Cleanroom Chair and ESD Seating Specifications, Seat Filtration, and Chemical Resistance

Whether outfitting a chair for a specific task or facility-wide outfitting, Terra Universal carries a wide selection of seating options catered for static-sensitive and cleanroom environments.

Below, we'll evaluate a host of different cleanroom-compatible options for ISO 3 to ISO 8 chairs and stools, as well as all static-control/ESD models tested to ANSI/ESD STM 12.1 for S20.20 compliant programs.

Cleanroom Compliant Seating Specifications

The ideal cleanroom chair is easy to clean, mitigates particulate generation, is non-shedding, and is chemically resilient to any cleaning or processing chemicals.

Chemical-Resistant Materials

Cleanroom cleaning regimens require routine usage of chemical sterilants and disinfectants, most of which are not compatible with typical economy-grade materials. Seating components must be thoughtfully designed to prevent deterioration, shedding, and off-gassing when used among common cleanroom disinfectants and sterilants including bleach, alcohols, quaternary ammonia, peracetic acid, and hydrogen peroxide formulations.

Plastics Chemical Compatibility Chart

Rubber and Synthetics Chemical Compatibility Chart

Metals Chemical Compatibility Chart

Easy to Clean Frames

Cleanroom chairs are designed to minimize gaps, cracks, and crevices where bacteria, particulate, and dirt or grime frequently proliferate. Clean-forward designs impede the ability of contamination to penetrate and thrive, while also ensuring that the design remains easy to clean.

Cleanroom chairs incorporate numerous features to ensure maintained cleanliness by reducing airborne particle generation and surface contamination.

Air Reservoir Diaphragm Lung Seat Cushions

ISO 3 cleanroom chairs from Terra's BioFit selection include a proprietary under-seat airflow-exchange system. An air reservoir encased in a protective pan attached to the seat discharges air from the seat cushion into the reservoir and prevents escape into the surrounding cleanroom environment. Built for cleanroom use from start to finish, the chairs are assembled in an ISO-rated cleanroom, wiped down, and packaged under a laminar flow clean hood. Cleanroom packaging prevents the chairs from encountering contamination during shipping and transport. On arrival, the chair remains wrapped until it arrives in a clean area suitable for unpacking and introduced to the cleanroom with minimal transferable contamination.

In-Seat Filtration and Particle Traps

In-seat filtration prevents particle-laden air from escaping the seat cushion when an operator sits down. Studies in residential environments indicate that walking and sitting alone may contribute up to 25% of all household dust particles resuspended into the air.

Cleanroom chairs with in-seat filtration and particle traps mitigate particle generation while allowing the seat to conform to the user’s body shape. The polypropylene filter media traps particles 0.1 microns and larger and allows unrestricted airflow with a filter permeability of 230 cfm/ft2.

Dauphin ISO 4 Polyurethane Cleanroom Chairs

Dauphin ISO 5 ESD-Control Chairs by

BioFit ISO 5 Ergonomic Cleanroom Chairs by

Sealed Seats and Backrests

Sealed seat pans and backs reduce particle accumulation within cracks and facilitate easier cleaning.

Terra BioSafe Cleanroom Chairs

Terra Universal's BioSafe® EZ-Clean Chairs cater to environments that compound, process, or package sterile products and ingredients. BioSafe products include cleanroom-compatible, electropolished 316L stainless steel construction. Electropolished stainless steel is corrosion and chemical resistant, thus, compatible with most cleaning agents.

These sterilization-ready components prevent off-gassing during high-heat or chemical decontamination processes including autoclave sterilization. EtO, VHP, or gamma irradiation. Continuous welds and bends ensure smooth surfaces for easy cleaning. BioSafe packages are ideal for life science applications including biologics, systems biology, and proteomics.

Additionally, BioSafe footrests are available for improving comfort and ergonomic posture over long shifts in the laboratory or cleanroom.

Terra BioSafe® Cleanroom Stools

Terra BioSafe® and BioFit Cleanroom Chairs

Anti-Static ESD Safe Chair Design

ESD seating for S20.20 programs requires strict point-to-point (RTT) and point-to-ground (RTG) resistance as defined by ANSI/ESD STM 12.1.

Anti-static, ESD-safe chairs are typical in facilities where charges transferring between the environment and products may damage or interrupt sensitive components and instruments. Common applications include communications, electronics manufacturing, defense, aerospace, circuit boards, and computer component assembly or rework.

ESD chairs dissipate charges generated by the friction of a chair as it rolls across the floor, as well as charges generated or retained by the human body.

The working principles of static dissipation are based on two methodologies. The first is that the chair components and materials will have electrical properties that reduce static charge generation. The second is that the chair design must safely redirect and dissipate any accumulated charges generated by equipment, operators, clothing, or footwear.

ESD Chair Options and Accessories

ESD Chair Drag Chains

ESD chairs with drag chains ensure maintained connectivity with the flooring system. Drag chains ensure continuity from the chairs to the ground, providing an additional ground point in the event the seating casters get dirty and fail. However, the floor must be static dissipative or conductive to accept and drain the charge from the chair.

Dauphin and Biofit ESD chairs offer numerous class-compliant casters, drag chains, and fabric materials for safe operation in ESD-sensitive or electrostatically protected environments.

Conductive vs Dissipative Casters

In electrostatically protected areas (EPAs), the flooring is typically constructed with composite, metallic-infused tiles that allow static charges to pass through the floor to a grounded connection. Therefore, all chairs, carts, and mobile equipment must have antistatic or conductive casters.

What is the Resistivity of Conductive Casters (DIN EN 12530 - 12533)?

Conductive casters are defined as wheels with an ohmic resistance of less than 10^4 Ω (ohms).

What is the Resistivity of Dissipative Anti Static Casters (DIN EN 12530 - 12533)?

Anti Static casters are defined as wheels with ohmic resistance of less than 10^7 Ω (ohms).

When Do I Need Conductive Casters?

Conductive casters offer the highest degree of protection for electrically sensitive environments. Conductive materials allow currents to immediately pass from surface to ground and also allow current to pass from the chair's frame or components to ground.

When Do I Need Anti Static casters?

Anti-static casters are suitable for environments where static sparks could ignite atmospheric dust, vapors, or combustibles. While anti-static wheels can limit static voltage generation on the wheel itself, the design is less efficient for protecting ultra-sensitive instruments. Anti-static chair casters are typically rated for a five-year operating life.

Static Dissipative Fabric and ESD Vinyl Chairs

What is the Resistance of Static Dissipative Fabric (ANSI/ESD ST 12.1 - 2006)?

Static-dissipative fabric requires a surface resistivity no greater than a resistance of 10^5 to 10^9 Ω (ohms).

Dauphins's 99% polyacrylic, 1% metal filament ESD-safe fabric ensures that errant charges effectively dissipate from the seat pan, back down through the frame, and discharge to a grounded floor.

ESD-safe vinyl upholstery is also available for chemical resistance and easier cleaning.

Where Can I Buy Cleanroom Chairs and ESD Seating Online?

Terra Universal manufactures a wide variety of stools and chairs for controlled environments, while also providing factory-direct sourcing for Biofit, Labconco, and Dauphin products. These product lines are well suited for manufacturing, cleanroom, and ESD environments due to their high manufacturing standards, broad configuration options, and industrial durability,

Contact a Terra specialist via phone, email, or web chat for assistance when selecting an on-budget seating option that is tailored to your facility's footprint and environment.

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