Airflow Principles for Industrial and ISO Clean Rooms
Why are airflow principles and ISO clean room standards so important? Compromised performance. Reduced life. Increased operating costs. These are just three consequences of particulates finding their way into large, complex, high-value products. Whether you're building a jet engine, assembling a satellite, or finishing a boat, cleanliness is critical for product quality.
Every manufacturer of marine, aerospace, or defense products understands that an industrial clean room is not optional. These clean air solutions have become essential for producing high-value products that have to deliver the highest levels of performance and reliability. What's less appreciated is the role and influence of the airflow principles employed to ensure that happens.
Industrial Clean Room and ISO Clean Room Standards
Dust and other particulates are pervasive in manufacturing facilities. To create a total clean air environment, it's necessary to extract contaminated air from the workspace and replace it with clean, filtered air.
This is essentially what happens inside an industrial clean room. Fans blow air in through High-Efficiency Particulate Arrestor (HEPA) or Ultra Low Penetration Air (ULPA) filters that capture almost all particulates. Additional fans draw air out of the room, either sending it to exhaust or recirculation.
Extracting air at a lower rate than it's blown in creates a positive pressure environment. This stops air entering from outside, through either doors or cracks and/or holes in the structure. Most industrial clean rooms follow this positive pressure principle. (Negative pressure is common only when dealing with biohazards that cannot escape).
There is an ISO clean room standard that defines classes of contamination/cleanliness. In general, higher cleanliness (a lower ISO class number) requires more air changes per hour. Clean rooms rated at ISO 6 and better measure airflow in speed rather than air change rate.
Figure 1. ACH Ranges for ISO Clean Room Classifications
Industrial Clean Room Airflow Principles
There are two common approaches to clean room airflow: Laminar flow and turbulent flow. A laminar flow system, often called a unidirectional airflow clean room, is configured to keep air moving in a single direction. Typically, this is from ceiling to floor, although cross-draft (side-to-side) systems are used in certain applications as well.
Laminar flow clean rooms need a large area of filters on the inlet side to achieve proper airflow. This can drive up both the initial expense and the cost of filter replacement.
In a turbulent airflow industrial clean room, air flows in a highly random motion. This is intended to dislodge particulates and encourage their movement towards the exhaust outlets. One advantage of this approach is that it needs a smaller area of filters than laminar flow.
Some clean rooms in manufacturing today adopt a hybrid or mixed airflow approach, using both laminar and turbulent flow.
Taper Draft Airflow as an Efficient Alternative to Laminar and Turbulent Flow
When an industrial clean room or ISO clean room has to accommodate large objects or structures, there is a high volume of air required. Duroair’s patented Taper draft airflow technology is an alternative that accomplishes this high volume of air with increased efficiency and improved productivity.
Rather than create laminar or turbulent airflow through the entire volume, taper draft seeks to put airflow where it's needed: Around the product.
Taper draft pulls air through filters located outside the clean room. This filtered air then flows over and around the product, creating an envelope of clean air that's almost completely particulate-free. Not only is the product kept contamination free, but drying times are reduced and overspray control is improved for painted products as well. Additionally, filter replacement becomes a more efficient task that's less likely to contaminate the clean room or create costly downtime.
Figure 2. Taper Draft Airflow to Meet ISO Clean Room Standards
Cleaner Facility Air and Streamlined Production
Cleanliness during assembly and finishing operations is increasingly a critical bottom-line factor in the manufacturing of complex, high-value products.
While conventional industrial clean rooms may employ either laminar or turbulent airflow, both of which are costly to operate, a modular clean room solution from Duroair utilizes taper draft technology for more cost-effective airflow management.
Our modular clean rooms achieve required contamination control where it's needed most while improving production quality, reducing processing times, and helping your manufacturing facility control capital expense and ongoing operating costs.
To discuss how we can engineer a modular clean room that will fit your facility, integrate with your workflow, meet your process requirements, and won’t break the bank, contact a Duroair clean air expert today to request a free consultation.
