Construction technical glossary

60 reference definitions on brushless construction tooling, concrete surface preparation, dust capture and site safety.

A(8) vibrations

Daily vibration exposure value, expressed in m/s2, calculated over a reference period of 8 hours. European Directive 2002/44/EC sets an action value of 2.5 m/s2 and an exposure limit value of 5 m/s2 for hand-arm vibrations.

See also: Directive 2002/44/EC, MSDs (musculoskeletal disorders)

Abrasive grain size (mesh)

An indicator of the size of abrasive particles in a sanding or grinding tool. The mesh graduation is inversely proportional to grain size: a 30 mesh grain is coarse (stripping, rough grinding) and a 400 mesh grain is fine (polished finish). The choice of grain determines the material removal rate and the resulting surface condition.

See also: Diamond grinding disc, Concrete grinding (floor), Diamond consumable

Angle grinder

A power tool whose working spindle is perpendicular to the motor axis, allowing grinding, cutting or sanding of flat or profiled surfaces. Available in several diameters (115 to 230 mm), it accepts various accessories: cutting discs, flap discs, diamond pads.

See also: Diamond cutting disc, Diamond grinding disc, Brushless motor

Anti-strain devices

A range of technical solutions designed to reduce physical strain on site workers: support arms, load balancers, and passive or active exoskeletons. These devices help limit awkward postures and repetitive efforts, complementing organisational measures.

See also: Passive exoskeleton, MSDs (musculoskeletal disorders), A(8) vibrations

Asbestos (fibres)

A fibrous mineral whose inhalation causes serious pulmonary diseases (asbestosis, mesothelioma). French regulations require classification of worksites into sub-section 3 or 4 depending on risk level, with appropriate respiratory protective equipment and source-capture H-class extraction.

See also: H-class dust extraction, OELV (occupational exposure limit value), Source capture (dust extraction at source)

Bonded abrasive

An abrasive tool in which the abrasive grains (corundum, silicon carbide, diamond) are held in a rigid matrix (grinding wheel, disc, pad). Bonded abrasives differ from coated abrasives (sandpaper) by their ability to work in wet conditions or on very hard materials.

See also: Diamond consumable, Metallic bond, Resinoid bond

Brushless motor

A brushless DC (BLDC) electric motor in which commutation is achieved electronically rather than by mechanical friction. The absence of brushes eliminates friction wear, extends service life, reduces thermal losses and improves efficiency, resulting in more consistent delivered power and reduced maintenance.

See also: Tool service life (MTBF), IP65 (protection rating)

Bush hammering

A surface treatment technique consisting of striking concrete or stone with a tool fitted with pyramidal points (bush hammer) to create a uniform roughness. This operation improves the adhesion of subsequent coatings and can be performed mechanically with adapted rotary heads.

See also: Shot blasting, Scarification, Surface cohesion

Coating adhesion

The ability of a coating (resin, paint, screed) to remain bonded to the concrete substrate over time under the effect of mechanical and thermal stresses. Adhesion is measured by a pull-off test in MPa and depends directly on substrate preparation (flatness, cohesion, open porosity).

See also: Surface cohesion, Roughness profile (CSP), Concrete surface preparation

Concrete chasing (groove cutting)

An operation of cutting straight grooves into a concrete floor or wall using a wall chaser fitted with diamond discs. Grooves are used for recessed service runs (cables, pipes), the creation of control joints or anti-slip surface treatment.

See also: Diamond cutting disc, Concrete drilling, Source capture (dust extraction at source)

Concrete drilling

An operation consisting of drilling through concrete or masonry using a drill, hammer drill or diamond core drilling machine. Drilling can be performed by percussion-rotation (small diameters) or by rotation alone with water cooling (large diameters, reinforced concrete).

See also: Core drilling, Diamond core bit, SDS hammer drill

Concrete grinding (floor)

A mechanical abrasion operation on the surface of a concrete floor to improve flatness, remove laitance and prepare the substrate for the application of a coating or surface treatment. It is carried out using single-disc or multi-head grinders fitted with diamond pads.

See also: Diamond grinding disc, Laitance, NF EN 13813, Flatness index, Surface cohesion

Concrete planing

An aggressive material removal technique using rollers or rotary carbide tools to level a concrete surface, remove resin build-up or strip bonded coatings. Planing is faster than grinding for major roughing operations.

See also: Scarification, Concrete grinding (floor), Laitance

Concrete polishing

A sequence of grinding passes with progressively finer grit sizes (from stripping to mirror finish) to obtain a bright, dense and sealed concrete surface. Polishing can be performed dry or wet and uses diamond pads with successive grit sizes from 30 to 3000 mesh.

See also: Concrete grinding (floor), Diamond grinding disc, Abrasive grain size (mesh), Industrial floor

Concrete saw

A petrol or electric saw fitted with a diamond blade for cutting deeply into concrete, reinforced concrete or bitumen. The concrete saw is used for trench cuts, isolation joints and selective demolition; it can operate dry or with water cooling.

See also: Diamond cutting disc, Concrete chasing (groove cutting), Source capture (dust extraction at source)

Concrete surface preparation

The set of mechanical operations (grinding, planing, shot blasting, scarification) intended to prepare the surface of a slab or screed before application of a coating, hardener or waterproofing treatment. The quality of surface preparation directly determines the durability of the finished system.

See also: Concrete grinding (floor), Shot blasting, Scarification, Surface cohesion

Control joint (contraction joint)

A groove cut into a slab or screed to control cracking caused by concrete shrinkage during drying or by thermal expansion. Control joints are cut with a saw or wall chaser at precise intervals after pouring, then filled with a suitable elastic sealant.

See also: Concrete chasing (groove cutting), Diamond cutting disc, Screed

Cordless tool technology

A power tool powered by a Li-ion or high-density Li-ion battery (18 V, 36 V or 54 V depending on the range) providing cordless working autonomy. Brushless cordless tools combine mobility, power comparable to corded versions and reduced maintenance.

See also: Brushless motor, Tool service life (MTBF)

Core drilling

A drilling operation used to extract a cylinder of material (concrete, stone, masonry) using a rotating diamond core bit. Core drilling is used to create openings for service runs (water, electricity, ventilation) or to collect samples for analysis.

See also: Diamond core bit, Concrete drilling, Diamond segment

Crystalline silica

A crystalline form of silicon dioxide (mainly quartz and cristobalite) present in concrete, mortar, brick and natural stone. Inhalation of crystalline silica dust can cause silicosis and is classified as a Group 1 carcinogen by IARC. The French regulatory occupational exposure limit value (OELV) is 0.1 mg/m3 for quartz.

See also: OELV (occupational exposure limit value), H-class dust extraction, Respirable dust (alveolar fraction), Source capture (dust extraction at source)

Demolition hammer (breaker)

An electric or pneumatic power tool operating solely in percussion mode for demolishing concrete, removing tiles and excavating hard materials. It differs from a hammer drill in that it does not rotate the tool.

See also: SDS hammer drill, Impact energy (joules), A(8) vibrations

Diamond consumable

An abrasive tool whose active part contains synthetic diamond crystals bonded in a metallic, resinoid or electroplated matrix. Diamond consumables (pads, discs, core bits, segments) are used for grinding, polishing, core drilling and sawing of hard materials such as concrete, stone or tile.

See also: Diamond grinding disc, Diamond cutting disc, Diamond core bit, Diamond segment, Metallic bond, Resinoid bond

Diamond core bit

A hollow cylindrical tool whose active edge is fitted with sintered or electroplated diamond segments. Mounted on a drill or core drilling machine, it allows large-diameter holes to be drilled in reinforced concrete, brick or stone, with water or dry cooling depending on the type of bit.

See also: Core drilling, Diamond segment, Concrete drilling

Diamond cutting disc

A circular disc whose periphery is fitted with sintered diamond segments or continuous diamond rim, used to cut concrete, reinforced concrete, ceramics or stone. The choice of disc depends on the material to be cut, the hardness of the aggregates and the cooling method (dry or wet).

See also: Diamond consumable, Diamond segment, Sintered diamond, Concrete chasing (groove cutting)

Diamond grinding disc

Circular grinding tool fitted with diamond segments or buttons, mounted on a single-disc or planetary floor grinder. Grinding discs come in various grit sizes (mesh) for the stripping, intermediate grinding and finishing stages on concrete or stone.

See also: Abrasive grain size (mesh), Diamond consumable, Concrete grinding (floor), Diamond segment

Diamond segment

The active element of a diamond core bit or cutting disc, consisting of a sintered metal matrix containing synthetic diamond crystals. Segments are brazed or laser-welded onto the tool body; their formulation (bond type, diamond concentration and size) is tailored to the hardness and abrasivity of the material being processed.

See also: Diamond core bit, Metallic bond, Sintered diamond, Diamond consumable

Directive 2002/44/EC

European directive on minimum safety requirements relating to the exposure of workers to risks from mechanical vibration. It defines action values and exposure limit values for hand-arm and whole-body vibrations, and requires employers to assess and reduce this risk.

See also: A(8) vibrations, MSDs (musculoskeletal disorders), Anti-strain devices

Dust extraction shroud

An accessory mounted on a power tool (sander, wall chaser, grinder) to channel emitted dust towards the extraction fitting. The shroud optimises source capture and reduces particle dispersion in the work environment.

See also: Source capture (dust extraction at source), H-class dust extraction, Concrete grinding (floor)

Flatness index

A measure of the geometric regularity of a floor, expressed as the maximum permitted deviation under a reference straightedge (generally 2 m). Standard NF EN 13813 classifies screeds according to their flatness tolerance; industrial slabs and floors intended for thin coatings require strict indices.

See also: NF EN 13813, Concrete grinding (floor), Surface cohesion

H-class dust extraction

The highest filtration level for industrial vacuum cleaners according to standard EN 60335-2-69. An H-class vacuum retains at least 99.995% of hazardous particles (silica, asbestos, lead) and is mandatory for work involving exposure to these dusts. It typically integrates a HEPA filter and a secure sealed-bag system.

See also: HEPA filter, Crystalline silica, Asbestos (fibres), Source capture (dust extraction at source)

HEPA filter

A very high-efficiency filter (High Efficiency Particulate Air) classified according to standard EN 1822. An H13 HEPA filter retains at least 99.95% of particles at 0.3 microns, while an H14 achieves 99.995%. These filters are integrated into H-class vacuum cleaners for the capture of hazardous dusts.

See also: H-class dust extraction, M-class dust extraction, Crystalline silica

Impact energy (joules)

A characteristic parameter of a hammer drill or demolition hammer expressing the kinetic energy transmitted to the tool at each impact, measured in joules (J) according to standard EPTA 05. High energy allows faster work in hard materials but increases vibration exposure.

See also: SDS hammer drill, A(8) vibrations, Directive 2002/44/EC

Industrial floor

A floor covering designed to withstand heavy loads, forklift traffic and intensive mechanical or chemical stresses. Industrial floors in polished concrete, epoxy resin or polyurethane require rigorous substrate preparation (flatness, cohesion, adhesion) in accordance with standard NF EN 13813.

See also: Concrete grinding (floor), NF EN 13813, Flatness index, Surface cohesion

Industrial vacuum cleaner

An extraction unit designed for intensive use on construction sites, classified according to filtration efficiency (class L, M or H according to EN 60335-2-69). Unlike domestic vacuum cleaners, industrial units feature appropriate tank capacity, high airflow and replaceable filters compatible with hazardous dusts.

See also: H-class dust extraction, M-class dust extraction, HEPA filter

Integrated dust extraction

A configuration of a power tool combining source capture (shroud, dust hood) with an M- or H-class vacuum connected directly to the tool. Integrated dust extraction is the most effective solution for complying with regulatory occupational exposure limit values (OELVs) on sites generating hazardous dusts.

See also: Source capture (dust extraction at source), H-class dust extraction, OELV (occupational exposure limit value), Dust extraction shroud

IP65 (protection rating)

A classification according to standard IEC 60529 indicating that equipment is totally protected against dust (digit 6) and against water jets from any direction (digit 5). For construction tools, IP65 guarantees use in dusty and wet environments without risk of internal deterioration.

See also: Tool service life (MTBF), Brushless motor

Laitance

A porous and low-resistance surface layer that forms on the surface of fresh concrete during the rise of bleed water. Laitance must be removed before applying a coating or screed, by grinding, shot blasting or scarification, to ensure good adhesion.

See also: Shot blasting, Scarification, Concrete grinding (floor), Surface cohesion

M-class dust extraction

An intermediate filtration level for industrial vacuum cleaners according to EN 60335-2-69: minimum efficiency of 99.9% on common harmful dusts. Suitable for hardwood dust, plaster or cement without elevated free silica or asbestos content.

See also: H-class dust extraction, HEPA filter, Source capture (dust extraction at source)

Metallic bond

A sintering matrix based on metal powders (cobalt, bronze, iron, tungsten) in which the diamond crystals of a segment or pad are embedded. The hardness of the bond is chosen according to the abrasivity of the material to be worked: soft bond for hard concrete, hard bond for soft or abrasive concrete.

See also: Sintered diamond, Diamond segment, Diamond consumable

MSDs (musculoskeletal disorders)

Conditions affecting muscles, tendons, nerves and joints caused by repetitive movements, awkward postures or prolonged vibrations. MSDs are the leading cause of occupational diseases in France; their prevention in construction relies notably on anti-strain devices and limiting exposure to vibrations.

See also: Anti-strain devices, A(8) vibrations, Directive 2002/44/EC, Passive exoskeleton

Multi-head floor grinder

A floor grinding machine fitted with several counter-rotating heads, offering greater stability, better flatness and a more uniform removal rate than a single-disc machine. Used for large industrial surfaces, it minimises rotation marks.

See also: Concrete grinding (floor), Diamond grinding disc, Single-disc floor grinder

NF EN 13813

European standard defining requirements for screed materials intended for interior floors. It establishes resistance classes for compression (C), bending (F) and wear (A), and the criteria for flatness, surface cohesion and surface hardness applicable before laying coatings.

See also: Flatness index, Surface cohesion, Concrete grinding (floor)

Noise level (dB)

A physical quantity expressing the sound pressure emitted by a tool, measured in decibels (dB). Sound pressure at the workstation (LpA) and sound power (LwA) are the two standardised indicators communicated by manufacturers. Above 85 dB(A), the wearing of hearing protectors is mandatory under Directive 2003/10/EC.

See also: Tool service life (MTBF), Directive 2002/44/EC

OELV (occupational exposure limit value)

The maximum concentration of a chemical agent in workplace air to which a worker may be exposed without health risk according to the current state of scientific knowledge. OELVs are defined by French regulations and expressed in mg/m3 or ppm; they may be binding or indicative.

See also: Crystalline silica, Asbestos (fibres), Respirable dust (alveolar fraction), Source capture (dust extraction at source)

Passive exoskeleton

A mechanical device worn by the operator to support the spine, shoulders or upper limbs during overhead work or in awkward postures. Unlike active (motorised) exoskeletons, passive models return energy through springs or elastic bands, without electrical power.

See also: Anti-strain devices, MSDs (musculoskeletal disorders), A(8) vibrations

Reinforced concrete

A construction material combining cement concrete with a metal reinforcement (high-adhesion steel bars). The presence of steel reinforcement influences the choice of diamond tools (reinforced-formula segments) and requires precautions during core drilling or sawing to avoid damaging the reinforcement.

See also: Core drilling, Diamond core bit, Diamond cutting disc

Resinoid bond

A matrix based on synthetic resin (phenolic, epoxy or polyimide) used to bind abrasives in grinding discs and polishing pads. Resinoid bonds offer good elasticity and a clean cut; they are well suited to finish sanding and concrete polishing.

See also: Metallic bond, Diamond consumable, Diamond grinding disc

Respirable dust (alveolar fraction)

The fraction of airborne dust whose particle size (below approximately 10 microns) allows it to reach the pulmonary alveoli during inhalation. These are the most hazardous dusts for health; their concentration is subject to occupational exposure limit values (OELVs).

See also: OELV (occupational exposure limit value), Crystalline silica, HEPA filter, H-class dust extraction

Roughness profile (CSP)

A standardised classification (Concrete Surface Profile) of the surface condition of concrete after mechanical or chemical treatment, ranging from CSP 1 (smooth surface) to CSP 10 (very rough surface). Each class corresponds to a recommended mechanical anchor for different types of coatings or resins.

See also: Shot blasting, Scarification, Bush hammering, Surface cohesion

Scarification

A mechanical surface treatment using rotors fitted with carbide or steel tools to score and roughen concrete, remove a degraded screed or strip a coating. Scarification is more aggressive than grinding and produces a high roughness profile (CSP 5 to 9).

See also: Concrete planing, Shot blasting, Roughness profile (CSP), Laitance

Screed

A layer of mortar or lean concrete poured over a slab to level its surface, integrate services or form the load-bearing finish for a floor covering. Standard NF EN 13813 classifies screeds according to their resistance to compression, bending and wear.

See also: NF EN 13813, Flatness index, Laitance, Concrete grinding (floor)

SDS hammer drill

A power tool combining rotation and percussion for drilling into concrete, masonry or stone. The SDS (Slotted Drive System) chuck in SDS-Plus and SDS-Max versions allows rapid bit changes and efficient transmission of impact energy, measured in joules.

See also: Concrete drilling, Core drilling

Shot blasting

A surface treatment process projecting steel shot at high speed onto concrete to remove laitance and open the pores. Shot blasting creates a standardised roughness profile (CSP) favourable to the adhesion of floor coatings, and generates little dust as the shot is recovered in a closed circuit.

See also: Laitance, Surface cohesion, Scarification, Bush hammering

Single-disc floor grinder

A floor grinding machine fitted with a single large-diameter rotating pad, suited to flat surfaces and wide spaces. The rotation speed and direction of the pad determine the contact pressure and aggressiveness of the treatment.

See also: Concrete grinding (floor), Diamond grinding disc, Multi-head floor grinder

Sintered diamond

A manufacturing process for diamond segments in which crystals are bonded by sintering (hot compression of a metal powder). Sintered tools offer a long service life and are suited to abrasive materials. In contrast, electroplated tools (diamonds deposited by electroplating) are more aggressive but wear faster.

See also: Diamond segment, Metallic bond, Diamond consumable

Source capture (dust extraction at source)

A prevention principle consisting of extracting dust as close as possible to the emission point, before it disperses into the surrounding air. Source capture is the most effective method for reducing operator exposure, recommended by INRS and made mandatory for certain regulated dusts.

See also: H-class dust extraction, OELV (occupational exposure limit value), Crystalline silica, Asbestos (fibres)

Surface cohesion

The mechanical resistance of the surface layer of a concrete substrate, measured by direct pull-off testing (pull-off test) in MPa. Standard NF EN 13813 defines minimum cohesion values according to screed resistance class; a substrate with insufficient cohesion must be treated before applying a coating.

See also: NF EN 13813, Laitance, Concrete grinding (floor)

Tool service life (MTBF)

MTBF (Mean Time Between Failures) is a reliability indicator for industrial equipment. For construction power tools, it is expressed in operating hours and determines preventive maintenance intervals.

See also: Brushless motor, IP65 (protection rating)

Wall and ceiling sanding

The application of mechanical sanding to vertical and overhead surfaces for the treatment of render, plaster and paint. Dedicated tools feature articulated heads and telescopic arms to reach overhead surfaces while limiting awkward operator postures.

See also: Concrete grinding (floor), Anti-strain devices, Source capture (dust extraction at source)

Wet suppression (dust control)

A technique for reducing airborne dust by adding water at the cutting or drilling point. Wet suppression reduces the dispersion of respirable dust but requires management of contaminated water and is incompatible with certain tools or environments (electrical hazard, freezing conditions).

See also: Source capture (dust extraction at source), Respirable dust (alveolar fraction), Crystalline silica