ergonomic hazard is a hazard arising from poor design of the task, workplace, tools, posture, force, repetition or workload, which can lead to musculoskeletal disorders, fatigue or errors.

Machine safety · Human factors

Explosion hazard

In machine safety, an explosion hazard is a condition with the potential for a rapid release of pressure and energy, for example from the ignition of an explosive atmosphere of gas, vapor or dust, or from the failure of a pressurized component.

Machine safety · Risk assessment

Fire hazard

In machine safety, a fire hazard is a condition with the potential to initiate or intensify fire, arising from combustible material, ignition sources such as hot surfaces, sparks or electrical faults, and oxygen.

Machine safety · Risk assessment · Technical documentation

Friction and abrasion hazard

In machine safety, a friction and abrasion hazard is a mechanical hazard caused by contact with moving rough surfaces, belts or rotating tools, which can remove skin and cause friction burns.

Machine safety · Risk assessment

Hazard point

In machine safety, a hazard point is a specific location where hazardous motion, energy or process conditions can cause harm, such as the nip between two rollers or the closing gap of a press tool.

Machine safety · Risk assessment · Technical documentation

Hazardous zone

In machine safety, a hazardous zone is any space within or around machinery in which a person can be exposed to a hazard. ISO 12100 calls it a hazard zone or danger zone.

Machine safety · Risk assessment · Technical documentation

Human error

In machine safety, human error is an action or omission that differs from the intended or required behavior. It must be considered in system design, without treating people as the sole control against a hazard.

Machine safety · Human factors

Impact hazard

In machine safety, an impact hazard is a mechanical hazard from being struck by a moving machine part, a workpiece or an ejected object.

Machine safety · Risk assessment

Line of fire

In machine safety, the line of fire is the path in which a person may be struck, crushed, sprayed or otherwise exposed if energy is released, for example along the travel path of a load or in front of a pressurized fitting.

Machine safety · Human factors · Maintenance

Mechanical hazard

In machine safety, a mechanical hazard is a hazard arising from machine elements that move, rotate, cut, crush or shear, or that hold stored energy.

Machine safety · Risk assessment

Nip point

In machine safety, a nip point is a location where rotating or moving elements can draw in and trap a body part, for example between two rollers or where a belt runs onto a pulley.

Machine safety · Risk assessment

Noise hazard

In machine safety, a noise hazard is a hazard arising from sound levels that can damage hearing or impair communication, including the perception of acoustic warning signals.

Machine safety · Technical documentation · EU

Nuisance trip

In machine safety, a nuisance trip is an unwanted protective stop that does not correspond to an actual hazardous demand, for example a light curtain interrupted by a passing part. Frequent nuisance trips can encourage bypassing.

Machine safety · Human factors

Pinch point

In machine safety, a pinch point is a location where a body part can be caught between two moving parts, or between a moving part and a fixed part.

Machine safety · Risk assessment · Technical documentation

Psychosocial stressor

In occupational safety, a psychosocial stressor is an organizational or social factor, such as time pressure, shift work, unclear roles or isolation, that can contribute to stress, fatigue, distraction or unsafe performance.

Machine safety · Human factors

Puncture hazard

In machine safety, a puncture hazard is a mechanical hazard from pointed tools, projections or materials that can penetrate the body.

Machine safety · Risk assessment

Radiation hazard

In machine safety, a radiation hazard is a hazard arising from ionizing radiation, such as X-rays, or non-ionizing radiation, such as laser light, ultraviolet, infrared or electromagnetic fields.

Machine safety · Risk assessment · Technical documentation

Shearing hazard

In machine safety, a shearing hazard is a mechanical hazard in which moving parts can cut or sever a body part by passing one another, or by passing close to a fixed edge.

Machine safety · Risk assessment

Slip, trip, and fall hazard

In machine safety, a slip, trip, and fall hazard is a hazard caused by poor footing, obstacles, changes in elevation or contaminated surfaces, which can make a person lose balance or fall from height.

Machine safety · Maintenance

Stored energy

In machine safety, stored energy is energy retained in mechanical, electrical, hydraulic, pneumatic, thermal, chemical or gravitational form after normal operation stops, for example in springs, capacitors, accumulators or raised loads.

Machine safety · Maintenance

Thermal hazard

In machine safety, a thermal hazard is a hazard arising from hot or cold surfaces, materials, flames or processes, which can cause burns, scalds, frostbite or heat stress.

Machine safety · Risk assessment · Maintenance

Unexpected startup

In machine safety, unexpected startup is an unintended activation of a machine that exposes people to hazardous motion or energy, for example caused by a control fault, an external influence or a start command given elsewhere.

Machine safety · Maintenance · Risk assessment

Vibration hazard

In machine safety, a vibration hazard is a hazard arising from hand-arm vibration, transmitted through handles and hand-held tools, or whole-body vibration, transmitted through seats or floors.

Machine safety · Technical documentation · EU

Avoidability

In machine safety, avoidability is the possibility that a person can avoid or limit harm once a hazardous event begins. It is one of the elements that determine the probability of harm in risk estimation.

Machine safety · Risk assessment · Human factors

Exposure (risk estimation)

In machine safety risk estimation, exposure is the frequency and duration with which people are exposed to a hazard. It is one of the elements that determine the probability of harm.

Machine safety · Risk assessment

Failure Modes and Effects Analysis (FMEA)

German: Fehlermöglichkeits- und Einflussanalyse (FMEA)

In reliability and safety engineering, Failure Modes and Effects Analysis (FMEA) is a systematic, inductive method for identifying the failure modes of items, their effects, causes and existing controls, and for prioritizing actions. When criticality is assessed as well, it is called FMECA.

Machine safety · Risk assessment

Fault Tree Analysis (FTA)

German: Fehlerbaumanalyse (FTA)

In reliability and safety engineering, Fault Tree Analysis (FTA) is a deductive method that analyzes combinations of causes leading to a defined top event. It represents these combinations with logic gates such as AND and OR and can be evaluated qualitatively or quantitatively.

Machine safety · Risk assessment

Hazard and Operability Study (HAZOP)

In safety engineering, a Hazard and Operability Study (HAZOP) is a structured, guideword-based method for examining deviations from the intended operation of a process or system. A multidisciplinary team applies guidewords to process parameters to find hazards and operability problems.

Machine safety · Risk assessment

Hazard log

In safety engineering, a hazard log is a controlled record of identified hazards, risk decisions, controls, status and evidence. It is maintained throughout the lifecycle and shows for each hazard whether it is open, mitigated or closed.

Machine safety · Risk assessment · Technical documentation

Job hazard analysis (JHA)

In occupational safety, a job hazard analysis (JHA) is a task-focused method that identifies the hazards and controls for each step of a job. It breaks a job into steps, identifies what can go wrong in each and defines how to prevent it.

Machine safety · Human factors · USA

Likelihood

In machine safety risk estimation, likelihood is the estimated chance that harm will occur, considering exposure and the probability of the hazardous event. It is combined with severity to estimate risk.

Machine safety · Risk assessment

Risk matrix

In safety engineering, a risk matrix is a matrix that combines severity and likelihood categories to support risk estimation or prioritization. Each cell assigns a risk level that guides whether and how urgently risk reduction is needed.

Machine safety · Risk assessment

Severity

In machine safety risk estimation, severity is the magnitude of possible harm. It considers how serious the injury or damage to health can be and how many persons can be affected.

Machine safety · Risk assessment

Adjustable guard

In machine safety, an adjustable guard is a guard that can be adjusted to accommodate different workpiece dimensions or operations. It is adjustable as a whole or has adjustable parts, and it keeps its setting during a given operation.

Machine safety · Human factors

Barrier guard

In machine safety, a barrier guard is a physical barrier that prevents access to a hazard. It works by separating the person from the hazard zone rather than by detecting the person.

Machine safety · USA

Fixed guard

In machine safety, a fixed guard is a guard attached so that it can be opened or removed only with tools or by destroying its attachment, for example by screws, nuts or welding.

Machine safety · Maintenance

Guard integrity

In machine safety, guard integrity is the ability of a guard to retain its protective function under expected loads, impacts, wear and environmental conditions over the life of the machine.

Machine safety · Maintenance

Guard opening

In machine safety, a guard opening is an opening in a guard whose size and distance from the hazard must prevent access. The permissible size depends on which body part could pass through it and how far the hazard lies behind it.

Machine safety · Risk assessment

In-running nip point

In machine safety, an in-running nip point is a location where rotating surfaces move toward each other or where a rotating surface approaches a fixed surface, so that body parts, clothing or hair can be drawn in.

Machine safety · USA

Interlocking guard

German: Verriegelte trennende Schutzeinrichtung

In machine safety, an interlocking guard is a guard associated with an interlocking device so that hazardous machine functions are controlled by guard position: they cannot run until the guard is closed, and opening the guard issues a stop command.

Machine safety · EU

Interlocking guard with guard locking

In machine safety, an interlocking guard with guard locking is a guard kept closed and locked until the risk from hazardous functions has ceased, for example until a spindle has run down.

Machine safety · EU

Linear motion

In machine safety, linear motion is movement along a straight path that can create crushing, shearing or impact hazards, for example where a moving part approaches a fixed part or a person.

Machine safety · Risk assessment

Minimum distance

In machine safety, the minimum distance is the calculated separation needed between a protective device or guard opening and a hazard, so that a person cannot reach the hazard before hazardous motion has ceased. ISO 13855 calculates it from approach speed, overall stopping time and an intrusion allowance.

Machine safety · Risk assessment

Movable guard

In machine safety, a movable guard is a guard that can be opened without tools and is therefore normally linked to the machine control system, typically through an interlocking device.

Machine safety · Human factors

Oscillating motion

In machine safety, oscillating motion is repeated angular movement around a pivot that can create trapping or impact hazards, for example where a swinging arm passes close to a fixed part.

Machine safety · Risk assessment

Perimeter guard

In machine safety, a perimeter guard is a barrier that prevents or limits access to a hazardous area around machinery, typically a fence enclosing a robot cell or an integrated production line.

Machine safety · Risk assessment

Point of operation

In machine safety, the point of operation is the location where work is performed on material, such as cutting, forming, drilling or pressing. OSHA's general machine guarding rule requires the point of operation of machines whose operation exposes an employee to injury to be guarded.

Machine safety · USA

Power transmission apparatus

In machine safety, power transmission apparatus are the machine components that transmit energy or motion, including shafts, belts, pulleys, gears, chains, sprockets and couplings, as distinct from the point of operation where work is done.

Machine safety · USA

Protective structure

In machine safety, a protective structure is a structure designed to prevent or reduce harm from ejected objects, falling objects, rollover or other mechanical events, for example a roll-over or falling-object protective structure on mobile machinery.

Machine safety · EU

Reach distance

In machine safety, the reach distance is the distance considered when determining whether a person can reach a hazard over, under, around or through a safeguard. It is based on body dimensions and is the input for choosing safe distances.

Machine safety · Human factors

Reciprocating motion

In machine safety, reciprocating motion is back-and-forth linear motion that can create crushing, shearing or impact hazards, for example at the ram of a press or the table of a planer.

Machine safety · Risk assessment

Rotary motion

In machine safety, rotary motion is continuous motion around an axis that can create entanglement, drawing-in, cutting or impact hazards, even at low speed and on smooth surfaces.

Machine safety · Risk assessment

Safe distance

In machine safety, a safe distance is a distance selected to prevent a person from reaching a hazard before hazardous motion has ceased. For physical barriers ISO 13857 gives safety distances based on reach; for protective devices ISO 13855 gives the calculated minimum distance.

Machine safety · Risk assessment

Self-adjusting guard

In machine safety, a self-adjusting guard is a guard that moves according to the workpiece and returns automatically to its protective position, so that only the part of the tool needed for the work is exposed.

Machine safety · USA

Tamper resistance

In machine safety, tamper resistance means the design characteristics that make defeat or unauthorized adjustment of a protective measure difficult, such as coded actuators, concealed mounting or tool-secured settings.

Machine safety · Human factors

Pick and place

German: Pick-and-Place

In automation and robotics, pick and place is the handling task in which a robot or handling system picks up parts at one position and places them at another, for example for sorting, packaging, assembly or machine loading.

Machine safety

Active opto-electronic protective device (AOPD)

In machine safety, an active opto-electronic protective device (AOPD) is an ESPE device that uses opto-electronic sensing to detect interruption of a protected field. Its own emitters and receivers create the field, as in safety light curtains and multi-beam light grids.

Machine safety · EU

Blanking

German: Blanking

In machine safety, blanking is a configured allowance for defined objects or areas within a protective sensing field, so that these objects do not trigger a stop. Fixed blanking ignores a fixed area; floating blanking ignores an object of limited size anywhere in the field.

Machine safety · Risk assessment

Electrical interlock

In machine safety, an electrical interlock is an interlock implemented through electrical contacts, wiring or electronic control logic, for example a guard switch wired to a safety relay that removes power from a drive.

Machine safety · Technical documentation

Electro-sensitive protective equipment (ESPE)

In machine safety, electro-sensitive protective equipment (ESPE) is protective equipment that detects persons by optical, capacitive, ultrasonic or other non-contact means and initiates a protective response in the machine control.

Machine safety · EU

Enabling device

German: Zustimmeinrichtung

In machine safety, an enabling device is a manually operated device that permits machine operation only while held in a specified position. Used with a start control, it lets a person work in the hazard zone with other safeguards suspended, for example during setup or teaching.

Machine safety · Human factors

Guard locking

German: Zuhaltung

In machine safety, guard locking is a function that keeps a guard closed until hazardous conditions have ended or release is permitted. It is typically realized by a guard locking device combined with an interlocking device.

Machine safety · EU

Hardwired interlock

In machine safety, a hardwired interlock is an interlock implemented primarily with dedicated wiring and components rather than programmable application logic, so that its behavior does not depend on software written for the machine.

Machine safety · Technical documentation

Hold-to-run control

In machine safety, a hold-to-run control is a control that permits operation only while it is continuously actuated. Releasing it stops the hazardous function.

Machine safety · Human factors

Interlock

German: Verriegelung

In machine safety, an interlock is a device or logic function that prevents or stops hazardous operation when specified conditions are not met, for example when a guard is open or a required state has not been reached.

Machine safety · Technical documentation

Manual reset

In machine safety, a manual reset is a reset initiated by a deliberate human action from a location with adequate visibility and control of the safeguarded area. It confirms that the area is clear before the machine can be restarted.

Machine safety · Human factors

Muting

German: Muting

In machine safety, muting is the temporary automatic suspension of a protective function under specified, monitored conditions, typically to let material pass through a light curtain while people are still detected.

Machine safety · Risk assessment

Presence-sensing device (PSD)

In machine safety, a presence-sensing device (PSD) is a device that detects a person or object in or approaching a hazardous zone and initiates a protective response, such as stopping hazardous motion.

Machine safety · USA

Pressure-sensitive mat

German: Schaltmatte

In machine safety, a pressure-sensitive mat is a protective device that detects a person by applied pressure and initiates a protective function, such as stopping hazardous motion or preventing a start while someone stands in the zone.

Machine safety · Maintenance

Protective device

German: Schutzeinrichtung

In machine safety, a protective device is a safeguard other than a guard that reduces risk by detecting a person, controlling access or initiating a protective function, either alone or in combination with a guard.

Machine safety · Risk assessment

Reset function

German: Rücksetzen

In machine safety, a reset function is a deliberate action that restores readiness after a protective function has been triggered. Reset must not initiate hazardous motion; a separate start command is needed.

Machine safety · Human factors

Restart prevention

German: Wiederanlaufverhinderung

In machine safety, restart prevention is a function that prevents hazardous motion from resuming automatically after power restoration, reset or removal of a protective demand, such as closing a guard.

Machine safety · Maintenance

Safety laser scanner

German: Sicherheitslaserscanner

In machine safety, a safety laser scanner is a protective device that monitors configurable areas using laser-based distance measurement. It is a type of electro-sensitive protective equipment that detects persons by diffuse reflection rather than beam interruption.

Machine safety · EU

Safety light curtain

German: Sicherheitslichtvorhang

In machine safety, a safety light curtain is an opto-electronic protective device that creates a sensing field and initiates a stop when the field is interrupted. It is a type of active opto-electronic protective device (AOPD).

Machine safety · EU

Safety zoning

In machine safety, safety zoning is the division of machinery into defined zones so that protective actions can be applied to the affected area, while other zones continue to run or remain in a safe state.

Machine safety · Risk assessment

Safety-rated interlock

In machine safety, a safety-rated interlock is an interlocking device designed and validated for use in a safety-related control function, with documented safety characteristics such as failure data and suitable architecture.

Machine safety · Technical documentation

Two-hand control device

German: Zweihandschaltung

In machine safety, a two-hand control device is a device requiring simultaneous use of both hands to initiate and maintain a hazardous machine function, so that the operator's hands are away from the hazard while it runs.

Machine safety · Human factors

Safety edge

German: Schaltleiste

In machine safety, a safety edge is a pressure-sensitive protective device, usually a profile along a moving part, that produces a stop signal when it is deformed by contact with a person or object. ISO 13856-2 covers pressure-sensitive edges and bars.

Machine safety

Safety switch (interlocking device)

German: Sicherheitsschalter

In machine safety, a safety switch is a position switch used as an interlocking device on a movable guard, detecting whether the guard is closed and, in versions with guard locking, holding it closed. ISO 14119 sets requirements for its design, selection and defeat prevention.

Machine safety · EU

Defined safe state

In machine safety, a defined safe state is a specifically documented safe condition for a machine, zone or function under defined circumstances. It names the concrete condition, such as torque off, brake applied or valve vented, that a safety function or procedure must reach.

Machine safety · Risk assessment · Technical documentation

Emergency stop

German: Not-Halt

In machine safety, an emergency stop is a complementary protective function intended to avert or reduce existing or impending hazards by stopping hazardous operation. It is initiated by a single human action and is not a substitute for safeguards or other protective measures.

Machine safety · EU · Technical documentation

Emergency switching off

German: Not-Aus

In machine safety, emergency switching off is an emergency action intended to remove electrical energy from all or part of an installation where electrical hazards, such as a risk of electric shock, are involved.

Machine safety · Technical documentation

Protective response time

In machine safety, protective response time is the time from detection of a protective demand to achievement of the required protective state. It covers the whole chain of sensor, logic and actuator, including the stopping of the machine.

Machine safety · Risk assessment

Safe Operating Stop (SOS)

German: Sicherer Betriebshalt (SOS)

In drive-based safety, Safe Operating Stop (SOS) is a safety function that maintains a stopped position while actuator power remains available. The drive monitors that the motor does not leave the standstill position beyond a defined tolerance.

Machine safety · Risk assessment

Safe state

German: Sicherer Zustand

In machine safety and functional safety, a safe state is a condition in which risk has been reduced to an acceptable level for the relevant situation. What counts as safe depends on the machine, the hazard and the task being performed.

Machine safety · Risk assessment

Safe Stop 1 (SS1)

German: Sicherer Stopp 1 (SS1)

In drive-based safety, Safe Stop 1 (SS1) is a safety function that initiates and monitors controlled deceleration of the motor, followed by Safe Torque Off (STO) or another safe condition once the motor has stopped or a limit is reached.

Machine safety · Risk assessment

Safe Torque Off (STO)

German: Sicher abgeschaltetes Drehmoment (STO)

In drive-based safety, Safe Torque Off (STO) is a safety function that prevents torque-producing energy from being applied to a motor. The motor cannot generate torque or force, but the drive is not electrically isolated.

Machine safety · Maintenance

Safely-Limited Speed (SLS)

German: Sicher begrenzte Geschwindigkeit (SLS)

In drive-based safety, Safely-Limited Speed (SLS) is a safety function that prevents motor speed from exceeding a specified limit. If the limit is exceeded, the drive initiates a defined fault reaction.

Machine safety · Risk assessment

Stop category 0

Under IEC 60204-1, stop category 0 is stopping by immediate removal of power to the machine actuators, resulting in an uncontrolled stop. The machine comes to rest by friction, inertia or mechanical brakes.

Machine safety · Risk assessment

Stop category 1

Under IEC 60204-1, stop category 1 is a controlled stop with power available to the machine actuators to achieve the stop, followed by removal of power when the stop is achieved.

Machine safety · Risk assessment

Stop category 2

Under IEC 60204-1, stop category 2 is a controlled stop with power remaining available to the machine actuators. The machine is stopped but energized and can resume motion without re-energizing.

Machine safety · Risk assessment

Stopping distance

In machine safety, stopping distance is the distance traveled by hazardous motion after initiation of a stop. It depends on speed, load, braking and the condition of the machine.

Machine safety · Risk assessment

Stopping time

In machine safety, stopping time is the elapsed time from initiation of a stop command until hazardous motion has ceased. It is part of the overall response time used to position protective devices.

Machine safety · Risk assessment · Maintenance

Emergency stop category

German: Not-Halt-Kategorie

In machine safety, the emergency stop category is the stop category according to IEC 60204-1 with which an emergency stop function is carried out. ISO 13850 and IEC 60204-1 require an emergency stop to function either as stop category 0 or stop category 1.

Machine safety · EU

Affected employee

Under OSHA’s lockout/tagout standard, an affected employee is a person whose work may be affected by equipment undergoing energy control, because they operate or use the equipment or work in the area where servicing or maintenance is being performed under lockout or tagout.

Machine safety · USA · Maintenance

Authorized employee

Under OSHA’s lockout/tagout standard, an authorized employee is a person trained and authorized to apply energy control procedures, that is, who locks or tags out machines or equipment in order to service or maintain them.

Machine safety · USA · Maintenance

Center of gravity

In machine safety, the center of gravity is the point at which the weight of an object can be considered concentrated for stability and handling calculations. It determines how a machine or part behaves when lifted, tilted or set down.

Machine safety · Technical documentation

Commissioning

German: Inbetriebnahme

In machine safety, commissioning comprises the activities that verify installation, configuration, function and safety of a machine or system before its operational release. It is a distinct life cycle phase with its own hazards.

Machine safety · Technical documentation

Competency assessment

In occupational safety, a competency assessment is the evaluation of whether a person can apply the required knowledge and skills under relevant conditions. It checks performance, not only attendance at training.

Machine safety · Human factors

Competent person

In occupational safety, a competent person is a person with the knowledge, training and authority needed to identify hazards and take corrective action. The authority to act is part of the definition, not an extra.

Machine safety · Human factors · USA

Corrective maintenance

German: Korrektive Instandhaltung

In maintenance, corrective maintenance is maintenance performed to restore function after a fault or failure. Because it is unplanned, it is often done under time pressure and on equipment in an unexpected state.

Machine safety · Maintenance

Decommissioning

In machine safety, decommissioning is the controlled removal of machinery from service, including the risks from residual energy, contamination, dismantling and disposal.

Machine safety · Technical documentation

Emergency procedure

In occupational safety, an emergency procedure is a controlled response for foreseeable emergencies, defining roles, communication, shutdown, evacuation and recovery.

Machine safety · Human factors · Technical documentation

Energy isolation

In machine safety, energy isolation is the physical prevention of energy transmission or release to equipment, using an energy-isolating device such as a disconnect switch, a line valve or a blank. Control circuit devices such as push buttons or selector switches are not energy-isolating devices.

Machine safety · Maintenance · USA

Inspection interval

In maintenance and safety management, an inspection interval is the specified time, usage or condition threshold between inspections of a machine, component or protective measure.

Machine safety · Maintenance

Lifting point

In machine safety, a lifting point is a designated location on a machine or part intended for the attachment of lifting equipment. It is designed and rated for the loads it has to carry.

Machine safety · Technical documentation

Lockout/tagout (LOTO)

In machine safety, lockout/tagout (LOTO) is a procedure for isolating hazardous energy, securing the isolation devices with locks or tags, and verifying a zero-energy state before servicing or maintenance work begins. In the USA it is governed by OSHA 29 CFR 1910.147.

Machine safety · USA · Maintenance

Lubrication specification

In machine documentation, a lubrication specification is controlled information defining lubricant type, grade, quantity, application point, method and interval for a machine.

Machine safety · Maintenance · Technical documentation

Maintenance interval

German: Instandhaltungsintervall

In maintenance, a maintenance interval is the specified time, usage or condition threshold between maintenance activities on a machine or component.

Machine safety · Maintenance

Permit to work

In occupational safety, a permit to work is a formal authorization process for defined hazardous work under specified controls. It records what work is done, where, by whom, which hazards and controls apply, and when the equipment is handed back.

Machine safety · Maintenance · Human factors

Pre-startup inspection

In machine safety, a pre-startup inspection is a check performed before operation to confirm that required conditions and protective measures are in place, typically before first startup or restart after installation, modification or major maintenance.

Machine safety · Maintenance

Pre-use check

In machine safety, a pre-use check is a user-level check before each use or shift to identify obvious defects or unsafe conditions. It is quick, visual or functional, and does not replace inspection or maintenance.

Machine safety · Human factors

Predictive maintenance

German: Vorausschauende Instandhaltung

In maintenance, predictive maintenance is maintenance based on condition data and analysis used to predict degradation or failure, so work is done when the data indicates it is needed.

Machine safety · Maintenance

Preventive maintenance

German: Vorbeugende Instandhaltung

In maintenance, preventive maintenance is planned maintenance intended to reduce failure probability and preserve required performance, carried out at defined intervals or according to prescribed criteria.

Machine safety · Maintenance

Process media specification

In machine documentation, a process media specification is controlled information defining the properties, limits, compatibility and handling of fluids, gases or other media used by machinery, such as hydraulic oil, coolant, compressed air or cleaning agents.

Machine safety · Technical documentation

Qualified person

In occupational safety, a qualified person is a person with demonstrated skills and knowledge related to the task, the equipment and its hazards. The qualification is shown, for example, through a recognized degree, certificate, training or experience.

Machine safety · Human factors · USA

Refresher training

In occupational safety, refresher training is repeat training used to maintain competence after time has passed, after a change, after an incident or when performance gaps are observed.

Machine safety · Human factors

Safe handling

In machine safety, safe handling means the methods for lifting, moving, transporting, storing or positioning machinery and materials without unacceptable risk.

Machine safety · Technical documentation · Human factors

Safe operating procedure (SOP)

In occupational safety, a safe operating procedure (SOP) is a controlled procedure defining how a task is performed safely and consistently, including the hazards, the controls and the required competence.

Machine safety · Technical documentation · Human factors

Safety-critical maintenance

In machine safety, safety-critical maintenance is maintenance whose quality directly affects a protective measure or safety function, such as work on brakes, interlocks, protective devices or safety-related control parts.

Machine safety · Maintenance

Simultaneous operations (SIMOPS)

In occupational safety, simultaneous operations (SIMOPS) are activities performed at the same time whose interactions can create additional hazards or control conflicts.

Machine safety · Risk assessment · Maintenance

Training needs analysis

In occupational safety, a training needs analysis is a structured determination of the required competencies based on tasks, hazards, roles and controls, compared with the competencies people currently have.

Machine safety · Human factors

Tryout (lockout/tagout)

In lockout/tagout, tryout is the verification step in which controls are operated or tested to confirm that energy isolation is effective before work begins. After the tryout, controls are returned to the off or neutral position.

Machine safety · USA · Maintenance

Zero-energy state

In machine safety, a zero-energy state is a verified condition in which hazardous energy has been isolated, dissipated, restrained or otherwise controlled, so it cannot cause harm during the work.

Machine safety · Maintenance