k 16877 thermal bulletin

8/3/2019 k 16877 Thermal Bulletin

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DuPont Personal Protection

THERMAL TECHNICAL BULLETIN

FACTS ABOUT INHERENT FLAME-RESISTANT

PROTECTIVE CLOTHING

“Flame resistant” clothing will not support combustion

ater the heat source is removed. There are two main

types o ame resistant abric used to manuacture ame

resistant clothing: abric made rom inherently ame

resistant fbers or chemically treated abrics.

The word “inherent” is defned as being involved in the

“constitution or essential character” o something (Re:

Merriam-Webster Dictionary). The word “inherent,” as it

relates to ame resistant clothing, means that the ame

resistant properties have always been a part o the fbers

used in the abric — rom the frst moment these fbers

were made. Because ame-resistance is an intrinsic

part o inherently ame resistant fbers, it is permanent,

and cannot be washed out or worn out o the fber nomatter how the garment is used or laundered. The terms

“treated” and “topically treated” reer to a manuacturing

step whereby a special mixture o chemicals is added

to a naturally ammable abric, such as cotton or cotton/

nylon blends, to make the fnal abric ame-resistant (FR).

Unlike abrics made with inherently FR fbers, chemically

treated FR abrics may have their ame resistant

properties diminished or removed completely depending

on how these abrics are laundered and/or which

chemicals they are exposed to in the work environment.

Understanding the basic dierences between “inherent”

and “treated” FR technologies is very important or those

responsible or evaluating, selecting, and wearing FR

garments. DuPont™ Nomex® IIIA and the new DuPont™

Protera™ abrics are “inherently” FR and provide excellent

protection rom fre and arc ash hazards.

Fabrics and garments made rom Nomex® IIIA have been

third party certifed to meet the requirements o NFPA

2112, and deliver superior protection across a range o

possible fre exposure conditions. Nomex® IIIA abrics

and garments are very durable with a long wear lie and

have a history o proven perormance. The DuPont™

Protera™ abric has been specifcally engineered to protect

against electric arc hazards, meeting NFPA 70E Category2 requirements. Like Nomex® IIIA, the ame resistant

properties o Protera™ abric come rom the inherently FR

fbers and cannot be washed out or worn away. Unlike

FR-treated cotton abrics, which have special chemicals

added to the base abric to achieve ame-resistance, the

inherent ame-resistance ound in Nomex® IIIA

and Protera™ abrics will not diminish regardless o the

laundry process.



1) Whyis“inherent”protectionimportanttome?

The ame-resistant (FR) properties o inherent abrics

cannot be washed out or worn away, period. This means

the ame-resistant properties o garments made o

inherent fbers cannot be compromised. It is crucial or

the wearer to know the ame-resistant protection is

always there.

2) Whatdoes‘inherentorthelieothe

garment’mean?

Only garments using abrics made o inherently ame-

resistant fbers are truly “inherent”.

3) HowcanFRpropertiesberemovedromagarment?

For FR-treated abric, such as FR cotton/nylon blends,

one way to remove its ame resistant properties is to use

regular chlorine bleach while washing the garment. Test

results shown in the chart below demonstrate this.

FrequentlyAskedQuestions

Char damage length is one o the key criteria used to

qualiy abrics as being “ame resistant”. NFPA 2112 sets

a requirement o less than or equal to 4 inches o char

damage length. As can be seen in the chart, while the

FR cotton/nylon abric passed this requirement when

new (0 washes), by 10 washes with regular detergent

and chlorine bleach, its char length had increased to

12 inches (the entire length o the sample burned).

While use o chlorine bleach may not be recommended

per some abric manuacturers’ laundry instructions,this can happen in the real world. It does not take many

washes with chlorine bleach to damage the ame

resistance properties o a FR cotton or cotton/nylon

abric. And unortunately, the wearer would not be able

to tell it was no longer ame resistant simply by looking

at the garment. With inherent abrics, the ame resistant

properties can not be removed.

Note that or DuPont™ Nomex® IIIA and Protera™ abrics

laundered and tested in the same way, even at 30 washes

with detergent and chlorine bleach, both abrics meet the

NFPA 2112 requirements or char damage length.

THERMAL TECHNICAL BULLETIN

0

2

4

6

8

10

12

Char Length

(in)

FR-treated Protera ™ Nomex® IIIA

0 Washings

10 Washings

20 Washings

30 Washings

Char Length 4 inches(NFPA 2112 requirement)

Notes: Fabrics were all home-laundered using household detergent and chlorine bleach,

ollowing the recommended instructions on the label.

Char length is the length that is damaged when 12 inch long abric samples are

tested using ASTM D6413 method.

Fabric soteners and/or dryer sheets should not be used in laundering FR garments

as they may contaminate the garment with chemicals that could be fammable

k 16877 thermal bulletin

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