This is a auto-generated Article of all your definitions within the glossary.
Glossary
This is a auto-generated Article of all your definitions within the glossary.
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Abrasive blasting respiratory protective device
breathing apparatus incorporating a protective hood or a blouse fitted with an impact resistant visor
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Accessory
item, or items, that are attached to the respiratory protective device (RPD) that are not necessary for the RPD to meet the requirements of the RPD performance standard and do not compromise its protection
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Acoustic isolation
algebraic difference, in decibels, between the one-third-octave-band sound pressure level measured by the microphone of the acoustic test fixture with a specially designed sound isolation test cup absent and the sound pressure level with the specially designed sound isolation test cup present
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Acoustic test fixture
(ATF) device that approximates certain dimensions of an average adult human head. An ATF is used for measuring the insertion loss of hearing protectors of the ear-muff type and includes a microphone for measuring sound pressure levels.
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Adequacy assessment
selection method identifying the respiratory protective device is able to reduce the wearer's inhalation exposure to acceptable levels
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Adequate respiratory protective device
(adequate RPD) RPD capable of reducing the inhalation exposure to an acceptable level
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Aerodynamic diameter
diameter of a unit density sphere having the same settling velocity as the particle in question
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Aerosol
suspension of solid, liquid, or solid and liquid particles in a gaseous medium, having a negligible falling velocity (generally considered to be less than 0,25 m/s)
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Aerosol penetration
ability of particles to pass through a particle-filtering material
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Air-arc cutting
arc gouging thermal gouging or cutting method for metallic materials that uses an electric arc. This method uses a carbon electrode that forms a groove by melting or burning, while an air jet attached to the electrode removes the molten material. This groove can be deepened using the same thermal method to form a cut.
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Air flow rate
volume of air passing through the filter per unit time
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Air flow resistance
pressure difference between upstream and downstream locations caused by the flow of air through the parts and components of a respiratory protective device such as an exhalation valve, inhalation valve, filter(s), and tube, etc.
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Air supply hose
hose for the supply of air at about atmospheric pressure
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Ambient air bypass
means to enable the wearer to breathe the ambient atmosphere before entering and after leaving a hazardous atmosphere
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Ambient air system
device used to deliver ambient air at a low pressure directly to a breathable gas respiratory protective device (manually or power assisted)
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Ambient atmosphere
air surrounding the wearer
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Ambient concentration
concentration of a compound in the air surrounding the wearer
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Ambient laboratory conditions
atmosphere where the temperature is between 16 °C and 32 °C and the relative humidity is between 20 % and 80 %
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Amps (Amperes)
A unit of electric current in the International System of Units (SI). One ampere represents the flow of one coulomb of electrical charge per second. In safety contexts, amperage is important when considering the risks associated with electrical hazards and equipment ratings.
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Anchor Point
A secure point of attachment for lifelines or lanyards, capable of supporting the forces generated during a fall.
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ANSI Z89
ANSI Z89.1 is a standard from the American National Standards Institute covering industrial head protection. It outlines the performance and testing requirements for hard hats in the United States, including impact resistance, electrical insulation (Class G, E, and C), and penetration resistance.
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Anti-Mist (Anti-Fog)
Anti-mist (or anti-fog) refers to coatings or treatments applied to safety lenses that prevent or reduce fogging. These coatings help maintain clear visibility in varying temperatures or high-humidity environments and are often essential in confined or indoor workspaces.
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Anti-Mist Performance
Anti-mist performance refers to a lens’s ability to resist fogging caused by temperature changes or humidity. This feature ensures clear vision in environments where fogging is common—such as when wearing masks or working in warm, moist conditions.
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Anti-scratch
Scratch-resistant lenses are marked ‘K’, meaning they pass an optional test for resistance to surface damage by fine particles under EN 166, the European eye protection standard.
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APC
Arc protection class
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Apertometer
Extended hemispherical dome for measuring the angular area of the field of vision (peripheral isopter) of an RPD when mounted on a headform
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APF (Assigned Protection Factor)
Assigned Protection Factor (APF) indicates the level of respiratory protection provided by a specific type of respirator when properly worn. An APF of 20 means the wearer will be protected from airborne contaminants up to 20 times the Workplace Exposure Limit (WEL) In welding, this is the minimum APF recommended to protect against harmful fumes and airborne particulates RPE with higher APFs (e.g. powered or full-face respirators) can also include integrated visors or face protection.
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Arc Flash
An arc flash is a dangerous release of energy caused by an electrical fault or short circuit. It results in a high-temperature explosion that can cause severe burns, fires, and even death. Arc flashes produce intense heat, light, and pressure waves, making arc-rated PPE essential for workers in electrical environments.
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Arcing
Arcing refers to the discharge of electricity that jumps through the air between two conductors, producing intense heat and light. This sudden burst can release dangerous UV radiation, infrared radiation, and flying molten metal particles. In eye protection, lenses must be designed to shield against these hazards.
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Arc protection class
class of arc thermal protection of a product tested in accordance with the box test method -
Arc rating
quantity, attributed to a product, that describes the protective performance when tested in accordance with the open arc test -
Arc thermal performance value
quantity of incident energy attributed to a product that describes its properties of attenuating the thermal effect of energy generated by an open arc -
Arc thermal protection
degree of thermal protection offered against an electric arc under specific arc testing conditions indicated by either an arc rating or an arc protection class -
Arc welding
electric welding method, that uses an arc that is generated between the rod-shaped metal electrode and the workpiece
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Assigned protection factor
(APF) anticipated level of respiratory protection that would be provided by a properly functioning respiratory protective device (RPD) or class of RPD within an effective RPD programme
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Assisted filtering respiratory protective device
filtering RPD where breathable gas is actively supplied to the wearer by the RPD
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Assisted filtering RPD
filtering RPD in which air is moved through the filter(s) by means of a blower in addition to the breathing of the wearer
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ASTM F2178
ASTM F2178 is a standard from the American Society for Testing and Materials that specifies test methods for arc-rated face protective products. It helps determine how face shields and hoods perform under arc flash conditions, particularly their ability to resist heat and impact from an arc blast.
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ATPV (Arc Thermal Performance Value)
ATPV is the rating assigned to PPE that indicates the level of protection against arc flash hazards. It represents the amount of incident energy (in calories per square centimetre) that a fabric or material can withstand before there is a 50% chance of causing a second-degree burn. The higher the ATPV, the greater the protection.
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Auto darkening filter
optical filter which varies the transmittance in the visible region of the spectrum depending on the presence of light emitted by an electric arc
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Averaged interactive flow rate
interactive flow rate averaged over 10 consecutive breathing cycles of the breathing machine
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Averaged maximum interactive flow rate
average of the highest flow rate within each breathing cycle of 10 consecutive breathing cycles of the breathing machine
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Averaged minimum interactive flow rate
average of the lowest flow rate within each breathing cycle of 10 consecutive breathing cycles of the breathing machine
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Averaged peak interactive flow rate
average of the maximum peak flow rate within each breathing cycle of 10 consecutive breathing cycles of the breathing machine
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Balaclava
one-piece garment designed to fit closely over the entire head and to extend downwards to cover the neck, but leaving the area of the eyes and at most the area of the eyes, nose and mouth uncovered
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Blacklight lamp
UV-A radiation source, generally a mercury vapour discharge lamp, with the bulb (high-pressure radiation source) or tube (low-pressure radiation source) made from light-absorbing, but UV-A transmitting, filter glass
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Blouse
garment, used as a facepiece, that covers the head and upper part of the body to the waist and wrists and to which air is supplied
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Blue light
Blue light is a part of the visible light spectrum with relatively short wavelengths and high energy. It is emitted by the sun, as well as digital screens, LED lighting, and some industrial tools. Long-term or intense exposure to blue light may contribute to eye strain and has been linked to retinal damage over time.
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Blue-light hazard
potential for a photochemically induced retinal injury resulting from optical radiation (3.2.1) exposure in the wavelength range 300 nm to 700 nm
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Body harness
means to enable certain components of a respiratory protective device to be worn on the body
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Body temperature pressure saturated
(BTPS) standard condition for the expression of ventilation parameters
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Breakopen
material response evidenced by the formation of one or more openings in the material specimen -
Breakopen threshold energy
quantity of incident energy attributed to a product (material or equipment) that describes the properties of a breakopen when exposed to heat energy generated by an open arc test -
Breakthrough concentration
concentration of test gas in effluent air at which a gas filter undergoing a gas capacity test is deemed exhausted
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Breakthrough time
time taken from the start of the test until the test gas and specified reaction products are detected at the specified breakthrough concentration at the downstream side of the filter under test
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Breathable air
air of a quality that makes it suitable for safe respiration
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Breathable gas
mixture of gases that is suitable for respiration without adverse effects to health
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Breathable gas cylinder
integral part of the respiratory protective device that contains the breathable gas supply
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Breathable gas quality
composition of a breathable gas as defined in relevant standards
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Breathing apparatus
device that enables the wearer to breathe independently of the ambient atmosphere
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Breathing machine assembly
breathing machine plus all connecting tubes, control valves and other necessary hardware leading to the trachea tube assembly
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Brim
rim surrounding the shell
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British Standards Institution’s (BSI) Kitemark™ scheme
The British Standards Institution's (BSI) Kitemark™ scheme is a certification mark that indicates a product or service has been independently tested and confirmed to meet specific quality and safety standards. It essentially provides assurance to consumers that a product or service is reliable and trustworthy, often going beyond minimum legal requirements. The Kitemark is a symbol of confidence, used by manufacturers and brands to demonstrate their commitment to quality and safety
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Bump Cap
A lightweight head protection device designed to protect the wearer from minor bumps and scrapes to the head, such as from low ceilings or overhead piping. Bump caps do not provide protection against falling objects and are not a substitute for industrial safety helmets. They are typically used in environments like warehouses, maintenance, and low-risk industrial settings.
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Burning time
time for which a flaming of the test specimen is visible after the end of the electric arc duration
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Charring
formation of carbonaceous residue as the result of pyrolysis or incomplete combustion
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Chin protector
component specifically designed to protect the chin
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Chin Strap
strap that is intended to pass under the wearer’s chin with two points of attachment to the helmet used with Type I helmets A chin strap is an accessory.
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class Sxxxx RPD
supplied breathable gas RPD, where Sxxxx equals the amount of breathable gas available for respiration in litres
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Closed hood
hood with an integrated face shield also known as a bee keeper hood
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Competent Person
An individual who has the knowledge and experience to identify hazards and take corrective measures regarding fall protection equipment.
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Component
part of a protective device, such as a window in a hood or a bracket to a face shield
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Continuous wave laser
(cw laser) laser continuously emitting radiation over periods of time greater than or equal to 0,25 s
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Correlation ratio
calculation of any potential bias between the upstream and downstream sampling systems
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Crown
the area on the upper, outer surface of a headform, centred on the mid coronal plane
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Design Registered
The design registered mark prevents others from using the design without permission and also indicates that the helmet is genuine.
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Desorption
process in which one substance (the filter medium) releases an absorbed or adsorbed substance
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Device
product (e.g. goggles, eye-guard/eye shield/face shield, balaclava, helmet), possibly combined with additional products for the side and/or the top of the head and/or the neck in order to give protection to eye, face and head for the intended use -
Downstream
(D/S) area or region into which fluid flows on leaving the test device
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D-Ring
A D-shaped metal ring on a harness used as an attachment point for lanyards or lifelines.
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Dynamic breathing resistance
Differential pressure caused by an RPD when the breathing gas is delivered by a breathing machine adjusted to a specified breathing minute volume and waveform
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Earmuff
hearing protector consisting of an ear-cup to be pressed against each pinna (supra-aural) or of an ear-cup to be pressed against the head, around the pinna (circumaural). The ear-cups can be pressed against the head with a special headband or neck band or by means of a device attached to a safety helmet or other
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Earplug
Hearing protector worn within the external earcanal (aural) or in the concha against the entrance to the external earcanal (semi-aural)
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EBT
breakopen threshold energy
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Efficiency
fraction or percentage of a challenge contaminant that is removed by a test device
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Elastance
pressure change resulting from a volume change
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Electrical Arc (Arc Flash)
An electrical arc (also known as an arc flash) is a type of arcing caused by a sudden release of electrical energy through the air due to a fault or short circuit. It produces extreme temperatures, blinding light, and pressure waves, all of which can cause severe injury. Eye and face protection used in environments at risk of arc flash must be specifically rated to protect against these intense thermal and radiant hazards.
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Electrically insulating helmet
safety helmet which protects the wearer against electric shocks by preventing the passage of dangerous current through the body via the head
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Electric arc
self-maintained gas conduction for which most of the charge carriers are electrons supplied by primary-electron emission
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ELIM
Incident energy limit
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EN 12492
A European standard for mountaineering helmets. It ensures helmets offer protection against impact, penetration, and have secure retention systems. In industrial use, this standard is sometimes referenced for work-at-height helmets due to its more comprehensive impact testing.
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EN 14052
A European standard for high-performance industrial helmets. It defines stricter safety criteria than standard industrial helmets (like EN 397), including greater impact protection from multiple angles and enhanced side protection.
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EN 166
EN 166 is a European standard that specifies the general requirements for personal eye protection. It applies to all types of protective eyewear—including safety spectacles, goggles, and face shields—used to protect the eyes against hazards that may cause injury or impairment. The standard sets out essential criteria for: Optical clarity Resistance to mechanical impacts Field of vision Durability Resistance to ageing, corrosion, and ignition Each product tested to EN 166 must meet rigorous performance and labelling requirements, and will be marked with specific symbols that indicate its level of protection, mechanical strength, and other key features (e.g., anti-fog or anti-scratch coatings).
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EN 169 (Static Filters)
EN 169 is the European Standard for welding filters with fixed shade levels (non-variable). These are typically used in basic welding shields. Protect against intense visible light and infrared radiation Do not adjust automatically to different light intensities Suitable for tasks with consistent arc brightness
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EN 170
EN170 is a European Standard that applies to ultraviolet (UV) filters used in eye protection. It specifies the performance requirements for protective lenses that filter UV radiation without altering colour recognition. Products certified to EN170 help protect the eyes from harmful UV rays in environments such as laboratories, UV curing operations, and outdoor work.
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EN 172
EN 172 is the European Standard for sunglare filters used in protective eyewear, including face shields and goggles. Primarily focuses on filtering out UV radiation and reducing visible sunlight to prevent eye strain and discomfort. EN 172 filters are rated for specific luminous transmittance levels (ranging from shade 1.5 to 5), making them suitable for industrial environments where bright light or sunglare could cause visual impairment or discomfort, such as welding, grinding, and cutting.
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EN 1731
EN 1731 is the European Standard for mesh-type eye and face protectors, typically made from metal or plastic mesh. • Used in environments where solid particles (like wood chips or grinding debris) are a hazard but optical radiation (like UV or IR) is not a concern • Common in forestry, gardening, and some industrial tasks • Does not provide protection against chemical splashes or optical radiation Mesh visors to EN 1731 offer impact protection while maintaining ventilation and visibility.
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EN 175
EN 175 is the European Standard for personal protective equipment (PPE) used in welding and allied processes. It specifies the requirements for protection against optical radiation (such as UV and infrared radiation) and physical hazards (such as molten metal splashes and flying particles). This standard applies to welding helmets, browguards, and face shields worn during welding, cutting, or grinding activities. EN 175 ensures that welding helmets and face shields provide the necessary protection against eye injury, skin burns, and overexposure to welding arcs.
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EN 365:2004
A European standard specifying the requirements for instructions and markings of fall protection equipment.
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EN 379 (Auto-Darkening Filters)
EN 379 covers auto-darkening welding filters, which adjust automatically in response to the welding arc. Allow wearers to keep the shield in position without lifting between tasks Protect against sudden changes in optical radiation, including UV, visible, and IR light Provide both safety and convenience for frequent or varied welding work
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EN 397
EN 397 is a European standard that specifies the physical and performance requirements for industrial safety helmets. It includes tests for shock absorption, resistance to penetration, and flame resistance. Helmets certified to EN 397 are typically used in construction and industrial settings.
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EN 50365
EN 50365 is a European standard for insulating helmets used for electrical work. Helmets meeting this standard provide protection against electric shocks (up to 1,000 V AC or 1,500 V DC) and are used in live working environments. These helmets must also comply with the basic requirements of EN 397.
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EN 812
A European standard for bump caps. These are lightweight head protectors used to guard against minor bumps and scrapes, but not suitable for protection against falling objects like industrial safety helmets.
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Eye shield
device which provides protection to the eye area
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Face shield
eye protective device covering the eyes and all, or a substantial part, of the face, which can be mounted directly or by help of an adjustable or non-adjustable carrier on the head using a support (headband) and/or harness, or mounted by help of an adjustable or non-adjustable carrier on a helmet
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Fall Arrest System
A system designed to safely stop a person already falling from a working height.
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Fall Factor
A ratio that describes the severity of a fall, calculated by dividing the distance fallen by the length of the lanyard.
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Filter
Optical Filter - Lens intended to protect the eye from excessive incident radiation by attenuating that radiation, generally within a given wavelength range
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Filter element
structure made of the filtering material, its supports and its interfaces with the filter housing
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Force®8
The Force®8 twin cartridge half mask with Typhoon™ valve offers superior low breathing resistance and a 4-point suspension harness with quick-release buckles. The mask is made with a durable thermoplastic rubber offering a superior fit to most face shapes. The mask accepts the full range of low profile Force®8 filters giving the Force®8 the flexibility to be used for many applications, providing filtering protection against particulates, many gases and vapours.
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Fractional efficiency
ability of an air cleaning device to remove particles of a specific size or size range
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Frame
structural component which supports and/or supplements the lens
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Full Body Harness
A harness that distributes fall forces across the thighs, pelvis, chest, and shoulders, used in fall arrest systems.
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Gas cutting
thermal method of cutting metallic material using gas and oxygen
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Gas filter capacity
mass or volume of a specific test agent that is removed or retained by a gas filter or combined filter under specified conditions of temperature, humidity, challenge test gas concentration and flow rate
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Goggle
eye protective device that fully encloses the orbital area and fits firmly on the face
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Ground Clearance
The minimum vertical distance required between the worker and the ground to prevent contact during a fall.
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GS-ET-29
GS-ET-29 is a certification mark awarded to welding protection equipment, particularly welding helmets and face shields, that comply with certain safety standards. This certification ensures that the equipment meets both the German and European safety requirements for welding safety. It evaluates a helmet’s or **visor’s resistance to impacts, optical radiation, and high temperatures, and may also cover filter performance in reducing UV and visible light exposure. GS-ET-29 includes specific testing for safety in arc welding, ensuring adequate protection for the eyes and face from molten metals, sparks, and high heat.
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Harm
injury or damage to the health of people, or damage to property or the environment
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Harness
A body support device consisting of straps secured around the torso and thighs, used in fall protection systems.
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Hearing level (of a pure tone)
Difference between the sound pressure level of this pure tone produced by the earphone in a specified ear simulator or acoustic coupler and the appropriate reference equivalent threshold sound pressure level at a specified frequency, for a specified type of earphone and for a specified manner of application.
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Hearing protector
Device worn by a person to prevent harmful effects from noise and other loud acoustic stimuli. Hearing protectors can include electronic devices for communication, or devices designed to play an active role in the reduction of the noise level between the hearing protector and the eardrum.
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Hearing threshold level (of a given ear)
Threshold of hearing expressed as hearing level at a specified frequency and for a specified type of earphone
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Helmet
device which covers a substantial part of the head
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Helmet accessories
any optional parts for special purposes such as chin strap, neck protector, drawlace and attachment devices for lamp and cable
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Helmet attachment
accessory which is not an integral part of the helmet and secured to helmet
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Helmet positioning index
(HPI) vertical distance, measured in the vertical longitudinal plane, between the reference plane of the reference headform and the lowest point of the helmet in the forehead region. HPI is provided by the helmet supplier and indicates the intended position of the helmet when worn.
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HEPA filter
filters with performance complying with requirements of filter class ISO 35 to ISO 45 as per ISO 29463-1
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High pressure mercury (vapour) lamp
high intensity discharge lamp in which the major portion of the light (3.2.2) is produced, directly or indirectly, by radiation from mercury operating at a partial pressure in excess of 100 kPa High-pressure mercury (vapour) lamps can be clear, phosphor coated (mercury fluorescent) and blended lamps. In fluorescent mercury discharge lamps, the light is produced partly by the mercury vapour and partly by a layer of phosphors excited by the
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Hood
product covering all areas of the head including or not the face and covering the neck (possibly offering 360° coverage, and if not an integral part of the clothing), covering also the shoulder area of the protective clothing, and not fitting closely over the entire head, possibly designed for being supported by a helmet
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Ignition
initiation of flaming and combustion
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Illuminant
Optical radiation with a relative spectral power distribution defined over the wavelength range that influences object colour perception
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Impact energy attenuation
ability of the helmet to manage the kinetic energy during an impact
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Impact Performance
Impact performance refers to the ability of protective eyewear or face shields to resist mechanical forces such as flying debris, projectiles, or blunt impacts. Standards like EN 166 and ANSI Z87.1 include impact resistance testing to ensure safety eyewear provides sufficient protection in hazardous environments.
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Incident energy
heat energy resulting from an electric arc, received at a unit surface area at a specified distance from the electric arc -
Incident energy limit
quantity of incident energy attributed to a product (material or equipment), below which the values of all product responses are underneath the Stoll curve and without leading to a breakopen -
Infrared (IR) radiation
Infrared radiation is a form of invisible light with longer wavelengths than visible light. It is experienced as heat and is commonly emitted by hot surfaces, furnaces, and welding equipment. Extended exposure to high levels of infrared radiation can cause eye discomfort, dryness, and, in severe cases, damage to the lens of the eye.
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Infrared lens hazard
potential for a thermal injury to the crystalline lens (and cornea) of the eye resulting from exposure to optical radiation in the wavelength range 780 nm to 3 000 nm
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Insertion loss
algebraic difference, in decibels, between the one-third-octave-band sound pressure level measured by the microphone of the acoustic test fixture with the hearing protector absent and the sound pressure level with the hearing protector present
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Intense pulsed light source
(IPL) compact xenon arc lamp, operated in a pulsed mode, usually filtered to emit visible radiation and near infrared radiation
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Interactive flow rate
flow rate through the filters of an assisted filtering RPD resulting from the combined action of the assisted filtering RPD and the breathing pattern generated by the breathing machine
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ISO 14001
An international standard for environmental management systems (EMS). ISO 14001 provides a framework that organisations can follow to minimise their environmental impact, comply with regulations, and continually improve their environmental performance. It is widely recognised and often part of a company’s commitment to sustainable practices
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ISO 9001
ISO 9001 is a globally recognized standard for quality management systems (QMS). It provides a framework for organizations to consistently meet customer and regulatory requirements and improve their processes. Essentially, it helps businesses demonstrate their ability to consistently deliver quality products or services.
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Isokinetic sampling
technique for air sampling such that the probe inlet air velocity is the same as the velocity of the air surrounding the sampling point
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JSP
Johnstone Safety Products
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JSPCheck™
is a system designed to help you verify the authenticity of your JSP Mk Evolution® head protection.
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Lanyard
A flexible line of webbing or rope used to secure a harness to an anchor point or lifeline.
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Laser radiation
coherent electromagnetic radiation with wavelengths up to 1 mm, generated by a laser
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Lens
light transmitting part of an eye or face protective device that permits vision
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Lens Fogging
Lens fogging occurs when moisture condenses on the surface of a lens, reducing visibility. It’s a common issue in PPE use, particularly when moving between temperature zones or wearing respiratory protection. Fogged lenses can pose a safety risk by obscuring vision.
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Lifeline
A component of a fall protection system consisting of a flexible line for connection to an anchor point to arrest a fall.
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Light Transmission
Light transmission refers to the percentage of visible light that passes through a lens or visor. It determines how light or dark the lens appears and affects visibility in different lighting conditions. Low light transmission is ideal for bright conditions, while high transmission is better for dim environments.
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Liner
Protective component of the helmet, positioned between shell and head, that primarily provides impact energy attenuation
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Liquid phase aerosol
liquid particles suspended in a gas
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Low pressure mercury (vapour) lamp
discharge lamp of the mercury vapour type, with or without a coating of phosphors, in which during operation, the partial pressure of the vapour does not exceed 100 Pa
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LT
luminous transmittance
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Luminous transmittance
Luminous transmittance refers to the amount of visible light that can pass through a lens or visor. • Expressed as a percentage (%) • High transmittance = more light passes through (clearer lens) • Low transmittance = darker lens (used for sunlight or welding glare protection) This property is critical in selecting lenses for environments with bright lighting, sunglare, or optical radiation, ensuring both visibility and eye comfort.
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Material
substance of which an item of protective equipment is made -
Measured maximum flow rate
volumetric flow rate of an assisted filtering RPD, determined in a laboratory test, when the RPD is in the condition which results in the highest air flow rate, where this condition takes into account the influences of temperatures, settings of RPD, pre-conditionings, use of accessories and others
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Measured minimum flow rate
Volumetric flow rate of an assisted filtering RPD, determined in a laboratory test, when the RPD is in the condition which results in the lowest air flow rate, where this condition takes into account the influences of temperatures, settings of RPD, pre-conditionings, use of accessories, and others
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Medium pressure mercury (vapour) lamp
Non-coherent radiation source containing mercury vapour at pressures ranging from 50 kPa to several hundred kPa1) This type of lamp emits mostly from 200 nm to 1 000 nm with the most intense lines approximately at 218 nm, 248 nm, 254 nm, 266 nm, 280 nm, 289 nm, 297 nm, 303 nm, 313 nm, 334 nm, 366 nm, 406 nm, 408 nm, 436 nm, 546 nm and 578 nm.
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Metabolic simulator assembly
metabolic simulator plus all connecting tubes, control valves and other necessary hardware leading to the trachea tube assembly
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Metal halide lamp
high intensity discharge lamp in which the major portion of the light is produced from a mixture of a metallic vapour and the products of the dissociation of metal halides Metal halide lamps can be clear or phosphor-coated.
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Monochromatic radiation
Optical radiation characterised by a single frequency
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Neutralization
action of bringing the aerosol to a Boltzmann charge equilibrium distribution with bipolar ions
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Noise Assessment
A noise assessment is a formal evaluation of noise levels in the workplace. It determines whether workers are at risk of hearing damage due to prolonged exposure to high sound levels, such as those from grinding, cutting, or drilling. Required under Control of Noise at Work Regulations 2005 (UK) May result in the implementation of hearing protection zones or provision of ear defenders/plugs While not directly linked to eye protection, noise assessments are a key part of overall PPE and occupational safety in welding and fabrication environments.
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Noise floor
output level of the measurement system with the test signal switched off and a test cup providing sufficient acoustic isolation in position
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Obsolescence Date
The date after which equipment should no longer be used, regardless of its appearance or condition.
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Open hood
hood where the eyes and part of the face are not covered
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Optical Class
Optical class refers to the clarity and quality of the lens used in eye protection. It is rated from 1 to 3, with Class 1 offering the highest level of optical clarity and being suitable for long-term use. Class 1: High optical quality for continuous use Class 2: For intermittent work Class 3: For occasional or short-term use only Choosing the correct optical class is essential to avoid visual distortion, eye fatigue, and discomfort during use.
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Optical particle counter
OPC particle counter which functions by illuminating airborne particles in a sample flow of air, converting the scattered light impulses to electrical impulse data capable of analysis to provide data on particle population and size distribution
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Optical Radiation
Optical radiation is the range of electromagnetic radiation visible to the eye (light) and invisible (ultraviolet (UV), infrared (IR)). PPE such as welding shields and laser safety goggles are designed to protect the eyes from harmful exposure to these radiations, which can cause short- or long-term damage.
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P3 Filter
A P3 filter is a high-efficiency particulate filter used in respiratory protective equipment. It is designed to protect against very fine particles, including metal fumes, dusts, and aerosols, often found in welding environments. Offers 99.95% filtration efficiency. A P3 Filter is essential when working in areas where welding fumes or hazardous airborne particles are present
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Particle counter
device for detecting and counting numbers of discrete airborne particles present in a sample of air
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Particle size
geometric diameter (equivalent spherical, optical or aerodynamic, depending on context) of the particles of an aerosol
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Particle size distribution
presentation, in the form of tables, numbers or graphs, of the experimental results obtained using a method or an apparatus capable of measuring the equivalent diameter of particles in a sample or capable of giving the proportion of particles for which the equivalent diameter lies between defined limits
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Peak
horizontal extension of the shell above the eyes
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Pendulum Fall
A swing-like fall that occurs when the anchor point is not directly above the worker, increasing the risk of injury.
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Penetration
Ratio of particle count detected downstream versus the particle count upstream
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Peripheral isopter
Field of vision while wearing an RPD
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Pink noise
Random noise signal with a spectral density that decreases by 3dB per octave, giving constant energy per octave.
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Plasma arc cutting
thermal cutting method for metallic materials that uses a constricted electric arc and a high- velocity jet of gas issuing from a constricting orifice to give a high-temperature plasma flame that melts and removes the metallic material
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Polarised
Polarised lenses are designed to reduce glare caused by light reflecting off flat surfaces like water, metal, or glass. They work by blocking horizontally polarised light waves, improving visual comfort and contrast. Polarised safety glasses are especially useful in bright, reflective environments.
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polycarbonate
Polycarbonates (PC) are a group of thermoplastic polymers containing carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, tough materials, and some grades are optically transparent. They are easily worked, molded, and thermoformed.
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Polygiene®
A trademarked antimicrobial treatment applied to textiles and PPE products to control odour and maintain freshness. Polygiene® technology works by preventing the growth of odour-causing bacteria on fabrics, which extends product life and reduces the need for frequent washing.
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Porous device
RPD incorporating materials, excluding filters, that can be penetrated by gases and vapours during aninward leakage test, leading to an increase of the inward leakage
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PPE (Personal Protective Equipment)
PPE refers to specialised clothing or equipment worn by workers to protect themselves from health and safety hazards. In industrial environments, this can include helmets, gloves, eye protection, high-visibility clothing, safety footwear, and respiratory protective equipment.
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Prescription Spectacles
Glasses made to an individual's specific vision correction needs, typically prescribed by an optometrist or ophthalmologist. In a PPE context, prescription safety spectacles combine vision correction with protective features like impact-resistant lenses and side shields.
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Protective helmet
helmet intended to protect at a minimum the upper part of the wearer's head against an impact
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Protector
product that can consist of one or more protective devices that offers protective performance required by this document for the area which is covered by the device
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Pulse separation
time between the end of one pulse and the onset of the following pulse, measured at the 50 % trailing and leading edges
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Reference aerosol
defined approved aerosol for test measurement within a specific size range
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Reference filter
primary device possessing accurately known parameters used as a standard for calibrating secondary devices
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Reference point
Fixed spatial position within the test chamber to which all objective measurements of the sound field characteristics are reference and which coincides with the midpoint of a line connecting the test subject's ear canal openings when the test subject is seated for measurements.
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Resistance to airflow
difference in pressure between two points in an airflow system at specified conditions, especially when measured across the filter element
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Respiratory
Refers to equipment designed to protect the user from inhaling hazardous substances such as dust, fumes, vapours, or gases. This includes devices like respirators and breathing apparatuses, commonly used in environments where air quality is compromised.
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Retention system
assembly that maintains the position of the helmet on the head during use; consisting of components for adjustment and improved comfort; a chin strap is not a retention system. A retention system may consist of webbing, webbing adjustment components used to lengthen and shorten webbing pieces and a buckle
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Retinal thermal hazard
potential for a thermal retinal injury resulting from exposure to optical radiation (3.2.1) in the wavelength range 380 nm to 1 400 nm
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Retractable Fall Arrest
A fall arrest device that automatically extends and retracts, allowing freedom of movement while providing fall protection.
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Reverberation time
Time required for the sound pressure level to decrease by 60dB after the sound source has stopped.
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RFID
Radio Frequency Identification – a technology that uses electromagnetic fields to automatically identify and track tags attached to objects.
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RFID Asset Management
A system using Radio Frequency Identification to track and manage safety equipment assets.
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RPD head form assembly
RPD head form with trachea tube assembly included
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RPD verification tool
Test device that simulates specific performance characteristic(s) of a respiratory protective device. The theoretical results from the test device are known and are compared with the actual results obtained in a given test laboratory when the test device is used with the appropriate test system in that laboratory.
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Sampling air flow
volumetric flow rate through the instrument
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Self-Contained Breathing Apparatus (SCBA)
SCBA is a type of respiratory equipment that provides clean, breathable air from an independent source (usually a compressed air cylinder). Used in confined spaces or high-risk environments where air may be oxygen-deficient or heavily contaminated Offers full-face coverage, protecting both respiratory system and eyes from harmful gases, vapours, and particles Essential for situations where standard ventilation and filtration are insufficient
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Servicing
The thorough examination and maintenance of equipment, often involving disassembly and replacement of parts.
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Shell
hard, smoothly finished material that provides the general external form of the helmet
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Shielding Gases
Shielding gases (e.g. argon, carbon dioxide, oxygen, hydrogen blends) are used to protect the weld area from atmospheric contamination. Although essential to welding, they can pose serious risks: Asphyxiation in confined spaces (due to oxygen displacement) Respiratory irritation, especially in poorly ventilated areas
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Shock Absorber
A device attached to a lanyard that reduces the impact force on the body during a fall.
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Short-circuit electric arc
intensive arc that can occur through switching or a short-circuit in electricity distribution installations
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Solid phase aerosol
solid particles suspended in a gas
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solvents
The term 'solvent' can be defined as a substance that has the ability to dissolve a given solute to form a solution with it.
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Sorption
Process in which one substance (the filter medium) takes up or holds another (the test gas), either by adsorption or absorption
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Sound attenuation
Difference between the threshold of hearing with and without the hearing protector in place for a test subject for a given test signal
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SRP
Suggested Retail Price - The price that a manufacturer or supplier recommends a product be sold for in stores. It serves as a guideline for retailers when setting prices, but actual retail prices may vary depending on market factors or promotions.
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Standard temperature pressure dry
(STPD) standard conditions for expression of oxygen consumption
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Static breathing resistance
differential pressure caused by an RPD when the breathing gas is passed through the device at a constant flow
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Stoll curve
Empirical model used to predict skin burn injury from thermal energy exposure
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Sunglare
Sunglare is intense, reflected or direct sunlight that can cause visual discomfort, eye strain, or temporary vision impairment. • Common in outdoor work, especially around reflective surfaces like water, glass, or metal • Can increase the risk of accidents or eye injuries • Protective eyewear with suitable filters or tinted lenses (e.g. EN 172 sun glare filters) can reduce sunglare exposure and improve visibility and comfort
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Sunglare Filtering
Sunglare filtering involves reducing excessive brightness and glare from sunlight using tinted or coated lenses. This function enhances visual comfort and safety in bright outdoor environments, such as construction sites or roads, without distorting colours or reducing clarity.
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Test line
line denoting the extent of protection of a helmet. The extent of coverage may exceed the test line. Helmets may have components below the test line which may be contacted during testing. Such contact does not invalidate the test.
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Textile component
part of a device, which is made from textiles
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Threshold of hearing
Lowest sound pressure level at which, under specified conditions, a person gives a predetermined percentage of correct detection responses on repeated trials
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TIL
Total Inward Leakage (TIL) is a measure of the percentage of airborne contaminants that leak into a respirator through the face seal, exhalation valve, or other paths. It reflects the effectiveness of the RPE in real-world conditions and is used in performance standards and certification testing.
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Trachea tube assembly
tube that simulates the human trachea, containing ports for the measurement of pressure, carbon dioxide content and temperature of breathed breathable gas, and interface connections permitting seating to the RPD head form, RPD torso or alternative (benchtop) fixture
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Trained observer
person trained in testing of eye and face protectors with a binocular visual acuity of a minimum of 1,0 (6/6 or 20/20) and wearing the appropriate refractive correction, if necessary, for the observation distance of the test
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Transmitted incident energy
incident energy received at a calorimeter when testing a product -
Ultraviolet hazard
potential for acute and chronic adverse effects to the skin and eye resulting from exposure to optical radiation (3.2.1) in the wavelength range 250 nm to 400 nm
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Ultraviolet (UV)
ulUltraviolet (UV) radiation is a type of invisible light emitted by the sun and some artificial sources, such as welding torches. It has shorter wavelengths than visible light and can damage the eyes and skin. Prolonged exposure without protection can lead to conditions such as photokeratitis (sunburn of the eye), cataracts, and long-term vision impairment.
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Unassisted filtering RPD
filtering RPD in which air is drawn through the filter(s) solely by the breathing of the wearer
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Upstream
(U/S) region in a process system traversed by a flowing fluid before it enters that part of the test device
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Visibility
Visibility refers to the clarity and range of sight available through PPE such as safety goggles, visors, or face shields. High visibility ensures that the wearer can see clearly and work safely, even in low light, high-glare, or dusty conditions. Good design reduces blind spots and optical distortion.
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Visible radiation light
Any optical radiation capable of causing a visual sensation directly
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Visor
eye protector covering either the eye area or both the eye area and all or parts of the face and offering protective performance required by this document for the area which is covered by the device
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Visual field score
(VFS) Summation of grid points contained within the peripheral isopter shadow cast onto the apertometer by the RPD
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Visual Inspection
A routine check of equipment for visible signs of damage or wear.
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Welding Fume
Welding fume is a harmful airborne substance produced during welding. It contains fine particles of metal and gases that can cause serious health issues when inhaled. Prolonged exposure can lead to: Cancer (classified by the HSE as a carcinogen) Chronic obstructive pulmonary disease (COPD) Neurological disorders (from exposure to metals in mild steels) Pneumonia and other respiratory infections
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Work at Height Regulations 2005
UK legislation outlining the responsibilities of employers and employees to prevent falls from height.
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Work Restraint
A system that prevents a person from reaching a fall hazard by restricting their movement.