C044 Fire Tutorial WP Aug 05

8/17/2019 C044 Fire Tutorial WP Aug 05

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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


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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.


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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.


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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.


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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.


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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

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• 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.


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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.


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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.


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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


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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


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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


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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.


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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


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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


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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


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


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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


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


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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


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Annex B

Figure B.1: IEC 60331 Test


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Figure B.2: IEC 60332-3 Test


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Figure B.3: EN 13823 (SBI) Test


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Figure B.4: UL 910/EN 50289-4-11 Test


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Figure B.5: IEC 61034 (EN 50268) Test

{Often referred to as the 3 metre cube smoke test}


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Figure B.6: IEC 60754-2 Test


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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.


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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



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



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)

Documents

C044 Fire Tutorial WP Aug 05