Does Glove Color Matter?

Not so long ago, the presence of color in a disposable glove indicated a latex-free glove. Nitrile exam gloves were usually some shade of blue. Latex gloves were a natural color, and looked like – well, latex.

But not anymore.

Nitrile exam gloves are now available in a rainbow of colors. Nitrile cleanroom gloves come in colors other than the standard white. And latex gloves are available in colors other than “natural.”

While choice is nice, does glove color matter?

Maybe.

Cleanroom Glove Color

In cleanroom and controlled environments, contamination is a constant concern. Contaminants can come from the glove, other materials, and from the workers.

White cleanroom gloves are the industry standard. Contamination is easier to see on a white glove. White also conveys and promotes the “clean” message to workers.

Color is a glove additive, and additives can react with the product or process. For this reason, less color is preferred. This is also true for white cleanroom gloves, as white is also an added color. Some white gloves contain less dye than others, reducing the risk of unwanted reactions.

While white is the industry standard, there are use cases for a colored cleanroom glove. A blue cleanroom glove may provide more contrast, making it easier for workers to do their job well.

Glove Color in the Lab

Laboratories are frequently faced with the possibility of cross-contamination. This can happen when an employee inadvertently transfers substances from one area of the lab to another on their gloved hands.

Assigning a specific glove color to each area of the lab can help. For instance, blue gloves could be used in one area, and white nitrile gloves in another. Wearing different colored gloves provides supervisors and employees a visual cue. This can help prevent costly errors caused by cross-contamination.

Colored Medical Gloves

Health care facilities often prefer a colored nitrile. This helps staff differentiate between latex and non-latex gloves.

A shade of blue is the traditional nitrile color of choice in medical facilities. But in recent years other colors such as gray, purple, and pink have become common.

Glove color can be useful in identifying glove failure. Double gloving, wearing a dark glove underneath a light colored glove, can help reveal punctures and small tears.

A Rainbow of Dental Gloves

Glove manufacturers that focus on the dental industry have marketed a rainbow of colored and scented nitrile and latex gloves.

Some dental offices like to color-coordinate their scrubs and gloves. Other offices prefer to use a dark blue nitrile exam glove to reduce the visibility of blood. For the dental hygienist, glove selection is most often a matter of personal choice.

Because glove color has become an effective marketing and branding tool, we will likely continue to see new exam glove colors. Glove color choice will still be influenced by the industry, purchasing decisions and cost.

What do you think?  Does glove color matter?

Editor’s Note:  This post was originally published on Dec. 13, 2011 and has been completely revamped and updated for accuracy and relevancy.

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Understanding Cleanroom Glove Classifications

Understanding Cleanroom Glove Classifications

Cleanroom gloves look a lot like exam gloves.  They’re available in nitrile, latex or vinyl materials.  They’re thin, ambidextrous and disposable.  But they have something extra – an ISO number or Class number.  What does this mean?

To understand cleanroom gloves, we need to understand why they are needed.  A “cleanroom” is an environment with a controlled level of contamination – dust, microbes and aerosol particles – to prevent damage to a product during manufacturing.  Think microelectronics, semiconductors, and biotechnology, where a particle 200 times smaller than a human hair can lead to expensive failures and downtime.

Cleanroom contamination is measured by the number of particles by volume of air at a particular particle size.  The air you breath contains about 35 million particles sized 0.5 µm and larger per cubic meter.  The air in a cleanroom will have much less, making the environment “cleaner.”

The First Cleanroom Standards

US FED STD 209E set the first cleanroom standards.  Airborne contaminates were measured as maximum particles per cubic foot. So a “Class 100” environment meant there was an upper limit of 100 particles/ft3, size 5 µm or smaller.  A “Class 10” meant no more than 10 particles/ft3.

US FED STD 209E Cleanroom Standards
Class maximum particles/ft3 ISO
equivalent
≥0.1 µm ≥0.2 µm ≥0.3 µm ≥0.5 µm ≥5 µm
1 35 7.5 3 1 0.007 ISO 3
10 350 75 30 10 0.07 ISO 4
100 3,500 750 300 100 0.7 ISO 5
1,000 35,000 7,500 3000 1,000 7 ISO 6
10,000 350,000 75,000 30,000 10,000 70 ISO 7
100,000 3.5×106 750,000 300,000 100,000 700 ISO 8

The New Standard

In 1999, the US Department of Commerce introduced a new classification system called ISO 14644-1.  This document established the certification requirements for air cleanliness areas, and airborne particulates are measured as particles per cubic meter rather than cubic foot.  So a Class 100 became ISO 5, and a Class 10 became ISO 4. While this new standard officially replaced the old Federal Standard 209-e in 2001, both classification terms are still in use.

ISO 14644-1 Cleanroom Standards 
Class maximum particles/m3 FED STD 209E
equivalent
≥0.1 µm ≥0.2 µm ≥0.3 µm ≥0.5 µm ≥1 µm ≥5 µm
ISO 1 10 2.37 1.02 0.35 0.083 0.0029
ISO 2 100 23.7 10.2 3.5 0.83 0.029
ISO 3 1,000 237 102 35 8.3 0.29 Class 1
ISO 4 10,000 2,370 1,020 352 83 2.9 Class 10
ISO 5 100,000 23,700 10,200 3,520 832 29 Class 100
ISO 6 1.0×106 237,000 102,000 35,200 8,320 293 Class 1,000
ISO 7 1.0×107 2.37×106 1,020,000 352,000 83,200 2,930 Class 10,000
ISO 8 1.0×108 2.37×107 1.02×107 3,520,000 832,000 29,300 Class 100,000
ISO 9 1.0×109 2.37×108 1.02×108 35,200,000 8,320,000 293,000 Room air

Glove Classifications

While there are no published standards that designate gloves as “ISO 5,” for instance, glove manufacturers understand the importance of maintaining specified particulate levels in cleanrooms.  Gloves are carefully laundered, dried, tested and packaged to ensure a particle count that is compatible with the cleanroom environment where they will be used. So a glove listed as Clean Class 10 or ISO 4 is compatible with a Class 4 cleanroom and up.  A “Controlled Environment” or Clean Class 1000 glove is suitable for ISO 6 and up environments.

 

Cleanroom Gloves – Balancing ESD and Cleanliness

[dropcap]C[/dropcap]leanroom environments in the electronics, nanotechnology and semiconductor industries are especially sensitive to static.  For this reason, the electrostatic discharge (ESD) property of cleanroom gloves worn by workers is an important consideration.

Electrostatic discharge damages the electrical characteristics of a semiconductor device.  It can also cause equipment to malfunction or fail, interfering with the normal operation of an electronic system.

An electrostatically charged surface can also attract and hold onto contaminants – bad news for the cleanroom environment.  Airborne particles can cause defects in a device’s electrical circuitry.

Controlling ESD

Failing to control ESD in a cleanroom can be expensive.  Static electricity damages electronics, leading to increased manufacturing costs and lower production yields, negatively affecting a company’s reputation and profitability.  One way that cleanrooms manage static charge is by using static dissipative materials.

Static dissipative materials fall somewhere between insulative and conductive materials.  There is electron flow through or over the material, but in a controlled fashion, by the surface resistance or volume resistance of the material.  It allows the charge to dissipate, or transfer slowly to ground without causing damage.

Cleanroom Nitrile Gloves Preferred

When selecting gloves for cleanroom applications where static discharge could harm the product, or where static could lead to contamination, nitrile gloves are the preferred choice.

Gloves made from natural rubber latex are inherently static insulative, holding on to a charge and releasing it in an uncontrolled manner, leading to damage.  The surface resistance of nitrile gloves, however, is normally on the border of insulative and static dissipative.  To be considered static dissipative, the glove should have a surface resistance of more than 1 x 105 but less than 1 x 1011 ohms/sq.  The surface resistance test results for a glove can usually be found on the manufacturer’s product information sheet.

Balancing ESD with Cleanliness

Interestingly, the cleaner the glove, the lower the glove’s ESD protection.  Tom Lesniewski and Kenn Yates of the TRW Space and Electronics Group conducted an evaluation of the cleanliness and ESD protective properties of cleanroom materials, including 7 different types of nitrile gloves.

They found a clear trend – as non-volatile residue (NVR) increased, surface resistance decreased.  The surface contaminants on a glove make the glove more static dissipative, especially in higher humidity.

Because there is clear tradeoff between cleanliness and charge dissipation rate, cleanrooms requiring a high level of ESD protection should choose a cleanroom glove only as clean as it needs to be for the ISO level of the cleanroom.

[note]

HandPRO Cleanroom Nitrile Gloves provide the moderate static dissipation needed to protect highly ESD sensitive devices from damage.  The gloves are also very clean, making them a contamination-free solution for cleanrooms requiring low ionic contamination.

Learn more about HandPRO 9100 Clean Class 100 Accelerator-Free Nitrile Gloves for ISO 5 & up.

Learn more about HandPRO 1700 Controlled Environment Nitrile Gloves for ISO 6 & up.[/note]

 

How does a cleanroom glove’s ESD property impact your manufacturing environment?  Share your comments below.

Cleanroom Gloves – Particles, Extractables and Selection

Cleanroom Gloves - Particles, Extractables and Selection

Cleanroom gloves are worn throughout the electronic, aerospace, solar, medical device and pharmaceutical industries to protect products from contamination during manufacturing.   Nitrile cleanroom gloves are a popular choice.   Compared with latex gloves, nitrile gloves offer better abrasion resistance and therefore less particulate shedding.  They provide excellent biohazard protection, and can be laundered to deliver the lowest particle and extractable levels.

Particle Levels

Cleanroom gloves, along with other cleanroom garments, are worn to protect the product or process from particle contamination caused by the shedding of human skin.  So the gloves themselves should have low airborne and liquid-borne particle contamination.  Particulates can arise during the manufacturing process, and glove manufacturers routinely test in order to trace and reduce sources of contamination.

The lowest contamination levels are obtained through multiple rinses in deionized water, followed by drying cycles in HEPA filtered driers.  To ensure the gloves stay very clean, they are then sorted and packed in double polyethylene bags in an ISO 5 or 4 cleanroom environment.

Ion Extractables

Ionic extractables are traces of elements that can leach out of a glove and harm the product being manufactured.  They include elements such as calcium, chloride, sodium, silicon, sulfites and zinc.  The type, mobility and amount of ion extractables can seriously affect the manufacturing process.  In the semiconductor industry, ions like sodium can induce conduction and low field breakdown in devices.  In disk drive manufacturing, chlorides can cause corrosion.

Testing for inorganic ions present on a glove’s surface include using an ion chromatograph and Couple Plasma, Flame-AA or GF-AA in accordance with ASTM guidelines.  It’s important to note that in this stringent test the extractable levels are much higher than ion transfer under normal, dry glove use.

Cleanroom Gloves – Selection Criteria

Cleanroom requirements vary from one manufacturer to another, even within the same industry.  When selecting cleanroom gloves, the particle levels should match the cleanroom environment.  The extractables should be as low as possible, but taken in consideration with the glove’s overall barrier properties, such as AQL, or pinhole rate.  A glove with impressively low extractables, but with a high pinhole rate will not keep the manufacturing environment as clean as a glove with a lower AQL.

What is most important for your cleanroom application (particles, extractables, grip, ergonomics) and why?  Share your comments below.

Disposable Glove Quality Testing

The FDA sets high standards to ensure the disposable gloves you purchase here in the U.S. perform as expected and provide an adequate barrier for their intended use.  To meet these standards, glove manufacturers have tight quality controls and manufacture gloves according to ASTM specifications and testing requirements.

A key quality measurement that glove manufacturers publish on glove boxes, bags and product literature is AQL, or Acceptable Quality Level.

Stated as a percentage, the AQL is a statistical measurement of the quality of the gloves.  An AQL of 2.5% means that statistically, only 2.5 gloves for every hundred gloves will fail a quality test.

How AQL is Determined

Let’s say a glove manufacturer produces 10,000 gloves from the same material, settings and processes.  Two hundred gloves would be pulled randomly from the line, throughout the batch, to be tested.  To meet an AQL of 2.5%, no more than 10 gloves can fail the quality tests.  If more than 10 gloves fail, the entire batch fails, and each glove must be tested individually for quality, or else the whole batch is discarded.  An AQL of 1.5% would mean that no more than 7 gloves could fail.

ASTM D5151 Test for Detection of Holes in Medical Gloves

Disposable gloves are subjected to numerous ASTM tests throughout the manufacturing process.  One test that medical and cleanroom gloves have in common is a test for pinholes.

ASTM D5151 is the Standard Test Method for Detection of Holes in Medical Gloves, often referred to as the “watertight” test or “water leak” test.   In this test, the gloves are each filled with 1000 ml of water at room temperature, secured at the cuff and hung vertically for two minutes to check for pinholes.  If water does not leak from the glove, it gets a “pass.”

The current FDA mandated maximum AQL for examination and cleanroom gloves on this test is 2.5%, down from the previous 4.0% prior to December 2008.  Some gloves, however, are manufactured and tested to meet the lower AQL of 1.5% required for surgical gloves.  This means higher quality and fewer pinholes.

Are Your Cleanroom Nitrile Gloves Full of Pinholes?

Cleanroom Gloves and Pinholes

Cleanroom and controlled environments have unique glove requirements.  While healthcare workers primarily wear gloves to protect themselves from bloodborne pathogens, a person working in a clean manufacturing environment primarily wears gloves to protect the product or process from contamination.

Pinholes in gloves provide a path for human-borne contaminants in the clean manufacturing environment.   Just one square inch of the surface of a person’s hand can contain 10,000 microorganisms!

So how common are pinholes in cleanroom gloves?

A study published in May 2011, Integrity of Disposable Nitrile Exam Gloves Exposed to Simulated Movement,  compared cleanroom nitrile gloves to medical-grade, low-modulus and general duty nitrile gloves.  A total of thirty different glove products were tested, including six cleanroom and nine medical-grade nitrile glove products.  A modified water-leak test was used to detect a 0.15 to 0.05 mm hole in different areas of the glove, including the thumb and pinky.  What did they discover?

“The cleanroom gloves, on average, had the highest percentage of leaks, and 50% failed the water-leak test.”

Two of the cleanroom nitrile gloves tested had an out of the box failure rate of 6.25%.  The medical grade and low modulus gloves had the lowest percentage of leaks.  Even the general duty gloves performed better than the cleanroom gloves tested.   However, two of the six cleanroom gloves tested had a failure rate of zero percent.  Why such a significant difference?

The study authors indicate that it could be due to differences in nitrile material formulation.  A low-modulus nitrile glove with a higher percentage of plasticizer, which is more water resistant, was expected to perform better in the water leak test.

What was not discussed in the paper is the AQL, or Acceptable Quality Level, of the gloves tested.  The AQL for the water leak test, a test that indicates what percentage of the gloves can fail a water test for pinholes, is set by ASTM at 2.5% for cleanroom gloves.  Many manufacturers, however, use the medical grade requirement of 1.5%.  This means that less than 1.5% of the gloves from any given lot could fail due to pinholes – substantially less than 2.5%.

Clearly, there are significant differences in the quality of cleanroom gloves on the market.  To protect your cleanroom environment, select cleanroom gloves made from consistently high quality low-modulus NBR materials, and an AQL of 1.5% or less.

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