CleanroomsUSA

Components of How a Softwall Cleanroom are Designed

Supporting Frame

The supporting frame for a softwall cleanroom consists of powder-coated steel or aluminum uprights, cross sections, and ceiling frames. It provides structural support for the filtration system, air handling units, light fixtures, and ceiling tiles. The frame's dimensions are tailored to meet the customer's requirements. Steel tubular framing includes welded T bars in the ceiling structure to support the filters.

Cleanroom Ceiling

The ceiling of a softwall cleanroom comprises a grid system supported by lightweight connectors. There are two types of ceiling grids: self-supporting and suspended. Self-supporting grids require heavy-duty aluminum or steel, with the number of posts determined by ceiling height and weight. Standard self-supporting grids are non-walkable but can be adjusted for maintenance access if necessary.

Hanging ceiling grids use turnbuckles and steel rods to support the ceiling, lighting, and filters. Despite their additional support, they are not walkable.

Ceiling height in softwall cleanrooms ranges from seven to ten feet, with custom sizes available. A two-inch clearance is necessary between filtration units and the facility ceiling, with filter units typically 16 inches in height.

Softwall Cleanroom Walls

Walls in softwall cleanrooms consist of clear, flame-retardant, outgassing thick vinyl strips. These lightweight, easy-to-install panels are easy to clean and available in various colors to match process needs and UV sensitivity. The walls are made of 40 mil vinyl, with door panels made of 80 mil. Panels are hung overlapping to create a barrier against the external environment.

The 40 mil vinyl panels are double the required thickness, making them tear-resistant. They are attached to the support frame using a grip track mounting system to prevent contamination.

Air Treatment System

The air treatment system is central to a softwall cleanroom, relying on airflow pattern, air supply, HEPA filters, and room air pressure. System classification is based on air changes per hour (ACH), which determines the ISO classification. Air change rates range from 10 to 250 times per hour, with higher rates correlating to higher ISO classifications.

HEPA Filters

High-efficiency particulate air (HEPA) filters are the industry standard for cleanroom air treatment, removing 99.97% of particulate matter at 0.3 microns, including dust, pollen, bacteria, and other contaminants. They consist of randomly placed fiberglass fibers of varying densities, with efficiency determined by fiber diameter and thickness.

The dense structure of HEPA filters requires a powerful air circulation system to move air through them.

HVAC System

HVAC systems control temperature and humidity in softwall cleanrooms, ranging from half ton to two-ton capacities. Multiple-panel designs with variable ducting are necessary to meet changing needs. Condensers can be air or water-cooled based on requirements.

Outside air is pulled into the HVAC system through pre-filters, passing through HEPA filters into the room. Air is forced downward toward the floor, exiting underneath the vinyl walls. In some cases, air conditioning may need to be ducted from the building's HVAC system.

Softwall cleanroom HVAC systems use a single-pass airflow, unlike solid wall cleanrooms, which may use single-pass or recirculating systems.

Lighting

The lighting of a softwall cleanroom is determined by process requirements. Placement of lights is crucial for proper air movement and filtration.

Common softwall cleanroom lighting types include recessed troffers, surface-mounted, and teardrop lights. Recessed troffers fit into suspended drop ceilings without interfering with airflow, suitable for high-classification cleanrooms.

Surface-mounted lights are used in lower classifications, mounted on the ceiling but not recessed, thus interfering with airflow.

Teardrop lights hang below the ceiling to allow airflow, avoiding turbulence, but they reduce headroom.