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Clean room ceiling design can combine the advantages of sound-absorbing, low-emitting acoustic ceiling tiles and gasketed ceiling grid suspension systems for a high-performance solution

Along with excellent sound absorption and low particle emission, performance considerations for clean room ceilings include high fire performance, high light reflectance, durability, ease of cleaning and inhibiting the growth of microorganisms such as MRSA.

Clean room ceiling panels and cleanroom ceiling systems

Clean rooms ceilings typically are drop ceilings, which are constructed of acoustic panels that lay in a suspended grid system. The ceiling panels generally are only available in white, and not in black  or colored ceiling tiles, which retains the feel of cleanliness within the space.

Cleanrooms filter the dust and contaminants out of the air and recirculate it in the space. Positive pressure, humidity controls, and special shoes and clothing also may be necessary to maintain strict quality levels. They can have very high ceilings or be lower and closer to those working inside them. They can span a vast manufacturing facility or small, specialized laboratory.

Clean rooms and facilities that may benefit from the control of contamination include aerospace, microelectronics, optics, food and beverage, pharmaceuticals, medical devices, and healthcare.

Food production, pharmaceuticals, aerospace and automotive manufacturing are just some of the many areas where controlled and classified clean rooms are essential. Clean rooms are zones where contaminants in the air are highly controlled. Without effective control, contamination can wreak havoc on products and processes.

International Organization for Standardization

Classification and low particle-emission requirements of ISO 14644-1

Clean room ceiling designs follow the International Organization for Standardization’s ISO 14644-1 “Cleanrooms and associated controlled environments-Part 1: Classification of air cleanliness by particle concentration.”

This standard specifies the classification of air cleanliness in terms of concentration of airborne particles in cleanrooms and clean zones. The particle size is measured in microns and the concentration in particles per cubic meters. A human hair is on average 100 microns in diameter and a red blood cell about 7 microns. The ISO cleanroom classifications look at particles starting at 0.1 microns and equal to or larger than 5 microns. 

Other than size, ISO 14644-1 does not detail the types of particles. These may be organic, such as wood, mold, mildew, bacteria and other microorganisms; or non-organic, such as metal and stone.

The current ISO 14644-1 standard, published in 2015, superseded previous versions and also replace the U.S. General Service Administration’s Federal Standard 209E “Airborne Particulate Cleanliness Classes in Clean Rooms and Clean Zones.” The prior U.S. FS209E referenced Class 1-100,000, based on particles per square foot. The ISO 14644 references ISO Class 1-9. In both standards’ classification, the lower number of Class 1 represented the most stringent classification, In other words, it is the cleanest.

Examples of ISO 14644-1:2015 cleanroom classification are:

  • An ISO Class 1 allows a maximum concentration level of only 10 0.1-micron particles per cubic meter.
  • An ISO Class 5, which formerly equated to Federal Standard 209E Class 100, allows a maximum concentration level of 100,000 0.1-micron particles (or 832 1-micron particles) per cubic meter.
  • An ISO Class 9, allowed a maximum concentration level of 8,320,000 1-micron particles per cubic meter.

As part of its regular review and revision cycle, the 2015 ISO standard will be reviewed again in 2020.1

Where high moisture content is expected, such as the glass-wash facilities, and where the clean room standard is required for sensitive equipment or contamination control, Rockfon® Medical™ Plus ceiling tile together with the barrier grid suspension system is used.

Nigel Tai, M.Arch., OAA, MRAIC, LEED AP

Associate with Diamond Schmitt Architects, on the design of University of Toronto Scarborough Campus’ Environmental Science & Chemistry Building

Acoustic ceiling tiles for clean room conditions

Our Rockfon® Hygienic Plus™ acoustic ceiling tiles meet low particle-emission requirements and have a clean room classification of ISO Class 5 (ISO 14644-1). 

Stone wool is the basis of our complete portfolio of ceiling products. It is non-combustible; our acoustic panels exhibit high fire performance. It has excellent sound absorption and high light reflection for acoustic and visual comfort under clean room conditions.

This natural basalt stone material does not absorb water. Our stone wool ceiling products also do not hold moisture and resist humidity. In addition, all of our stone wool acoustic ceiling solutions are GREENGUARD® Gold certified for low chemical emissions.

Because stone wool is not organic, it has no nutritional value; therefore, it provides no sustenance to mold, mildew, bacteria and another microorganism such as Methicillin-Resistant Staphylococcus Aureus (MRSA).

Gasketed ceiling grid systems for controlled environments

These grid systems are designed for use in ISO 14644-1 controlled environment facilities and our Chicago Metallic® BarrierGrid® exposed metal suspension systems feature ceiling gasketing. The precision-applied, factory-installed, closed-cell PVC foam gasket grid restricts air movement between cleanrooms’ plenums and the clean process work areas.

The BarrierGrid suspension grid is made from hot-dipped galvanized steel with aluminum-capped runners and tees for superior corrosion resistance. Butt-cut cross tees keep all of the ceiling grid components in the same plane for a uniform appearance and maximize the perimeter seal to panels.

All of our BarrierGrid suspension systems are ICC-ES listed for seismic applications, and our heavy-duty 1-3/8-inch wide-face ceiling suspension also is fire-rated. Our metal ceiling systems also inhibit the growth of mold and bacteria through their inherent material performance. Made with recycled content, they are can be locally recycled at the end of their useful lives as a clean room ceiling system.


1. International Standard ISO 14644-1:2015, “Cleanrooms and associated controlled environments-Part 1: Classification of air cleanliness by particle concentration,” second edition 2015-12-15



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