TRANSMISSION AND DISTRIBUTION
Arc flash suits vs. daily
work wear
Information from e-Hazard
Safety is simply difficult. Electrical arc flash protection requires complex processing of an electrical network, integration of the network data
into a risk matrix and then another complex set of engineering requirements for the personal protective equipment. The easiest option is to
rely on a clothing supplier to tell an engineer what is required.
It is not that that all companies do this,
but from working with many arc rated
equipment and clothing manufacturers,
this is the general consensus amongst the
majority. When asked what is required, the
supplier usually approaches the contract
with risk as the main focus. The supplier
provides for the highest rated flash suit.
Ask the engineer who has to standardise
on clothing and they will often settle on
the worst case scenario, a flash suit. For
most people the first thing that comes to
mind when hearing the words “arc flash
protection” and the answer will most likely
be a flash suit.
When arc flash became a hot topic to
the mass industrial population around
five to ten years ago, the focus was to
get workers behind the highest level of
protection available at the time. As with
any subject, as research offers new insights
the aim shifts from a basic solution to
an optimised solution. The flash suit has
become old news. The question should
change from “what is the highest rating
that can be supplied?”, to “what is the
minimum required?” The focus should also
include the lower energy tasks which can
cause as much harm. In addition to a flash
suit companies must start using arc rated
daily work wear.
Almost 80% of serious accidents
investigated by Hugh Hoagland (an
American arc flash safety expert) were
due to the ignition of non-arc rated
clothing. Get rid of the non-arc rated
clothing and these numbers will start
decreasing. Workers will want to use arc
rated protection if it is simple, comfortable
and always available. This article will
introduce the concept of daily work
wear comprising of personal protective
equipment (PPE) and personal protective
clothing (PPC). It will, however, start with
what to avoid. It is strongly recommended
that all persons involved in arc flash safety
read the NFPA70E [1] to gain more insight
from this article.
radiation. Workers operating on electrical
equipment posing an electrical arc flash
hazard should be protected against such
high temperatures.
Industry provided workers with flash suits
to mitigate this risk of injury when exposed
to an arc flash. In many cases studied,
it is observed that the incident energy is
substantially less than the rating of a flash
suit. Thinking about it practically, would one
use a flash suit while fault finding inside a
motor control centre panel as shown in
Fig. 1. So, in the cases investigated,
persons enter the work area without any
arc rated protection and subsequently
sustain severe second and third degree
burns. What is then the solution for such
applications?
Defining the change
In knowing when to use arc rated protection,
the arc flash hazard should be defined and
known by every worker. An arc flash hazard
is a dangerous condition associated with
the possible release of energy caused by
an electric arc [2]. The NFPA70E further
provides information that an arc flash
hazard may exist when energize electrical
conductors or circuit parts are exposed
or when they are within equipment in a
guarded or enclosed condition, provided
a person is interacting with the equipment
in such a manner that could cause an
electric arc.
When an arc flash hazard is present,
arc rated protection must be made
compulsory. Merely instructing a worker
to implement the arc flash hazard
terminology and protecting themselves
is inadequate. It is the responsibility of the
employer to provide the following:



The engineering study or using the
NFPA70E tables to define the arc flash
energy levels
Labelling to create awareness as
to when arc rated protection is
compulsory
Training to understand and interpret
field signage and usage of the correct
protection levels when required
The above three points aim to supplement
the usage of the appropriate protection
level for associated hazard. It is in no way
comprehensive enough to encompass
the entire electrical safety program. The
clothing categories and its constituents are
now explained.
Hazard risk categories
This section now introduces the NFPA70E
– 2012 Table 130, 7 (C) (16) Protective
clothing and personal protective
equipment (PPE). Once the employer has
defined the required level of protection
[see 3a] the protective gear should be
defined interms of hazard risks categories
Defining the problem
An electrical arc flash originates from
a breakdown in the insulation medium
creating a conductive plasma which can
reach temperatures exceeding 30 000°C.
Heat propagates from the plasma in the
form of a plasma spray and infra-red
Fig. 1: Motor control centre (MCC) panel or bucket.
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TRANSMISSION AND DISTRIBUTION
Hazard/risk category
(HRC)
0 (non-arc rated)
Personal protective clothing and personal protective equipment
Non-melting or untreated natural fibre (i.e., untreated cotton, wool, rayon, or
silk, or blends of these materials) with a fabric weight of at least 150 g/m2
Shirt (long sleeve)
Pants (long)
Protective equipment
Safety glasses or safety goggles (SR)
Daily work wear
Heavy duty leather gloves (AN)
Daily work wear and PPE used for day to
day tasks are now discussed.
Arc-rated long-sleeve shirt and pants or arc-rated coverall
Arc-rated face shield or arc flash suit hood
Arc-rated jacket, parka, rainwear, or hard hat liner (AN)
Protective equipment
Hard hat
Safety glasses or safety goggles (SR)
Hearing protection (ear canal inserts)
Heavy duty leather gloves
Leather work shoes (AN)
Arc-rated clothing, minimum arc rating of 8 cal/cm2
Arc-rated long-sleeve shirt and pants or arc-rated coverall
Arc-rated flash suit hood or arc-rated face shield and arc-rated balaclava
Arc-rated jacket, parka, rainwear, or hard hat liner (AN)
2
Protective equipment
Hard hat
Safety glasses or safety goggles (SR)
Hearing protection (ear canal inserts)
Heavy duty leather gloves
Leather work shoes
Arc-rated clothing selected so that the system arc rating meets the required
minimum arc rating of 25 cal/cm2
Arc-rated long-sleeve shirt (AR)
Arc-rated pants (AR)
Arc-rated coverall (AR)
Arc-rated arc flash suit jacket (AR)
Arc-rated arc flash suit pants (AR)
3
Arc-rated arc flash suit hood
Arc-rated gloves
Arc-rated jacket, parka, rainwear, or hard hat liner
Protective equipment
Hard hat
Safety glasses or safety goggles (SR)
Hearing protection (ear canal inserts)
Leather work shoes
Arc-rated clothing selected so that the system arc rating meets the required
minimum arc rating of 40 cal/cm2
Arc-rated long-sleeve shirt (AR)
Arc-rated pants (AR)
Arc-rated coverall (AR)
Arc-rated arc flash suit jacket (AR)
Arc-rated arc flash suit pants (AR)
4
The focus of this article is on daily work
wear consisting of HRC 1, HRC 2 and a
discussion of prohibited items. The next
few sections will explain the contents of
the Table 1.
Hearing protection (ear canal inserts)
Arc-rated clothing, minimum arc rating of 4 cal/cm2
1
(HRC). HRC 1 and HRC 2 are generally
termed daily work-wear while HRC 3 and
HRC 4 are generally termed flash suits.
Arc-rated arc flash suit hood
Arc-rated gloves
Daily work wear is defined as a long
sleeved shirt, long trousers or a one piece
cover all. A jacket may be provided as an
option where required.
Due to an incorrect perception created
in some sectors that flash suits are
required only in medium and high voltage
applications, many low voltage workers
work in panels with no arc rated protection.
It is a common misconception that a
non-arc rated overall will protect against
an arc in a low voltage system. In order to
demonstrate this point, www.arcwear.com
compared the performance of common
work place overalls when exposed to an
electric arc. Fig. 2 shows the test rig with
three samples consisting of an arcrated
aramid, polyester cotton combination
and cotton.
When the arc was initiated all three
clothing types ignited as shown in Fig. 3.
After arc extinction, the arc rated aramid
stopped burning. The polyester-cotton
burnt and dripped whilst the cotton only
burnt without dripping. This study presented
an important finding which was able to
explain why 80% of all fatal and disabling
injuries result from the ignition of clothing.
In such cases the arc is extinguished within
a few milliseconds, however, the ignited
clothing remains and acts as a fuel which
continues burning long after the arc has
cleared. By simply donning daily work wear,
the number of fatal accidents globally
owing to ignition of non-arc rated clothing
will start to decrease.
An underlying benefit is that arc rated
PPC has an additive effect when used in
layers. For example if the worker required
50 cal/cm 2 before using daily work wear,
the company supplied a 50 cal/cm 2
flashsuit. Now, if the company rolls out
15 cal/cm 2 daily work wear, the flash
suit requirements may be reduced to
35 cal/cm 2, i.e. a lighter and cheaper
flashsuit. It is very possible that industry
may be able to write off the cost of daily
work wear against the savings achieved by
procuring lower rated flashsuits.
Arc-rated jacket, parka, rainwear, or hard hat liner (AN)
Prohibited items
Protective equipment
From the practical demonstrations shown
in Figs. 2 and 3 as well as the requirements
of the NFPA70E – 2012 it should be noted
that fabrics, findings, zippers and linings
made up of meltable (thermoplastic)
fibres such as acetate, acr ylic, nylon,
polyester, polypropylene, polyethylene,
Hard hat
Safety glasses or safety goggles (SR)
Hearing protection (ear canal inserts)
Leather work shoes
Table 1: NFPA70E - 2012 Table 130, 7 (C) (16) protective clothing and personal protective equipment (PPE).
Legend: AN: as needed (optional); AR: as required; SR: selection required.
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TRANSMISSION AND DISTRIBUTION
but will extinguish when the source is
removed.
Workers should utilise daily work wear
typically ranging from 8 cal/cm2 to
15 cal/cm2 before entering the workplace.
Even if the worker fails to use a flash suit,
the daily work wear will limit the severity of
the burn injuries compared to the clothing
ignition scenario. Such clothing should
comply with either IEC 61482-2 [4] or
ASTMF1506 [5].
Fig. 2: Test rig comparing the performance of common industrial PPE.
Many terms have been utilised to explain
fabric historically such as flame retardant,
flame resistant, fire retardant, fire resistant,
inherently fire resistant, treated material,
amongst others. All arc rated clothing
display such traits, however, not all the
aforementioned fabric types are arc rated.
End users should always look for a cal/cm 2
rating permanently affixed to the garment
and a valid test report from an accredited
laboratory. Samples of valid reports can
be found at www.arcwear.com/arctest/
arctest.php.
Face protection – arc rated face shields
poly-cotton and spandex shall not be
permitted [3]. An incidental amount of
elastic used in underwear and socks is
however permitted.
The exception exists where the above fibres
are used in blends and meets either the
IEC 61482-2 [4] or the ASTMF1506 [5] arc
rating specification standards.
Clothing
As stated above, around 80% of all arc
flash related fatalities and disabling injuries
are dueto the ignition of non-arc rated
clothing. Getting workers into arc rated
clothing will go a long way in preventing
fatalities. The reason for this is that arc rated
clothing may ignite during arc exposure,
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Arc rated face shields should comply
with ASTM F2178 [6] and ANSI Z87.1[7].
A face shield should typically clip on
to an existing safety cap, however, the
test methods require that the system be
tested as it would be used in the field. This
requirement means that the ratchets, clips,
visor/face shield, chin cup and brow cup
TRANSMISSION AND DISTRIBUTION
edif specified during the procurement
stage.
Fall arrestors are not explicitly listed in
Table 1, however, with the recent focus on
fall protection in terms of fatality prevention
a renewed focus is required. ASTM F887
[10] provides the electrical arc testing
guideline for fall protection equipment.
General note
Fig. 3: Post arc exposure: the cotton PPE burns whilst the poly-cotton burns and drips.
Glove
class
Maximum use
voltage AC/DC
Glove label
colour
00
500 V/750 V
Beige
0
1000 V/1500 V
Red
1
7500 V/11 250 V
White
2
17 000 V/25 500 V
Yellow
3
26 500 V/39 750 V
Green
4
36 000 V/54 000 V
Orange
Table 2: ASTMD120 dielectric
classification of gloves.
are all exposed to the requirements of the
ASTMF2178 [6] test method.
It is not uncommon to find clear face
shields in the workplace. Such face shields,
when exposed to an electric arc, will burn,
melt and drip onto clothing increasing the
severity of the burn.
Hand protection – shock and arc flash
protection
Any person who has received a shock
whilst working inside a panel can vouch on
the ease at which such an incident could
occur. An action which has the potential
to result in shock has the potential to cause
an arc flash. As such, safety standards
require protection against both electrical
shock and electrical arcflash.
Dielectric gloves tested to the ASTM D120
[8] should be used for shock protection.
Some information is provided in Table 2.
It is important to note that the dielectric
glove is present in various colours; however
the colour of the label cannot change as
it is standardised per Table 2.
The natural rubber glove does not aim to
provide mechanical protection. In fact a
single instrument wire can puncture the
dielectric glove. It is for this reason and
also for added arc flash protection that
leather over protectors are used.
Gloves should be inspected each time
before use. The gloves should be inspected
for pinholes, cracks, ozone damage and
embedded objects. A dielectric test is
required on the dielectric gloves once
every six months in order to comply with
the NFPA70E– 2012.
The ASTM working committee F18.65.08
chaired by Hoagland developed and
published ASTMF2675-13 [9] in June 2013.
This standard will facilitate the arc testing
of dielectric gloves which was previously
not possible. The standard will no doubt
pave the path towards developing more
comfortable single glove solutions for arc
flash and electrical shock.
Miscellaneous PPE
Hearing protection and safety glasses are
always required. Face shields and hoods
are not designed to attenuate noise nor
are these explicitly design for mechanical
impact.
Shoes, socks and hearing protection
are usually not directly exposed to the
arc. If exposed to an electric arc, fairly
good arc ratings were attained from
standard issue work wear during informal
testing. Leather shoes per formed well
when exposed to 50 cal/cm 2 while yellow
hearing protection inserts withstood
25 cal/cm 2. These items of PPE should be
manufactured to the relevant South African
National Standard and may be arc test
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The exclusion regularly questioned is the
protection against hot oil release. Hot oil
release has resulted in fatalities previously
and is a valid concern. Tests have shown
that oil increases the ignitability of almost
any garment. It is also accepted that
little can be done to protect workers
who are engulfed in flaming hot oil. Tests
per formed by www.arcwear.com and
www.e-Hazard.com show that arc rated
PPE dosed with oil burnt at the points of
contamination. Most standards require that
under such conditions, special precautions
are taken such as remote operation and
de-energised work amongst others. A selfcontained breathing apparatus (SCBA)
should be considered when exposure to
hot oil release cannot be circumvented.
This will at least address the hazard of toxic
smoke and hot air inhalation. The employer
should assess each application uniquely
and ensure that workers are not exposed
to hot oil release.
Conclusion
Between five and ten years ago the South
African market focused on flash suits. The
low risk applications were pushed to the
back burner. The reality is that the low
risk applications do have the ability to
produce substantial arc energies. Such
energies may not warrant a flash suit,
however, these have the ability to ignite
non-arc rated clothing. The ignition of nonarc rated clothing is responsible for around
80% of all serious arc rated injuries. Since
the low risk tasks, are the most common,
daily work wear should be donned before
workers enter the workplace. The best of
protection is that which is always available
whilst being done subconsciously.
Daily work wear consists of long sleeved
shirt, long trousers or a one piece coverall.
A jacket may be provided as an option
where required. Hard hat, face shield,
dielectric gloves and leather protectors,
safety shoes, safety glasses and hearing
protection must be used as part of the
daily workwear ensemble.
Supplying daily workwear will allow the
worker to utilise lower rated flash suit due
to the additive effects of layering arc rated
garments.
Contact Zarheer Jooma,
e-Hazard, Tel 016 889-4311,
zarheer@e-hazard.com 