Chemical Engineering May 2023 - 18

Organization
for
Standardization
(ISO; Geneva, Switzerland; www.
iso.org). Currently, the committee is
working to revise the standard that
covers chemical protective clothing
- ISO 16602. Items covered by this
standard include totally encapsulating
suits, liquid-tight or spray-tight
suits, coveralls, jackets, trousers,
aprons, smocks, hoods, sleeves
shoe and boot covers and so on. The
revisions to ISO 16602 will focus on
improving test methods and aligning
its specifications on an international
scale. The team envisions that once
these revisions are complete, the
updated ISO 16602 standard could
potentially be adopted as a nationally
recognized standard in the U.S.
that could be used for certification of
industrial products. " The goal is to
be able to have third-party guidance
around certifications for products
so that users will be confident in the
product they should be wearing for a
certain risk level, " says Newsom.
All-encompassing protection
While the landscape for chemicalprotective
standards is still evolving,
such certification standards for
fire-protective products have been
well-established
through organizations
like the National Fire Protection
Association (NFPA; Quincy,
Mass.; www.nfpa.org). This has led
to a rising trend in PPE solutions that
are manufactured to provide both
chemical resistance and flame resistance
in a single product. " The NFPA
just implemented a new certification
program for combined chemical
and flame protection. The standards
have always had an optional flameresistance
test that some manufacturers
did utilize, but the test methods
have been improved with this
revision, " explains Newsom. The
update, she adds, makes the PPE
standards more aligned
with
the
flame-resistance certifications used
for the oil-and-gas production and
electric vehicles.
Another step forward in PPE
flame-protection certifications is the
use of full flame-engulfment tests
using mannequins. Basically, the
mannequin is equipped with PPE
products and set on fire using propane
torches (Figure 2). After the
18
flame engulfment,
the level of protection
provided by the
PPE can be measured
by analyzing
the amount of body
burn during various
durations of flame
exposure. UL has
added such tests to
their chemical testing
standards as an
option, in the event
that flame resistance
is required in
addition to chemical resistance.
Shutterstock
FIGURE 2. Mannequins are often used to test the effectiveness of flameresistant
PPE items
The evolution of PPE testing
To test and certify PPE products
against chemicals, the first consideration
is the format of material the
user will encounter - liquid, vapor
or particulate matter. Because of
the wide breadth of chemicals in
use across industry, UL uses a list
of around 20 representative chemicals
for PPE testing to cover chemicals
with similar properties, such
as vapor pressure. " For liquids and
vapors, we will typically start with a
chemical permeation test in a cell
- you simply put a gas or liquid on
the surface of the material and you
see how much comes through on
the backside over different exposure
times, " notes Newsom. The specifics
of the tests depend on many
factors, including chemical exposure
levels and whether the fluid is
pressurized. For particulate matter,
rather than testing samples of the
PPE material itself, the focus is on
airborne exposure, meaning that the
full PPE ensemble must be considered.
" For evaluation of exposure to
particulate matter, we use live subjects
who are dressed in the PPE
ensemble that is being tested. We
put them in a room with fluorescent
particulate matter so we can see if
any of it penetrates the ensemble, "
she explains.
Another crucial point of consideration
in evaluating PPE effectiveness
is at interfaces - the areas of
the ensemble that require a seal to
prevent hazardous exposure. Such
interfaces include the seal around
a facemask, and the ends of the
sleeves and legs of garments, as well
as the waistband of the garment, if it
does not cover the full body.
UL's PPE tests also increasingly
consider user comfort. A breathability
test looks at not only the
ability of air to pass through the
material, but also the evaporation
of sweat through the material, helping
to ensure that workers do not
overheat. Breathability has now
been added as an option to several
PPE standards, whereas it was
previously unconsidered in many
PPE evaluations.
Another area where PPE standards
and testing are continually
evolving is in the provision of wearable
devices that include electronic
components, such as " smart " safety
glasses with augmented-reality capabilities
and wearable locationtracking
devices. " UL issued a standard
recently related to virtual- and
augmented-reality devices, and we
have been getting more requests to
look at these devices from an occupational
standpoint, " says Newsom.
However, she says, UL's current
safety standards for industrial eyewear
cannot be applied to virtual or
augmented-reality glasses, but work
is underway to develop new standards
or revise current standards so
that they can better apply to these
types of devices. Furthermore, over
the past year, UL's fire-service standards
have been updated to add
hazardous-location testing requirements
for electronic devices used in
PPE. Newsom expects that similar
electrical-safety
and
hazardouslocation
requirements will be added
to chemicals-related standards with
subsequent revisions.
■
Mary Page Bailey
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM MAY 2023
http://www.iso.org http://www.nfpa.org http://WWW.CHEMENGONLINE.COM
Chemical Engineering May 2023

Table of Contents for the Digital Edition of Chemical Engineering May 2023
