Annex IV of NR12 – Glossary

Positive action: when a movable mechanical component inevitably moves another component together with itself, by direct contact or by means of rigid elements, the second component is said to be actuated in a positive manner, or positively, by the first component.


Self-propelled fertilizer: machine designed for the application of solid granular fertilizer and developed for the sugar cane sector.
Pulled fertilizer: agricultural implement which, when coupled to a tractor, can perform the operation to apply granular or powder solid fertilizers.
Meat mincer: machine with two or more parallel tractioned toothed cylinders that rotate in reverse direction, through which pre-cut meat pieces are passed. It is composed by: structure, feeding mouth, traction toothed cylinders and discharge area. The grinding operation involves inserting the through feeding meat, passing it through the toothed cylinders and taking mince from the discharge area.

Kneader: machine designed for industrial or commercial use to obtain a homogeneous mixture of dough. Basic Composition: structure, actuation, mixer, bowl and protections. For its operation, the actuation system transmits power to the mixer that performs rotational movement without translational movement, causing the mixer to rotate and mix the ingredients for dough production. The actuation system can simultaneously transmit power to the mixer and to the bowl while keeping both in rotational movement. In some cases, the bowl rotates by the mechanical action of the mixer over the dough. Both the mixer and bowl can have constant or variable rotational speed.

Pitch angle: angle formed between the slope of the means of access and the horizontal plane.

AOPD (Active Optoelectronic Protective Device): device used to detect the interruption of the optical emission by an opaque object present in the specified detection zone, as light curtain, multiple beam laser presence detector, laser area monitor, and safety photocells to control access. Its function is performed by sensors and optoelectronic receivers.

Instructional seat: seat of self-propelled machinery designed exclusively for instructional purposes.

Auto test: functional test performed automatically by the device itself, at system startup and during certain periods, for verification of failures and defects, taking the device to a safe condition.

Low speed or reduced speed: speed lower than the operation speed, compatible with the safe work.

Swing Arm Cutting Machine: machine intended for cutting leather and similar materials, operated by a worker, providing with a non-moveable cutting surface corresponding to the maximum available area and an arm containing the moveable impact surface i.e., press base, which is capable of moving in a horizontal arc movement on the cutting surface.

Die Cutting Machine: machine intended for cutting leather and similar materials, operated by a worker, in which the impact surface is connected or attached to the bridge that moves horizontally and vertically on a non-moveable cutting surface.

Mixer: machine designed for industrial or commercial use intended to obtain a homogeneous mixture of pasta or creams, light or medium consistency. It is basically composed of a frame, actuation, interchangeable beaters that can have various geometries, basin and protections. The engine transmits power to the beater, causing it to turn and mix the ingredients for mass production while keeping the basin fixed. During the operation, the beater features rotational movement on its axis, and may also have circular translational movement, denominated planetarium, while the basin remains fixed. The beater may have continuous or variable translational and rotational speed. In some cases the basin can be moved manually or electrically in the vertical direction for operational adjustment.

Deceiving: act of simply canceling the normal and safe operation of machine devices or systems, using any available objects for actuation; such as, screws, needles, pieces in metal plate, everyday items, such as, keys and coins or tools necessary for the normal use of the machine.

Category: Classification of parts of a safety related control system, with regard to their resistance to defects and their subsequent behavior in the defective condition, which is achieved by combination and interconnection of parts and / or by reliability. The performance with regard to the occurrence of defects in parts of a control system related to safety, is divided into five categories (B, 1, 2, 3 and 4) according to ABNT NBR 14153 – Safety of machinery – Safety related parts of control systems – General principles for design, equivalent to EN 954-1 – Safety of machinery – Safety related parts of control systems, which takes qualitative principles into account for selection. In the international community, the EN 954-1, in the substitution process, coexists with its successor, EN ISO 13849-1:2008 – Safety of machinery – Safety related parts of control systems, which establishes a quantitative criteria that is no longer divided into categories, but at levels of “A” to “E”, being “E” the highest. To select the level, which is called performance level (PL), it is necessary to apply complex mathematical formula according to the probability of failure in selected safety components – Safety Integrity Level (SIL), informed by the component manufacturer. It can be said that a particular safety component with SIL3 characteristic meets the requirements of Category 4.

Category 3: When the behavior of the system allows that:

a) when an isolated defect occurs, the safety function is always fulfilled;
b) some defects are detected; but not all; and
c) the accumulation of undetected defects leads to the loss of safety function.

Category 4: when the safety related parts of control systems shall be designed so that:

a) an isolated failure in any of these safety related parts does not lead to the loss of safety functions; and
b) an isolated failure is detected before or during the next actuation on the safety function, for example, immediately, to turn on the command, to the end of the operating cycle of the machine. If this detection is not possible, the accumulation of faults shall not lead to the loss of safety functions.

Safety switch: a component associated with the protection used to stop the dangerous movement and keep the machine stopped while the protection or door is open, with physical-mechanical contact, such as, electro-mechanical; or without contact, such as optical and magnetic. It shall have positive break, dual channel, normally closed contacts and be monitored by safety interface. The safety switch shall not allow to be bypassed – deceiving by simple means, such as screwdrivers, nails, tapes, etc.

Electromechanical safety switch: a component associated with a protection used to stop the dangerous movement and keep the machine off while the protection or door is open. It operates through physical contact between the body of the switch and the actuator, as the safety limit. It is subject to mechanical wear and shall be used in a redundant manner, when the risk analysis requires so, to prevent a mechanical failure; such as, the breake of actuator inside the switch. This leads to the loss of the safety condition. It shall also be monitored by safety interface for electrical fault detection and shall not allowed to be bypassed – deceiving by simple means, such as, screwdrivers, nails, tapes, etc. It shall be installed using the principle of positive action and break so as to ensure the interruption of the electrical control circuit, while keeping the contacts normally closed (NF) and connected rigidly when the protection is opened.


Cotton harvester: the cotton harvester has a rotating spindle system that removes the cotton fiber without damaging the vegetative part of the plant, i.e., stems and leaves. Certain models are characterized by the separation of fiber and seed, concomitant to the harvesting operation.
Coffee harvester: self-propelled agricultural equipment that performs the “seed dropping” and harvesting coffee.
Sugar cane harvester: Equipment that allows to harvest sugar cane in a uniform manner, by having a base cutting system which is able to cut the sugar cane over the soil. It has an elevator system that moves the cut cane to the transfer unit.
Forage harvester or self-propelled forager: self-propelled agricultural equipment suitable for harvest and forage maize, sorghum, sunflower and others. It cuts the plants, being able to harvest or collect, triturate and collect the crop in separate transshipping containers or vehicles.
Grain harvester: machine designed to harvest grains, such as, wheat, soy, corn, rice, beans, etc. The product is collected by means of a cutting platform and conducted to the threshing and separation area, in where the grain is separated from the straw, which is expelled as the grain is transported to the grain tank.
Orange harvester: self-propelled agricultural machine that harvest orange and other similar citruses.
Configurable Safety Controller (CCS): computerized electronic equipment – hardware, which uses configurable memory to store and internally interlocks specific functions of the program- software, such as, sequencing, timing, counting and safety locks, by controlling and monitoring through safety inputs and outputs from several types of machines or processes. It shall have three basic operating principles: redundancy, diversity and self-test. The installed software shall ensure its effectiveness so as to minimize the possibility of errors arising from human failure in design, in order to avoid compromising any safety related function as well as not allow any alteration in specific safety functions.

Programmable Logic Controller – CLP Safety: computerized electronic equipment – hardware, which uses programmable memory to store and internally run specific instructions and functions – software, such as, logic, sequencing, timing, counting, arithmetic and safety lock by controlling and monitoring through safety inputs and outputs from several types of machines or processes. The CLP safety shall have three basic operation principles: redundancy, diversity and self-test. The installed software shall ensure its effectiveness so as to minimize the possibility of errors arising from human failure in design, in order to avoid compromising any safety related function as well as not allow any alteration in specific safety functions.

Two-hand control device: device that requires, at least, the simultaneous action of both hands to initiate and maintain any machine operation by providing a measure of protection to the operator while there is a dangerous condition.

Continuous action control device: manually controlled device that initiates and keeps the parts of the machinery or equipment operating only while it is actuated.

Limited movement control device: control device, a single actuation of which, permits only a limited amount of travel of a machine or equipment element, thus reducing the risk as much as possible, excluding any movement until the device is deactivated and actuated again.

Interlocking device: mechanical, electro-mechanical, magnetic or optical safety switch designed for this purpose and safety inductive sensor that works by sending a signal to the power supply and stopping the dangerous movement every time the protection is removed or open.

Mechanical restraint device: device that introduces into a mechanism a mechanical obstacle, such as a wedge, spindle, strut, scotch, etc., which, by virtue of its own strength, can prevent any hazardous movement, for example, fall of a slider in case of normal restraint system failure.

Inhibitor or baffle device: physical obstacle, which without completely prevent access to a danger zone, that reduces the probability by restricting the access possibilities.

Limiting device: device that prevents a machine or part of a machine from exceeding a given limit, for example, space limit, pressure limit, etc.

Safety distance: distance that protects people from reaching of danger zones, under specific conditions for different access situations. When used guards, i.e. physical barriers that restrict access of the body or parts, the minimum distances listed in Section A of Annex I of this Standard must be observed, which shows the main charts and tables of ABNT NBR NM-ISO 13852 – Safety of Machinery – Safety distances to prevent danger zones being reached by the upper limbs. The safety distances to prevent access of the lower limbs are determined by ABNT NBR NM-ISO 13853 and shall be used only when there is a risk only for the lower limbs. When there is a risk for the upper and lower limbs, the safety distances provided in the standard for upper limbs shall be met. The ABNT NBR NM-ISO 13852 and ABNT NBR NM-ISO 13853 have been merged into a single standard, EN ISO 13857:2008 – Safety of Machinery – Safety distances to prevent danger zones being reached by upper and lower limbs, which is not translated in Brazil yet.

Diversity: application of components, devices or systems with different principles or types, thus reducing the probability of a hazardous condition.

Keyed or similar mechanical interlock: type of coupling which, once in operation or activated, cannot be disengaged until the hammer has performed a complete cycle. The concept also includes certain types of coupling that can only be disengaged only in certain positions of the operating cycle. Presses with this type of coupling are extremely dangerous, and manufacturing is prohibited.

Tractive equipment: equipment that develops the activity for which it was designed, moving through the propulsion system of another machine that conducts it.

Stairs with riser: permanent means of access with a pitch angle between 20° (twenty degrees) and 45° (forty-five degrees), whose horizontal elements are steps with riser.

Stairs without riser: means of access with a pitch angle between 45° (forty-five degrees) and 75° (seventy-five degrees), whose horizontal elements are steps without riser.

Ship type ladder: permanent means of access with a pitch angle between 75° (seventy-five degrees) and 90° (ninety degrees), whose horizontal elements are bars or crossbar.

Slippage: movement of the crankshaft and eccentric beyond a defined stop point.


Hydraulic excavator in forestry application: excavator designed to perform construction work, which can be used in forestry application by installing of special devices that enable cutting, delimbing, processing or loading logs.
Confined space: any area or environment not designed for continuous human occupancy, which has limited means of access and egress, with insufficient ventilation to remove contaminants or where there might be oxygen deficiency or enrichment.

Specification and technical limitation: for the purposes of this Standard informations detailed in the machine or manual, such as: capacity, rotational speed, maximum dimensions of tools, weight of disassembly parts, adjustment data, PPE requirements, frequency of inspections and maintenance, etc.

ESPS (Electro-Sensitive Protective Systems): system composed of devices or components operating together, with the purpose of protecting and sensing human presence, including at least: sensing device, monitoring or control device and output signal switching device .

Cognitive requirement: requirement linked to mental processes such as perception, attention, memory, reasoning, mental agility, language and interpretation. It involves the need to absorb information and memorization through sensitive capture, i.e., vision, hearing, tactile sense, etc. to interpret, understand, evaluate, discriminate and then react, make a decision or perform an action in the interaction between the humans and other elements of the system or machine.

Worker fatigue: mental or physical, local or general, non-pathological manifestation of an excessive work stress, completely reversible by rest.

Fail safe: the fail safe principle requires a system that enters in a safe state, when a safety related component failure occurs. The main precondition for the application of this principle is the existence of a safe state in which the system can be designed to enter in this state when failures occur. The typical example is the train protection system (safe state = stopped train). A system may not have a safe state, for example, an airplane. In this case, the safe life principle, which requires the application of redundancy and high reliability components to be sure that the system always work, shall be used.

Utilization phase: phase that includes all stages of construction, transport, assembly, installation, adjustment, operation, cleaning, maintenance, inspection, deactivation and disassemble.

Cold cut slicer: machine with a in disc-shaped tractive blade used for slicing cold cuts. The most common type has a disc-shaped rotating blade with adjustable protection to cover it, like disc edge and cold cut carriage. The slicing operation is performed by back and forth movement of the cold cut carriage, which leads the material to be processed on the rotating blade. This type of machine creates risks to the workers during the operation, manual adjustment of protection to expose the blade for cutting, cleaning and sharpening operation. More modern machines have disc-shaped rotating blades with back and forth movement on a horizontal table without access to the movement area of the blade. The cutting zone is accessed through a vertical chute, which works as a feeder, and a interlocked moveable protection, which prevents the access to the blade. The discharge of the processed material occurs by a conveyor belt or a tray.

Bread Slicer: machine designed for professional use to cut bread into uniform and parallel slices. It is basically composed of structure, actuation, guards and cutting device. The cutting device can slice the product both vertically and horizontally, and may consist of a set of serrated knives that cut by oscillatory movement or by a continuous saw that cuts that cuts by the movement in one direction. For the operation, the engine transmits power to the moving cutting device while the bread is introduced to the loading area for cutting operation, conducted by the feeding device.


Feller buncher: Forestry tractor to cut and bunch the trunks for felling the tress through the use of cutting implements with disc or circular saw and claws to hold and bundle several trunks simultaneously.
Tractive forager: agricultural implement which, when coupled to a tractor, can perform the operation of harvesting or gathering and triturating of fodder plant, and the triturated material, like fodder, is stored in separate containers or vehicles to be transferred.
Degree of protection – IP: two-digit numeric representation that identifies the characteristics of the enclosures against the intrusion of solid or liquid objects, as described below:

1 (first) digit – indicates the degree of protection of the equipment against the ingress of solid objects:

0 – unprotected;
1 – Protected against solid objects with diameter larger than 50 mm (fifty millimeters);
2 – Protected against solid objects with diameter larger than 12 mm (twelve millimeters);
3 – Protected against solid objects with diameter larger than 2.5 mm (two millimeters and half);
4 – protected against solid objects with diameter larger than 1 mm (one millimeter);
5 – protected against dust;
6 – totally protected against dust;

2 (second) digit – indicates the degree of protection of the equipment against the ingress of the water:

0 – unprotected;
1 – protected against vertically falling water drops;
2 – protected against vertically falling water drops when tilted up to 15° (fifteen degrees);
3 – protected against water sprayed at an angle up to ±69° (plus or minus sixty-nine degrees);
4 – protected against water splashing;
5 – protected against water jets;
6 – protected against sea waves or powerful jets;
7 – protected against immersion;
8 – protected against submersion.


Harvester: Forestry tractor to cut the trunks for felling the trees, using a processor head that cuts the trunks one at a time, and that is capable of cleaning the branches and subsequently cutting into standard sized logs.
Agricultural and forestry implement: device without its own driving force that is connected to a machine and which, when pulled, dragged or operated, allows the execution of specific operations focused on agriculture, livestock and forestry, such as soil preparation, cultivation, planting, harvesting, trenching for irrigation and drainage, transportation, distribution of feed or fertilizer, pruning and felling trees, etc.

Indelible information or symbol: that applied directly on the machine, which must be preserved legible during the entire usage time of machine.

Safety interface: device responsible for monitoring, verifying the connection, location and operation of other devices in the system, preventing the occurrence of a failure resulting in the loss of safety function, such as safety relays, configurable safety controllers and CLP safety.

Interlocking with a lock: protection associated with an interlocking device with a locking device, in a way that:

– The hazardous functions covered by the protection cannot operate while the machine is not closed and locked;
– The protection remains locked in the closed position until the risk of accident due to hazardous machinery functions has disappeared; and
– When the protection is locked in the closed position, the hazardous machinery functions can operate, but closing and locking the protection do not initiate the operation of these functions.

They are generally presented in the form of two part electro-mechanical safety switch: body and actuator – latch.

Laminator: machine designed for professional use in the food industry. It is intended to laminar the dough by consecutive back and forth movement between rotating rollers tractioned with height adjustment. Rotating rollers can have interchangeable cutting, offering the option to press and cut the dough.

Tail lights: device designed to emit a light signal to indicate the presence of a machine.

Burning threshold: surface temperature that defines the boundary between the absence of burns and a superficial partial burn caused by skin contact with a heated surface for a specific period of time.

Handle or handgrip: auxiliary device that is incorporated into the machine structure or affixed on it, which has the purpose of allowing access.

Self-propelled agricultural and forestry machinery: machine designed for agricultural and forestry activities that moves on land with its own propulsion system.

Self-propelled machinery: for the purposes of this Standard, any machine that moves on land with its own propulsion system.

Construction machinery for agroforestry application: machine originally designed to perform works related to construction and moving the soil and that receives specific devices to perform works related to agroforestry activities.

Machinery and equipment: for the purposes of applying this Standard, this includes the machinery and equipment for non-domestic use and moved only by non-human force.

Stationary machinery: machine that remains fixed in a workstation, i.e., transportable to use on a bench or in another stable surface where it can be fixed.

Manual machinery or equipment: hand-held machine or equipment.

Designed machinery or implement: every equipment or device designed, calculated, sized and constructed by a qualified professional, for the proper and safe use.

Meat grinder – Mincer: machine that uses endless screw to grind meat. It consists of feeding tray for meat entrance and endless screw within the duct that leads towards the cutting blade and then to the perforated neck – discharge area.

Bread crumb grinder: machine designed for professional use to mechanically reduce bread parts toasted in flour. It is comprised of a base, feeding tray, actuation, protections and grinding device.

Monitoring: intrinsic function of the component design or performed by safety interface that provides functionality of a safety system when a function of component or device is reduced or limited, or when there is a hazardous situation due to changes in process conditions.


Cultivators or micro-tractor: self-propelled two-wheeled equipment used to pull several implements, from soil preparation to harvesting. It is characterized by the fact that an operator walks behind the equipment during the work.
Pole chain saw: machine similar to chainsaw, equipped with extension cable for greater range in pruning operations.

Chainsaw: motorized saw with gripping handle mainly used for cutting and pruning trees, compulsorily equipped with:

a) manual or automatic chain brake, which consists of a safety device that stops the rotation of the chain, triggered by the left hand of the operator;
b) chain catcher, which consists of a safety device that reduces the course of chain in the event of breakaway, preventing the chain from reaching the operator;
c) right hand protector, which consists of rear protection to prevent the chain from reaching the hand of the operator in case of breakaway;
d) left hand protector, which consists of front protection to prevent the operator’s hand from involuntarily reaching the chain during the operation; and
e) accelerator safety lock, which consists of device that prevents unintended acceleration.

Muting: automatic and temporary deactivation of a safety function by means of the safety components or control circuits responsible for the safety during normal operation.

Optional: device or system not covered in this Standard, such as auxiliary headlamps.


Another type of micro-tractor and self-propelled lawnmower: small machine intended for general services and maintenance of residential or commercial gardens. Its total gross weight without attachments does not exceed 600 kg (six hundred kilograms).
Work permit – Work order: written, specific and auditable document, which contains at least the service description, the date, the location, the name and the function of workers and the persons responsible for the service and the implementation of work and safety procedures.


Traction planter: agricultural implement which, when coupled to a tractor, can plant crops, such as seeds, seedlings, tubers or the others.
Eternal stairs or platforms for self-propelled agricultural, forestry and construction machinery in agroforestry applications: support device that is not permanently attached to the machine.

Operation post: the place of the machinery or equipment where the worker operates the machine.

Work station: anywhere on the machinery and equipment where the intervention of the worker is required.

Servo-driven eccentric mechanical press: a machine using torque motor or servo-motor mechanically connected to the drive shaft of the machine. The servo-drive must be interlocked with the safety system. This type of actuation shall have a restraint of the hammer, which can be incorporated in the motor itself. The redundant braking system shall be dimensioned so that it can block the movement of the hammer at any angle of the eccentric, in case of emergency or in case of intervention for maintenance. The system must be interlocked to the electrical safety control system and designed to meet the Category 4 (four) protection level.

Professional qualified for the supervision of technical training: professional who proves the completion of specific courses in the area compatible with the course being taught, with registration in the relevant professional council, if necessary.

Legally qualified professional: qualified professional with registration in the relevant professional council, if necessary.

Technically trained professional or worker: one who received training under the guidance and responsibility of a qualified professional.

Qualified professional or worker: one who proves the completion of a specific course in the area, which is recognized by the official educational system.

Fixed distance protection: protection that does not completely cover the danger zone, but prevents or reduces access due to its size and its distance from the danger zone, for example, perimeter grid or protection tunnel.

Psycho-physiological: characteristic that encompasses what constitutes the distinctive character of a particular person, including their sensory, motor, physics and cognitive capabilities, of which, among others, highlight the issues related to reflexes, posture, balance, motor coordination and the movement mechanisms which vary between individuals. It includes, at least, anthropological, psychological, physiological knowledge relative to the human beings. It also covers the issues such as levels of alertness, sleep, motivation and emotion, memory and learning.


Self-propelled sprayers: instrument or machine used in agriculture for the control of pests, weeds and insects. Its main function is to control of the dosage in the application of pesticides or fertilizers on certain areas.
Superficial partial thickness burn: burn that completely destroys the epidermis, but spares the hair follicles, sebaceous glands and sweat glands.

Ramp: permanent mean of access, which continuous and inclined in a pitch angle between 0° (zero degrees) and 20° (twenty degrees).

Redundancy: application of more than one component, device or system in order to ensure that if there is a failure in one of them during its function, the other will be available to perform that function.

Safety relay: component with redundancy and electronic circuit dedicated to actuate and supervise the specific safety functions, such as safety switches, sensors, emergency stops, ESPEs, valves and contactors, ensuring that in case of failure or malfunction in these or in their wirings, the machine stops the operation and does not allow the initialization of a new cycle until the defect is repaired. It shall have three basic operating principles: redundancy, diversity and self-test.

Positive break – Positive opening operation of a contact element: effectuation of contact separation as a direct result of a specific movement of the actuator of switch key through non-resilient parts, i.e., non-dependent on the springs action.

Selector – Selector switch, validation device: selector switch or control mode selector with a restricted access or a password so that:

a) can be locked in each position, preventing the change of position by unauthorized workers;
b) each position corresponds to a single command or operation mode;
c) the selected control mode has priority over all other control systems, with the exception of emergency stop; and
d) the selection becomes visible, clear and easily identifiable.

Band saw for cutting meat in retail: machine used in butchery to cut meat, especially meat on the bone, consisting of two pulleys that guide the serrated band, wherein the movement of the lower pulley is tractioned. It is operated by a single worker located in front of the machine, leaving the sides and back free. There is constant exposure of the operator to the cutting area by handling the piece of meat to be cut.

Symbol – Pictogram: standardized schematic drawings intended to represent certain single indications.

Fall protection system: structure fixed to the machine or equipment, designed to prevent the fall of persons, materials or objects.

Mechanical braking system: mechanical system used to safely stop the hazardous movement, which ensures return to the braked position when there is an interruption on the power supply.

Bead: most rigid – reinforced part of the tire that comes in contact with the rim, ensuring fixation.

Work stress – Work strain: internal response of the worker when exposed to work pressure, which is dependent on the individual characteristics, for example, size, age, ability, skill, dexterity, etc.

Stand-in tractor: agricultural tractor wherein the operating platform consists only of a small floor at both sides to support the feet and operation, due to its small size.


Agricultural tractor: self-propelled medium to large machine that is designed to pull or drag agricultural implements. It has a wide range of applications in agriculture and livestock, and characterized by having at least two axes for tires or tracks and a weight greater than 600 kg (six hundred kilograms) without ballast or implements and minimum gauge of more than 1280 mm (one thousand two hundred eighty millimeters) between the rear tires.
Narrow agricultural tractor: small sized tractor intended for the production of fruits, coffee and for other applications where the space is restricted and used for small sized implements. It has a minimum gauge less than or equal to 1280 mm (one thousand two hundred eighty millimeters) between the rear tires and total gross weight above 600 kg (six hundred kilograms).
Safety valve or block: component connected to the machine or equipment for the purpose of allowing or blocking the passage of liquids, fluids or gaseous, such as compressed air and hydraulic fluids so as to start or stop the functions of the machine or equipment. It must have a monitoring system for the verification of connection, position and operation, preventing the occurrence of failure resulting in the loss of safety functions.

Danger zone: Any area within or around a machine or equipment where one might be exposed to risk of injury or harm to health.