Cleanroom; Powder Containment, PCS, Negative Pressure Containment

What is a “hardwall” clean room?

Hardwall modular cleanrooms provide a completely enclosed, rigid free-standing structure with vents to exhaust air. Terra Universal fabricates the framing from powder-coated or stainless steel; wall panels are available in clear acrylic, static-dissipative PVC, polycarbonate and tempered glass, as well as opaque white polypropylene.

Because they can be specified, built and installed in a fraction of the time associated with brick-and-mortar clean rooms, modular hardwall rooms are ideal for fast ramp-up projects or short production cycles that may not merit the expense and delay of a conventional room.

Why should I choose a hardwall clean room over a softwall clean room?

Hardwall clean rooms can maintain pressure differentials, which may be required to meet certain standards for cleanliness (ISO 5 or 6, as well as USP compounding regulations). Their wall panels are more durable and easier to clean than softwall panels or curtains.

Hardwall construction also allows temperature and humidity control, which is enhanced in a recirculating clean room design using vertical air returns in conjunction with A/C units. Unlike softwall designs, hardwall cleanrooms can provide negative-pressure containment.

What modifications are required for a containment clean room application?

A negative-pressure containment room must pull more air out than it introduces through ceiling fan/filter units. Air is typically exhausted through ductwork tied to a ventilation fan.

Ductwork most often runs along the bottom perimeter of the clean room and draws air from multiple locations along the room perimeter to minimize disruption to laminar flow. The ventilation fan mounts on the floor outside the cleanroom, or ductwork may pass exhaust upward to a roof-mounted fan. In order to maintain negative pressure, this fan must be capable of pulling about 30% more air than the HEPA filters introduce.

Depending on the application, a containment room may require exit filtration: either HEPA/ULPA filters for particles and aerosols, and/or carbon filters to remove chemical fumes.

Can a hardwall clean room accommodate multiple production suites?

Internal walls and careful positioning of ceiling Fan/Filter Units (FFU) allows you to configure a facility with many rooms, each operating at a different ISO cleanliness level. Some points to keep in mind:

• Clean room requirements typically specify a pressure differential between 0.025 – 0.05”WC between adjoining rooms of differing ISO classifications. Terra’s Smart Control Systems simplify this task by allowing FFU speed adjustment from a central control panel.
• Certification of multi-room facilities often requires logging of pressure levels, which correlate to cleanliness and (in a containment application) environmental safety. Smart Controls are available with automated data logging that helps meet this requirement.
• Smart Controls also provide automated end-of-shift set-back mode, which saves energy without compromising clean room integrity.

What other environment controls or protections can hardwall cleanrooms provide?

Beside controlling particulate contamination and internal positive or negative pressure, hardwall cleanrooms are available to meet these special requirements:

• Static Control: select static-dissipative PVC panels for optimal protection against electro-static discharge. Ceiling-mount ionizing bars neutralize charges on workstations. Eliminating surface charge build-ups also removes “static cling” that attracts and holds airborne particles.
• Temperature: in addition to module A/C units, Terra also provides insulated hardwall panels to enhance thermal stability. For improved thermal efficiency, select a double-wall BioSafe Clean Room.
• Relative Humidity: Terra offer desiccant-based dehumidification modules as well as ultrasonic humidifiers.
• Fire and Explosion Resistance: Call to discuss requirements for NEMA Class I, Division 1 explosion-proof FFUs, lights and wiring, available on any Terra clean room. Terra also provides fire-safe wall and ceiling panels that meet FM 4910 Clean Room Materials Flammability Test Protocol for flame spread, smoke contamination and resistance to corrosives.
• Microbial Control: UV germicidal lights with an occupancy-sensor safety cut-off help maintain sterile conditions in bio/pharmaceutical clean rooms.
• Vapor and Particle Removal: Reverse-flow FFUs capture particles generated in localized cleanroom spaces to minimize contamination. Vapor removal FFUs eliminate trace amounts of VOCs from make-up air to prevent chemical fume contamination.
• Energy-Efficiency Compliance: Terra helps meet Title 24 and other energy-efficiency requirements through use of EC motors, LED lighting and other low-energy devices.
• ADA Compliance: Call for information on ADA-compliant access ramps, doors and controls.