Why Industrial Cleanrooms and Microclimates
No matter what kind of controlled environment and industry you’re working within, maintaining a safe and productive cleanroom is absolutely essential to your daily operations and reputation.
Getting the right HEPA air filter, having a laminar airflow hood, and even making sure that employee apparel and cleaning supplies don’t contaminate the environment, can all contribute to keeping cleanroom temperature and humidity levels consistent.
Understanding Cleanroom Humidity Levels
High humidity levels may cause additional cleanroom problems, such as the growth of bacteria, product degradation/damage, corrosion, and static electricity. Static electricity directly interferes with the movement of particles inside of the cleanroom, which can cause serious production problems. High humidity levels can cause solvents to evaporate and water to cool and condense moisture. Thus, compromising both process control and quality. In a pharmaceutical environment, high humidity levels in the cleanroom may lead to clogs due to powder inconsistency.
Common cleanroom guidelines state that Relative Humidity (RH) levels in cleanrooms should remain between 30-40% RH at all times. Usually, temperatures below 21 degrees Celsius (70 degrees Fahrenheit) have a +/- 2% RH band. Even though cleanrooms are pressurized, you’ll still need to take extra care to ensure that humidity levels in the cleanroom don’t fluctuate.
Constantly fluctuating humidity levels make cleanroom employees uncomfortable.
These issues can lead to costly mistakes, low-quality products, and may even cause serious production delays.
The ideal Cleanroom Temperature
In general, the temperature of a cleanroom should be 21 degrees Celsius, or 69.8 degrees Fahrenheit. Usually, a fluctuation of 2 degrees Celsius is permissible.
Like humidity levels, it’s important to maintain a standard temperature in cleanrooms to keep employees comfortable. The reason why their comfort matters is even more interesting.
When cleanroom cleaning staff or technicians shiver or even sweat, they release a higher amount of particles into your cleanroom. This can contaminate the environment and compromise production standards.
10 Interesting facts of Industrial Microclimates
- Visible indoor air particles constitute only about 10% of particles present in indoor air.
- It may be possible to see particles as small as 10 microns under favorable conditions.
- The majority of harmful particles are 3 microns or less in size.
- Particles of 1 micron or less adhere to surfaces by molecular adhesion. Scrubbing is generally the only way to remove them.
- Larger particles tend to settle out of the atmosphere due to weight.
- Smaller, “respirable” particles remain virtually suspended in the air until breathed in.
- Approximately 98-99% of all particles by count are in the size range of 5 microns or less. These particles tend to remain in suspension or settle out so slowly
- To guarantee controlled product quality and reduced product reject rates, Microclimates are an economic solution. The MC combines direct fume/ dust collection (source elimination) and secondary fume/dust displacement, replacing the extracted air with absolute filtered and conditioned air, providing local air balance.
- The Microclimate consists of internal lighting and roller curtains, to isolate the area from production, and to provide optimal access and ergonomics.
- Microclimates can be applied on different parts of the production line, with different ISO classes, rating from ISO 8 to ISO 6, and advanced air conditioning (e.g. low humidity air) to fit the different functions of the production line.
Economic driver for Microclimates
Rather than building the full production line in an expensive clean room, Microclimates are a local solution to deliver clean room air quality on the required locations. The location choice can protect the products produced, the production equipment and most importantly the operators.
This is especially relevant, when the product is unprotected or in a vulnerable production stage. Finally, the Microclimate contributes to stable conditions, by local balancing of the air at key production areas.
How to design a Microclimate
A Microclimate design starts with clear definition of the application, process demand and product requirements:
- Clear understanding of the process. This includes the presence of temperature gradients (e.g. extruder), identification of pollutant sources and definition of the product demands in respect to air quality and relative humidity, including the required ISO class.
- Identification of main pollutants, like both Fumes and UFP’s (Ultra Fine Particles). This needs to be identified by an onsite measurement program.
- Local air balancing in the different ‘stages’ and functions of the production line is done by GCM modeling. This provides a pre-installation, modeling based performance guarantee at minimized air replacement (ventilation) rates.
The design results in zoning of the production stages, with individual ISO classes. This is necessary to guarantee the required production conditions during operations.
Technical benefits of Microclimates
Microclimates are small, separate areas within a larger surrounding manufacturing site that has it’s own atmospheric condition. The area may contain a few square meters or a whole room or hall. Advantages of well-designed microclimates at Industrial sites include:
- A reduction of capital expenses compared to classical clean rooms
- In combination with necessary fume and dust collection (source elimination), the Microclimate reduces the concentration of fumes, prior to forming Ultra Fine Dust and condensing Aerosols. After validating Microclimate is built, a direct correlation between the ISO class (air quality) of the Microclimate and the number of surface defects of the product is confirmed.
- Proactive modeling determines the required Microclimate ventilation-rate in combination with the optimal operating temperature (equally distributed). This results in a locally balanced air distribution with a significant lower air consumption as normal clean rooms. This results in reduced energy consumption and improved economics.
The Human factor
Microclimate validation studies of production lines, packaging lines, film extruders, sheet extruders, and multi-layer film extrusions, show that for stable production results the interference of operators and maintenance should be executed in a ‘smart’ and controlled way. Next to optimal design and advanced implementation solutions, the human factor needs to be considered. Adequate training and operational procedures must be implemented to ensure constant product quality and ISO Class.
Additional Benefits of effective industrial Microclimates
When designing new or update existing Microclimates, there are additional benefits to be achieved:
- Improving line stability (feeding / vacuum)
- Reduced damage to process equipment (e.g. rolls)
- Minimized Surface defects
- Increase product quality
- Realized material upgrade
- Reduced operational costs
- Reduction in the number of line stops (downtime)
- Indoorclimate solutions are able to optimize thermal comfort much more effectively than radiators. They achieve better vertical temperature equilibrium in indoor space thanks to their design, which aligns with human body preferences.
- Operator health and satisfaction
- Sufficient cooling capacity: DT of 5 to 10 ºC
- Ability to create local optimized conditions around heat sources (energy recovery)
- Integrated in the existing HVAC installation