07/26/2025
Sterile and Nonsterile Cleanroom Garments, Particle Emission Testing, Sterile and Nonsterile Gowning: Part 1 – Materials and Components
Introduction: Part 1
Cleanroom garments are worn by operators working in certified cleanrooms to protect the product and the processes inside the cleanroom from human sourced contamination and to maintain the integrity of the cleanroom. Selection and correct use of these garments has a significant impact on the performance of the cleanroom. Use of the optimum gowning reduces particle shedding and can allow the use of lower air change rates.
This series of articles is intended to provide an overview of cleanroom gowning divided into four parts:
Part 1: Materials and Components
Part 2: Operational Aspects
Part 3: Aseptic Facility Requirements
Part 4: Aseptic Operational Aspects
Cleanroom Garments
Reusable and disposable, single use cleanroom garments are considered Class 1 medical devices that are validated. Additionally, gamma sterilization validation of reusable and disposable, single use sterile cleanroom garments are validated to a sterility assurance level of 10-6 SAL.
It is recommended that the selection of reusable or disposable, single use cleanroom garments be based on fabric performance test results, quality of construction and particle emission test results. The decision to use reusable or disposable single-use apparel is based on multiple factors such as:
How the product is manufactured
Manufacturing process
Ability of the cleanroom garment laundry to service the customer with reusable garments
The number of garments required during cleanroom manufacturing
Disposable, single-use apparel is used during cleanroom manufacturing of toxic or biohazardous products or when the process uses hazardous chemicals such as acids or alkali. Single-use apparel is also used if a reusable cleanroom garment laundry service is not readily available or if the limited number of garments required for the cleanroom manufacturing application do not make the use of reusable cleanroom garments cost effective.
Fabric
Fabrics used in cleanroom garments are woven or nonwoven. Each type of fabric has specific advantages and disadvantages. Reusable cleanroom fabrics are manufactured using 99 percent continuous filament polyester and 1 percent to 6 percent continuous filament polyester/carbon combination yarns to minimize particle shedding from the yarn. Reusable fabrics chosen must be cleanable using the recommended garment cleaning process and compatible with a validated sterilization process.
Nonwoven fabrics are constructed of a polyolefin fiber. There are six types of nonwoven fabrics:
Spun bonded or thermal bond
Flash spun
Melt blown
Spunbonded/melt blown/spun bonded (SMS)
Film laminate
Microporous film laminate
Evaluation of Fabrics Using ASTM and AATCC Test Methods
There are several test methods devised by the American Society for Testing and Materials (ASTM) and by the American Association of Textile Colorists and Chemists (AATCC) to evaluate woven and nonwoven fabrics.
Weight
The weight of the fabric determines its strength and durability (ASTM D-3776 Standard Test Methods for Mass Per Unit Area (Weight) of Fabric); heavier weight fabrics increase the strength and durability of the garments, though this must be balanced with operator comfort. Lighter weight fabrics can improve operator comfort. Additionally, grab tensile and tongue tear tests give an indication of the strength and durability of the fabric (ASTM D-5034 Standard Test Method for Breaking Strength and Elongation of Textile Fabrics (Grab Test)).
Pore Size
The pore size is an indicator of barrier efficiency. The smaller the pore size, the more particles that will be entrained. Calendaring is a process used on reusable, high performance, high-density electro-static device (ESD) fabrics to reduce pore size. Tyvek™ and microporous laminate fabrics used in disposable, single-use cleanroom garments do not have pores and therefore not only entrain more particles but provide a protective barrier for the operator when handling hazardous liquids and materials.
Moisture V***r Transmission Rate
The moisture v***r transmission rate (MVTR) evaluates the ability to move moisture through the fabric and translates to more comfort to the operator. Moisture buildup causes the operator to feel hot due to the increase in humidity between the fabric and the body (ASTM E96-00 (Standard Test Methods for Water V***r Transmission of Materials)).
Particle Filtration Efficiency and Bacterial Filtration Efficiency
Particle filtration efficiency (ASTM F-2101-22 Standard Test Method for Evaluating the Bacterial Filtration Efficiency (BFE) of Medical Face Mask Materials, Using a Biological Aerosol of Staphylococcus aureus) and bacterial filtration efficiency (ASTM F-2299/2299M Standard Test Method for Determining the Initial Efficiency of Materials Used in Medical Face Masks to Pe*******on by Particulates Using Latex Spheres) tests evaluate the ability of the fabric to contain both viable and non-viable contaminants.
Air Permeability
Air permeability is the ability of a fabric to allow air to pass through it, which is quantified by the volume-to-time ratio per area (ASTM D-737 Standard Test Method for Air Permeability of Textile Fabrics). Airflow in heating and cooling processes, such as the cooling process of the body, contains contaminants that can be transferred to the product. The lower the permeability or transfer of air from within the garment to the outside, the lower the risk of contamination to the manufacturing environment and potentially to the final drug product.
Splash Resistance
There are several tests to determine the splash resistance of the fabric or its ability to resist absorption of liquids. These characteristics allow the operator to be better protected from spills in the cleanroom environment.
Static Decay and Surface Resistivity
Static decay testing (FTMS 101C Method 4046: (Electrostatic Decay)) and surface resistivity testing (TM076-TM76-TM 76 Electrical Surface Resistivity of Fabric) are performed to document if the fabric is static dissipative. Fabrics outside of the static dissipative range of 105 – 1011 Ω-2 may cause an electrical discharge and subsequent product failure.
Special Pe*******on Resistance Tests
There are additional tests that can be used if required for nonwoven fabrics:
Chemical pe*******on resistance
Viral pe*******on resistance
Drug pe*******on resistance
Resistance to pe*******on by blood and body fluids
Garment Life
All reusable, woven cleanroom garment systems will deteriorate over time due to wear, wash/dry/wear cycles, and sterilization. The useable life of a garment should be established—suppliers usually provide recommendations which can be confirmed with tests by the company. The test results over time should not be significantly different from the original results, thereby confirming the durability of the fabric and construction characteristics used for that application for the defined life.
The results of the baseline testing performed in the installation/operation qualification (IOQ) validation are used to assess the cleanroom reusable or disposable, single-use garment’s durability for use, washing and sterilization (typically autoclave or Gamma Irradiation) cycles as applicable. The number of times garments are used should be monitored.
Seam Construction
A seam is a joint consisting of a sequence of stitches uniting two or more pieces of material. Prior to stitching any seams, the edges of the cleanroom fabric panel should be prepared to eliminate the possibility of loose threads, frayed edges or seam separation which may cause contamination in the cleanroom. Reusable, woven cleanroom fabric edges are either overlock (serged) stitch or laser fused edge. Disposable, single use nonwoven cleanroom fabrics are typically heat-sealed for a fused, beaded edge using pressure and heat-activated adhesive.
The two types of joining seams recommended for the construction of cleanroom garments are bound with single needle stitching for disposable, single use nonwoven garments and lapped (flat felled) with double needle stitching for reusable, woven garments. ASTM D-6193-16 Standard Practice for Stitches and Seams stipulates seams used for construction of personal protective garments should contain six to seven stitches per inch.
Components
Components or “findings” are supplementary items used in the construction of both reusable, woven garments and disposable, single-use nonwoven cleanroom garments. They should be cleanroom compatible and gamma irradiation and/or autoclave compatible. They should be installed on the garment in a way that minimizes the entrapment and/or release of contamination while in use.
Snaps
Snaps are post and socket type 304 stainless steel or plastic. Lesser grade stainless steel snaps will corrode and cause particulation when the garment is worn in the cleanroom.
Binding Tape
Binding tape and straps are the same reusable, woven or disposable, single use nonwoven cleanroom fabric as the cleanroom garment.
Sewing Thread
Only polyester, silicone free thread is used in the construction of all cleanroom garments. Silicone and similar organic compounds are airborne molecular contaminants (AMC) which cause a film deposition on surfaces in the cleanroom.
Zippers
Polyester zippers are the recommended closures for cleanroom coveralls and frocks, as they are self-lubricating and shed less than their metal equivalents, they are cleanroom compatible, gamma compatible and recommended for both coveralls and frocks for better encapsulation of the cleanroom operator. Snap front frocks will cause more particles to shed during cleanroom operations.
Garment Style
The garment style recommended for both reusable woven cleanroom garments and disposable single-use nonwoven cleanroom garments is designed with a minimal number of seams and components.
Coveralls
Coveralls are a one-piece garment with a zipper closure covering the entire body from the neck to the wrists and ankles. Coveralls with a zipper covering (placket) meet CE 0321 Type 5 and Type 6 specifications for both reusable and disposable single use cleanroom garments used in Europe. The diameter of the leg is large enough for typical shoes worn in the cleanroom to slide easily through the opening without snagging or tearing and fit comfortably into the legging of the cleanroom boot.
Boots
Both reusable and disposable, single use cleanroom boots are a covering for the foot and lower portion of the leg. The sole material is typically non-skid for wearer safety and compatible with the application environment. The upper portion of the boot is high enough to cover the pant leg up to the calf. Snaps, ties and elastic at the top of the boot secures the boot to the leg of the coverall. The sizing and fit of the boot are snug over the shoe to prevent slips, trips or falls in the cleanroom. Note that the covering of the pant leg is required to provide overall containment of particulate within the garment “system”.
Shoe Covers
Shoe covers are designed to contain contamination and cover the shoe. Reusable cleanroom fabrics are typically not as effective as the disposable, single use shoe cover. The sole is non-skid, and some shoe covers have a carbon grounding strip that is placed inside the wearer’s shoe. It is recommended if street shoes are worn into the cleanroom gowning room that they are cleaned by mechanical means or by stepping (at least three steps) on a sticky mat or permanent contamination control flooring and covered with a disposable, single use shoe cover prior to entering the gown room and donning boots.
Bouffants
Bouffants are lightweight and elasticized hair covers. Both reusable woven and disposable, single use nonwoven bouffants completely cover all hair and ears. Bouffants are typically donned prior to entering the gown room and may or may not be worn under hoods. It is a best practice to position a mirror near the exit door of a change area to allow personnel to check the correct fitting of their gowning, including ensuring all hair is within the bouffant.
Hoods
Hoods are coverings designed to fit over the head, neck, shoulder, and facial area (including forehead) to contain and control migration of hair and particles. The ties, snaps, elastic or a combination of all at the back of the hood enables the hood to be fitted properly to provide a snug fit to the wearer’s head. Reusable hoods may have a sewn-in facemask or snaps to insert reusable or disposable facemasks. Disposable, single use hoods are a pullover, full face opening design with a full drape over the shoulders. A split bib drape on the reusable hood is not recommended due to the increased likelihood of a particle excursion at the neck area when moving the head. The hood is constructed of the same fabric as the coverall and boot to limit human sourced contamination.
Frocks
Frocks are three-quarter length garments with a design similar to cleanroom coveralls and a full front closure. Frocks are used in cleanrooms of less critical air cleanliness classifications. A full-length zipper closure is recommended rather than snap front closure to prevent contamination generated by the wearer’s street clothing from escaping into the cleanroom area. Frocks are also used when we go from a dirtier area to a clean area for something simple like dropping off samples.
Gloves
Gloves are cleanroom compatible, powder free and packaged in cleanroom compatible packaging. Gloves may be reusable polyester or disposable vinyl, polyvinyl chloride (PVC), latex, or nitrile. When selecting glove materials it is important to note that some people have allergies to different materials.
Contact GxP Cellators Consultants Ltd.
GxP Cellators Consultants Ltd. is a well-regarded contract services organization that offers comprehensive Good x Practices (GxP) services in Manufacturing, Laboratory, Distribution, Engineering, and Clinical practices to a range of industries, including Biopharmaceuticals, Pharmaceuticals, and Medical Devices. We work closely with our esteemed life sciences clients to assist them in establishing greenfield or brownfield projects, guiding them from the project stage to regulatory approval for their GxP sites.
Our team comprises highly qualified experts specializing in Good Manufacturing Practices (GMP), Good Laboratory Practices (GLP), Good Clinical Practices (GCP), Good Distribution Practices (GDP), Cleanroom Operations, and Engineering Operations. Our Subject Matter Experts (SMEs) undergo extensive training and possess the essential knowledge and skills to excel in their respective domains.
We also have a team of highly skilled validation specialists with expertise in equipment and utilities qualifications, computerized system validations (CSV), thermal validations, clean utilities validation, and cleanroom validations. If you need assistance preparing your facilities or site equipment, don't hesitate to contact us at info@gxpcellators.com.
Cleanroom garments are worn by operators working in certified cleanrooms to protect the product and the processes inside the cleanroom from human sourced con...
