UL & Industry Terminology Made Simple

We are proud of our UL Certification, which confirms our ability to trace any bobbin or component back to
its source of raw material. We can also detail where every lot of raw material was used in our
manufacturing process. You can count on Plasti-Coil for quality assurance through every step of the
production process.

Definitions of the Often-Used Terms in the Coil industry
UL 94 Flammability Classifications

Relative Thermal Index
(RTI):

Temperature Index
(TI):

94 5VA:
(bars and plaques)

94 V-1:
(Vertical Burning)*

1. No flaming or glowing - 60
seconds after the last flame
application.
2. No ignition of the cotton
by dripping particles.
3. No holes in plaques.
A one-time retesting of a set
of test specimens is allowed
if only one testbar fails.

1. Maximum flaming time per
specimen per flame
application is 30 seconds.
2. Maximum burning time,
total of 5 specimens, is 250
seconds.
3. No ignition of cotton by
dripping particle
4. Maximum afterglow time,
per specimen is 60 seconds.
5. No afterglow ignition of
cotton.

A numerical rating, expressed in
degrees Celsius, which results from
long-term thermal aging and the
evaluation of a specific property.
The value assigned is based on a
comparison of a new material against
a known or control material.

(ASTM definition): A number which
permits comparison of the
temperature/time characteristics of an
electrical insulating material, or a
simple combination of materials,
based on the temperature in degrees
Celsius. This is obtained by
extrapolating the Arrhenius plot of
life versus temperature to a specified
time, usually 20,000 hours.

94 5VB:
(bars and plaques)

94 V-2:
(Vertical Burning)*

Thermal Class: A group designation based on the RTI for a
combination of materials.

1. No flaming or glowing - 60
seconds after the last flame
application.
2. No ignition of the cotton
by dripping particles.
3. A hole in the plaque is
acceptable.
A one-time retesting of a set
of test specimens is allowed
if only one testbar fails.

1. Maximum flaming time per
specimen per flame
application is 30 seconds.
2. Maximum burning time,
total of 5 specimens, is 250
seconds.
3. Ignition of cotton by
dripping particle
4. Maximum afterglow time,
per specimen is 60 seconds.
5. Afterglow ignition of cotton.

Amorphous: The molecular
chains have NO distinct uniformity
or pattern. The chains are farther
apart than in a crystalline resin.
• Benefits: Low in mold
shrinkage
• How Established: Low mold
temperatures

Crystalline: Refers to the
molecular structure of the resin
(polymer). The degree of
crystallinity refers to uniformity and
closeness of the molecular chains
forming the polymer and resulting
from the formation of solid crystals
with a definite geometric pattern.
• Benefits: Dimensional
stability, low post mold
shrinkage
• How Established: High
mold temperatures

94 V-O:
(Vertical Burning)*

94 HB:
(Horizontal Burn)

UL is not affiliated with
plasti-coil, inc. and does not
endorse the Web site.

1. Maximum flaming time per
specimen per flame
application is 10 seconds.
2. Maximum burning time,
total of 5 specimens, is 50
seconds.
3. No ignition of cotton by
dripping particle
4. Maximum afterglow time,
per specimen is 30 seconds.
5. No afterglow ignition of
cotton.

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The HB rating is given if the
burn rate, measured between
the two marks, does not
exceed:
• 40mm/min. for 3.0mm
testbar thickness
• 75mm/min. for < 3.0mm
testbar thickness
If the testbar stops burning
before reaching the 100mm
mark.

* A one-time retesting of a set of five testbars is allowed if
only one testbar exceeds the single burn time or if the total
burn time of one set exceeds the required value by not more
than five seconds. (V0O = 55 sec.; V-1 and V-2 = 255 sec.

USA
Plasti-Coil, Inc.
901 Geneva Parkway North,
Lake Geneva, WI 53147,
U.S.A.
Tel: 1-262-249-5620
Fax: 1-262-249-5630
Email: info@plasticoil.com
ISO-9001:2008 Certified

Hong Kong
Plasti-Coil (Asia) Co., Ltd.
Unit 2301, 23 Floor,
Chuang's Enterprises Building
No. 382 Lockhart Road, Wanchai,
Hong Kong
Tel: 852-2110-8193
Fax: 852-2110-8608
Email: sales@plasticoil.com.hk

CHINA
Foshan Shunde Plasti-Coil Co., Ltd.
Block C, 1 Jie Fang Road,
Xi Chong Countryside, Lun Jiao,
Shunde, Foshan, China (Post Code:
528308)
Tel: 86-757-2733-6673
Fax: 86-757-2733-6687
Email: factory@plasticoil.com.hk
ISO-9001:2000 Certified