Hygienic solutions for ISO 14644 cleanrooms

With cleanrooms being one of the most hygienic work environments, it’s no surprise that they follow stringent hygiene practices. This includes constant monitoring of various factors to eliminate the risk of contamination and prevent compromising the safety of the end product or user. One of these methods of monitoring cleanroom environments is via ISO cleanroom grades. These classifications are defined by the International Organisation for Standardisation (ISO) under the standard ISO 14644-1. These classes specify the cleanliness of air in cleanrooms based on the concentration of airborne particles. This classification system ranges from ISO Class 1 (the cleanest) to ISO Class 9 (the least clean). The process of assigning and maintaining an ISO class to a hygienic environment helps determine the level of cleanliness required for its intended use.

What are the ISO cleanroom grades?

The ISO cleanroom grades determine an areas classification by focusing on the concentration of particles in the air. Particle size is usually measured in microns (µm), and ISO 14644-1 focuses on particles as small as 0.1 µm to 5 µm. Different ISO classes limit the number of particles of certain sizes allowed in a cubic meter of air. This is due to smaller particles being extremely problematic in sensitive manufacturing environments due to the contamination risk and the chance of electrostatic discharge which could damage sensitive equipment.

Here’s a summary of the ISO cleanroom grades and the allowable particle concentration per cubic meter (m³) of air, for various particle sizes:

How do ISO classes work alongside GMP (Good Manufacturing Practice)?

In pharmaceutical manufacturing, the hygiene standards within cleanroom environments are also usually classified by GMP grades. These classifications are slightly more complex than ISO 14644-1 as it monitors and specifies the allowable particle concentration while both at rest and in operation.

Here’s how GMP Grades compare with ISO Classes:

How to determine air flow requirements:

ISO classes also provide guidance on the airflow system required in a cleanroom based on its specification. Stringent hygiene areas, such as ISO classes 1-5, require laminar/unidirectional airflow as well as HEPA (High-Efficiency Particulate Air) or ULPA (Ultra-Low Penetration Air) filters to ensure a high degree of cleanliness.

While HEPA filters are still required for the less stringent ISO classes, such as 6, 7 & 8, turbulent airflow is often sufficient. This type of airflow system directs the air in a more diffused and random pattern. While this is less effective than laminar flow at removing particles, turbulent airflow still reduces the particle concentration through consistent filtration.

The combination of proper airflow and high-efficiency filtration ensures that particles are continuously removed from the air, maintaining the cleanliness levels required for the specific ISO classification.

How do ISO grades impact furniture within a cleanroom environment?

These grades not only impact the airflow and particle measure within a controlled environment, but they also have a significant impact on the furniture you choose. The design and use of furniture within a cleanroom is particularly important for ISO classes 5-8, with restrictions on the materials, construction and maintenance of equipment. These considerations ensure that the furniture does not contribute to contamination and supports the overall cleanliness and safety of the room in question.

Material selection:

While it is important for the materials used in a cleanroom to have high chemical resistance for stringent hygiene processes, it is also vital that the furniture consists of non-particle shedding materials. Stainless steel is usually the go-to material for cleanroom furniture and equipment as it is both non-shedding and non-porous. This prevents both microbial growth and the release of particulates that can compromise the cleanroom’s air quality.

Alternatively, specialised lab furniture (such as Trespa or Sealwise) may be used thanks to the anti-microbial coating preventing the growth of bacteria and fungi. These coatings reduce the risk of contamination from surfaces that come into contact with workers, equipment, and/or pharmaceuticals.

Design and construction:

To aid cleanability, furniture should have minimal components, joints and hinges that could become dirt traps during the clean down process. There should also be easy access to all surfaces with mobile equipment particularly favourable so that the surrounding area can be effectively sanitised.

Airflow and particle control:

It’s important that the furniture used does not interfere with the required airflow – especially in areas using laminar flow systems to prevent particles from settling. Particularly important for ISO class 5 cleanrooms, efforts should be made to use perforated or slatted shelves, benches and tables to allow air to move freely and reduce disruption.

Seating:

In pharmaceutical cleanrooms, seating must meet specific cleanliness and ergonomic requirements to ensure comfort and safety for personnel while maintaining cleanroom standards. Chairs and stools should avoid the use of fabric or textile materials which can trap particles and are difficult to clean. Instead, non-porous, easy-to-clean materials like vinyl or polyurethane are preferred. ESD-compliant seating should also be considered in areas where the buildup of static electricity is a concern for sensitive equipment or manufacturing processes.

Building an ISO-compliant cleanroom

To stay compliant with ISO 14644-1, careful consideration must be taken to select appropriate equipment with the ISO classification system heavily influencing the selection, design, and maintenance of furniture within the pharmaceutical sector. It must assist with airflow where possible and be manufactured from an easy to clean, non-shedding material. This ensures sterility and achieves the necessary levels of cleanliness required for a stringent hygiene environment.