Date post: | 06-Jul-2018 |
Category: |
Documents |
Upload: | asdrubal-kakakian |
View: | 219 times |
Download: | 0 times |
of 26
8/17/2019 C044 Fire Tutorial WP Aug 05
1/26
1
Subject: A Tutorial on Cable Fire Safety (Updated)
From: Dr. T. C. Tan, DMTS, SYSTIMAX Labs
B.Sc (Eng), DIC, PhD, CEng, FIEE
Date: 9th
March 2005
Modified: 12th
August 2005
1. Introduction
The proliferation of local area networks (LANs) and the increasing use of structured cabling
systems in many commercial office buildings have resulted in heavy concentration of
communication cables in ceiling and/or under-floor voids. Some of these cables have low or
unknown fire performance since there are no requirements in Europe and Asia currently for
marking these cables according to their fire performance. This is in contrast to the situation in North
America and Mexico where all communication cables must meet one of four levels of fire-
resistance requirement and bear the necessary markings. This hierarchy of cable fire requirement is
mapped to the different installation practices. These cable markings are useful for the fire or health
and safety inspectors and insurance surveyors because they facilitate the identification of the cable
safety performance level and are valuable from a building inspection and risk assessment
standpoint.
Also, fire codes or regulations vary widely across the world. In North America, fire codes exist for
communication cables and a large emphasis is placed on the reduction in flame spread, fire
propagation and smoke generation. In Europe and Asia, fire codes/regulations do not exist for
communication cables (Regulations do exist for other construction products such as wall panels,
ceiling tiles and floor coverings). However, in some European countries, some customers do place
more emphasis on the reduction of smoke and acid gases generation due to the existence of low
smoke, zero halogen (LSZH) European cable standards. These standards have now been revised to
be more generic to allow other materials to be used. This paper compares the current requirements
in North America and internationally, and discusses new developments in Europe which could lead
to the setting up of a hierarchy of communication cable fire performance levels that will be basedon installation practices and risk assessment. A list of the abbreviations used is given in Annex A.
2. Standards
When considering the fire performance of communication cables, several criteria must be taken into
account. These are:
• Fire Resistance (sometimes referred to as Circuit Integrity Test)
• Flame Spread and Fire Retardance
• Heat Release Rate and Total Heat Release
• Smoke Generation• Toxicity
• Smoke Corrosivity
8/17/2019 C044 Fire Tutorial WP Aug 05
2/26
2
CommScope Solutions Proprietary
Use pursuant to Company instructions
Annex B provides photographs of some of the fire test methods.
2.1 Fire Resistance
The fire resistance or circuit integrity requirement is a special one and is required for connection to
certain fire-life-safety control systems such as sounders/bells/sirens, combined speaker-strobe
devices, fire-fighter phones, control and indicating equipment. The test requires cables to maintain
circuit integrity under specific fire conditions (for example, flame test at 1000 °C for 3 hours and
still maintaining circuit integrity). The main related standards are:
• IEC 60331
• EN 50200
This requirement needs the use of cables with special construction. Typical communication cables
cannot be used.
2.2 Flame Spread and Fire Retardance
The aim of choosing a communication cable with low flame spread and high fire retardance is to
prevent the burning cables from propagating the fire to other parts of the building too quickly. This
will allow more time for the people involved to make their escape from the fire. The main related
standards are:
• UL VW-1 Bunsen Burner
• UL 1581 Vertical Tray or IEEE-383 Vertical Tray
• CSA FT-4/IEEE-1202
• UL 1666
• UL 910 or NFPA 262 or CSA FT-6
• EN 50289-4-11
• IEC 60332-1 series or EN 50265 series
• IEC 60332-3 series or EN 50266 series
• FIPEC Scenario 1 and Scenario 2
These standards require the whole finished cable(s) to be tested. Figure 1 and Table 1 provide the
requirements in the United States (US). These requirements are set in the National Electrical Code
(NEC) Articles 770 and 800 which are issued by the National Fire Protection Association (NFPA).
NEC Article 800 has four levels of fire-resistance requirement. All communication cables must
meet one of the four levels and bear the necessary markings. As an example, a cable that is rated
CM/MP cannot be installed in the riser environment unless the cables are enclosed in metallic/non-
combustible trunking. This will ensure that the fire does not propagate too quickly to the otherfloors even when the fire-stopping mechanism has been compromised. The NEC is revised every
three years.
The UL VW-1 is a small-scale test whereas the UL 1581, UL 1666 and UL 910 are all intermediate-
scale tests. The Canadian Standards Association (CSA) FT-4 test is slightly more stringent than the
UL 1581 due to the fact that the ignition source is angled at 20°. The UL/CSA designation for
meeting this test is CMG/MPG.
8/17/2019 C044 Fire Tutorial WP Aug 05
3/26
3
CommScope Solutions Proprietary
Use pursuant to Company instructions
Fire Tests Cable rating identification
VW-1
Bunsen Burner
UL 1581
Vertical Tray
UL 1666
Riser Test
UL 910
Steiner Tunnel
(NFPA 262)
Low
High
F i r e P
e r f o
r m
a n c e
CMP/OFNP/OFCP
CMX
CM/OFN/OFC
CMR/OFNR/OFCR
Figure 1: US cable fire tests, hierarchy and identifications
DESIGNATION TEST REQUIRED USE
CMX UL VW-1 Residential
CM/MP/OFC/OFN UL 1581 Vertical Tray
IEEE-383 Vertical Tray
General Purpose Except
for Riser and Plenum
CMR/MPR/OFCR/OFNR UL 1666 General Purpose and Riser
CMP/MPP/OFCP/OFNP UL 910/NFPA 262 General Purpose, Riser
and Plenum
Note: Prefix C or M is for copper media and prefix OF is for optical fiber media.
Table 1: US NEC Article 800 for communication cables
EN 50289-4-11 is based on the UL 910 test method but with heat release and time-to-ignition
measurements as mandatory requirements rather than optional and an additional test for flaming
droplets. It is an intermediate-scale test. Note that both UL 910 and EN 50289-4-11 are test methods
and do not have pass/fail requirements.
8/17/2019 C044 Fire Tutorial WP Aug 05
4/26
4
CommScope Solutions Proprietary
Use pursuant to Company instructions
Currently, IEC 60332-1 and 60332-3 series of standards1 are widely used internationally as cable
fire test methods. These tests were originally developed for power/energy cables and have since
being revised to cater for communication cables. The IEC 60332-1 is a small-scale test using a 1
kW burner as the ignition source and a single cable or wire as test sample. It is similar to the UL
VW-1 test.
The IEC 60332-3 is an intermediate-scale test where bundles of cables are used (IEC 60332-3-10
provides description for the test apparatus). This series of standards have five categories, namely:
• Category A F/R NMV 7 litres per meter IEC 60332-3-21
• Category A NMV 7 litres per meter IEC 60332-3-22
• Category B NMV 3.5 litres per meter IEC 60332-3-23
• Category C NMV 1.5 litres per meter IEC 60332-3-24
• Category D NMV 0.5 litres per meter IEC 60332-3-25
NMV stands for non-metallic volume. The number of cable samples required is calculated from the
NMV for the different categories. Annex C provides comparison between IEC 60332-3, UL 1581
Vertical Tray and UL 1666 test methods.
EN 50265 and EN 50266 series of European Norms (standards) are basically the European version
of IEC 60332-1 and IEC 60332-3 series of standards.
FIPEC (Fire Performance of Electric Cables) was a European Commission and industry funded
project set up to develop methods for measuring the fire performance of cables. The test apparatus
consisted of modifying the existing IEC 60332-3 test to include heat release and smoke
measurement. The FIPEC project found that the most significant variable in the current IEC 60332-
3 test was in cable mounting, and concluded that consideration of NMV does not necessarily
provide a risk hierarchy. Changes to sample mounting, the option of a backboard with a more
powerful ignition source and an increased airflow provide a better discrimination between cable fire performances for FIPEC test methods when compared with current IEC 60332-3 tests.
FIPEC has two test methods, namely test method Scenario 1 and Scenario 2. Cable mounting
procedure is determined by cable diameter. Cables having a diameter greater than 5 mm were
mounted in a single spaced row, and smaller cables were mounted in non-twisted spaced bundles.
Test method Scenario 1 is considered to be slightly more severe than IEC 60332-3. The ignition
source is 20 kW and the airflow is increased to 8000 litre per minute. In test method Scenario 2,
considered to be more severe than IEC 60332-3, the ignition source is 30 kW, the airflow is 8000
litre per minute and a non-combustible backboard is added. The FIPEC test methods have been
adopted for the Reaction-to-Fire Euroclassification of cables under the Construction Product
Directive, 89/106/EEC (see Section 3.1).
1 A few years ago, IEC revamped their fire standard documents by splitting them up into a series of documents. For
example, the former IEC 60332-3 document consists of test apparatus description and all the test procedures andrequirements for different categories. This is now split into a series of IEC 60332-3-x documents, consisting of adocument for test apparatus description and various documents for the different categories of fire test procedure and
requirements. This process will permit amendments and new requirements to be introduced easily.
8/17/2019 C044 Fire Tutorial WP Aug 05
5/26
5
CommScope Solutions Proprietary
Use pursuant to Company instructions
The UL 910, EN 50289-4-11 and FIPEC Scenario 1 and Scenario 2 are sometimes referred to as
integrated fire tests since they measured essential fire hazard properties such as flame spread,
smoke generation and heat release, all in the same respective tests. This is far more useful and
realistic. The other test methods just measure only one variable, flame spread.
Table 2 provides a comparison between IEC 60332-1, IEC 60332-3, FIPEC Scenario 1 and
Scenario 2, UL 910 and EN 50289-4-11 test methods.
2.3 Heat Release Rate (HRR) and Total Heat Release (THR)
Heat is the energy output of a fire. When the aftermath of a disastrous fire is being investigated, one
of the most common questions is: Why did the fire get so large? HRR and THR (THR is calculated
by working out the area under the HRR curve) are useful variables for quantifying a fire size and
are important variables in describing fire hazard (except for explosions). This is because:
• HRR and THR are driving forces for fire, that is, heat makes more heat, which in turn
increases the temperature of the fire. This does not occur, for instance, with carbon
monoxide. Carbon monoxide does not make more carbon monoxide.• The generation of most other undesirable fire by-products such as smoke, toxic gases and
temperatures, generally tends to increase with increasing HRR and THR.
• High HRR/THR indicates high threat to life and are intrinsically dangerous. This is because
high HRR/THR cause high temperatures and high heat flux conditions, which may prove
lethal to occupants.
The main related standards are:
• EN 50289-4-11
• FIPEC Scenarios 1 & 2
HRR and THR are optional requirements in UL 910.
Small-scale test methods do exist for measuring HRR and THR (e.g Cone calorimeter, ASTM
E1354) but these tests are only useful for initial material assessment work.
Recent EU-funded British Steel fire tests at the UK Building Research Establishment/Fire Research
Station (BRE/FRS) indicated that temperatures exceeding 800°C can cause structural steel beams to
severely deform2 which will render the building unsafe after the fire.
2.4 Smoke Generation
Some fire fatalities are caused by the failure of people involved to make their escape from the fire in
the time available. There are many reasons for this, but one that has attracted increasing attention is
the effect of smoke. Dense smoke reduces visibility and causes suffocation. The aim of choosing a
cable with low smoke generation is to allow people to escape a building fire with minimum
suffocation and not having their visibility impaired. The main related standards are:
2 B. R. Kirby, ‘British Steel Technical European Fire Test Programme’, Fire, Static and Dynamic Tests of Building
Structures; G. Armer & T. O’Dell (1997), pgs 111-126, Conference Proceedings.
8/17/2019 C044 Fire Tutorial WP Aug 05
6/26
IEC 60332-1
(EN 50265 series)
IEC 60332-3
(EN 50266 series)
FIPEC
Scenarios 1 & 2
UL 910
Cable orientation Vertical Vertical Vertical Horizontal
Test requirements Flame spread Flame spread,
Oxygen index (optional)
Flame spread,
Heat release,
Smoke opacity,
Time-to-ignition
Flame spread,
Smoke opacity,
Heat release (option
Time-to-ignition (opti
Ignition source 1 kW Burner 20.5 kW Burner
(73.8 MJ/hr)
(70,000 BTU/hr)
Scenario 1: 20 kW Burner
Scenario 2: 30 kW Burner plus
non-combustible backboard
(108 MJ/hr)
(102, 364 BTU/hr)
87.8 kW Burner
(316.5 MJ/hr)
(300,000 BTU/hr
Flame application
time
60 s
for cable diameter 25 mm
2400 s for Categories A & B
1200 s for Categories C & D
1200 s 1200 s
Length of test
sample
0.6 m (2 ft) 3.5 m (11.5 ft) 3.5 m (11.5 ft) 7.6 m (25 ft)
Cable layers
and spacing
Not applicable.
Single cable
Number of layers depends on
NMV.
Touching for cable diameter6.7 mm
Single layer spaced Single layer touchi
Air velocity None 5000 litre/min 8000 litre/min 1.22 m/s
(240 ft/min)
Pass/Fail Criteria Distance between onset of
charring and lower edge of
top support > 50 mm and
burning < 540 mm from lower
edge of top support
Charred portion < 2.5 m
(8.2 ft) above bottom edge of
burner (Flame extinguish
after 1 hr).
Depends on
CPD Euroclassification
Refer to CMP/MPP/O
/OFCP requiremen
Flame front < 1.52 m (5 f
Peak Optical Density 0
Average Optical Density
Standardisation International and CENELEC International and CENELEC EU CPD
and CENELEC
UL, CSA and Mexi
Table 2: Comparison between various fire test methods
6
CommScope Solutions Proprietary
Use pursuant to Company instructions
8/17/2019 C044 Fire Tutorial WP Aug 05
7/26
7
CommScope Solutions Proprietary
Use pursuant to Company instructions
• UL 1685
• UL 910
• EN 50289-4-11
• EN 13823 (SBI)
• IEC 61034 or EN 50268
All these standards require the whole finished cable(s) to be tested.
UL 1685 uses the UL 1581 test method but with peak smoke release rate and total smoke
requirements added. The UL designation for meeting this test is ‘LS’ (Limited Smoke), i.e. CM-LS.
In the US, it is a mandatory requirement in the plenum environment to install low smoke and very
fire retardant cables. These cables must meet the CMP/MPP/OFNP/OFCP requirements with the
UL 910 test. There is also another test method in the US known as the NBS smoke chamber and
this is referenced in the ASTM E662 standard. The only drawback with this standard is that the test
is carried out on the polymeric material used (i.e. cable sheath and conductor insulation materials
are tested separately) rather than the whole finished cable(s).
IEC 61034 or EN 50268 is sometimes referred to as the 3-meter cube test due to the size of the test
chamber used. Part 1 provides details of the test apparatus and Part 2 defines the test procedure and
pass/fail requirements. This test was originally developed for power/energy cables and was intended
to simulate a cable fire in an underground train tunnel. One problem with this test method when
applied to communication cables relates to the calculation of the number of test samples required.
This (sample) number is dependent on the overall diameter of the cable. For a cable with an overall
diameter of 4.8 mm (typical diameter of plenum-rated communication cables), the number of test
samples required is 21 whereas for a cable with an overall diameter of 5.1 mm (typical diameter of
IEC 60332-1 rated LSZH communication cables), the number of test samples required is 8. This
massive difference in cable test samples provides massively different test results. In practice, this
difference does not exist since the number of communication cables installed in a 9 m2 work area isthe same irrespective of the cable diameter.
The UL 910, EN 50289-4-11 and FIPEC Scenarios 1 & 2 tests are more useful and realistic since
they are integrated fire tests. IEC 61034 or EN 50268 only measures smoke emission.
2.5 Toxicity
Toxicity is also a complex subject. The toxicity issue has typically being perceived to be related to
all halogenated cables. However, it is a known fact that all burning cables (both halogenated and
non-halogenated) produce toxic gases. According to fire fighters and fire experts, the most common
cause of fire fatality is due to the inhalation of carbon monoxide (CO) gas which is toxic and
odourless. Cable fire research work 3 at the UK BRE/FRS showed that some commonly used LSZH
data cables produce more CO gas than the CMP-rated cables when burned (see Figure 2). This work
is co-funded by the UK Government. This is likely due to the tendency that LSZH data cables burn
more rapidly and quickly reduce the oxygen available in the concealed space.
3 ‘A study of Cable Insulation Fires in Hidden Voids’ - A Partners in Technology (PIT) programme for the UK
Department of Transport, Environment and the Regions (DETR) contract reference CI 38/19/131 (cc985), March 1996.
8/17/2019 C044 Fire Tutorial WP Aug 05
8/26
8
CommScope Solutions Proprietary
Use pursuant to Company instructions
The US National Electrical Manufacturers Association (NEMA) has also developed toxicity data
using the NEMA/NYS (New York State) protocol4 (see Figure 3). The data indicates that there is no
significant difference in toxicity (LC50 values) between fluoropolymer, PVC and polyolefin (i.e.
polyethylene and polypropylene) materials.
Traditional material-based toxicity test methods such as the Naval Engineering Standard (NES) 713
have been found to be unsuitable. These test methods are not realistic and are only useful for initial
material assessment work. Toxic hazards must be assessed over a range of fire scenarios and not on
material-based test methods only. Toxicity information should be used as part of a relevant total fire
hazard assessment where parameters such as ignitability, fuel load, heat release, flame spread and
smoke emission are also considered.
Carbon Monox ide (CO) Generat ion
-0.050
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0 500 1000 1500 2000 2500 3000 3500
Tim e (sec)
C o n c e n t r a t i o n ( % )
LSZH
CM P
Figure 2: CO emission from CMP-rated and IEC 60332-1 rated LSZH cables
4 National Electrical Manufacturers Association, 1987, ‘Registration Categories of the National Electrical
Manufacturers Association for Compliance with the New York State Uniform Fire Prevention and Building Code’, R.
Anderson, P. Kopf, pub Arthur D. Little Inc.
8/17/2019 C044 Fire Tutorial WP Aug 05
9/26
9
CommScope Solutions Proprietary
Use pursuant to Company instructions
Figure 3: NEMA toxicity data
2.6 Acidity and Smoke Corrosivity
In addition to smoke, gases are also evolved from materials involved in a fire. Depending on the
compounds used for manufacturing the cables, some of these gases may be acidic in nature. For
example, cables insulated and/or sheathed with PVC can generate hydrochloric acid gas when
affected by fire. In addition, most LSZH compounds are made from ethylene-vinyl-acetate (EVA -
this compound is a polyethylene copolymer) which generate acetic acid when affected by fire.
There are concerns that these acidic gases may cause damage to modern electronic equipment and
building structure. This has led to the perception that acidic gas is related to corrosivity.
The two commonly quoted standards for testing acidic gas generation are:
• IEC 60754-1 (EN 50267-2-1): HCL gas generation• IEC 60754-2 (EN 50267-2-2 & EN 50267-2-3): pH and Conductivity
Both test methods call for polymeric material testing rather than testing on the whole finished
cable(s). This means that both the cable outer sheath and the conductor insulation need to be tested.
In the IEC 60754-2 standard, the pass/fail limit for pH is set at > 4.3 even though the pH for pure
water (neutral) is 7. The limit of 4.3 basically ensures that most halogenated compounds will not
meet this standard. Hence, this has resulted in the perception that corrositivity is related to
halogenated cables only.
8/17/2019 C044 Fire Tutorial WP Aug 05
10/26
10
CommScope Solutions Proprietary
Use pursuant to Company instructions
Other test methods exist for measuring corrositivity in terms of metal loss. Two of these methods
are ASTM D5485 (Cone corrosimeter) and ISO DIS 11907 but these are not commonly used.
The perception that corrositivity is related to halogenated cables only is now being challenged.
Several decades of research work carried out by Lucent Technologies Bell Laboratories have shown
that modern digital equipment are particularly vulnerable to airborne particles, most of which are
potentially corrosive ionic compounds. This work has recently been extended to include the
possible causes of equipment failure from smoke exposure in cable fires. This is because in a fire,
ionic contaminants associated with fillers, flame retardants, colorants or by-products of the
polymerisation reactions may be released and deposited on circuit boards. The research showed that
the most common cause of equipment failures following exposure to smoke from cable combustion
is not loss in thickness of structural metals or metal circuitry from direct deposition of acidic gases
but rather electrical shorts and arcing that cause excessive crosstalk and malfunctioning
components. This phenomenon is known as the ‘Leakage Current Effect’. The research also showed
that smoke contaminants from some burning LSZH data cables are as damaging as those from some
halogenated ones5,6. This work on digital electronic equipment reliability (DEER) indicated that
there are damage mechanisms to electronic equipment associated with fires that cannot beadequately assessed by determining the pH or conductivity or by metal loss. Hence, current
international test methods such as IEC 60754 are not adequate for assessing DEER.
In addition, some plenum communication cables do not have problem with DEER. This is due to
the fact that there is virtually no propagation of fire along the length of the cable. Hence, the amount
of compound burnt will be limited and this will result in less ionic contaminants being generated.
In summary, acidity is not relatable to corrosivity. Further, there is no mention of corrosivity in IEC
60754-2. Phenomenon such as leakage current and metal loss are more accurate measures of
corrosion damage effects of fire effluents. The test methods for measuring leakage current and
metal loss are given in IEC 60695-5-37
. In the US, the test method for leakage current is UL Subject1985.
3. New Developments on Communication Cable Fire Hazard
New developments are occurring in the industry and in the regulatory environment with regard to
cable fire hazard and risk assessment/management. These developments include the publication of a
Design Guide8 by BRE-Loss Prevention Council (LPC), the publication of a Technical Briefing
Report9 by the Association of British Insurers (ABI), the inclusion of cables in the European
Construction Product Directive (CPD) and the identification of a new cable fire performance level
known as limited combustible by the National Fire Protection Research Foundation (NFPRF) and
UL in the US.
5 IWCS, Leakage Current Smoke Corrosivity Testing - Comparison of Cable and Material Data,J. T. Chapin, et al, 1996.6 NFPRF Fire Risk and Hazard Research Assessment Research Application Symposium, ‘Comparison of
Communications LAN Cable Smoke Corrosivity by US and IEC Test Methods’, J. T. Chapin, et al, June 1997.7 IEC 60695-5-3: ‘Fire Hazard Testing – Part 5-3: Corrosion damage effects of fire effluent – Leakage current and metal
loss test method’8 ‘The LPC Design Guide for the Fire Protection of Buildings’, Loss Prevention Council, June 1997 & Sept 1998.ISBN 0 902167 97-99 ‘Fire Hazard of Communication Cables in Ceiling, Floor and Vertical Voids’, Association of British Insurers, Nov
2000. ISBN 1 903193 11 7
8/17/2019 C044 Fire Tutorial WP Aug 05
11/26
11
CommScope Solutions Proprietary
Use pursuant to Company instructions
3.1 European Construction Product Directive (CPD), 89/106/EEC
The CPD was enacted in 1989 and applies to all construction products. One of the essential
requirements of the CPD (Essential Requirement No. 2) relates to safety in the case of a fire. A new
testing and classification scheme was agreed by the EC Fire Regulators Group (FRG) for the
implementation of the CPD and in particular, relating to the harmonisation of Reaction-to-Fire
testing of construction products. The FRG is a group of national fire regulators and their technical
advisers/experts.
The classification scheme comprises a table of ‘Euroclasses’ from Class A1 (highest performance)
to Class F (no performance determined) and a range of tests and performance criteria for
determining a Reaction-to-Fire classification for construction products, excluding flooring. To
cover all but the highest and lowest classifications, EN 13823 SBI (Single Burning Item) test was
developed.
In December 1998, communication cables were accepted as construction products within the EC,
and are, therefore subjected to the requirements for Reaction-to-Fire testing and Euroclassification.The FIPEC test methods have been adopted and Annex D provides the proposed EuroClasses for
cables in the CPD. There are seven EuroClasses and enhanced fire performance (i.e. plenum rated)
cables are in EuroClass B1ca. The parameters listed under main classifications are mandatory
requirements whereas those listed under additional classifications are optional. Many member states
are unlikely to adopt the optional acidity requirement since it is not in the CPD for all the other
construction products. Once approved, mandatory cable fire performance marking will be required
by the Directive, and for the first time in Europe, a ‘hierarchy’ of cable fire requirements exist.
These cable markings are useful for the fire or health and safety inspectors and insurance surveyors
because they facilitate the identification of the cable safety performance level and enhanced fire risk
assessment.
3.2 The LPC Design Guide for the Fire Protection of Buildings
This BRE/LPC publication allows architects and building designers to take into account insurers’
recommendations for the fire protection of buildings. These relate mainly to the protection of
business by minimising fire and smoke damage and business interruption. The overall objective of
the Design Guide is to assist in reducing financial loss by providing guidelines to contain the fire to
one compartment of the building, and ensuring that when combustible materials such as cables are
used in the construction of a building, they do not make significant contribution to the growth and
propagation of the fire. Building regulations are concerned primarily with the escape of the building
occupants, that is, they only address life safety issues and will not necessarily result in the provision
of adequate property protection. The BRE/LPC Design Guide aims to complement the statutory building regulations and provides additional requirements set by the insurers. The increased
standards required by the insurers are designed not only to provide safety for the people involved in
the fire, but also to protect the asset of the business and to minimise the cost of fire damage to
buildings and their contents.
Section 4.7.2 of the Design Guide deals with cables installed in ceiling and under-floor voids and
recommends that the cables should be ‘tested and approved to IEC 60332-3 or other specification
acceptable to LPC’. Section 4.7.3 deals with cables installed in communication rooms and
recommends that ‘where cables are installed in a cavity of 300 mm or greater, then the cables used
should be tested and approved to UL 910 or other specification acceptable to LPC and the platform
8/17/2019 C044 Fire Tutorial WP Aug 05
12/26
12
CommScope Solutions Proprietary
Use pursuant to Company instructions
floor should have fire resistance of 15 min integrity and insulation when exposed to the heating
conditions of BS 476, Part 20 (1987)’. Cables not meeting these requirements must either be sealed
in fire retardant trunking/ducting, or the cavity where the cables are installed is protected by an
automatic gaseous system (connected to a fire detector and alarm system) or a sprinkler system.
The LPC Design Guide has taken a major step in setting the minimum cable fire performance
requirements for the cabling industry. It presents the insurers’ standards for fire protection of
buildings and is intended to assist architects and other building professional advisers in reconciling
the provisions of national legislation standards with the recommendations of the insurance industry.
3.3 The Association of British Insurers (ABI) Technical Briefing Report on ‘Fire Hazard
of Communication Cables in Ceiling, Floor and Vertical Voids’
Recently, the ABI published a Technical Briefing Report for insurers that provided further guidance
to the insurance industry in establishing their strategy. This technical report complements the LPC
Design Guide and is based on the cable fire safety research work carried out by SYSTIMAX
Solutions, other cable manufacturers and polymer suppliers, and in collaboration with BRE/LPC,
UL and the UK DETR. This report concludes with the following recommendations:• For new buildings or during major refurbishment’s, the recommendations given in part 4.7
of the LPC Design Guide for the Fire Protection of Buildings should be followed.
• As construction products, communication cables are included in the new developments in
the EC Fire Regulators’ group for the harmonisation of Reaction to Fire Testing within
Europe as required by the CPD, this will result in new requirements for testing and
classification of cables for life safety. It is important for insurers to promote higher
requirements than regulators, to reduce the potential business interruption exposure.
3.4 NFPA 90A Limited Combustible Requirements
Last year, the NFPRF and UL in the US identified a new cable fire performance level known aslimited combustible. According to NFPA Article 90A, for a product exposed to airflow in plenum
to be classified as limited combustible, the fuel load of the product must be ≤ 8.14 MJ/kg (3500
BTU/lb), have a flame spread index (FSI) of 25 and a maximum smoke developed index (SDI) of
50. These numbers must be generated in accordance with procedures set forth in NFPA 259 (for
fuel load) and NFPA 255 (for FSI and SDI). The requirements for limited combustible cables
exceed those of CMP/MPP/OFNP/OFCP (using UL 910/NFPA 262 test). Table 3 provides a
comparison between NFPA 255 and NFPA 262, and Table 4 provides a comparison between
limited combustible and CMP/MPP/OFNP/OFCP rated cables.
NFPA 255 NFPA 262
Apparatus Steiner Tunnel Steiner Tunnel
Test duration 10 mins 20 mins
Position of steel rack 0.298 m (11.75 in) above
chamber floor
0.203 m (8 in) above
chamber floor
Width of steel rack 0.514 m (20.25 in)
(80% more cable
specimen)
0.286 m (11.250 in)
Table 3: Comparison between NFPA 255 and NFPA 262
8/17/2019 C044 Fire Tutorial WP Aug 05
13/26
13
CommScope Solutions Proprietary
Use pursuant to Company instructions
Limited Combustible
Rating
CMP/MPP/OFNP/OFCP
Rating
Test NFPA 255 UL 910/NFPA 262
Flame spread Flame spread index of 25 1.524 m (5 ft)
Smoke generation 50 smoke developed
index
Up to 10 times less severe
than Limited CombustibleRating
Temperature rating Required Not required
Heat aging Required Not required
Humidity aging Required Not required
Slitting Required Not required
Fuel load limit 8.14 MJ/kg per NFPA
259 test
Not required
Table 4: Comparison between Limited Combustible and CMP/MPP/OFNP/OFCP rating
4. Conclusion
All these developments are major steps in setting the minimum or enhancing the cable fire
performance requirement for the structured cabling industry. A hierarchy of fire performance levels
mapped to the installation practices plus mandatory cable fire performance markings will definitely
enhance risk assessment and provide an additional tool to effective risk management. The key
message is that ‘the right cable should be installed in the right environment’ so as to reduce risk to
fire hazard.
SYSTIMAX® SCS has a range of communication cables that are suitable for premise cabling.
Tables 5 to 8 provide a summary of the fire performance properties and rating of copper cables.
8/17/2019 C044 Fire Tutorial WP Aug 05
14/26
14
CommScope Solutions Proprietary
Use pursuant to Company instructions
SYSTIMAX PowerSum Cable TypesProperties
1061C-004 1061C-025 2061B-004 3051A-004 3061A-004 4061A-004
Jacket PVC PVC LSPVC LSZH LSZH FEP
Insulation HDPE HDPE FEP HDPE HDPE FEP
− − − − − − Fire Resistance
IEC 60331 N N N N N N− + + + − − − + + +
Y Y Y NT NT Y
N
(Y: 1061B)
Y Y N N Y
N N Y N N Y
N N N N N Y
Y Y Y Y Y Y
Flame Spread/Fire Retardance
CMCMR
CMP
Limited Comb.IEC 60332-1
IEC 60332-3a
Y NT Y N Y Y
Heat ReleaseRate/Total Heat
Release− − + − − + +
− − − − + + + + +
N N Y N N Y
SmokeCMP
IEC 61034 N N NT Y Y NT
Toxicity − − − − − −
− − − − − + + − Acid GasIEC 60754-2 N N N Y Y N
SmokeCorrosivityIEC 60695-5-3:
Leakage current
− − − − + − − + +
Notes:
N Non-compliance NT Not Tested
a Cables that are tested to meet IEC 60332-3 are tested to meet Category A.
Table 5: Summary of SYSTIMAX PowerSum cable fire performance properties and rating
8/17/2019 C044 Fire Tutorial WP Aug 05
15/26
15
CommScope Solutions Proprietary
Use pursuant to Company instructions
SYSTIMAX GigaSPEED XL Cable TypesProperties
1071E-
004 2071E-
004
3071E-
004
3071E3-
004
1081A-
004
2081A-
004
3081A-
004
Jacket PVC LSPVC LSZH LSZH PVC LSPVC LSZH
Insulation HDPE FEP HDPE HDPE HDPE FEP HDPE
− − − − − − − Fire ResistanceIEC 60331 N N N N N N N
− + + − − − − + + −
Y Y NT NT Y Y NT
Y Y N N Y Y N
N Y N N N Y N
N N N N N N N
Y Y Y Y Y Y Y
Flame Spread/
Fire RetardanceCMCMRCMP
Limited Comb.IEC 60332-1
IEC 60332-3 a NT Y N Y NT Y YHeat ReleaseRate/Total Heat
Release− + − − − + −
− − + + + − − + +
N Y N N N Y N
SmokeCMP
IEC 61034 N NT Y Y N NT Y
Toxicity − − − − − − −
− − + + − − + Acid GasIEC 60754-2 N N Y Y N N Y
SmokeCorrosivityIEC 60695-5-3:
Leakage current
− − + − − − − + −
Note:
N Non-compliance NT Not Tested
a Cables that are tested to meet IEC 60332-3 are tested to meet Category A.
Table 6: Summary of SYSTIMAX GigaSPEED XL cable fire performance properties and
rating
8/17/2019 C044 Fire Tutorial WP Aug 05
16/26
16
CommScope Solutions Proprietary
Use pursuant to Company instructions
SYSTIMAX GigaSPEED X10D Cable TypesProperties
1091A-004 2091A-004 3091A-004
Jacket PVC LSPVC LSZH
Insulation HDPE FEP HDPE
− − − Fire Resistance
IEC 60331 N N N− + −
Y Y NT
Y Y N
N Y N
N N N
Y Y Y
Flame Spread/Fire Retardance
CMCMRCMPLimited Comb.
IEC 60332-1
IEC 60332-3 a
NT Y Y
Heat ReleaseRate/Total HeatRelease
− + −
−
−
+
+
N Y N
SmokeCMPIEC 61034 N NT Y
Toxicity − − −
− − + Acid GasIEC 60754-2 N N Y
Smoke Corrosivity
IEC 60695-5-3:Leakage current
− − + −
Note: N Non-compliance
NT Not Testeda Cables that are tested to meet IEC 60332-3 are tested to meet Category A.
Table 7: Summary of SYSTIMAX GigaSPEED X10D cable fire performance properties and
rating
8/17/2019 C044 Fire Tutorial WP Aug 05
17/26
17
CommScope Solutions Proprietary
Use pursuant to Company instructions
SYSTIMAX Category 3 Cable TypesProperties
1010A-xxx 2010B-xxx 3010-xxx
Jacket PVC LSPVC LSZH
Insulation PVC PVC HDPE
− − − Fire Resistance
IEC 60331 N N N− + −
Y Y NT
Y Y N
N Y N
N N N
Y Y Y
Flame Spread/Fire Retardance
CMCMRCMPLimited Comb.
IEC 60332-1
IEC 60332-3 a
Y Y N
Heat ReleaseRate/Total HeatRelease
− + −
−
−
+
+
N Y N
SmokeCMPIEC 61034 N NT Y
Toxicity − − −
− − + Acid GasIEC 60754-2 N N Y
Smoke Corrosivity
IEC 60695-5-3:Leakage current
− − + −
Note: N Non-compliance
NT Not Testeda Cables that are tested to meet IEC 60332-3 are tested to meet Category A.
Table 8: Summary of SYSTIMAX Category 3 cable fire performance properties and rating
8/17/2019 C044 Fire Tutorial WP Aug 05
18/26
18
CommScope Solutions Proprietary
Use pursuant to Company instructions
Annex A
ABBREVIATIONS
ABI: Association of British Insurers
ASTM: American Society for Testing and Materials
BRE/FRS: Building Research Establishment/Fire Research Station
CEN: European Committee for Standardization
CENELEC: European Committee for Electrotechnical Standardization
CPD: Construction Product Directive
CSA: Canadian Standards Association
DEER: Digital Electronic Equipment Reliability
DETR (UK): Department of Transport and the Regions (UK)
EVA: Ethylene-Vinyl-Acetate
FSI: Flame Spread Index
FRG: Fire Regulators GroupHCL: HydroChLoric
IEC: International Electrotechnical Committee
IWCS: International Wire and Cable Symposium
LPC: Loss Prevention Council
LSZH: Low Smoke Zero Halogen
NBS: National Board of Standards
NEC: National Electrical Code
NEMA: National Electrical Manufacturers Association
NES: Naval Engineering Standard (UK)
NFPA: National Fire Protection Association
NFPRF: National Fire Protection Research Foundation NMV: Non-Metallic Volume
PVC: PolyVinyl Chloride
SBI: Single Burning Item
SDI: Smoke Developed Index
UL: Underwriters Laboratories
8/17/2019 C044 Fire Tutorial WP Aug 05
19/26
19
CommScope Solutions Proprietary
Use pursuant to Company instructions
Annex B
Figure B.1: IEC 60331 Test
8/17/2019 C044 Fire Tutorial WP Aug 05
20/26
20
CommScope Solutions Proprietary
Use pursuant to Company instructions
Figure B.2: IEC 60332-3 Test
8/17/2019 C044 Fire Tutorial WP Aug 05
21/26
21
CommScope Solutions Proprietary
Use pursuant to Company instructions
Figure B.3: EN 13823 (SBI) Test
8/17/2019 C044 Fire Tutorial WP Aug 05
22/26
22
CommScope Solutions Proprietary
Use pursuant to Company instructions
Figure B.4: UL 910/EN 50289-4-11 Test
8/17/2019 C044 Fire Tutorial WP Aug 05
23/26
23
CommScope Solutions Proprietary
Use pursuant to Company instructions
Figure B.5: IEC 61034 (EN 50268) Test
{Often referred to as the 3 metre cube smoke test}
8/17/2019 C044 Fire Tutorial WP Aug 05
24/26
24
CommScope Solutions Proprietary
Use pursuant to Company instructions
Figure B.6: IEC 60754-2 Test
8/17/2019 C044 Fire Tutorial WP Aug 05
25/26
25
CommScope Solutions Proprietary
Use pursuant to Company instructions
Annex C
IEC 60332-3 Category A, B UL 1666
Length of test sample 3.5 m (11.5 ft) 3.7 m (12 ft)
Cable orientation Vertical Vertical
Cable layers and
spacing
Number of layers depends on NMV.
Touching for cable diameter ≤ 6.7 mm
Single layer touching
Ignition source 73.8 MJ/hr
(20.5 kW or 70,000 BTU/hr)
556 MJ/hr
(154.4 kW or 527,000 BTU/hr)
Flame application time 40 mins 30 mins
Air velocity 5000 litre/min
(0.083 m3/s)
3.5 m/s
Low smoke requirement None None
Pass/Fail criteria Charred portion < 2.5 m (8.2 ft) above
bottom edge of burner (Flame extinguish
after 1 hr).
Cables cannot propagate flame
to 3.7 m (12 ft) and maximum
temperature is not to exceed
454.4 °C.
Table C.1: Comparison between IEC 60332-3 Category A, B and UL 1666 (CMR/OFNR
rating)
IEC 60332-3 Category C, D UL 1581 Vertical Tray
Length of test
sample
3.5 m (11.5 ft) 2.4 m (8 ft)
Cable orientation Vertical Vertical
Cable layers and
spacing
Number of layers depends on NMV.
Touching for cable diameter ≤ 6.7 mm
Single layer.
1
2 cable diameter spacing
Ignition source 73.8 MJ/hr
(20.5 kW or 70,000 BTU/hr)
73.8 MJ/hr
(20.5 kW or 70,000 BTU/hr)
Flame application
time
20 mins 20 mins
Air velocity 5000 litre/min
(0.083 m3/s)
5 m/s
(0.65 m3/s)
Low smoke
requirement
None None
Pass/Fail criteria Charred portion < 2.5 m (8.2 ft) above
bottom edge of burner (Flameextinguish after 1 hr).
Cables damage height is to be less than
8 ft.
Table C.2: Comparison between IEC 60332-3 Category C, D and UL 1581 Vertical Tray
(CM/OFN rating)
Note: UL 1685 uses the UL 1581 test method but with peak smoke release rate and total smoke
requirements added.
8/17/2019 C044 Fire Tutorial WP Aug 05
26/26
26
Annex D
Class Test method(s) Classification criteria Additional
classification
Aca EN ISO 1716 PCS ≤ 2,0 MJ/kg (1) andPCS ≤ 2,0 MJ/kg (2) and
FIPEC20 Scen 2 (6)
And
FS ≤ 1.75 m and
THR 1200s ≤ 10 MJ and
Peak HRR ≤ 20 kW and
FIGRA ≤ 120 Ws-1
B1ca
EN 50265-2-1 H ≤ 425 mm
Smoke production (3, 7) andFlaming droplets/particles
(4) and Acidity (5)
FIPEC20 Scen 1 (6)
And
FS ≤ 1.5 m; and
THR 1200s ≤ 15 MJ; and
Peak HRR ≤ 30 kW; and
FIGRA ≤ 150 Ws-1
B2ca
EN 50265-2-1 H ≤ 425 mm
Smoke production (3, 8) andFlaming droplets/particles
(4) and Acidity (5)
FIPEC20 Scen 1 (6)
And
FS ≤ 2.0 m; and
THR 1200s ≤ 30 MJ; and
Peak HRR ≤ 60 kW; and
FIGRA ≤ 300 Ws-1
Cca
EN 50265-2-1 H ≤ 425 mm
Smoke production (3, 8) andFlaming droplets/particles(4) and Acidity (5)
FIPEC20 Scen 1 (6)
And
THR 1200s ≤ 70 MJ; and
Peak HRR ≤ 400 kW; and
FIGRA ≤ 1300 Ws-1
Dca
EN 50265-2-1 H ≤ 425 mm
Smoke production (3, 8) andFlaming droplets/particles(4) and Acidity (5)
Eca EN 50265-2-1 H ≤ 425 mm
Fca No performance determined
(1) For the product as a whole, excluding metallic materials.
(2) For any external component (i.e. sheath) of the product.(3) s1 = TSP1200 ≤ 50 m
2 and Peak SPR ≤ 0.25 m2/s
s1a = s1 and transmittance in accordance with EN 50268-2 ≥ 80%s1b = s1 and transmittance in accordance with EN 50268-2 ≥ 60% < 80%
s2 = TSP1200 ≤ 300 m2 and Peak SPR ≤ 1.5 m2/s
s3 = not s1 or s2
(4) For FIPEC20 Scenarios 1 and 2: d0 = No flaming droplets/particles within 1200 s; d1 = No flaming droplets/ particles persisting longer than 10 s within 1200 s; d2 = not d0 or d1.
(5) EN 50267-2-3 : a1 = conductivity < 2.5 µS/mm and pH > 4.3 ; a2 = conductivity < 10 µS/mm and pH > 4.3;
a3 = not a1 or a2. No declaration = No Performance Determined.(6) Air flow into chamber shall be set to 8000 ± 800 l/min.
FIPEC20 Scenario 1 = prEN 50399-2-1 with mounting and fixing according to Annex 2FIPEC20 Scenario 2 = prEN 50399-2-2 with mounting and fixing according to Annex 2
(7) The smoke class declared for class B1ca cables must originate from the FIPEC20 Scen 2 test.(8) The smoke class declared for class B2ca, Cca, Dca cables must originate from the FIPEC20 Scen 1 test.
Symbols used: PCS – gross calorific potential; FS – flame spread (damaged length); THR – total heat release; HRR – heat
release rate; FIGRA – fire growth rate; TSP – total smoke production; SPR – smoke production rate; H – flame spread.
Table D.1: Proposed EuroClasses of reaction to fire performance for cables (as in EC
CONSTRUCT 04/652, April 2004)