MAS-100 NT Ex®

Explosion-proof version of active air sampler MAS-100 NT (discontinued)

The MAS-100 NT Ex is the explosion-proof version of the world's best-selling air sampler and the premium version of the portable MAS-100 instruments. It is used for microbiological monitoring of air in rooms with increased explosion hazards for example due to solvents or gases. Equipped with a high-precision mass flow sensor it stands for highest safety and is therefore mainly used in sensitive areas and cleanrooms.

Important: The MAS-100 NT Ex® is being discontinued. A successor product will be announced in Q3 2026.

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HIGHEST AIR SAMPLING COLLECTION EFFICIENCY AND SAFETY IN EXPLOSIVE ENVIRONMENTS

  • Explosion protection according to the ATEX product directive 2014/34/EU (ATEX 114). 
  • Developed according to GAMP 5, fully validated according to ISO 14698 and EN 17141
  • Can be used in ISO 14644-1 cleanroom class 5/GMP Grade A without air outlet filter
  • Disinfectable with vaporized and gaseous hydrogen peroxide and many industry-standard disinfectants
  • Perforated lids are autoclavable and interchangeable between instruments
  • Compatible with different agar plates, e.g. ready-to-use 90mm standard-, 55mm contact- or Growth Direct® plates
  • Additional safety through integration of a HEPA air outlet filter that can also be retrofitted and replaced independently
  • Integrated mass flow sensor with temperature and pressure compensation for environment-independent air sampling
  • Precision seal between perforated lid and sampling head without sealing ring facilitates cleaning and disinfection
  • Rotatable sampling head for air sampling with horizontal air flow

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Calibrated Air Flow Sensor for Reliable Sampling

A calibrated mass flow sensor in the MAS-100 NT Ex ensures consistent air collection, independent of ambient pressure or temperature. This standardised air flow allows comparisons across locations and conditions, making it a gold standard in active air sampling.

The flow sensor is calibrated using a MAS-100 Regulus digital anemometer, certified in our ISO 17025-accredited calibration laboratory. This ensures full traceability of the collected air volume to international standards.

Optional HEPA H13 Air Outlet Filter

The MAS-100 NT Ex microbial air sampler is designed for cleanroom class 5 (ISO 14644-1, GMP grade A). Its high-quality, low-particle components eliminate the need for an additional air outlet filter.

For multi-zone use or when changing cleanroom classes, a built-in HEPA H13 air outlet filter can be advantageous. The MAS-100 NT Ex is available with this filter, and existing units can be retrofitted with a HEPA H13 filter kit. The transport case accommodates the instrument with or without the filter module.

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Further accessories »

PERFORATED LIDS – Optimized for Maximum Collection Efficiency

The precision, robustness, and material of the perforated lid directly influence collection efficiency and the long-term stability of results. We ensure uniform hole distribution, precise lid-to-instrument fit, and easy handling—even with gloves. Lids are fully interchangeable between instruments, allowing one unit to operate while another lid is autoclaved.

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Further accessories »

CALIBRATION

All results of active microbial air samplers depend on correct air flow and air volume. That is why we ensure that the calibration of our instruments can be traced back to international standards via the certified MAS-100 Regulus digital anemometer and via our ISO 17025 accredited calibration laboratory. Each step in this cascade is fully documented, giving you the confidence to produce reliable results every time.

To the digital anemometer MAS-100 Regulus »
To our calibration service »

Product essentials

    • Air flow rate 100 standard liters per minute (SLPM)
    • Accuracy of air flow ±2.5%
    • Physical cut off diameter d50 = 1.1um with standard perforated lid 300x0.6mm
    • Rechargeable battery, autonomy approx. 2 hours (approx. 12'000L)
    • Automatic calibration function with MAS-100 Regulus digital anemometer
    • Can be used with 300x0.6mm and 400x0.7mm perforated lids for various culture plate formats 
    • Height 27cm, Ø 11cm (17cm with handle), weight approx. 2.4kg 
    • Integrated sequential sampling mode (SQS) to divide a sample into partial volumes for statistical collection over a longer period of time.
      • Dialogue-controlled menu operation
      • Five pre-programmed sampling volumes, adjustable from 1 to 2000 liters
      • Adjustable 'out of specification' air flow limit selectable between 2.5% and 25%.
      • Adjustable start delay between 1-120 minutes
      • Calibration certificate configurable with own user data (company logo, department, address)
      • Computer-based software for configuration, qualification and calibration
      • Locking of an operation via computer software possible (protected mode)
      • Programmable sampling sequences
      • Time with date display 
      • Calibration reminder with the option to lock the instrument when the calibration interval has expired
        • MAS-100 NT Ex microbial air sampler
        • Perforated lid 300x0.6mm (standard) or 400x0.7mm
        • Calibration certificates for air sampler and digital anemometer (issued by own ISO 17025 accredited calibration laboratory)
        • Communication and charging cable with region-specific adapters
        • Aluminum dust cover
        • Carrying case
        • Allen key for adjusting the plate holder

        The production of the MAS-100 NT Ex microbial air sampler will be discontinued by the end of August 2026. After that date a supply can not be guaranteed anymore. 

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        Impaction principle in microbial air sampling


        For active microbial air sampling based on the impaction principle, a predefined volume of air is drawn through a perforated sieve. The air and the particles in it are accelerated and directed onto an agar plate positioned below the sieve.

        Due to inertia, particles above a certain size are impacted onto the agar medium. After appropriate incubation, microbe-bearing particles become visible as colony forming units (CFU), can be counted and reported as CFU/m3. The particle size at which 50% of the particles impact and the other half remain in the air stream is called the cut off diameter d50 (um). 

        Great emphasis is placed on precision in the manufacture of MBV perforated sieves. This ensures that the cut off diameter is identical in all holes and that microbial air sampling is repeatable.

        FAQ

        The MAS-100 NT Ex complies with the essential health and safety requirements relating to the design and construction of equipment and protective systems intended for use in potentially explosive atmospheres given in Annex II to Directive 2014/34/EU of the European parliament and of the Council, dated 26 February 2014.
        It bears the marking Ex II 3G Ex ec IIC T4 Gc.
        A conformity statement issued by Electrosuisse bearing the certificate number SEV 08 ATEX 0143 X is available upon request from welcome@mbv.ch.

        Dirt may be removed from the exterior of the instrument by wiping with a clean cloth moistened with a mixture of 60-80% alcohol/deionized water.
        For a reference see Sandle, T. and Satyada, R. (2015): Assessment of the disinfection of impaction air sampler heads using 70% IPA, as part of cleanroom environmental monitoring, European Journal of Parenteral and Pharmaceutical Science, 20 (3): 94-99.
        The perforated lid and dust cover can be cleaned by ultrasound and wiping with a clean cloth moistened with 60-80% alcohol/deionized water.

        Both sampling heads collect with 100 L/min. They both have the same physical outer dimensions and mechanically fit on all current MAS-100 air samplers.

        There are two application-relevant differences:

        1) Different Feller tables have to be applied (see download section) as the probability of two CFU hitting the same hole are different.

        2) Due to the smaller hole diameter of the 300x0.6 (0.6mm) the air flow speed is much higher (about 20 m/s vs 11 m/s for the 400x0.7).

        This higher airspeed translates into a better collection efficiency (D50=1.1 micrometer vs 1.6 micrometers).

        For these reasons, the 300x0.6 has become the standard sampling head. However, some customers have collected vast amounts of data using the 400x0.7 head and for historical comparability want to further use this lid.

        Also: The microbial air sampler MAS-100 Eco is only compatible with the 400x0.7.


        Want to dive deeper? Our full FAQ section covers many more questions about the MAS-100 NT Ex. Take a look — the answer you’re looking for might already be there!

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        OTHER VERSIONS OF THE MAS-100 NT MODEL


        In order to meet the requirements of individual applications even more specifically, various special versions of this popular environmental monitoring instrument have been developed in addition to the standard version of the MAS-100 NT. Our expert Andy Zingre explains in 3 minutes how these versions differ and which applications the special versions of the MAS-100 NT are tailored to.

        To the quick tip video »

        ​MAS-100 NT Ex HEPA

        Specialized in microbiological air monitoring in potentially explosive environments of various cleanroom classes with zone changes: the MAS-100 NT Ex with a factory-installed HEPA H13 air outlet filter to protect against carryover of contamination.

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        BASIC VERSION MAS-100 NT

        World's best-selling air sampler and base model of the MAS-100 NT Ex. In distinction to the MAS-100 NT Ex, the MAS-100 NT is designed for microbiological air monitoring in non-hazardous environments.

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        MAS-100 NT HEPA

        Specialized in microbiological air monitoring in various cleanroom classes with zone change: the MAS-100 NT with a factory-installed HEPA H13 air outlet filter to protect against carry-over of contamination.

        Learn more »

        Downloads

        FACTSHEET

        Microbial air sampler
        MAS-100 NT Ex (German)

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