number for Class 100 is 3,000. Again, those numbers are recommended, not regulated.
Another concern is ionic content — the measure
of the amount of residual ions, either positive or negative — on the gloves. Non-volatile residue, or NVR,
is a potential contaminant with various implications
to products or activities. Silicone, for example, can’t
be present in aerospace manufacturing in a cleanroom
environment because it can impact the effectiveness
of some adhesives. Sodium ions can cause conduction
and low field breakdown in semiconductor manufacturing, while chlorides can trigger corrosion in disk
Ionic residuals and the insulative properties
of the base glove material also dictate how well a
material behaves in terms of electrostatic discharge
(ESD) — another important consideration in the
cleanroom, especially in the electronics sector.
Since natural rubber latex is an excellent insulator, it isn’t viable for ESD-sensitive applications.
Remember what happened when you rubbed a balloon over your hair when you were a kid? Not what
you want in a cleanroom dedicated to the assembly
of sensitive electronics. A nitrile glove is by far the
Protecting the person
While preserving the sanctity of the cleanroom is
an important component of glove selection, it can’t
take precedence over the safety and protection of the
worker. Cleanroom hazards fall into three categories:
physical, biological, and chemical, each of which
requires unique characteristics from a glove.
Most physical hazards are what you might
expect — sharp or abrasive objects and surfaces
that can cut, scratch, or penetrate the skin. These
types of hazards can present a challenge in terms of
glove design. Innovations in materials are improving durability in cleanroom gloves, but today true
cut protection still requires wearing a cut-resistant
glove under the cleanroom glove.
Biological hazards are common in aseptic manufacturing and research and include risks associated
with handling potentially pathogenic materials.
Gloves for these tasks typically are thin, single-
use, disposable gloves designed to provide a reli-
able barrier between the biological agent and the
skin. They are similar to surgical gloves, although
cleanroom gloves — for any type of cleanroom
environment — are always powder-free, for obvi-
ous reasons. Barrier efficacy or integrity for this
type of product is evaluated by testing the gloves
for pinholes. As with any mass-produced product,
these gloves typically are held to a manufacturer-
determined acceptable quality level (AQL). This is
another metric informed decision-makers need to
know before choosing a glove, understanding that
the lower the AQL, the better quality the barrier.
Chemical hazards are different, because vari-
ous chemicals and chemical compounds can react
in different ways to materials used in gloves —
and to the skin beneath those gloves. Workers in
cleanrooms typically handle small quantities of
hazardous chemicals, and most cleanroom gloves
are designed appropriately, as single-use gloves
focusing primarily on splash-resistance. This means
the gloves are designed to provide initial protection
when a chemical splashes onto the hands, giving
the worker adequate time to remove and dispose of
the glove immediately and don a replacement.
Ensuring protection without compromise
There was a time when serving these two distinct
needs — protecting the product and the person
— wasn’t possible to the standards we find acceptable today. Fortunately, that no longer is the case.
Advanced materials and new design and cleaning
processes ensure the availability of a glove that can
provide adequate protection for the job without
compromising the purity of the cleanroom.
While cleanroom gloves start out as any other
typical single use glove they go through additional
manufacturing steps to ensure they meet the rigorous requirements of cleanroom personal protective
equipment. Those steps include multiple washing
and leaching, or rinsing, cycles to remove production chemicals and thoroughly clean the finished
gloves. The final laundering happens in a cleanroom
itself, and those gloves then are bagged (or double-bagged) in vacuum-sealed plastic bags in yet another
cleanroom. Truly sterile gloves go through a sterilization process involving irradiation after cleaning
and packaging. It’s an expensive, time-consuming
process and some manufacturers may cut corners.
Responsible decision-makers should ask questions
about the cleaning and packaging processes used by
their cleanroom glove manufacturer.
Cleanroom gloves must protect not just the
person wearing the gloves, but the cleanroom environment itself and the products within that environment. Today’s technologies make it possible to
mitigate all of these risks.
1. http://www.slideshare.net/Heidi Tuomi/r3-naan-
Don Cronk is the Regulatory Affairs & Technical
Services Manager for Ansell’s Single Use Global