HALOGEN VERSUS NON-HALOGEN
MATERIALS FOR
TELECOMMUNICATIONS
WIRE & CABLE •..
WHAT ARE THE PROS AND CONS?
Charles A. Glew
HALOGEN VERSUS NON-HALOGEN
MATERIALS FOR
TELECOMMUNICATIONS
WIRE & CABLE...
WHAT ARE THE PROS AND CONS?
ABSTRACT
INTRODUCTION
"I/you can measure it, you
can tell something about it. "
Unshielded twisted pair cables (herein
after referred to as UTP's) used in
telecommunication and data transmission
applications are extensively used within
commercial buildings as a network for
voice and data communiucations from floor
-to-floor within vertical, horizontal and
plenum air spaces. The materials used on
these cables may act as a medium for flame
propagation within a building.
Lord Kelvin
Charles
A. Glew
Herein lies the dilemma of the debate over
the use of halogen versus non-halogen
materials in cables. This paper addresses
the impact of the debate on . twisted pair
cables used for premise wiring for local
area network cables. To assume the use of
non-halogenated materials in cables is
better versus halogen or vice versa should
not be the issue...rather the debate should
be waged over performance specifications
that measure the pros and cons of each
material. This paper attempts to objec­
tively balance the issue with a review of
fire hazard assessment, physical per­
formance, processability and electrical
performance.
Groups such as the Polyolefins Fire
Performance Council, a unit of the Society
of Plastics Industry, Inc. has undertaken
broad ranging studies on corrosivity and
round robin testing on a range of
halogenated
materials
versus
non­
halogenated. These types of studies move
toward the goal of developing a
performance standard which characterize
materials. All interest groups must take
part in this debate from the materials
suppliers of fluoropolymers to polyvinyl
chloride to polyolefins. In addition, the
wire and cable industry must also play an
active role in this debate so that the issues
of physical properties, electrical perfor­
mance and processability become an inte­
gral part of the evolution of materials
standards and performance.
UTP's use a wide range of materials
with the predominate thermoplastic
materials being polyethylene, polypropy­
lene, fluoropolymers and polyvinyl
chloride. The halogenated materials are
especially effective when fire retardancy is
required, and chlorine, bromine and
fluorine are the predominately used
materials.
CHART#1
PREDOMINANT
HALOGENS USED
IN WIRE & CABLE
MATERIALS TO ENHANCE
FIRE RETARDANCY
ELEMENT
Chlorine
Fluorine
Bromine
POLYMER
PVC
CPE
ECTFE•
FEP
PVDF
Ad<l�ive to PE and PP
.,Cont.ain� both F/uorir>tt and Ch/orifMI
In today's market, the non-flame
retardant materials such as polyethylene,
polypropylene and urethane are flame
retarded with non-halogenated systems via
materials compounding such as antimony
trioxides, hydrated alumina, molybdate,
magnesium or phosphate complexes or
with halogenated systems via chlorine,
bromine or fluorine.
CHART#2
Materials Selection
And Flame
Retardancy
The most stringent fire and smoke retar­
dancy requirement pertains to plenum
cable. Plenum cable materials usage have
grown 18% to 20% annually in the last two
years with explosive growth from the PVC
and polymer alloy type products such as
Smokeguard.
POLYET'rlYlE�E
POLYPROP'r'LENE
POLYOLEFINS
RUBBERS
FLAME RETARDANCE
REQUIRED
URETHANES
YES
NON·HALOGEN
POLYMER
SILICONE
HALOGEN POLYMERS
•PVC
• FLUOROPOLYMERS
•CHLORINATED
RUBBERS
CHART#6
FLAME RETARDANT
F.R. ADOITIVt for PIE, PIP, ud TPE
FLAME RETARDANT POLYMERS
PLENUM CABLE RAW
MATERIAL USAGES, 1993
HALOGEN
COPPER AND FIBER OPTIC CABLES
(MLBS.)
�AGNESIUM
CO�PLEXES
I.E. (Mg(OH) 2
PVDF
Smokeguard Type
Polymer Alloys
FEP
ECTFE
Pri•ary
P1ioary
Primary
P1imary
Insulation Joe!«- rlSU�� Jacka- lrisulalJ:>n Jacka· !risulation Jacka"'l &Bi.Cle, �9 &Buffer "'9 &Buffer "'l
&Bti'fer
In the U.S. and Canada, a very
stringent set of standards exist for flame
retardancy for communication and data
communications cables. The plenum cable
test U.L.910/CSA FT-6 and riser cable test
U.L. 1666 are much more severe than the
predominately used International fire test
IEC 332-3 which is similar to the IEEE
383/U.L. 1581 test.
CHART#3
U.L /CSA
DESIGNATION
• CMP /MPP
CABLE
FIRE TEST
FLAME
ENERGY
Plenum U.L. 910
CSA FT-6
Horizon1al
BTU/HR
Riser
U.L. 1666
Vertical
527,000
BTU/HR
FT-4
Vertical
70,000
BTU/HR
BtrnerAngle �
IEEE 1581
Vertical
70,000
BTUJ H�
Burne, ng o0
CMR/MPR
CMG/MPG
CM/MP
70,000 BTU
VERTICAL TRAY TESTS
IEEE 383
FT-4
IEC332-3
PARAMETER
oo
Cable
Spacing
6' Wide on Center
112 Cable Oiamelsr
Enclosure
Size
Specified
Specified
Not
1x2x4
Propagation
2.4 m/96"
From Bottom
1.5m /59"
2.5m
(MaximLm Limit
300,000
Smoke
Generation
Not
dTray
---
oo
200
9· Wide on Center
1/2 Cabie Diameter
Bundled if <1/4'
From BUrner
<.25 Peak Meler, <.40 Peak Meters
Squared
SquarOO
P..- Second
Per Second
<95 Meters
Squared Over
20 Minute Test
Correspondingly, the efficiency of a
materials fire retardancy must be evaluated
against this broader definition of flame
retardancy.
225 5 575 4330 9 370 10 670 230
Total: 5,800
Total: 13,700 Total: 10,900
%OF MARKET
17%
41%
32%
I
CHART #4
- --
Based on
Vofume
Meter
98"
A brief review of the market and the ex­
plosive growth of local area network cables
within commercial buildings provides an
indication of the importance of materials
selection for communication and data
cables. The market grew 21% in linear
footage between I 992 and 1993. It is
forecasted to grow 6% to I 0% annually
through 199 5.
STP
18,000,000
18,900,000
18,900,000
19,845,000
21,829,500
357,210,000
314,344,800
370,336,528
232,489,414
197,616,002
555,862,500
786,469,500
1,017,203,400
1,249,311,978
1,444,327,623
195,840,000
176,256,000
167,443,200
167,443,200
167,443,200
1,295,970,300
1,573,883,128
1,669,089,592
1,831,216,325
Total Linear FT.
1,126,912,500
Data Based Primarily on Survey Prepared by
Solvay Polymers of the U.S. Plenum Market
To assess the pros and cons of materials
selection for UTP premise cables, the
following criteria should be used:
A. Fire Hazard Assessment
B. Physical Characteristics·
Fire hazard assessment involves four
basic principals which requires perfor­
mance measurement:
1.
2.
3.
4.
Fire Retardancy and Propagation
Smoke Generation Characteristics
Corrosivity
Toxicity
CHART#7
FIRE HAZARD ASSESSMENT
TELECOMMUNICATIONS MARKET
Data Grade UTP
Total Lbs.(M) Consumed 1993: 33,780
None
<l 50 Met8fS
Squared Over
20 MinU:e Test
U.S. CABLE SHIPMENTS IN LINEAR FEET: 1990-1996 (Revised 9/92)
1991
1992
1993
1994
1995
Voice Grade UTP
10%
C. Processability, and
D. Electrical Properties
CHART#5
Fiber
1 100 2 280
Total: 3,380
1. FIRE RETARDANCY
• Plenum
• Riser
• FT-4
• U.L. 1581
3. CORROSMTY
• Cone
Carorimeter
• C-Net
2. SMOKE SUPPRESSANl
CHARACTERISTICS
• Plenum
• U.L. 1666 'LS'
• U.L. 1581 'LS'
4. TOXICITY
•Univ.of
Pittsburgh
• International and
Military Standards
In an effort to compare halogen
materials versus non-halogen materials, a
review of each area is required.
1. FIRE RETARDANCY
AND PROPAGATION
A fundamental test for ignitability of
materials is the oxygen index test or
ASTM D-2863.
The test expresses in percent the
minimum concentration of oxygen that
will support flaming combustion. The test
is a well established method to
characterize materials of the same family,
but erroneous conclusions can be drawn if
varying materials i.e. (PVC's or polyole­
fins) are subjected to full scale flame cable
testing.
The following provides a hierarchy of
flame retardancy from least to most
severe:
CHART#B
SUMMARY OF THE
FLAME TES T PROCEDURES
Test
Procedure
Sample Fails
Test If
816 C Flame is
applied for 15
sec. each application with
15 sec. between
applications, or
cessation of
burning whichever is longer.
1. Cable supports
flame longer
than 60sec.
UL
1581
A 70,000 Btu
1. Cables are
blistered and
charred at
8 feet level.
UL
1666
A 527,000 Btu
1. Cables must
not propagate
flame to the
top of the
12 foot high
compartment.
W/-1
.
UL
910
flame is applied
for 20 minutes
to cables on a
vertical tray.
flame is applied
for 30 minutes
to cables in a
test chamber.
A 300,000 Btu
flame is applied
for 20 minutes
to cables on a
horizontal tray
inside a tunnel
with 240 fpm
draft.
2. Emits flaming
drops which
ignites the
cotton on
the floor.
1. Flame travel
exceeds 5.0ft.
2. Peak smoke
optical density
exceeds 0.5.
3. Average smoke
optical density
exceeds 0.15.
The variability of materials versus
oxygen index versus the VWl test is de­
picted in Chart #9.
materials. Noteworthy, this test is the
predominate benchmark fire test for zero
halogen materials.
CHART#9
The more severe fire tests such as the
riser cable test or the plenum cable test,
using the same material as insulation and
jacket in a four pair cable construction
with zero halogen materials performed
poorly. All samples failed. The low halo­
gen cable passed the riser test only with an
oxygen index of greater than 37. The
PVC based products with an oxygen index
greater than 32 passed the riser and the
PVC polymer alloy types with an oxygen
index greater than 48 passed the most
severe U.L910 plenum cable test.
COMPARISON OF
HALOGEN, LOW HALOGEN,
AND
NON-HALOGEN MATERIALS
Oxygen Index as a measurement varies
dramatically by material: i.e.
OXYGEN INDEX VW-1 PASS/FAIL
MATERIAL
PVC
>.26
Pass
>30
Low Halogen
Less than 14%
Pass
>35
Zero Halogen
Variability in
Pass/Fail
In the hierarchy of flame test for wire
and cable, the results compare PVC, a low
halogen with less than 14% halogen con­
tent and a zero halogen material.
The VW I test was performed on a 24
awg unjacketed sample with a greater than
26 oxygen index passing with PVC insu­
lation and a greater than 35 oxygen index
required to pass with zero halogen mater­
ials. These results were demonstrated on
each subsequent test which were
increasingly severe.
In the 70,000 BTU flame test, the PVC
material required a greater than 29 oxygen
index while the zero halogen material re­
quired an oxygen index of greater than 40.
CHART#tO
4035-
+
PASS
t---
�
-
30-
>29 0.1
+
PASS
PASS
>40 0.1.
35 -
>32 0.1.
-
>370.1.
ALL FAILED
SAMPLES
30
PVC
Low Halogen
Zero Halogen
PASS
25
CHART#12
4 PAIR 24 AWG.
JACKET/INSULATION
300,000 BTU PLENUM
U.L. 910 CABLE TEST
PASS
45 -
I
>300.1.
>480.1.
ALL FAILED
SAMPLES
ALL FAILED
SAMPLES
35
25
Smokeguard
Type Polymer
Alloy
Low
Halogen
Zero
Halogen
2. SMOKE GENERATION
CHARACTERISTICS
25
F'I/C
+ ---uJ
45
40 -
ss--L!J
70,000 BTU FLAME TEST U.L. 1581
I
4 PAIR 24 AWG.
JACKET/INSULATION
527,000 BTU RISER
U.L. 1666 CABLE TEST
65
4 PAIR 24 AWG.
JACKET/INSULATION
OF SAME MATERIAL
45
CHART#tt
Low Halogen
Zero Halogen
This test closely approximates the
inter­
performed
test
predominate
nationally (IEC 332-3) which is used in
the European wire and cable market. This
fire test methodology would seem to be
the highest feasible fire retardancy level
for a zero halogen unshielded twisted pair
cable based on presently available
Smoke is the airborne product evolved
when materials such as plastics decom­
pose by heat or burning. Smoke as de­
fined here obscures visibility thus
impeding the escape of people who may
be trapped within a fire situation or inhibit
the efforts of fire fighters to rescue and
suppress the fire. The predominat test
methods evaluate smoke generation and
can be broken into two categories: the
small scale materials test and the full scale
wire and cable tests. Historically, the ple­
num cable test has measured smoke
generation via light obscuration and most
recently, Underwriters Laboratories has
set up limited smoke test methodologies
inconjunction with the riser, FT-4 and
U.L.1581 vertical tray tests. These limited
smoke or "LS" tests are a definitive step
toward performance standards for smoke
generation in assessing materials in an
overall fire hazard assessment.
Non-halogen material and the fluoro­
polymer materials have historically been
very low in smoke generation while some
of the traditional PVC materials per­
formed poorly. Tremendous strides have
been made in PVC materials which have
been pushed by the more stringent smoke
generation requirements within the wire
and cable market. This exemplifies the
need to place performance standards on
materials to optimize the development of
improved properties.
CHART#13
SMOKE TESTS
SMALL SCALE MATERIALS SAMPLES
..
,,
""'"""
NBS Smole
CUMb$1
A.STM 662
Sample Size
SmaN (3' x 3')
6.6 In. 2
Alea Exposed
Co11e Cil k>rlmeler
C11oa111ber
A.STMD0.21.-4
Afil��oe
Smal
2
3/4 In,
Variable
Variable
1/81n.
Measure
M ..hod
Light
Ob$curMion
Light
Obscurl'!ltion
Gf"avimetric
Rodont
RadiMt
HNl:Flw:
Micro Bunsen
Burne,
Flmne;tlfM!lf
HOM. Flw:
CHART#14
-
.......
SMOKE TESTS
FULL SCALE WIRE & CABLE
Sample Size
Measure
F�O/H""
Exposure
Sm"e1/FT-6
U.L. 1666
fllHrlNI
U.l. 1S81 & Fl-4 TMta;
'Wme.llT,ay
Cables 1n
Horizorta! TrlPJ
12'Wide
Cables In
VerticllllTrlll)'
24'Wide
Vertica1Tr81f
12"Wk»
Light
Ob&curNOO
Light
Obt.curation
U.l.910
AS"tM 662 NBS SMOKE CHAMBER
TYPICAL VALES Non-Flaming
Zero Halogen
Materials
50to 100
Flaming
Cables In
Light
Ot:i.curaion
300,000 BTU/Hr.
5Zl ,000 BTU/Hr. 70,000 BTI..1/Hr.
Flame With 240 FT
Flame Test
Flame Teat
Per MimA:e Drlllt
•u.L. 1685 is a standard conjunction with the
riser cable, FT-4 and U.L. 1581 Vertical Tray Tests
that measure smoke release rate and light
obscuration; "LS" designation for applicable
products for 1993 NEC.
angstrom printed copper circuit board.
The resistance is measured and defined in
terms of a percentage corrosivity factor
which is the difference between intial and
final resistance referenced to a standard
board of 8 ohms resistance. This test and
all corrosion target tests have a high de­
gree of variability but the chart that
follows provides a ranking of materials
based on the CNET test results.
CHART#16
50to 100
100to 150 100to 150
LowHalogen
Materials
(Less than 14% Halogen Content)
Specialty PVC
Alloys &
Smokeguard
Type Pr oducts
150 to 200
150 to 200
Randomly
Sampled
Polyethylene
250to 750
280 to 390
CNET TEST RESULTS
HALOGENATED
MATERIALS
% of
Corrosivity
CPE (Chlorinated Polyethylene)
10.9
Low Halogen
4.5
(Chlorine Fire Retardant System)
(Less than 14% Halogen Content)
PVC - Wire and Cable Grade
14.2
PVC - Smoke Suppressed
11.7
PVC - Low Acid Gas Generation
Randomly
Sampled
PVC
170to 350
280 to 740
Douglas Fir
380 to 438
11O to 156
SMiot,Tes,t
Thickness
Exoosure
CHART#15
ASTM 4100
Sman (3' x 3')
16 In.
The NBS smoke chamber ASTM 662
best characterizes materials in a flaming
and non-flaming mode. Chart #15 pro­
vides a range of randomly selected
materials tested in the NBS chamber from
polyethylene to PVC to Douglas Fir.
Today non-halogen materials, low.-.·
halogen materials and even modified low
smoke specialty PVC alloys perform
relatively similar in the NBS smoke
chamber test. Full scale fire testing to
exceed the "LS" limited smoke test and
the U.L.910 Steiner Tunnel test can be
passed by all of these materials.
3. CORROSIVITY
Increasing attention is being given to
the measurement of corrosivity when
comparing materials. The numerous test
methods characterize the corrosive aspect
of gases in fires which in the real world
situation would effect the survivability of
computer hardware and telecommunica­
tions equipment. Many of the corrosivity
standards are in the formative stages with
emphasis being placed on the test method­
ologies reproducibility and accuracy to
depict corrosion in a full scale fire
scenario. Unfortunately, no one test satis­
fies all criteria. A wealth of comparative
material data exists from the CNET test
method (Centre National d'Etudes et de
Telecommunications) which captures the
combustion gases and exposes a 170,000
8.8
PVDF
12.9
PTFE
14.1
NON-HALOGENATED
MATERIALS
% of
Corrosivity
PE
0.0
Nylon
0.6
EVNATH
0.6
LOPE
3.5
The CNET test should be used as
benchmark only and clearly does not fully
correlate to the real fire environment in
which the variability of heat, condensed
water vapor and oxygen play an important
role.
Efforts are underway to employ the
cone corrosimeter inconjunction with full
scale wire and cable tests.
The cone corrosimeter test uses a com­
bustion chamber and exposes a copper cir­
cuit target.
For example, a 45,000
angstrom probe can be exposed to a range
of heat fluxes up to 100 KW/m2. The re­
sistance to change is measured and the
corrosion is defined in terms of metal loss
in angstroms.
CHART#17
CONE CORROSION TEST
GAS SAMPLING SYSTEM
FLOW: 10 SCAN
AIIBENT
AIR BLEED
TffERll� PL���f"
,
IIPL
ALTER
I
FLOW
H
PUMP
IETER
COIIE
CALORIMETER
As a part of a more full scale cable test
and similar to the work being done on the
"LS" limited smoke requirement, U.L. has
set up an Ad Hoc Committee to apply the
cone corrosimeter test apparatus to the
plenum, riser, FT-4 and U.L.1581 tray
cable tests. Initially, the objective would
be round robin materials testing on
commonly available materials used in
cables to include UTP cables. The test
would provide a performance benchmark
for corrosivity and move the total
performance standard forward in its
attempt to list "LC" or low corrosion
cables. The cone corrosimeter would
collect the gases from the plenum, riser,
FT-4 or U.L.1581 test and develop a
pass/fail standard for corrosion as well as
for flame spread and smoke. This test
methodology promotes an overall fire
hazard assessment which fosters a per­
formance specification.
4. TOXICITY
Biological toxicity provides the final
benchmark. The University of Pittsburgh
test was utilized by the State of New York
Building Code #15/11201 to register all
wire and cable materials. The study pro­
vides one of the most extensive research
projects that ranks materials toxicity.
Clearly, the results of the study do little to
separate halogen materials from non­
halogen materials. To the surprise of
many researchers, all materials commonly
used in wire and cable grouped relatively
close together. In the University of Pitts­
burgh test, combustion toxicity test
animals are exposed to the fumes gene­
rated by materials heated in an oven. The
LCso value is the concentration of ma­
terial which causes 50% mortality of the
test animals i.e. (lethal concentration or
dose). The unit is LCso in grams and
correspondingly the lower the value, the
more toxic the material.
Based upon the NEMA (National
Electrical Manufacturers Association)
classification groupings, five single ma­
terial categories were developed with the
following results:
Mean LCso Value
Linear Density(g./m) = 1500 n p
[D/2+t) 2 -(d/2)2]
D "".' Conductor Diameter (mils)
t = Insulation Thickness (mils)
p= Density (g/cm 3 )
LC so (meters)= LC so
(grams) I Linear Density
For a Four Pair Cable with Jacket
Polyolefins
9.9 grams
Linear density of insulation(g/m) =
8 x linear density of single insulated
conductor
Core diameter over twisted pairs
(mils)= 5(D+t)
PVC
17.6 grams
Hydrocarbon Rubber
18.4 grams
Chlorinated Rubber
22.7 grams
1. FIRE RETARDANCY TEST
a. Plenum Cable U.L.910 / FT-6
b. Riser Cable U.L.1666
c. FT-4 Vertical Tray
d. U.L.1581 Vertical Tray
3. CORROSIVITY
U.L.1685
i.e. CMR-LS (Limited Smoke)
Insulation Calculation
8.9 grams
UNDERWRITERS LABORATORY
AD HOC COMMITTEE
USING THE CONE CORROSIMETER FOR CABLE TESTING
2. SMOKE GENERATION
This data can be extrapolated to assess
the LC 50 value in meters which would be
most relevant to wire and cable and to
provide a comparison of halogenated
cables versus non-halogenated cables
relative to toxicity of a four pair UTP
cable. In an effort to transform LC.So
grams into an LCso value in meters, the
following calculation must be made:
Fluoroplastics
CHART#tB
I.e. CMR
It is important not to take these results
out of context. By themselves this data is
unsatisfactory for choosing safer cable
materials. As long as carbon backboned
organic polymers are used, carbon mono­
xide remains one of the most toxic sub­
stances for human biological toxicity
whether it be a synthetic material such as
plastic or a naturally found material such
as wood.
Ad Hoc Proposal
To List Low
Corrosion cables 'LC'
i.e. CMR-LS-LC
CABLES PASSING ALL ASP ECTS OF THIS FIRE HAZARD
ASSESSMENT TRIANGLE
Examples: CMR-"LS" - "LC" I CMG-"LS" - "LC"
Linear density of jacket(g/m)= 1t
(core diameter) tj p
LC (meters)= 1500 LC50 (grams) /
Uacket linear density + insulation
linear density)
(Calculations and formula from the paper: Using Com·
bmtion Toxicity Data in Cable Selection" by S1anley
Kaufman, Rosalind Anderson, et al, IWCS Proceedings,
Nov. 1988.)
Assuming that the following haloge­
nated cables were produced in a UTP four
pair CMR cable or a four pair CMP cable,
the following data appearing in Chart #19
would result.
CHART#19
CHART#21
PROCESSING SPEEDS OF
24 AWG INSULATION
LC ro (METERS) FOUR PAIR CABLES
Tensiles
Thicknesses
Specific
Gravity
Material
LC50
LC50
Ins.
(Mils)
Jkt.
(Mils)
Ins.
(PSI)
Jkt.
(PSI)
Value
Mean
Meters
Mean
LEVEL OF FIRE RETARDANCY
OXYGEN
<14%
L(Yoll
HALOGEN
350.1.
All PVC
CMR
1.35/1.40
6
20*
3000
2000
17
1.39
350.1.
ZERO
HALOGEN
350.1.
FEP
All Fluoroplastic
CMP
1.75/2.19
6
8
25(')0
4000
8
1.09
300.1.
FRPE
(HALOGENATED
Zero Halogen
CM
1.40/1.50
8
30*
1500
1500
35
1.2
PVC
350.1.
SMOKEGUARD
350.1. TYPE POLYMER
ALLOY
1000
"Wall Thickness Adjusted Based on Physical Properties and the
Requirements of U.L. 444 For Cable Wall Thicknesses
Assuming that the following haloge­
nated cables were produced in a UTP four
pair CMR cable or a four pair CMP cable,
the following data appearing in Chart #19
would result.
This analysis normalizes the variations
of raw materials tests for toxicity (LCso
mean value) and the physical require­
ments of that material on a finished 4 pair
UTP cable based on the U.L. 444 CMP
requirement where thicknesses must be
increased based on tensile strength. PVC
with LCso value mean of 17 surpassed a
zer6 halogen product with a LCso value
mean of 35 based on lower wall thickness
requirement. Therefore, the LCso meters
mean of 1.39 was superior to the zero
halogen material with a LCso meter mean
value of 1.20 even though the LCso mean
was 17 and 35 respectively.
The LCso value in meters of a PVC
CMR type cable was the lowest based on
these two factors:
1. The LCso value in grams, and
2. The physical characteristics of the ma­
terial which allow for thinner PVC wall
thicknesses based on its superior physical
properties (i.e., tensile strength).
PHYSICAL PROPERTIES
Physical properties effect the fire
hazard equation. Relative to toxicity, all
material group very closely together
especially when you calculate the LCso
value in meters based on increased wall
thickness required for zero halogen
materials. The following comparison of
materials in final cables must be assessed
before any conclusions can be crawn as to
superiority of zero halogens materials vs.
halogenated materials used in com­
munications cables.
24 AWG INSULATION
AND JACKET MATERIALS
SEM·
JAO<ET FIGIOPIIC
PVC
[-
i:,...
i '"'
;
0..
3000
4000
FT. /MINUTE
5000
PROCESSING SPEEDS
OF 4 PAIR JACKETS FOR
RISER OR PLENUM C ABLE
HALOGEN vs. NON-HALOGEN
vs. TENSILE STRENGTH
24AWG
2000
CHART#22
CHART#20
THNWA/J.
i,,....
FE!'
>OP£
LEVEL OF FIRE RETARDANCY
OXYGEN
<U'\
�OOEN ��
�
iii
iii
A
§�
I
0..
0..
400.1.
<14%LOW
HALOGEN
ii-•
400.L
ZERO
HALOGEN
ii-•
600.1.
FLUOROPOLYMER
PVDF
400.1.
FRPE
(HALOGENATED)
�
g
�
IIATERW.S
It is clear that halogenated materials
have superior physical characteristics.
Correspondingly, a customer would seem­
ingly use less material (thicknesses in
mils) both as the insulation and jacket.
PROCESSABILITY
•'
As most cable manufacturers know,
materials development is half the battle
while processability of materials on a
range of extrusion equipment is very im­
portant. A four pair UTP cable requires a
special balance of materials. An insula­
tion grade must process over 24 awg wire
in thin wall (6-8 mils) applications at high
speeds of 4,000 to 5,000 feet per minute
without cone breaks or spark failures.
Jacket grades allow for a somewhat wider
window and for a four pair UTP cable,
jacket processing speeds should be 500 to
600 feet per minute. There are clear
differences between halogen, low halogen
and zero halogen materials with respect to
processing thin wall products as
Commercially available
insulations.
highly filled zero halogen materials are
extremely difficult to process in this
respect.
400.1.
PVG
500.1.
SMOKEGUARD
TYPE POLYMER
ALLOY
,...
0
400 500 550 600
FT. /MINUTE
ELECTRICAL
PERFORMANCE
Probably the most difficult challenge
facing the cable design engineer is the
issue of electrical performance of UTP
local area network cables. Increasingly
demanding specifications have evolved
with the advent of the category program.
CHART#23
TWISTED PAIR
CATEGORY PROGRAM
Cole<py
ApplicobloS!Mdald
1
U..444
2
ISDN &Lo.o,
Si-f Data
ICEA S-80-57';
IBM Type 3 Media
Token Ring
Voice
3
LAN & Medium
Speed Data
4
Exteoded
Distance
LAN
ICEA s.90-5-,,;
u.. ....
u.. ....
ICEA S·00-576
ANSl,EIA/11A·568
CtillWY)rv 3
u.. ....
ICEA 5.90-5-,,;
TIAm41.8.1
Catego,y 4
NEMA
'LOloltloss'
U..444
High Speed
LAN
ICEA S-80-576
TIA TR41.8.1
SM
T;pieol Usage
V<>tco
RS232
IBM3270
IBM 3X-AS/400
RS232
100a..s�ff
4Mbps
Tai;en Ring
Extended Distance
100MeT 1135 m)
16Mbpo
Tolen Ring
Extended Ol:$tance
100a.seT (1 SO m)
16 Mbps
CICe<py 5
Token Ring
NEMA
COOi�
'LCM Lou Extended F,equency"
CHART#24
MAXIMUM ATTENUATION
(dB/305 m)
CHART#26
HALOGENATED MATERIALS
DIELECTRIC
CfJNSTANr
VALUES
TO MEET
O\TEGORYS
ATIENUATION (dtll
70 ---- ------ ----60 -r:=::::-;:
CA
::,;
OE
�G QR;;:;;;'y';"31- ---- ------1150
c=::J CATEGCflY • l--------ilt-1-
CA :rE G OA 5
4-0 _,_-_...;
"' ;;; ;,;;; .;...;..J---�------it-1..
30 --------..-111--<r____________
FEP
Y
20 --------ti=f:r.flllt-la----<a--la--1.....,..
10 ----::--c=-1'r.l
1
•
8
10
16
FREQUENCY (MHz)
20
25
., ,
fl
., 100
(!,
The key material performance require­
ment necessary to meet the attenuation,
impedance and crosstalk requirements of
the category program is dielectric con­
stant. In addition, the demands for
category 5 cables which run at frequencies
from 20 mhz to 100 mhz require low
dissipation factors from materials.
CHART#25
FOR CATEGORY 5 CABLE
Dielectric Constant and Dissipation Factor
Are Critical...
Dielectric
Constant
1 mhz
FE P
Smokeguard Ins. SRPVC
PE
pp
ECTFE
Smokeguard Jacket
PVDF
FRPE (Halogenated)
Low Halogen (<14%)
Zero Halogen
Oxygen
Index
90
2.1
35
2.6 -2.8
19
2.2
19
2.3
60
2.6
50
3.3
60
9.0
2.6 -3.0 28-30
2.4 -2.8 32-35
3.3 -3.6 37-39
Zero halogen materials compounded
with flame retardants significantly de­
teriorate both the dissipation factor as well
as the dielectric constant. FEP (fluori­
nated ethylene propylene) optimally pro­
vides the best electrical performance as
well as fire retardancy for category 5 UTP
cables. Based on the efficiencies of this
halogenated material as well as the
efficiencies of Smokeguard type polymer
alloys and semi-rigid PVC for category 3
cables, it is difficult to find alternate
materials that are not halogenated and
pass the most severe fire retardancy test
(i.e., U.L. 910 Steiner Tunnel). A non­
halogen materials electrical characteristics
and fire performance are antagonistic
properties. Charts #25, #26, and #27 pro­
vides a review of electrical properties ex­
pressed in dielectric constant and oxygen
index.
55
i';j 50
� 45
>:
L:
UJ 40
0
-
NON-HALOGENATED
& LOW HALOGENATED
MATERIALS
DIELECffi/C
CONSTANT
VALUES
TO MEET
2AND 1
DIELECffi/C
CONSTANT
VALUES
TO MEET
4AND3
ECTFE
CHART#27
DJfJ.ECTRIC
CONST/WT
VALUES
TO MEET
C.AlEGORY5
PVDF
-
��g,'i.Ei? UARO ----R
ALLOY JKT.
4AND3
LOW HALOGEN
SMOKEGUARD POLYMER
I
ALLOY INS .•
I
• PE
PP.
- SMOKEGUARD SR INS. -
•sRPVC
30
DIELECTRIC
OONST»fr
VAI
•.IES
TO MEET
DIELECTRIC
OONST»fr
VALl£S
TO MEET
•
2AND1
3.6
---X...,.
ZERO HALOGEN
FRPE
25
2.0
2.4
2.8
3.2
3.6
--Z. 9.0
DIELECffi/C CONSTANT
CONCLUSION:
Against these performance standards,
the objective of zero halogen unshielded
twisted pair cables may be unrealistic and
more importantly unwarranted. Clearly
the objective of both the materials
suppliers and the wire and cable industry
should be toward safer cables which are
tested to performance standards. The
ideal UTP local area network cable would
be a plenum rated, low s.moke, halogen
free, category 5 electrical rated product
Thi.s.­
with excellent processability.
remains a noble target, but much can be
20
24
28
3.2
DIELECTRIC CONST»fr
9.0
accomplished by challenging performance
standards.
It is clearly debatable whether the issue
of corrosivity or toxicity distinquish or­
ganic based polymers from one another
and secondly whether the test methods
which require further validation are in the
interest of improved cable performance
and public safety. At a minimum, we
must set up a total performance criteria
that assesses the pros and cons of each
material so that zero halogen materials
can show their attributes vs. halogenated
materials and vise versa.
CHART#28
CONCLUSION:
A COMPARISON OF COMMUNICATION CABLE MATERIAL BASED ON
HALOGENATED, L(J.N HALOGENATED AND ZERO HALOGEN MATERIAL S
FIRE HAZARD ASSESSMENT
Zero
Halogen
<14%
Low Halogen
Halogenated
Material
Flame Retardancy
and Propagation
Fair
Good
Excellent
Smoke Suppressant
Characteristics
Excellent
Excellent
Excellent
Excellent
Good
Fair
Low
Corrosivity
All Carbon Backboned Material Relatively Similar
Except Where Wall T hickness of Cables Varv Dramatically
Toxicity
PHYSICAL & ELECTRICAL PROPERTIES
Zero
Halogen
Physical Properties
i.e., Tensile Strength
Poor
Electrical
Properties
PE -Excellent But Will
Not Pass VW-1
FR Polyolefin -Fair
Passino VW-1
Processabilily
Insulation
Jacket
*
**
***
* *"*
Poor
Fair
<14%
Low Halogen
Good
*
**
Good
Passes
VW-1
Good
Good
Halogenated
Materials
Excellent
FEP -Excellent ****
Passes VW-1
PVC - Good ***
Passes VW-1
Excellent
Excellent
PE - Polyethylene
FR - Flame Retarded Polyethylene With Non-Halogen Fire Retardant
PVC - Polyvinyl Chloride
FEP - Florinated Ethylene Propylene
RECOMMENDED PERFORMANCE REQUIREMENTS FOR LOW SMOKE,
LOW CORROSIVITV, LOW TOXICITY INSULATION AND JACKET COMPOUNDS
FOR UNSHIELDED TWISTED PAIR CABLES COMMUNICATIONS CABLES
I.
Phyaical Prcpartiea
Tensile Strength, psi
Elongation (\)
Air Aging
7 days at 100° c
Tensile - Minimum\
of Unaged Sample
Elongation - Minimum I
of Unaged Sample
Cold Bend
II.
1400
U.L. Revision Reqd.
to U.L. 444
100
U.L. Revision Reqd.
to U.L. 444
75,
6o 0 c Rated per
U.L. 444
60
6o 0 c Rated per
U.L. 444
-17 .:!:2
I. FIRE RETARDANCY
AND PROPAGATION
OXYGEN INDEX TEST
U.L. 444
Fir• Basard A•••••••nt
A.
s.
c.
Fire Retardancv
Plenum
CMP
U.L. 910
Riser
CMR
U.L. 1666
General Purpose
CMG
FT-4
IEEE JSJ
CM
U.L. 1581
smoke suooressant Characteristics
Plenum
CMP
Riser
CMR - LS
Apply U.L. 1685 test
'!'ethodology
1nconJunct1on with
riser cable test
General Purpose
FT-4
CMG - LS
Apply U.L. 1685 test
methodology
inconjunct1on with
FT-4 test
IEEE JSJ/
U.L. 1581
CM - LS
Apply U.L. 1685 test
methodology
inconjunction with
IEEE J83 test
LS
corrosivitv Test
Plenum
Riser
CMP-LS-LC
CMR-LS-LC
As per U.L. 910
requirement
Perform U.L. 910 test.
Capture gases and adapt
cone corrosimeter test
procedure to determine
corrosivity on copper
probe•
o.
General
Purpose
CMG-LS-LC
Perform CSA FT-4 test and
adapt cone corrosimeter test
procedure to determine
corrosivity on copper
probe•
IEEE J8J
CM-LS-LC
Perform U.L. 1581 test and
adapt cone corrosimeter test
procedure to determine
corrosivity on copper
probe*
Toxicity Test
Univ. of
Pittsburgh
Pass/Fail
Electrical Testing
EIA/TIA
TSB 36 & 40
EIA/TIA
TSB 36 & 40
EIA/TIA
TSB 36 & 40
VW-1 FLAME TEST
Wire should not
conVf!I( flame to
lhe flag or bum
for more lhan 1 min.
after 5 flame applica­
tions of 15 seconds
each or lhe time until
flaming ceases
Perform U.L. 1666 test
and adapt cone corrosimeter
test procedure to determine
corrosivity on copper
probe•
• Testing required to determine exact performance
requirement.
III.
FIRE HAZARD
ASSESSMENT TEST
METHODS
Perform benchmark testing
and set materials
requirement that no ·
insulation and/or jacket
should fall below an Lc50
value of� 9rams or develop
Lc50 value in meters,
example Lc50 meter >l.O
Category
5 Values
Performed on UTP cable
category
4 Values
Performed on UTP cable
Category
3 Values
Performed on UTP cable
(whichever is
longer), between
applications.
The cotton must
NOTlgnrte.
U.L 1581
VERTICAL FLAME TEST
(IEEE - 383 TEST)
1I V �
Flame Spread
Beyond The 8-Foot
level Fails Test
/
1'
70,000 BTU/Hr.
/
Flame From
,,Jo·
10 Inch Burner � II
2'
/
U.L 1666 RISER CABLE TEST
2' X 2'
Exhaust
Opening
�
;�;.e�ct
ToPass:�
-(Building)
Root
Ill. CORROSIVITY
CONE CORROSION TEST
GAS SAMPLING SYSTEM
(Building)
2nd Floor
�12'
p-opogate
abvoe
12 feet.
4'
lock Wall
Burner
Building)
1st Floor
Concrete
Slab on
Earth
H
°'"'
CAl.£Ft"'4ETIR
CNET TEST APPARATUS
U.L 910 STEINER TUNNEL TEST
PMMA CYll'<DER
OUTGOING
AJR
INCOMING AIR
/
MEASUREMENT
OF
RESISTANCE
IV. TOXICITY
300,000 BTU/Hr. Methane Flame Wrth 240 FooVMin. Oran.
Exposed for 20 Minutes.
1. Flame spread must not exceed 5 feet
beyond end of 4 1/2 foot ignition flame
2. Smoke generation must not exceed peak
optical density of 5 (33% light transmission)
and average optical density of . 1 5
(70"/o light transmission).
II. SMOKE GENERATION
ASTM E662
NBS SMOKE DENSITY CHAMBER
NEW YORK STATE TOXICITY TESl
ARTICLE 15
UNIVERSITY OF
P ITTSBUR GH -TEST15
Biography
Charles A. Glew has a Bachelor of
Science
Degree
in
Industrial
Technology
from
I3owling
Green
University and a Masters Degree in
Business Administrations from Bryant
Charlie has been an active
College.
contributor to the National Electrical
Manufacturers Association and the
Society for Plastics Engineers. He served
as co-Chairman of the NEMA Materials
Advisory Subcommittee on Toxicity..
Acknowlcdgcmcnts
The author wishes to thank Guerry
Grune and Tony Sansone who provided
technical support and guidance in
preparing this paper. The efforts of Tina
Sundstrom for her assistance in preparing
the text of the paper and Jay Munsey for
his preparation of many of the charts is
very much appreciated. Finally. let me
thank my wile. Kathie. for her continued
support and assistance in this and all my
endeavors.
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Carlos
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