How to select a microbial air sampler

Selecting a microbial air sampler is best done with a specific application in mind. Routine cleanroom monitoring, isolator and RABS applications, compressed-gas sampling, two-media sampling, interval-based continuous monitoring, and applications requiring additional built-in controls to support a 21 CFR Part 11-controlled workflow can each require a different model or sampling approach. In regulated environments, the selected sampler should also support method justification, long-term trending, investigations, and audit review.

All SAS air samplers are fully compliant with ISO 14698 and EN 17141 guidelines.^{5, 16}  SAS air samplers are also compatible with gloved environments where contamination protocols are important, due to having a durable, non-touchscreen keypad – that is also safe for use with commonly used sprayed and wiped disinfectants.

This guide matches common viable air sampling applications with the most appropriate microbial air sampler. Bioscience International's technical support team has more than 30 years of technical and industry experience and is happy to discuss application-specific requirements, confirm the appropriate model, or provide a quote when a customer is ready to order.

Quick model guide

• Most routine cleanroom viable air monitoring: the SAS Super 180 is the most popular choice for many applications. It collects samples efficiently at 180 L/min, the fastest flow rate available that is validated as safe and effective for the collection and growth of microorganisms. Sampling records cannot be edited or selectively altered. Optional Password Mode can prevent routine operators from changing the approved sample volume or accessing instrument menus.
• Routine monitoring requiring more granular built-in controls for 21 CFR Part 11-controlled workflows: the SAS Super ISO 180 provides the same validated microbial collection performance as the SAS Super 180, together with: individually authenticated users, granular Operator/Supervisor/Administrator permissions, an electronic audit trail, sampling records that (same as SAS Super) cannot be edited or selectively altered, expanded internal record capacity, password-protected PDF and LIMS-friendly XML export, and administrator-controlled USB modes.
• Existing 100 L/min SOPs, non-cleanroom sampling, or extended interval sampling: the SAS Super 100 is appropriate when an established SOP, validation package, or historical monitoring method specifies 100 L/min. Its slower flow rate provides a longer sampling time for a given volume, which can be useful in non-cleanroom environments such as food manufacturing where 1,000 L samples may not be practical due to higher bioburdens. The longer sampling duration can also support interval sampling used to meet continuous-monitoring needs. Optional Password Mode (like with the SAS Super 180) can restrict operators to running a previously authorized sample volume, without device menu access. Customers requiring individual user authentication, multiple permission levels, and an electronic administrative audit trail should select the SAS Super ISO 100.
• Two-media sampling at the same location and timepoint: the SAS Duo 360 collects two samples simultaneously using two different media types, such as TSA and MEA.
• Isolator or RABS viable air monitoring: the SAS Super Isolator places the sampling head inside the barrier while the instrument controls remain outside. It is available in both 180 L/min and 100 L/min models.
• Compressed air or compressed gas microbiological monitoring: the SAS Pinocchio Super II and SAS Pinocchio CR are designed for sampling from pressurized gas lines. The SAS Pinocchio CR is an all-stainless-steel, autoclavable model.

Matching sampling needs to the right air sampler model

The table below matches common microbial air monitoring requirements with the SAS model or sampling approach that best fits the application, sample volume, media strategy, data-integrity requirements, and operational needs. All SAS air samplers meet the requirements outlined in ISO 14698 and EN 17141 with respect to collection efficiency, particle emissions, and air turbulence.^{5, 16}

Bioscience International is happy to provide a quote for a selected model, and its technical support team is also pleased to provide a complimentary review of application-specific requirements before a final selection is made.

Selection factors that drive the choice

In viable active air sampling, a known volume of air is drawn through a sampling head so airborne microorganisms impact onto agar for incubation and colony counting. Six practical factors usually determine the most appropriate sampler: application, data-integrity requirements, sample volume, flow rate, media strategy, and long-term method support.^{1, 2, 3, 4}

• Application and sampling environment: The first factor to define is the sampling environment. Routine cleanroom monitoring, isolator/RABS monitoring, two-media sampling, repeated interval sampling, and compressed air or gas monitoring each create different equipment and workflow requirements. Barrier systems are especially important because the sampling head and instrument controls may need to remain on opposite sides of the barrier.¹
• Data integrity and 21 CFR Part 11-controlled workflows: Both the SAS Super and SAS Super ISO can be incorporated into a 21 CFR Part 11-compliant process when supported by appropriately designed and validated SOPs, access controls, training, review, retention, backup, and record-management practices. Optional SAS Super Password Mode provides a useful fixed-method control: without the shared device password, a routine user can only power the sampler on, run the previously authorized sample volume, and power it off; menus and parameter changes remain locked. The SAS Super ISO is generally preferred when the organization wants more granular controls built directly into the sampler, including individually authenticated users, Operator/Supervisor/Administrator permissions, an electronic audit trail, expanded record capacity, sampling records that cannot be edited or selectively altered, password-protected PDF and LIMS-friendly XML export, and administrator-controlled USB modes. Both product lines share the same fundamental SAS impaction method, validated collection performance, standard-media compatibility, 100 or 180 L/min choices, and ISO/IEC 17025 calibration support.^{6, 15}
• Sample volume, frequency, and throughput: The target sample volume, sampling frequency, and number of locations per shift determine how practical the method will be during routine operations. These choices also affect CFU/m³ reporting and the ability to detect contamination in low-bioburden environments.¹
• Flow rate: The SAS Super 180 provides efficient sample collection for most routine cleanroom programs. The SAS Super 100 is primarily used when an existing SOP or validation package specifies 100 L/min, when a longer sampling time is useful in a non-cleanroom environment, or when interval sampling is used to support continuous monitoring. Air sampling at 180 L/min is the fastest rate available that is validated as safe and effective for the collection and growth of a broad spectrum of microorganisms. End users considering higher flow rates should complete viability validation studies at those speeds with the specific microorganisms being monitored before implementation.
• Media strategy and plate exposure: The monitoring plan may require bacteria-focused media, yeast/mold-focused media, or both. Plate size and agar fill level can affect airflow and impaction behavior. Programs seeking long-term comparability generally control both variables and align calibration practices with the plates used for routine sampling.^{3, 5, 6}
• Calibration, documentation, and long-term support: Collection-efficiency data, traceability of sampled volume, practical cleaning and handling, and long-term service support all affect how reliably the method can be justified and maintained. ISO/IEC 17025 accreditation is particularly meaningful when the calibration scope specifically covers air sampler calibration, because CFU/m³ reporting, trending, and investigations depend on an accurate sampled volume. Using an air sampler with a d₅₀ value that has been physically validated by a third party following ISO 14698 and EN 17141 guidelines is strongly recommended, especially for companies operating in regulated industries and subject to audits. Without real-world validation, a calculated d₅₀ value is purely theoretical.^{1, 4, 8, 9, 16}

Higher-grade environments such as ISO 5 often use higher sample volumes or more frequent sampling to expand detection in low-bioburden conditions. Higher-bioburden areas, in contrast, often use lower sample volumes or shorter sampling times to reduce plate overgrowth that would prevent reliable CFU counting. In those situations, sample volume or sampling time is usually the first adjustment. Flow rate should be selected as part of the method rather than used in place of appropriate sample-volume planning.¹

Sampling-head selection is also part of method design. Some programs prefer sterile disposable heads – such as the Disposable Sterile Sampling Heads for SAS Air Samplers – to reduce preparation and handling in controlled environments, while others prefer reusable heads that align with established cleaning, reuse, and material-control procedures.  Bioscience International offers both choices.

Documenting the selection rationale

In regulated environments, an air sampler selection is easier to justify when the selection rationale connects directly to the contamination control strategy, explains how results will be compared over time, documents how sampled-volume accuracy will be maintained through calibration, and identifies how the method will be supported over time.^{1, 4}

ISO 14698, EN 17141, and EU GMP Annex 1 are common reference points for viable air sampling method justification. Documented collection-efficiency data and volume traceability help demonstrate that the selected sampler is suitable for the intended environment and monitoring objective. A complete rationale should also explain why the selected model and sampling approach fit the media plan, handling practices, SOP requirements, and long-term comparability needs.^{1, 5, 7}

• Rationale traceability: The rationale should link the sampler selection to the contamination control strategy and risk assessment.¹
• Comparability: The rationale should explain how sample volume, flow rate, method standardization, plate size, and agar fill level support meaningful trend review over time.^{1, 5, 6}
• Calibration approach: The rationale should explain how calibration competence and traceability support confidence in sampled-volume accuracy, and particularly whether the ISO 17025 accreditation scope specifically covers air sampler calibration.^{4, 9}
• Environmental fit: The rationale should explain how the selected model fits the controlled area, barrier practice, or utility application without creating unnecessary workflow or sanitization complications.^{1, 2}
• Data-integrity fit: The rationale should document whether the program requires fixed-method password protection, individually authenticated users, role-based permissions, an electronic audit trail, controlled export paths, or some combination of instrument-level and procedural controls. When SAS Super Password Mode is used, the SOP should also define password custody, who may change the approved sampling method, and how the configured operator ID is assigned and controlled.^{6, 15}
• Flow-rate fit: If the method requires 100 L/min because of an existing SOP, historical validation, interval-sampling requirement, media-exposure consideration, or another method-specific reason, the 100 L/min configuration of either the SAS Super or SAS Super ISO should be selected. The choice between those product lines should then be based primarily on the required access, attribution, audit-trail, and export controls.

This documentation gives purchasing, QA, validation, and microbiology teams a common basis for reviewing the selection. Additional guidance is available in the Bioscience International Best Practices FAQ. Bioscience International is also happy to review a proposed sampling plan or model selection when additional input would be helpful.⁸

Why SAS is often selected for viable active air sampling

SAS air samplers combine full compliance with ISO 14698 and EN 17141 guidelines, documented collection-efficiency performance, sampled-volume accuracy supported by ISO 17025 accredited calibration, compatibility with standard microbiological media, and long-term product support. These attributes help regulated monitoring programs maintain consistent methods and comparable data over time.^{1, 4, 5, 6, 7, 8, 9}

Active air samplers may appear similar on a specification sheet, but the differences often become most important after purchase, when the sampler must be justified, calibrated by an ISO 17025 accredited lab, incorporated into SOPs, used consistently by multiple operators, serviced, and supported over time.

• Method justification: SAS air samplers have been validated in an industrial wind tunnel and have measured, published d₅₀ values. The d₅₀ is the particle size at which the sampler achieves 50% collection efficiency under the specified test condition. This third-party physical validation supports full compliance with ISO 14698 and EN 17141 guidelines and helps technical teams document sampler suitability under EU GMP Annex 1 expectations.^{1, 4, 5, 7}
• Data-integrity options: Optional SAS Super Password Mode can lock a sampler to a validated sample volume so routine operators can execute the approved method without gaining access to instrument menus or parameter changes. The SAS Super ISO adds more granular controls, including individually authenticated users, role-based permissions, an electronic administrative audit trail, expanded record capacity, and password-protected PDF and LIMS-friendly XML export. Customers can therefore select the model whose built-in controls best match their SOPs and surrounding record-management systems.^{6, 15}
• Sampled-volume accuracy: Bioscience International is accredited by A2LA to ISO/IEC 17025:2017 specifically for air sampler calibration, certificate #5699-01. Accredited calibration with NIST-traceable certificates helps maintain confidence in the sampled volume used for CFU/m³ reporting and long-term trending.^{4, 6, 8, 9}
• Filter-free exhaust design: SAS air samplers are designed to operate without requiring an exhaust HEPA filter. This eliminates a filter that can add pressure drop as it fills up, require a validated replacement procedure, and retain microbial contamination from previous sampling environments.^{13, 14}
• Media flexibility: SAS air samplers accept standard 55 mm contact plates and 90 mm Petri dishes. Standard media formats support procurement flexibility, familiar incubation procedures, method standardization, and comparison with historical results.^{5, 6}
• Long-term continuity: Bioscience International provides lifetime support for SAS instruments, with no age-based end-of-life cutoff. Standard service turnaround averages an industry-leading 2-3 days from receipt of the instrument, with expedited service available upon request.^{8, 9}

These capabilities continue to matter after the sampler is placed into service. Strong documentation supports audit and investigation responses. Standard media compatibility helps laboratories maintain familiar procedures and purchasing options. Long-term service support protects continuity of the monitoring program over the life of the instrument.

Bioscience International supports SAS users throughout the life of the instrument with ISO 17025 accredited calibration, IQ/OQ validation, preventative maintenance, service, troubleshooting, and application guidance.

Questions to ask when comparing microbial air sampler vendors

Purchase price is only one part of the total cost of an air sampling program. The total cost also includes the effort required to maintain the method, document calibration, investigate results, train operators, obtain suitable media, and keep the sampler in service. A lower purchase price may be offset by higher costs or additional work in these areas.

• Collection efficiency: Does the vendor provide documented d₅₀ collection-efficiency data based on actual physical validation, rather than only theoretical calculations, to support method justification?
• Calibration scope: Does the provider's ISO/IEC 17025 scope specifically cover air sampler calibration?
• Data-integrity controls: What controls does the intended workflow require: fixed-method password protection, individual user authentication, role-based permissions, a time-stamped audit trail, non-editable sampling records, controlled removable-media access, or validated electronic export? Which controls are built into the sampler, and which must be supplied by SOPs or surrounding systems?
• Exhaust design and HEPA-filter controls: Does the sampler require an exhaust HEPA filter? If so, how is actual sample flow verified as the filter loads, what validated replacement procedure is used, and how is retained material controlled to minimize potential carryover between sampling locations?
• Method fit: Does the sampler support the sample volume, media strategy, and flow rate required by the method?
• Media compatibility: Does the sampler accept the standard microbiological media formats already used by the laboratory?
• Workflow fit: Does the model fit the intended application, including routine cleanroom monitoring, interval sampling, isolator/RABS monitoring, simultaneous two-media sampling, and compressed-gas monitoring?
• Long-term support: Will the vendor provide calibration, service, replacement parts, and troubleshooting throughout the expected life of the instrument?
• Application support: Will the vendor help confirm the appropriate model and sampling approach before purchase and provide support after installation?

Frequently asked questions about microbial air sampler selection

How much air should a microbial air sampler collect?

The appropriate sample volume depends on the environment, expected bioburden, and the decision the sample must support. Low-bioburden environments often use higher sample volumes to improve detection sensitivity. Higher-bioburden environments may require lower sample volumes or shorter sampling times to avoid plate overgrowth that prevents reliable CFU counting.¹

When is the SAS Super 100 most appropriate?

The SAS Super 100 is most appropriate when an existing SOP, validation package, or historical monitoring method specifies 100 L/min and the site wants to preserve method continuity. Its slower flow rate allows a given sample volume to be collected over a longer period, which can be useful in non-cleanroom environments such as food manufacturing. The longer sampling duration can also support interval sampling used to meet continuous-monitoring needs.^{5, 6}

When is the SAS Super 180 usually preferred?

The SAS Super 180 is usually preferred for routine cleanroom viable air monitoring because it collects common sample volumes efficiently, most commonly a 1,000 L (1 m³) sample. At 180 L/min, it reduces collection time per location while preserving the target sample volume. Air sampling at 180 L/min is the fastest rate available that is validated as safe and effective for the collection and growth of microorganisms.^{5, 6, 16}

When should a customer choose the SAS Super ISO instead of the SAS Super?

The SAS Super ISO is generally preferred when a customer wants individually authenticated users, Operator/Supervisor/Administrator permissions, an electronic administrative audit trail, expanded record capacity, sampling records that cannot be edited or selectively altered, password-protected PDF and LIMS-friendly XML export, and administrator-controlled USB modes built directly into the sampler. The SAS Super remains a strong choice when the customer has an established SAS Super workflow or when optional fixed-method Password Mode, together with the customer's SOPs and surrounding systems, provides the appropriate level of control. In Password Mode, a routine user without the shared device password can only power the sampler on, run the previously authorized sample volume, and power it off; menus and parameter changes remain locked. Unlike the SAS Super ISO, however, this shared password does not individually authenticate operators or generate an electronic audit trail. Both product lines share the same fundamental SAS impaction method, validated collection performance, standard-media compatibility, 100 or 180 L/min choices, interval sampling, cleanroom suitability, and ISO/IEC 17025 calibration support.^{5, 6, 15, 16}

Is the SAS Super compatible with 21 CFR Part 11 requirements?

Yes. The SAS Super 100 and SAS Super 180 can be incorporated into a 21 CFR Part 11-compliant process when the customer's SOPs, validation, access controls, training, system configuration, review, retention, backup, and record-management practices are properly designed and implemented. Optional Password Mode adds a technical fixed-method control by preventing users without the shared password from accessing menus or changing parameters while still allowing them to run the previously authorized sample volume. The SAS Super ISO provides more granular controls within the sampler, including individual user authentication, role-based permissions, and an electronic audit trail, which can simplify implementation for customers who prefer a more out-of-the-box approach.^{6, 15}

Can the SAS Super prevent routine operators from changing a validated sampling method?

Yes. Bioscience International can enable optional Password Mode on compatible SAS Super units with firmware 7.04 or later, generally during routine calibration service; older units require a PC-board upgrade. Once a non-default password is configured, a person without the password can only power the sampler on, press START to run the same sample volume programmed before Password Mode was activated, and power the sampler off. All menus, parameter changes, and other functions remain locked. The customer may control the password, or Bioscience International can retain it if the customer wants routine personnel to have no ability to modify the validated settings. Password Mode uses one shared device password; it does not provide individual user accounts or an electronic audit trail.⁶

When is a dual-head microbial air sampler useful?

A dual-head microbial air sampler is useful when a monitoring program requires two samples to be collected simultaneously at the same location and timepoint, often using two different media types such as TSA and MEA. Each SAS Duo 360 head operates independently, so using one head does not change that head's programmed sample volume.^{5, 10}

What matters most in isolator or RABS viable air sampling?

In isolator and RABS applications, the first consideration is how the sampling head and instrument controls will be positioned relative to the barrier. The SAS Super Isolator allows the sampling head to remain inside the controlled environment while the operator and controls remain outside. The sampling head can remain in place during VHP decontamination cycles, and the model is available in 100 L/min and 180 L/min versions.^{1, 11}

Why does ISO/IEC 17025 calibration matter for microbial air sampling?

Viable active air sampling depends on a known sampled volume. Calibration therefore affects confidence in CFU-per-cubic-meter reporting, long-term trending, and investigations. ISO/IEC 17025 accreditation is particularly meaningful when the accreditation scope specifically covers air sampler calibration.^{4, 9}

Does a microbial air sampler need an exhaust HEPA filter?

Current microbial air-sampling regulations do not require an exhaust HEPA filter. The relevant requirements are that the sampler not create a contamination risk and that it maintain a known sampled volume. An exhaust HEPA filter can retain bacteria, mold, and other particles from previous environments, and pressure drop can restrict airflow as the filter loads. A sampler that uses an exhaust HEPA filter therefore needs a validated control to verify actual airflow and ensure the filter is replaced before loading affects sampled volume. SAS air samplers are designed to operate without an exhaust HEPA filter, avoiding this added maintenance, airflow-restriction, and potential carryover concern.^{1, 13, 14}

Are all agar plates interchangeable for active air sampling?

Often yes, provided that plate diameter, height, and agar fill level remain similar. Changes in plate size or agar fill level can alter airflow and impaction behavior and may change the measurement system. Programs seeking long-term comparability generally control these variables and evaluate any change before incorporating it into the routine method. ISO 17025 accredited calibrations performed by Bioscience International use the end user's actual media when provided, supporting consistency between calibration and operational use.^{5, 6}

Which SAS microbial air sampler is best for routine cleanroom monitoring?

The SAS Super 180 is the gold-standard choice for most routine cleanroom viable air monitoring because it provides efficient throughput, accepts standard media, and is supported by ISO 17025 accredited calibration. The SAS Super ISO 180 adds more granular built-in controls for customers focused on 21 CFR Part 11-controlled workflows. The SAS Super 100 and SAS Super ISO 100 are appropriate when the method requires 100 L/min or longer-duration interval sampling. The SAS Duo 360, SAS Super Isolator, SAS Pinocchio Super II, and SAS Pinocchio CR address more application-specific requirements.^{5, 6, 10, 11, 12, 15}

What should buyers ask before choosing a microbial air sampler vendor?

Buyers should confirm that the sampler supports the required sample volume and flow rate, accepts standard media without proprietary lock-in, and provides the data-integrity controls required by the customer's procedures. They should also confirm that the vendor provides d50 collection-efficiency data based on physical validation, appropriate calibration documentation, application-specific guidance, and service throughout the life of the instrument. These factors matter because the sampler becomes part of the end-to-end monitoring procedure and must remain reliable under audit scrutiny.^{1, 4, 5, 8, 9}

Why standardize on SAS microbial air samplers instead of using different air samplers across sites?

The SAS family has been an industry standard for microbial air sampling for more than 30 years while continuing to incorporate relevant new technology. SAS air samplers are widely cited in peer-reviewed literature and trusted across pharmaceutical, biotechnology, medical-device, government, food, beverage, and hospital applications. Standardizing on SAS can simplify SOPs, operator training, media handling, calibration planning, replacement parts, service support, and long-term trend review across multiple rooms, buildings, or sites. ISO 17025 accredited calibration also provides a traceable audit record.^{5, 6, 8, 9}

Quote and application support

Bioscience International would be pleased to help, whether the appropriate model is already clear and a quote is needed, or whether additional discussion would be helpful before making a selection.

Please contact Bioscience International for a quote, model recommendation, or application discussion.

References

1. European Commission, EudraLex Volume 4: EU GMP Annex 1 (Manufacture of Sterile Medicinal Products), published 25 Aug 2022. PDF
2. U.S. FDA, Sterile Drug Products Produced by Aseptic Processing — Current Good Manufacturing Practice (Guidance for Industry). FDA page Direct PDF
3. ISO 14698-1:2003 (Biocontamination control — General principles and methods) overview. ISO page
4. ISO/IEC 17025:2017 (General requirements for the competence of testing and calibration laboratories) overview. ISO page
5. Bioscience International, Products (SAS microbial air samplers): ISO 14698 and EN 17141 compliance, independently assessed d₅₀ efficiency values, and standard 55 mm / 90 mm media compatibility. products.htm
6. Bioscience International, SAS Super 100 and SAS Super 180: sampling speed, standard 55 mm / 90 mm media compatibility, interval sampling, optional fixed-method Password Mode, electronic record transfer, and calibration information. sas_100_180.htm
7. Bioscience International, Home page: industrial wind-tunnel validation with published d₅₀ values; ISO/IEC 17025:2017 accredited calibration with NIST-traceable certificates; lifetime product support. index.html
8. Bioscience International, Environmental Monitoring Best Practices FAQ: ISO/IEC 17025 calibration rationale, air sampler calibration scope, A2LA certificate #5699-01, standard media compatibility, and lifecycle support policy. best_practices_faq.htm
9. Bioscience International, Services: ISO/IEC 17025:2017 calibration, A2LA certificate #5699-01, validated airflow calibration methods, NIST-traceable calibration, IQ/OQ services, and standard service turnaround. services.htm
10. Bioscience International, SAS Duo 360: dual-head microbial air sampler for collecting two samples simultaneously using different media types. sas_duo360.htm
11. Bioscience International, SAS Super Isolator: 100 and 180 L/min microbial air sampler models for isolator and RABS applications, including VHP-compatible sampling-head placement. sas_isolator.htm
12. Bioscience International, SAS Pinocchio Super II and SAS Pinocchio CR: compressed air and compressed gas microbiological monitoring, including an all-stainless-steel autoclavable option. sas_pinocchio.htm
13. U.S. Environmental Protection Agency, What Is a HEPA Filter?: HEPA filters capture dust, pollen, mold, bacteria, and other airborne particles. EPA page
14. U.S. Environmental Protection Agency, Air Pollution Control Technology Fact Sheet — HEPA and ULPA Filters: filter pressure drop should be monitored, and filters should be replaced when pressure drop becomes unacceptable. EPA fact sheet
15. Bioscience International, SAS Super ISO 100 and SAS Super ISO 180: individually authenticated users, role-based permissions, electronic audit trail, sampling records that cannot be edited or selectively altered, storage for up to 1,200 completed runs, password-protected PDF and LIMS-friendly XML export, and administrator-controlled USB modes. sas_iso.htm
16. Bioscience International, SAS Compliance with ISO 14698 and EN 17141: third-party physical and biological collection-efficiency testing, particle-emission testing, and airflow-disturbance testing. EN 17141 and d₅₀ validation

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