Wiki — standards,
legislation and terminology

ACD

IEC classification for vacuum cleaners designed to collect combustible dust in areas without official ATEX zone classification. Defined in IEC 60335-2-69:2021, Edition 6.0, Annex AA, clause AA.3.208. ACD vacuum cleaners are certified for internal Zone 20 — meaning the machine itself is built to withstand a continuously explosive atmosphere inside the collection container — but are not approved for external use in Zone 20, 21 or 22. ACD is not an ATEX approval and cannot replace a full ATEX certificate from a Notified Body when documentation of Zone 20 safety is required. Category 1D equipment (internal Zone 20) may never be self-certified; EU type-examination by a Notified Body is mandatory under ATEX Directive 2014/34/EU. ACD machines must use bypass or side-channel blower motors — through-flow motors are explicitly prohibited per clause AA.22.204. Frequently and erroneously confused with ATEX certification.

Additive manufacturing

Manufacturing process in which an object is built up layer by layer from a digital model, as opposed to subtractive methods that remove material. In life science and pharma, additive manufacturing is used for prototypes, medical devices, implants and – increasingly – for personalised dosage forms. The most common industrial methods are Selective Laser Sintering (SLS), Selective Laser Melting (SLM), Direct Metal Laser Sintering (DMLS) and Electron Beam Melting (EBM) – all based on powder materials. Polymeric and metallic powders used in these processes are in most cases combustible and require ATEX-certified collection equipment. Prior to EN 17348:2022 no harmonised European standard existed specifically for vacuum cleaners used in additive manufacturing.

Inerting

Safety engineering method that eliminates the risk of explosion by bringing the vacuumed powder into direct contact with an inerting medium – water or oil – inside the collection tank. The principle is that explosive dust particles are immediately surrounded by a medium that blocks access to oxygen and neutralises all electrical and mechanical ignition sources. In water immersion (wet mix), powder is mixed with water in the tank. In oil inerting, powder is surrounded by an inerting oil that is chemically neutral towards the most reactive metals. Water immersion is suitable for most reactive metal powders but is insufficient for pyrophoric metals – aluminium, magnesium and titanium – which can react with water and release hydrogen gas. These require oil inerting. Inerted vacuums are certified internally as Zone 20 (Category 1D) and are marked in accordance with ATEX 2014/34/EU and EN 17348 WT (Wet Type Dust Collector).

Oil inerting

Inerting method in which the vacuumed metal powder is directed into an oil chamber inside the collection tank and completely surrounded by inerting oil. The oil prevents any contact between powder and atmospheric oxygen, thereby eliminating the risk of ignition. Unlike water immersion, oil does not react chemically with pyrophoric metals such as aluminium and magnesium, and no hydrogen gas is generated. Oil inerting is the internationally recognised standard method for vacuum collection of self-igniting and pyrophoric metal powders in additive manufacturing and other processes involving reactive metals. Vacuums with oil inerting are typically classified as Category 1/2D (Zone 20 internal, Zone 21 external) and are certified to ATEX 2014/34/EU and IECEx by a notified body.

Powder Bed Fusion

Generic term for a group of additive manufacturing methods that use an energy source – laser or electron beam – to melt or sinter layers of powdered material on a powder bed. The most common are Selective Laser Sintering (SLS) for plastic powders and Selective Laser Melting (SLM) / Direct Metal Laser Sintering (DMLS) for metallic powders. After each print job, large quantities of unused powder remain in the build chamber and powder bed. This powder must be collected, sieved and reused. Residual powder from powder bed fusion is typically classified as combustible and – in the case of metallic powders – also as conductive and potentially reactive. Safe collection requires ATEX-certified equipment, and efficient reuse requires a PRS system (Powder Recovery System) with an integrated cyclone.

PRS

Integrated system for collecting and recovering unused powder from powder bed fusion printers. A PRS system combines an industrial vacuum with a high-efficiency cyclone pre-separator that separates up to 98% of the powder before it reaches the filters, collecting it cleanly in a separate detachable stainless steel tank. The tank can then be connected to sieving equipment and the powder returned to the printing process. PRS systems are particularly relevant for metallic powders used in SLM and DMLS, as these powders are expensive and recovery is economically critical. ATEX-certified PRS systems are typically marked II 2GD or II 1/3D and comply with NFPA 484 paragraph 11.2.4.4.1 (cyclone without filter media) and paragraph 13.4.1 (Group E atmospheres).

Pyrophoric

Property of certain substances – particularly fine metal powders – that enables them to ignite spontaneously on contact with air, moisture or frictional heat, without an external ignition source. In additive manufacturing, the most significant pyrophoric materials are aluminium and aluminium alloys, magnesium, titanium in nanoparticle form and certain nickel-based superalloys. Pyrophoricity is particle-size-dependent and is significantly amplified at the very fine particle sizes typically used in SLM and DMLS. For pyrophoric powders, conventional ATEX dry vacuuming is insufficient, and water immersion can be hazardous as aluminium and magnesium react with water and release flammable hydrogen gas. Oil inerting is the only safe collection method.

NFPA 484

American fire safety standard for the safe handling, storage and processing of combustible metals and metal powders. Published by the National Fire Protection Association (NFPA), USA. Contains specific requirements for additive manufacturing: paragraph 13.4.1 covers equipment certified for Class II, Group E atmospheres (conductive metallic dust), and paragraph 11.2.4.4.1 specifies requirements for cyclones without filter media in powder recovery systems. NFPA 484 is the primary reference standard in the North American context for 3D printing with metallic powders and is actively cited by Tiger-Vac as the compliance basis for PRS systems. In the European context it is supplemented by ATEX 2014/34/EU and EN 17348.

TEFC motor

Electric motor with a fully enclosed housing that prevents the ingress of dust and moisture, cooled by an external fan mounted on the motor shaft. TEFC motors are robust industrial motors with an IP protection class typically IP54–IP65, suitable for environments with dust, moisture and aggressive atmospheres. In ATEX contexts, TEFC motors are used in vacuum cleaners for 3D printing and additive manufacturing, as they withstand the mechanical and thermal loads associated with close proximity to printing machines. They differ from bypass motors, which use the working air for cooling and are therefore more sensitive to heat and high duty cycles.

Activated carbon filter

A filter that retains gaseous substances and vapours by adsorption onto activated carbon. Unlike HEPA and ULPA filters, which capture particles, an activated carbon filter is the only filtration principle that effectively removes volatile organic compounds (VOCs), acid vapours and other gaseous contaminants from an airstream. Activated carbon has an extremely large internal surface area — typically around 1,000 m² per gram — and vapour molecules bind physically to the carbon structure as air passes through it. The filter’s capacity is finite: the surface gradually becomes saturated and the carbon cartridge must be replaced regularly. When wet vacuums are used to collect volatile or corrosive liquids in cleanrooms or ATEX environments, an activated carbon filter is mandatory as a complement to particulate filtration — the two filter types address fundamentally different problems and cannot substitute for one another.

Adsorption

A physical-chemical process in which molecules from a gas or liquid bind to the surface of a solid material. Distinct from absorption, where the substance is taken up into the volume of the material. In activated carbon filters, adsorption is the governing principle: organic vapour molecules bind to the enormous internal surface of the carbon granules via weak intermolecular forces (van der Waals forces). Adsorption capacity depends on molecular size, vapour pressure and temperature — heavier, less volatile molecules are adsorbed more readily than light gases such as hydrogen.

Aerosol

A suspension of fine liquid droplets or solid particles in air. Aerosols are generated when liquids are dispersed mechanically — for example when a wet vacuum collects an aggressive liquid and returns the air without adequate filtration, or when cleaning liquids are sprayed in a cleanroom. In regulated environments, aerosols are particularly problematic because they can carry corrosive, toxic or infectious substances and penetrate deep into the lungs. Aerosol droplets in the range of 1–10 µm remain airborne for extended periods. In cleanrooms, aerosols can compromise ISO classification (ISO 14644-1) and cause cross-contamination of products and equipment. An activated carbon filter is necessary when aerosols contain volatile substances — particulate filters alone capture the droplets but not the vapours released when the droplets evaporate inside the filter.

Aerosol Testing

Factory test performed on each individual HEPA-filtered vacuum unit before delivery. The test verifies not just the HEPA filter in isolation, but the entire airflow path — including gaskets, joints and the filter housing — for leaks, using a controlled aerosol injection and a downstream particle counter. It differs from the DOP/PAO test, which is normally performed at the installation site as a periodic verification. Factory aerosol testing provides documented assurance that each individual unit performs as stated on the data sheet — regardless of whether gaskets are correctly seated and the filter is airtight. In regulated pharma environments, a factory-issued aerosol test report is a significant contribution to IQ/OQ validation documentation, as it replaces or supplements the need for a new leak test at installation.

ADC

A biologic medicine consisting of an antibody linked to a highly potent cytotoxic substance (payload). ADCs are designed to target cancer cells precisely, but the payload is typically so potent that it is classified as OEB 4–5. Handling ADCs in production requires closed systems, BIBO filtration and full PPE corresponding to the cytotoxic substance's OEB classification.

AISI 316L

Austenitic stainless steel with low carbon content (L = Low Carbon) and molybdenum addition, providing high corrosion resistance to acids, alkalis and chlorine-containing cleaning agents. The industry standard material for contact surfaces in OEB 4–5 environments. Electropolishing (Ra ≤ 0.6–0.4 µm) is the typical requirement at these levels. Contrasts with AISI 304, which is sufficient at OEB 3.

API

The active substance in a medicine — the chemical compound that has the therapeutic effect. APIs vary enormously in potency; highly potent APIs (HPAPIs) require special containment measures when handled. The vast majority of APIs in active production and development have no official OEL value and are classified via OEB banding.

ATEX

Collective term for the two EU directives governing equipment (2014/34/EU) and workplace safety (1999/92/EC) in explosive atmospheres. ATEX-certified equipment is designed and tested to avoid acting as an ignition source. Important in OEB contexts: many highly potent substances are also combustible, so OEB requirements and ATEX requirements may arise simultaneously for the same substance and equipment.

Autoclaving

Sterilisation method where equipment is exposed to saturated steam at 121°C or 134°C under pressure for a given time. Kills bacteria, viruses, fungal spores and other microorganisms. In OEB environments, autoclaving is used to sterilise accessories, hoses and nozzles before and after use. Plastic materials such as ABS and PVC do not withstand repeated autoclaving; PEEK, PVDF and EPDM do. Container properties must be verified with a leak test after the autoclave cycle as deformation can create leaks.

BIBO

System for safe filter replacement in high-risk environments without exposing the operator to the collected particles. The filter is placed in a plastic bag before removal, preventing contamination. Mandatory at OEB 4–5 and when handling HPAPI. Distinguished from BO systems (Bag-Out), which only seal the filter during removal, not during insertion.

BEI / BLV

The highest permitted concentration of a substance or its metabolites in biological material (blood, urine) from an exposed worker. BEI/BLV supplements OEL as a biological measure of exposure and can capture exposure via skin and oral routes that air measurements do not reveal. Set by national authorities for selected substances.

BO system

Simpler variant of the BIBO system where the filter or collection container seals during removal (bag-out) but not necessarily during insertion. Used at OEB 3–4 when the risk is moderate and BIBO is assessed as excessive. The choice between BO and BIBO depends on the substance's OEB level and the specific risk assessment.

Brushless motor

An electric motor without carbon brushes. Unlike traditional universal motors, brushless motors generate no carbon particles during operation. This is critical in OEB 3–5 environments, as carbon particles from the motor would otherwise require an additional downstream filter to prevent them mixing with the collected contaminating material and being discharged into the room. Also provides lower noise levels and longer service life.

Bypass

A leak or channel in the filter construction that allows air to pass around the filter medium. Bypass can arise from deformation of the filter frame (heat, mechanical impact), incorrect installation or defective gaskets. Even a microscopic bypass reduces filter effectiveness dramatically — the filter is intact, but the system is not safe. Can only be detected by leak testing or DOP/PAO scan test, not by visual inspection.

Carbon brushes

Graphite electrodes in traditional universal motors that transfer current to the rotor's commutator rings. Carbon brushes wear down during operation and generate carbon particles that mix with the suction air. In OEB environments this is a risk, as the carbon particles can mix with the collected contaminating dust and be discharged via the filter. Solution: either an additional downstream filter for the motor exhaust, or — ideally — brushless motors that generate no carbon particles.

CCS

A documented, systematic strategy describing all the measures a company takes to control contamination in the production environment. Introduced as a requirement in EU GMP Annex 1 (2022). CCS must cover premises, equipment, personnel, processes and cleaning. The selection and qualification of a vacuum cleaner typically forms an element of the CCS in sterile and OEB-regulated environments.

Cleanroom

A controlled environment with documented limits for airborne particles, temperature, humidity and pressure. Classified under ISO 14644-1 in classes 1–9, where ISO 1 is the cleanest. In pharmaceutical production, work typically takes place in ISO 5–8. Important: ISO class only describes particle count — not hazard. A vacuum suitable for a cleanroom is not automatically suitable for OEB 4, unless the substance also requires it.

Containment

Collective term for technical and procedural measures that prevent pharmaceutical substances from spreading to the environment. The containment level depends on the substance's OEB classification and ranges from simple filter systems (OEB 1–2) through closed systems (OEB 3–4) to fully isolated process lines with BIBO filtration (OEB 5). Distinct from OEB: OEB describes the need (substance hazard). Containment describes the solution (the physical barrier).

Corrosive

A substance that chemically destroys or irreversibly damages living tissue, metals or other materials on contact. Corrosive properties depend not only on concentration — even dilute acids or bases can be corrosive when left in contact with sensitive surfaces over time. In the EU, corrosive substances are classified under the CLP Regulation with the GHS05 hazard pictogram (corrosive effect). When corrosive liquids are spilled, correct collection equipment is critical: materials must be chemically resistant (AISI 316L, PEEK, PVDF), equipment must not generate static electricity if the liquid is also flammable, and exhaust air from the wet vacuum must be filtered with an activated carbon filter to retain any vapours released.

Cytostatics

Medicines that inhibit or stop cell division. Used primarily for cancer treatment but do not distinguish between cancer cells and healthy cells — they are toxic to all living tissue. Even microgram quantities can damage bone marrow, be mutagenic, cause miscarriages or increase the cancer risk for those handling them. Cytostatics typically belong to OEB 4–5 and require closed systems, BIBO filtration and IQ/OQ/PQ qualification of cleaning equipment.

Dust class L, M and H

Classification of ACD and industrial vacuum cleaners based on filter penetration, and thus suitability for handling dust of varying hazard levels. Class L (light hazard): filter penetration below 1 %. Class M (medium hazard): below 0.1 % — required for pharmaceutical processes and dust types harmful to the respiratory system. Class H (high hazard): below 0.005 % — the highest level, relevant for carcinogens, pathogens and highly potent pharmaceutical active substances. Class H additionally requires that the essential filter can only be removed with a tool, and that the machine stops operating if the filter is missing. All three classes require certification by a Notified Body.

Dust group IIIA, IIIB and IIIC

ATEX classification of dust and combustible substances according to electrical conductivity and reactivity. IIIA: combustible flyings — lint, fibres, wood shavings — that ignite readily. IIIB: non-conductive dust types — encompassing the vast majority of organic powders including flour, sugar, lactose and most pharmaceutical API powders and plastic powders. IIIC: electrically conductive dust types — including metal dusts (aluminium, magnesium, iron, copper) and graphite. IIIC is the most demanding group: a vacuum cleaner certified for IIIC is automatically also suitable for IIIA and IIIB. The dust group appears directly in the ATEX marking and is a mandatory selection criterion when choosing equipment for specific materials.

Decontamination

Process that reduces or removes contaminating substances from equipment, surfaces or environment to a defined, safe level. In OEB environments, a distinction is made between cleaning (removal of visible dirt) and decontamination (reduction of chemical or biological contamination to a validated endpoint). When in doubt, decontamination should take priority. Methods include wet decontamination with peroxide, aldehyde or alcohol, steam treatment and in extreme cases destruction.

DOP/PAO test

Method for verifying HEPA and ULPA filter integrity using an aerosol generator and photometer. DOP (Dioctyl Phthalate) and PAO (Poly-Alpha-Olefin) are the aerosol liquids typically used. The test reveals bypasses and leaks in the filter frame that are not visible to the naked eye. For ULPA U15, DOP/PAO scan testing is mandatory under EN 1822-1 — the oil thread test is not acceptable. At OEB 5, the test is performed at commissioning, at filter changes and at least annually.

Dust collector

Stationary or mobile unit that captures dust and particles directly at the source during production. Unlike a vacuum cleaner, a dust collector is dimensioned for higher air volumes and is integrated into the production process, operating continuously during operation. Used at tablet presses, granulators, blenders and other process points where dust is generated as a direct consequence of the process. The Danish equivalent term is partikelfanger.

EHSQ

Collective term for the function in a company that manages environment, occupational health and quality. In the pharma approval process for OEB equipment, EHSQ (or EHS) is one of the four key functions that assesses exposure risk and occupational health requirements. The EHSQ function determines OEB classification, defines PPE requirements and approves the containment strategy.

Electropolishing

Electrochemical surface treatment that removes the outermost layer of stainless steel, leaving a bright, extremely smooth surface with a low Ra value. Electropolished surfaces are harder for microorganisms and chemicals to adhere to and easier to clean and decontaminate. The industry's typical requirements in OEB environments: Ra ≤ 0.6 µm electropolished at OEB 4; Ra ≤ 0.4 µm at OEB 5. An important design criterion when selecting equipment for highly potent environments.

EPD

A mandatory document that employers must prepare under the ATEX Workplace Directive 1999/92/EC. The EPD must describe the zone classification of explosive areas, the technical and organisational protection measures in place, the allocation of responsibilities, and the procedures that ensure those measures are maintained. The document must be updated whenever significant changes are made to equipment, processes or work practices. An EPD is not an optional best practice — it is a legal requirement, and its existence and content are checked during health and safety inspections. The introduction of new ATEX equipment or a change of accessories in a classified zone generally triggers an update to the EPD.

EPDM

Synthetic elastomer with good chemical resistance to water, steam, acids and alkalis. Used for gaskets, hoses and accessories in OEB 3–4 environments. EPDM is autoclavable and compatible with most disinfectants. Cannot be used with oil products or organic solvents. Documented chemical resistance must always be verified against the specific cleaning agents used in the facility.

ESD

Sudden transfer of electrical charge between two objects with different potential. In ATEX environments, ESD is a potential ignition source. ESD-safe vacuums are equipped with an earthing point and antistatic hoses that safely dissipate static electricity. In OEB environments with combustible substances, ESD may require both ATEX certification and ESD protection.

Filter bag

Single-use bag of synthetic or paper material placed inside the vacuum's collection tank. In pharma and cleanroom applications, synthetic filter bags are used as they are denser than paper and provide better dust retention during closure and handling. Certain regulated environments require that used filter bags are handled as contaminated waste.

Filter module

A sealed, replaceable module that encapsulates the HEPA or ULPA filter. When the filter is spent, the entire module is removed as one unit without the operator needing to touch the filter medium directly. This significantly reduces the exposure risk during filter changes. At OEB 4–5, filter modules must be replaceable via a BIBO mechanism. A filter module in an otherwise leaking construction is insufficient — the entire system must be H-class classified.

GMP

Quality management system for the manufacture of medicinal products and medical devices. GMP defines requirements for premises, equipment, personnel, documentation and cleaning to ensure products are consistent and safe. In the EU regulated by EudraLex Volume 4. OEB is not mentioned directly in GMP, but GMP's requirements for cleanability, material selection and documentation reflect precisely the mechanisms OEB addresses in practice.

H-class

The highest system classification for industrial vacuum cleaners under EN 60335-2-69. An H-class vacuum cleaner is tested and documented to retain highly potent, carcinogenic and biological substances as a complete system — motor, hose, joints, container and filter considered as one. H-class is the minimum requirement from OEB 2 upwards. Key distinction: A vacuum with an H14 filter is not automatically H-class — the system as a whole must be tested.

HEPA

Filter class retaining at least 99.95% (H13) or 99.995% (H14) of particles at MPPS in accordance with EN 1822. HEPA H14 is the standard requirement for routine GMP cleaning in sterile production areas. Important: An H14 filter element in a leaking construction does not provide H-class system performance. The test of the filter and the test of the system are two different things.

HPAPI

Highly potent active pharmaceutical ingredients with a therapeutic daily dose below 1 mg or an OEL below 10 µg/m³. HPAPIs require closed systems, containment equipment and BIBO filtration when cleaning. The category includes cytostatics, certain hormones and many ADC payloads. Some HPAPIs are also combustible, so ATEX requirements may arise alongside OEB requirements.

Inerting

Process where an inert gas (typically nitrogen or argon) replaces oxygen in a closed space or system to prevent oxidation or explosion. In OEB 5 environments, inerting is used in integrated vacuum systems where the hazardous dust is neutralised with liquid or nitrogen during collection, causing it to lose its biological or chemical activity. Also reduces the explosion risk when handling combustible HPAPIs.

IQ / OQ / PQ

Three-stage qualification programme for equipment in GMP environments under EU GMP Annex 15. IQ (Installation Qualification) documents correct installation. OQ (Operational Qualification) verifies that equipment functions as intended under defined operating conditions, including tightness, filtration and alarms. PQ (Performance Qualification) confirms that equipment delivers the required performance under realistic production conditions over time. Protocols and reports for each stage must be archived and available at inspection. Mandatory from OEB 4 upwards.

ISO class

Classification of cleanrooms by particle concentration per cubic metre of air. ISO 1 is the cleanest, ISO 9 corresponds to normal outdoor air. Pharmaceutical production typically operates in ISO 5–8. ISO class and OEB are two independent axes: the ISO class says how many particles are permitted — not how hazardous they are. Equipment may be suitable for an ISO 4 cleanroom but unsuitable for OEB 4, and vice versa.

Isolator

A hermetically sealed working chamber under negative pressure where the operator works via fixed gloves (gloveports) without direct contact with the material. Isolators are used at OEB 5 and in the manufacture of sterile medicines to completely eliminate exposure. Vacuum cleaners used in connection with isolators must be directly connected to or integrated into the isolator system, so collection and filter changes never take place in the open room.

Contamination

Unintended introduction of foreign substances into a product, process or environment. In pharma production, cross-contamination is particularly critical: dust from one active substance transferred to another product can have serious consequences for patient safety. Vacuum cleaners are a primary source of contamination spread if they are not correctly filtered and hygienically constructed.

Corrosion

Chemical or electrochemical degradation of a material through reaction with its environment. Acids, bases, oxidants and halides can attack metals, plastics and elastomers, gradually weakening equipment mechanically or leading to sudden failure. In chemical environments, correct material selection is essential: stainless steel AISI 316L, PEEK, PVDF and PTFE are examples of materials with documented resistance to most aggressive liquids. Corrosion in collection equipment is a direct safety hazard — a corroded vessel can fail and expose the operator to its hazardous contents. Even “mild” acids can degrade standard plastics over time if the material’s chemical resistance has not been verified.

Conductive hose

A suction hose with a continuous, measurable electrical connection from one end to the other, typically via an embedded copper wire or conductive spiral. A conductive hose differs fundamentally from an antistatic hose: antistatic means the material slows charge build-up on the surface, but does not guarantee a measurable, continuous connection. In ATEX zones, a conductive hose is a requirement, not an option, because only a conductive hose can function as a verifiable link in the earthing chain from the outermost point of the nozzle to the chassis bolt of the vacuum cleaner. EN 17348:2022 specifies that parts in direct contact with the dust stream must have a resistance of less than 10&sup8; Ω measured in accordance with EN 60079-32-2. A hose labelled “antistatic” is not sufficient documentation of this.

Laminar airflow

A controlled, unidirectional airflow in which air moves in parallel layers without turbulence. Developed by Willis Whitfield at Sandia National Laboratories in 1962 as the founding principle of the modern cleanroom: by directing filtered air laminarly through the room, particles are consistently displaced away from the critical work area rather than circulating randomly. In pharmaceutical production, laminar airflow is used above filling lines and in Grade A zones to minimise particle concentration at the product itself. The opposite of turbulent ventilation, which mixes the air and distributes particles unpredictably.

Leak test

Test that verifies a vacuum system maintains negative pressure without leaks. Performed with a vacuum gauge and optionally particle smoke or UV-sensitive spray. Leak testing is critical because a bypass is not visible to the naked eye. Recommended at least annually at OEB 3, mandatory annually at OEB 4–5. Must also be performed after transport to a new zone, as vibration and mechanical impact can create new leaks.

M-class

Middle system classification for industrial vacuum cleaners under EN 60335-2-69. An M-class vacuum is designed for handling health-hazardous substances including certain chemicals and biological materials. Sufficient at OEB 1. At OEB 2 and above, H-class is required. Distinguished from filter class: M-class is a system class, not a filter class.

MPPS

The particle size — typically 0.1–0.3 µm — that penetrates a filter most easily. HEPA and ULPA filter classes are measured and classified at MPPS as this represents the worst case for the filter. A HEPA H14 efficiency of 99.995% therefore refers to efficiency at MPPS. Particles larger or smaller than MPPS are actually retained more effectively.

Multi-Recovery

Term for vacuum cleaners that can switch between dry and wet recovery by changing the filter configuration. For dry recovery, a microfilter bag and cloth filter are used as pre-filtration stages; for wet recovery, these are replaced by a liquid filter assembly designed to handle liquid without damaging the HEPA final filter. The HEPA filter remains fitted in both configurations, ensuring all exhaust air is filtered. Tiger-Vac uses the suffix MR (Multi-Recovery) on models with this capability, for example the ASL-10 HEPA MR. Multi-Recovery design is relevant in environments where both liquid spills and dry dust occur and a single machine must cover both tasks.

Mutagen

A substance that can cause permanent changes to DNA (mutations) in living cells. Mutagenic substances are particularly serious in occupational health contexts, as DNA damage can be cumulative and irreversible. Many cytostatics and certain HPAPIs are mutagenic. Mutagenic substances are typically classified in OEB 4–5 and require closed systems, BIBO and IQ/OQ/PQ qualification of cleaning equipment. Classified under CLP as Muta. 1A, 1B or 2.

Notified body

An independent third-party organisation accredited by an EU member state to assess and certify products subject to EU legislation requiring mandatory third-party control. For ATEX equipment in category 1 and 2, certification from a notified body is mandatory — the manufacturer cannot self-declare conformity. The notified body issues an EU-type examination certificate and is responsible for verifying that the equipment meets the harmonised standards. Examples of ATEX notified bodies include INERIS and LCIE (France) and PTB (Germany). Category 3 equipment does not require a notified body — the manufacturer may self-declare conformity.

OEB

Classification system that groups pharmaceutical substances by health hazard into bands 1–5. OEB 1 is the least hazardous (>1,000 µg/m³), OEB 5 requires fully closed systems and isolators (<0.1 µg/m³). OEB is not legally binding — it is an industry-created assessment tool used when no official OEL value has been set for a substance. Although OEB is not legislation, the requirements are reflected in practice via GMP, REACH and occupational health legislation.

OEL

The highest permitted airborne concentration of a substance that a worker may be exposed to during a working day (typically 8 hours). Measured in µg/m³. OEL is used as the basis for determining OEB class and selecting the appropriate containment level. The vast majority of pharmaceutical substances in active production and development have no official OEL value, as toxicological documentation is lacking. In these cases, OEB banding is used as an alternative.

PEEK

High-performance thermoplastic polymer with exceptional chemical resistance, thermal stability (up to approximately 250°C) and mechanical strength. Used for gaskets, hoses, nozzles and accessories in OEB 4–5 environments. Resists autoclaving, hydrogen peroxide, aldehydes and most organic solvents. Significantly more expensive than standard plastics such as ABS or PVC, but the correct choice when cleanability and chemical resistance are critical.

Point extraction

Extraction of dust or vapour directly at the point where it is generated — before it disperses into the working environment. Far more effective than general room ventilation, as the contaminant is captured at source. Proximity to the source is critical: even a few centimetres of additional distance significantly reduces capture efficiency. Used in pharmaceutical manufacturing, 3D printing with metal powder, and any process with localised dust or fume generation.

PPE

Equipment worn by the worker to protect against exposure to hazardous substances: gloves, mask, goggles, coverall, respirator. In the OEB hierarchy, PPE is the last line of defence — technical solutions (containment, ventilation, closed systems) are always prioritised first. PPE level is determined by the EHSQ function based on OEB class. During service and filter changes in OEB environments, the PPE level is typically higher than during the cleaning operation itself.

PTFE lamination

Filter media with PTFE lamination have an ultra-thin layer of PTFE on the surface of the filter medium, making the surface extremely smooth and chemically resistant. PTFE-laminated filters are harder for fine particles to penetrate, easier to clean (via pulse-jet), and more resistant to moisture and aggressive chemicals. Used as the standard material for HEPA H14 and ULPA U15 filters in OEB 3–5 applications.

PVDF

Fluoropolymer with high chemical resistance and thermal stability. Used as an alternative to PEEK in equipment for OEB 4–5 environments. PVDF withstands strong acids, alkalis, oxidants and most organic solvents. Good resistance to UV and ionising radiation. Autoclavable. Selected when PEEK's price level is disproportionate or when PVDF's specific properties better suit the specific environment.

Ra value

Measure of surface roughness expressed as the average absolute deviation from the mathematical centreline measured in micrometres (µm). The lower the Ra value, the smoother and more easily cleaned the surface. In OEB environments, indicative requirements based on GMP practice apply: Ra ≤ 0.8 µm at OEB 3, Ra ≤ 0.6 µm at OEB 4, Ra ≤ 0.4 µm at OEB 5. Electropolishing is the typical method for achieving these values.

RABS

A physical barrier system that separates the operator from the critical production area without fully enclosing it. RABS is used in sterile production environments and when handling highly potent substances as a compromise between open LAF benches and fully enclosed isolators. A distinction is drawn between open RABS (airflow maintained, but physical access is restricted) and closed RABS (hermetic enclosure with glove panels). EU GMP Annex 1 (2022) explicitly names RABS as an accepted solution for Grade A production. Vacuum cleaners used in conjunction with RABS must be designed for use outside the barrier with a connected extraction arm system, or integrated directly into the system.

Risk assessment

Systematic identification, analysis and evaluation of risks in a production process or environment. In OEB contexts, risk assessment is the foundation for determining OEB class, selecting containment level and specifying equipment requirements. GMP and REACH require documented risk assessments. In the absence of an official OEL for a substance, internal risk assessment is the only basis for equipment selection. ICH Q9 is the international guidance document for quality risk management in pharma.

Safebag

A sealed single-use bag with an integrated closure and carrying system that allows transport and disposal of contaminated collection material without exposure. Safebags are designed so they can be removed from the vacuum and sealed in one movement without opening them in the free zone. Used at OEB 2–4 when a BIBO system is assessed as excessive. Unlike ordinary disposable filter bags, safebags are specifically designed to retain their contents during handling and transport.

Sandia National Laboratories

An American national research and development laboratory operated under the United States Department of Energy (DOE). Founded in 1949 in Albuquerque, New Mexico. Sandia is the source of one of the most significant discoveries in cleanroom history: in 1962, physicist Willis Whitfield at Sandia developed the modern laminar airflow cleanroom, which reduced particle concentrations a thousandfold compared to existing rooms. The discovery was rapidly adopted by the defence industry, aerospace and subsequently the pharmaceutical industry as the founding principle of all cleanroom production. Whitfield’s work is documented and published by Sandia National Laboratories. Photo credit for the portrait of Willis Whitfield: MESA / Sandia National Laboratories. sandia.gov

SAT

Acceptance test performed at the final installation site to verify that equipment functions correctly under actual operating conditions. SAT differs from FAT (Factory Acceptance Test) performed at the manufacturer's premises. In OEB environments, SAT is critical because documentation of filter integrity and system tightness from the manufacturer does not replace on-site verification after transport and installation. SAT is an element of the OQ phase of IQ/OQ/PQ.

Solvent

A liquid that dissolves other substances without chemically reacting with them. In pharmaceutical and laboratory production, organic solvents such as ethanol, acetone, isopropanol, toluene and methanol are used for cleaning, extraction and synthesis. Most organic solvents are flammable, harmful to health by inhalation, and classified as VOCs. When collecting spills, correct equipment is critical: the wet vacuum must be ATEX-rated (earthed, no ignition sources), and exhaust air must pass through an activated carbon filter to prevent solvent vapours from being returned to the working environment. Standard plastic tanks are typically not chemically resistant to organic solvents.

Sensitising substances

Substances that can trigger an allergic reaction upon repeated exposure. The first exposure typically produces no visible symptoms, but the body forms antibodies. Upon subsequent exposure — even in very small quantities — the reaction can be severe: skin rash, asthma, breathing difficulties or anaphylactic shock. The exposure threshold decreases over time: a person who has been exposed for years reacts more strongly than a new employee. Sensitising substances typically belong to OEB 3.

SMEPAC

Standardised industry method for measuring a vacuum or process equipment system's actual containment performance under realistic operating conditions. SMEPAC is the only widely recognised method for quantitative documentation of containment and is requested in OQ protocols and at regulatory inspections. SMEPAC-tested means that the equipment under specified test conditions achieved a defined containment target — it is not an approval stamp, but a professional reference that enables objective equipment comparison. Developed by ISPE.

SOP

A written work instruction describing step by step how a specific task must be performed. In pharma environments, SOPs are mandatory for all critical operations — from filter changes and cleaning to transport and disposal. Without an approved SOP, the task typically cannot be performed. SOPs are part of the GMP documentation system and must be available at inspection. Filter change intervals, cleaning procedures and leak test frequency are defined in the SOP rather than following the manufacturer's general recommendation.

Sterile production

Manufacture of sterile medicinal products under conditions that prevent microbial contamination. Requires strictly controlled environments (typically Grade A/B), personnel airlocks, HEPA-filtered LAF airflow and cleaning procedures documented in accordance with GMP Annex 1 (2022). Cleaning equipment brought into sterile areas must be sterile or sterilisable and constructed without dead zones that could harbour microorganisms.

Three-stage filtration

Filtration system with three successive barriers. In a typical cleanroom vacuum: (1) a disposable filter bag retaining coarse particles, (2) a primary filter (cloth or polyester) removing finer particles, and (3) a HEPA or ULPA final filter ensuring the discharged air is clean. Three-stage filtration significantly extends the ULPA filter's service life by protecting it from coarser particles.

Through-flow motor

Motor type in which the air drawn into the vacuum cleaner is also used to cool the suction motor itself. The air stream passes through the motor housing and over the electrical windings. Through-flow motors are inexpensive and efficient for general use, but are explicitly prohibited in ACD-certified vacuum cleaners, per IEC 60335-2-69, clause AA.22.204. The prohibition exists because the drawn-in air may contain combustible dust, which in contact with the motor’s electrical components and hot surfaces could ignite. ACD machines instead use bypass motors or side-channel blowers, in which the cooling air is kept completely separate from the working air at all times.

Tiered banding system

A structured method for OEB classification that uses available toxicological information in a hierarchy of tiers. When an official OEL value is lacking, data on pharmacological potency, toxicity, genotoxicity and analogue considerations are used to place a substance in the correct OEB band. The less data available, the more conservatively (high) the substance is classified. The method is described in ISPE Risk-MaPP and is used globally by pharma companies as an alternative to official limit values.

Thermite reaction

An exothermic chemical reaction that occurs when aluminium or zinc comes into contact with rust (iron oxide) on an adjacent metal surface under heavy impact or friction. The reaction produces extremely energetic “white hot” sparks that are sufficient to ignite flammable gases, vapours and dust clouds, and are classified as an ignition source under EN 1127-1. This is precisely what makes galvanised steel pipes and aluminium nozzles problematic in ATEX zones: not because the materials are electrically insulating, but because they can initiate a thermite reaction under mechanical impact. Stainless steel avoids both of these scenarios and is the standard material in professional ATEX accessories. The hazard is documented in IChemE research literature and is addressed explicitly in EN 1127-1.

Thru-Flow motor

Motor type in vacuum cleaners where the cooling air for the motor flows through the same air path as the suction air and then passes out through the ULPA or HEPA filter. This ensures that motor heat is not recirculated, and that all air — including the cooling air — is filtered before discharge. The Thru-Flow design is the standard in cleanroom vacuums as it prevents the motor chamber from becoming an uncontrolled particle source.

ULPA

Filter class exceeding HEPA in effectiveness. U15 retains at least 99.9995% of particles at MPPS. Required in cleanrooms from ISO 4 upwards and in OEB 4–5 applications. For U15 and above, EN 1822-1 requires mandatory scan testing (PAO/DOP) — the oil thread test permitted for H13 and H14 is not acceptable for U15. This is a specific requirement in EN 1822-1 with direct consequences for what can be accepted as documentation in an OQ protocol.

VOC

Organic chemical compounds with a sufficiently high vapour pressure to evaporate under normal conditions and appear as gas in the air. In industrial and laboratory contexts, the term covers a broad range of substances: alcohols (ethanol, isopropanol), ketones (acetone), aromatic hydrocarbons (toluene, xylene), chlorinated solvents and many others. VOCs are typically flammable, harmful to health by inhalation and potentially neurotoxic with prolonged exposure. In cleanrooms and regulated environments, VOCs are particularly problematic because they pass freely through HEPA and ULPA particulate filters — gas molecules are fundamentally smaller than the particles the filter was designed to retain. An activated carbon filter is the only effective filtration method for VOCs in vacuum cleaners and extraction equipment.

Validation

Documented evidence that a process, system or equipment consistently produces a result meeting predefined specifications and quality requirements. In GMP environments, validation is mandatory for critical equipment and processes. For vacuum cleaners in OEB environments, validation typically involves the IQ/OQ/PQ sequence, documentation of filter integrity, leak testing and cleaning protocols. Validation documentation must be archived and available at regulatory inspection.

Willis Whitfield

American physicist employed at Sandia National Laboratories who in 1962 invented the modern laminar airflow cleanroom. Whitfield’s solution — directing HEPA-filtered air unidirectionally and continuously through a room — reduced particle concentrations a thousandfold and revolutionised the manufacture of microelectronics, medical devices and pharmaceutical products. Whitfield worked at Sandia for over 40 years and received numerous awards for his contribution. His cleanroom has been described as “the most valuable invention ever to come out of Sandia.” Source and photo credit: MESA / Sandia National Laboratories. sandia.gov

Wipe test

Method for surface validation where defined areas are wiped with a moistened swab sample that is then analysed for residues of potent substances. Used to document that cleaning and decontamination have reduced surface concentration to an acceptable level. Standard method following NIOSH NMAM Surface Sampling Guidance, optionally combined with ASTM D6661. Mandatory element of cleaning validation at OEB 4–5. Typically performed after filter changes, major service and when introducing equipment to a new zone.

WIP

Cleaning procedure where equipment is washed in place without disassembly. WIP-compatible vacuum equipment can be placed directly in a wash cycle, which is critical in OEB facilities where exposure during disassembly must be minimised. An alternative or supplement to manual decontamination.