Right-Sized Contamination Control: Annex 1 Compliance for Small Enclosures

By Richard TimbrellNovember 2, 2026

Small isolators, transfer chambers, and laboratory equipment present very different decontamination challenges to cleanrooms, requiring a risk-based approach, robust validation, and appropriately scaled technology to comply with Annex 1 requirements.

For pharmaceutical manufacturers, contamination control has become more demanding at the same time as facilities have grown more complex, specialized, and operationally pressured. The European Union’s revised Annex 1 guidelines for good manufacturing practice (GMP) reinforces the need for a holistic, risk-based contamination control strategy (CCS), with greater emphasis on reducing operator intervention and applying robust controls to cleaning and decontamination strategies (1).

However, this revised guidance goes beyond the simple question of whether a facility has appropriate cleaning and decontamination procedures in place. Labs and facilities must also consider whether these controls form part of a wider risk-based strategy that can be justified, repeated and validated.

Within this consideration, it’s crucial to remember that not all environments will face the same contamination control challenges. Aseptic pharmaceutical manufacturing, for instance, may be more concerned with viable microbial contamination and the risk of contamination entering critical processing zones, while microbiology labs may need to prioritise control of cross contamination between different organisms.

What these differing settings have in common is the fact that the operational consequences of contamination are substantial. Whether these differences are product quarantine, repeat testing, product rejection, or even shutdown, they all result in a loss of production time, which is compounded when the source of contamination itself also needs to be investigated. A 2025 article from Siemens states that downtime in pharmaceutical manufacturing can cost between USD 1.4 and USD 6.8 million per hour (2).

Why Smaller Spaces Need a Different Contamination Control Approach

Decontamination has traditionally been considered on two ends of a spectrum, one end of which consists of manual cleaning and decontamination of individual surfaces and the other of large automated decontamination systems that are appropriate for treating whole rooms. Yet, the smaller spaces in between are often overlooked. These spaces can range from biological safety cabinets, pass-through hatches, material transfer chambers, and incubators to other enclosed equipment.

Critically, these spaces can prove trickier to decontaminate effectively given the complexity of their internal geometry and the likelihood of their consisting of fans, filters, or other forms of sensitive electronics or materials. As a result, the decontamination delivery system designed for large rooms, often resulting in heavy capital investment, isn’t necessarily the appropriate choice for smaller enclosures.

Alternatively, a smaller volume of space doesn’t correspond to a smaller version of the decontamination technology. For example, while a centrifugal nebulization decontamination system producing hydrogen peroxide across a 5–10 micron range may be appropriate at room scale, in a much smaller enclosure this droplet size variation is far more significant, making repeatability harder to achieve.

With regards to Annex 1 compliance, the objective should not be to find the most automated decontamination system available, nor to assume that compliance requires replacing otherwise serviceable equipment. Cleanroom technicians should strive to establish a controlled, repeatable and validated process that matches the scale of the application as well as the contamination risk.

Defining and Validating the Process

While selecting an appropriate decontamination strategy is important, it is not the starting point. The first step for any pharmaceutical manufacturer, laboratory, or life sciences organization should be understanding exactly what they are trying to control. Without understanding the specific risk, organizations risk decontaminating for its own sake, rather than developing a process designed around a defined requirement.

This understanding is also key given that contamination risks will vary from application to application. These may be viruses, fungi, bacterial spores, or other forms of contamination. There may also be additional considerations when defining the risk, such as controlling cross-contamination between samples or preventing residue being left behind within the enclosure.

Once the objective is clear, the next challenge is identifying the variables that will influence the effectiveness of the process. For a hydrogen peroxide vapor (HPV) process, for instance, factors such as temperature, humidity, injection rate, and material compatibility can all affect performance.

Validation should demonstrate that the process works consistently and goes beyond proving a one-time success. This validation requires the process to be tested in the most difficult locations, establishing predefined acceptance criteria and demonstrated repeated efficacy across multiple runs.

The physical evidence supporting this validation should include documented cycle parameters, operating limits, and defined load conditions, alongside appropriate testing methods such as biological or chemical indicators where required. Regardless of variations in the specific approach according to the application, the fact remains that contamination control decisions must be supported by objective evidence rather than judgement alone.

Choosing the Right Level of Engineering Control

A 2024 PDA survey representing the global pharmaceutical industry one year after the revised EU GMP Annex 1 came into effect found that 50% of respondents reported needing capital investment of over USD 100,000 for facility upgrades (3). For some facilities, the upgrades may mean replacing existing isolators with dedicated gassing isolators, installing new filling or processing equipment, upgrading cleanrooms and HVAC systems or bringing in additional environmental monitoring.

For new facilities or applications with particularly high contamination risks, these investments may be appropriate. However, Annex 1 compliance should not automatically translate into replacing existing equipment. The starting point must remain the contamination control strategy: the risk that needs to be controlled and what level of engineering control is required to manage it.

This risk assessment is a particularly important consideration for established facilities, where existing assets may still have significant operational life remaining. Organizations also need to consider whether there is sufficient space available, how the new utilities will be integrated and what disruption installation will inevitably create.

In a pharmaceutical environment, the operational impact can be as significant as the capital cost itself because taking equipment or production processes offline for installation and qualification can affect material movement, validated processes as well as overall production capacity.

Manufacturers should, therefore, not assume that existing equipment should always be replaced, but consider whether it can meet the identified contamination control requirements. If it cannot deliver the required levels of control, replacement may be justified.

Bridging the Gap Between Manual Processes and Fixed Infrastructure

There is a need for solutions that lie between manual intervention and large fixed automated systems. A well-designed retrofit or portable decontamination system can provide a way to introduce automation and validation without requiring replacement of existing infrastructure.

For facilities with smaller assets, approaches aimed at smaller-volume applications, such as the ProXcide Mini (Inivos), can provide greater flexibility. Rather than investing in separate fixed systems for each enclosure, organizations can establish a validated decontamination strategy that can be deployed where required, so long as each application is appropriately assessed and validated.

As pharmaceutical operations become more diverse, contamination control strategies will increasingly need to accommodate a wider range of assets, environments, and workflows. The challenge for manufacturers is not simply achieving compliance through what may be hasty investment today, but creating approaches that both provide the level of assurance required for the specific risk being managed and remain practical and adaptable as processes evolve.

References

1. EC. EU GMP Annex 1: Manufacture of Sterile Medicinal Products. EudraLex Volume 4, August 2022.
2. Christian, W. Every Hour Counts: How Low-Code Transforms Pharma Manufacturing from Costly Downtime to Competitive Advantage. Blog Post, Siemens.com, Dec. 3, 2025.
3. Pharmalliance Consulting. Annex 1 One Year Later: 20 Must Know Insights! Blog Post, March 6, 2025.

About the Author

Richard Timbrell is Head of R&D and Commercial Product at med-tech leader Inivos.
Inivos will be exhibiting on stand K104 at Lab Innovations 2026 at the NEC, Birmingham, where the team will be showcasing decontamination solutions and equipment, including controlled environments, cleanrooms, and turnkey laboratory facilities.