Technical Lib

Fire Performance Systems&Cables

INTRODUCTION

A working fire detection and alarm system will increase the level of safety in a building by automatically warning occupants of fire before they would otherwise detect it.

To ensure the system works, the system must be designed correctly, products must be correctly selected and the systems must be correctly installed and maintained. It is recommended that all systems are designed, installed, commissioned and maintained by contractors who are approved by LPCB to LPS 1014 and that they are connected to Alarm Receiving Centres approved to LPS 1020.

Listings in this section include:

Products

· Control and indicating equipment including voice alarm and power supplies
· Wireless, flame, beam, aspirating, smoke, heat and multi-sensor detectors
· Manual call points
· Line units including input and output devices
· Alarm warning devices including visual alarms, loudspeakers and sounders
· Cables
· Alarm transmission equipment
· Signalling systems

Products are approved in accordance with a range of standards. The details of these standards are given at the front of each section relevant to the product. Some of the above products may be hard wired or wireless (Radio link). Wireless products should also be approved to EN 54-25.

Systems

Fire detection and alarm systems are approved for system compatibility in accordance with:
· LPS 1054: Requirements and testing procedures for the approval and listing of component compatibility for fire detection and alarm systems.
· EN 54 - Part 13: Compatibility assessment for system components.

Design, installation, commissioning and maintenance contractors

Contractors are approved in accordance with:
· LPS 1014: Requirements for certificated fire detection and alarm system firms.
· LPS 1020: Alarm Receiving Centres


Fire rated cables

This section is split into two categories, section 8.1 fire resistant cables and section 8.2 fire retardant cables.

Both types of cables are required to perform differently in the event of a fire.

Fire resistant cables are designed such that in the event of a fire they maintain circuit integrity

Fire retardant cables are designed such that in the event of a fire they limit the generation and spread of fire and smoke.


Fire resistant cables

This section lists fire resistant cables for use in fire safety, fire detection and fire alarm systems and other applications where specifications require cables with specific performance in the event of a fire.

BS 5839-1:2013 Fire detection and fire alarm systems for buildings. Code of practice for system design, installation, commissioning and maintenance

BS 5839-1:2013 includes requirements for fire resistant cables for fire detection and alarm systems. It calls for 'Standard' and 'Enhanced' fire resistant cables and defines the requirements for these in Clause 26.2. These cables have to comply with EN 60702-1 (with a polymeric sheath), BS 7629-1 or BS 7846.

'Standard' fire resisting cables also have to:
a) achieve at least Class PH30 when tested in accordance with EN 50200:2006.
and
b) maintain circuit integrity when exposed to a special flame / mechanical shock / water spray sequence equivalent to achieving a duration of 30 minutes when tested in accordance with EN 50200:2006 Annex E.

'Enhanced' fire resisting cables also have to:
a) achieve a 120 minute survival when tested in accordance with EN 50200:2006,
and
b) maintain circuit integrity when exposed to a special flame / mechanical shock / water spray sequence equivalent to achieving a duration of 120 minutes when tested in accordance with BS 8434-2:2003+A2:2009.

Only cables complying with these requirements are listed as 'Standard' or 'Enhanced' under BS 5839-1, Clause 26.2.

BS 8519:2010 Selection and installation of fire-resistant power and control cable systems for life safety and fire-fighting applications - Code of practice

BS 8519:2010 gives guidance and recommendations on the selection and installation of power and control cable systems which are required to maintain their circuit integrity for life safety and fire-fighting applications. It also gives specific recommendations for electrical system design for such applications, and recommended limits for survival times.

Category 1: means of escape (30 min fire survival time).

Category 3: fire-fighting (120 min fire survival time)
.
Building Regulations 2010 - Fire Safety - Approved Document B
The Building Regulations 2010 - Fire Safety - Approved Document B - Volume 2 - Buildings other than dwelling houses defines a protected power circuit to be able to continue to function during a fire. A protected circuit for operation of equipment in the event of fire should consist of a cable meeting at least the requirements of PH30 when tested in accordance with EN 50200. Larger or complex buildings may require fire protection systems to operate for extended periods during fire and guidance on such systems is given in BS 5839-1, BS 5266-1 and BS 8491 (BS 7346-6).

Other Standards Used
The other standards and test methods currently used for certification are listed below. This list includes some "withdrawn" standards. Where possible, these will be replaced by the superseding standards when certificates are renewed. However, where withdrawn standards are called up by current standards, certification to the withdrawn standard may need to be maintained until the calling standard is amended to remove the reference:

- BS 6387:1994 Performance requirements for cables required to maintain circuit integrity under fire conditions
- BS 7629-1:1997 Thermosetting insulated cables with limited circuit integrity when affected by fire. Part 1: Multicore cables
- BS 7629-1:1997 (Incorporating Amendment Nos.1 and 2) Thermosetting insulated cables with limited circuit integrity when affected by fire. Part 1: Multicore cables (The provisions introduced by amendment No.1: 2004 are effective from 1st April 2004)
- BS 7629-1:2008 Electric cables - Specification for 300/500 V fire resistant screened cables having low emission of smoke and corrosive gases when affected by fire - Part 1: Multicore and multipair cables
- BS 7846:2000 Electric cables 600/1000V armoured fire-resistant cables having thermosetting insulation and low emission of smoke and corrosive gases when affected by fire
- BS 7846:2009 Electric cables - Thermosetting insulated, armoured, fire - resistant cables of rated voltage 600/1 000 V, having low emission of smoke and corrosive gases when affected by fire - Specification
- BS 8434-2:2003+A2:2009 Method of test for assessment of the fire integrity of electric cables - Part 2: test for unprotected small cables for use in emergency circuits- EN 50200 with a 930°C flame and with water spray
- BS 8491:2008 Method for assessment of fire integrity of large diameter power cables for use as components for smoke and heat control systems and other certain active fire safety systems
- BS 8519:2010 Selection and installation of fire-resistant power and control cable systems for life safety and fire-fighting applications - Code of practice
- EN 50200:2006 Method of test for resistance to fire of unprotected small cables for use in emergency circuits
- EN 50267-2-1:1999 Common test method for cables under fire conditions- tests on gases evolved during combustion of materials from cables - procedures - Determination of the amount of halogen acid gas
- EN 50267-2-3:1999 Common test methods for cables under fire conditions - Tests on gases evolved during combustion of materials from cables - Procedure 2-3: Procedures - Determination of degree of acidity of gases for cables by determination of the weighted average of pH and conductivity
- EN 60332-3:2009 Tests on electric and optical fibre cables under fire conditions - Part 3: Test for vertical flame spread of vertically mounted bunched wires or cables
- EN 60702-1:2002 Mineral insulated cables and their terminations with rated voltage not exceeding 750V - Part 1: Cables
- EN 61034-2:2005 Measurement of smoke density of cables burning under defined conditions - Part 2: Test procedure and requirements (IEC 61034-2)
- EN 61034-2: 2005 Measurement of smoke density of cables burning under defined conditions
- IEC 60331-1:2009 - Tests for electric cables under fire conditions - Circuit integrity - Part 1: Test method for fire with shock at a temperature of at least 830°C for cables of rated voltage up to and including 0,6/1,0kV and with an overall diameter exceeding 20mm.
- IEC 60331-2:2009 - Tests for electric cables under fire conditions - Circuit integrity - Part 2: Test method for fire with shock at a temperature of at least 830°C for cables of rated voltage up to and including 0,6/1,0kV and with an overall diameter not exceeding 20mm.
- IEC 60331-21:1999 Tests for electric cables under fire conditions - Circuit integrity - Part 21 Procedure and requirements - Cables of rated voltage up to and including 0,6/1,0kV
-
IEC 60332-3:2009 Tests on electric cables under fire conditions - Part 3: Tests on bunched wires or cables
- IEC 60754-1:2011 Tests on gases evolved during combustion of materials from cables - Part 1: Determination of the amount of halogen acid gas
- IEC 60754-2:2011 Tests on gases evolved during combustion of materials from cables - Part 2: Determination of acidity (by pH measurement) and conductivity
- IEC 61034-2:2005 Measurement of smoke density of cables burning under defined conditions

Notes:
1) The rated voltages Uo/U recognised for BS 6387:1994 are, 300/500V and 450/750V, and for BS 7629-1 are 300/500V, where Uo is the power-frequency voltage to earth and U is the power-frequency voltage between conductors.
2) Testing of single core cable to BS 6387:1994 is not recognised by the standard. This is because it requires the cable to have at least two metallic elements. Therefore LPCB approval of single core cable is based on the cable being tested in a stainless steel conduit.
3) All BS 6387 approvals must include EN 50267-2-1 (acid gas) and EN 61034-2 (smoke density) testing
4) MICC Cables approved to BS 5839-1:2002+A2:2008 Clause 26.2 must be sheathed with an overall polymeric covering.
5) EN 50200:2006 Annex E and BS 8434-2:2003+A2:2009 provide methods of test that meet the requirements for a special flame / mechanical shock / water spray sequences described in BS 5839-1:2013, Clause 26.2 d) and e), respectively.
6) BS 8491 does not cover cables with a voltage rating that exceeds 600/1000V or where the external cable diameter is less than 20mm.
7) BS 8519 standard covers both Power and Control cables; different test methods apply to each cable type. Control cables up to & including 4.0mm2 can be approved to BS 8519.


Fire retardant cables

This section lists fire retardant cables for use in fire safety, fire detection and fire alarm systems and other applications where specifications require cables with specific performance in the event of a fire.

Flame retardant cables are designed with the objective of limiting the generation and spread of fire and smoke.


The below list is typical of the standards to which apply to fire retardant cables

EN 50267-2-1:Common test method for cables under fire conditions- tests on gases evolved during combustion of materials from cables - procedures - Determination of the amount of halogen acid gas

      Fire Performance Standard

American & Canadian

Fire Resistance Level

Test Requirement

NEC Article

NEC Article

NEC Article

NEC Article

800

770

725

760

Communication/ Multipurpose Cable

Optical Fibre Cable

Class 2/3 Cable

Power Limited, Fire protective signaling circuit cable

Residential Cables

Restricted use (Lowest)

UL1581 VW-1 CSA-FT1

CMX

N.A.

CL3X CL2X

N.A.

General Purpose Cables

UL-1581 (Vertical Tray)

CSA-FT4 (Vertical Tray)

MP CM

OFN OFC

CL3 CL2

FPL

Riser Communication Cables

UL1666 (Vertical Shaft)

CSA-FT4 (Vertical Tray)

MPP CMR

OFNR OFCR

CL3R CL2R

FPLR

Plenum Communication Cables (Highest)

UL-910 (Steiner Tunnel)

CSA-FT6 (Steiner Tunnel)

MPP CMP

OFNP OFCP

CL3P CL2P

FPLP


European

Property

Grade

Applicable Standard

Definition

Flame Retardancy

PVC/LSZH

IEC 332-1

A single cable is clamped vertically in a metal screen and a flame is applied for 60 sec. The cable has to be self extinguishing.

CEI 20-35

Reduced flame propagation

PVC/LSZH

IEC 332-3A/B/C

The test measures the non propagation of fire of a bunch of cables. With a number of cable pieces of 3.5m long each, the cable are subject to burning by a horizontal flame for 20 mins (part C) or 40 mins (part A) and must not burn for more than 2.5m from the top of the burner.

VDE 0472, part 804 A/B/C

BS 4066 part 3A/B/C

CEI20-22 2/3

NBN C30.004

NFC 32070 C1-C2

IEEE 383

Smoke Density

LSZH

IEC 1034 part 1 & 2

The test measures the level of light transmittance of the sample prepared per IEC 1034-2 using the apparatus specified IEC 1034+1. It measures the value of smoke generated (AO) in a 3m cube test chamber.

VDE 0472 part 816

BS 6742

CEI 2037-3

NFF 16101

UNE 21-172 part 1&2

ASTM E-662

Acid Gas Emission (Halogen Content)

LSZH

IEC 754 part 1

The test measures the halogen gas (HCL) content evolved during combustion. The 0.5% acid has been accepted as a working definition of zero halogen.

VDE 0472 part 815

BS 6425-part 1

CEI 2037-1

UNE 21-147 P1

Corrosive Gas Emission

LSZH

IEC 754-part 2

The amount of acid gas evolved during combustion is expressed in terms of a) conductivity of a solution of the gas in water, in which case the lower the result the lower the acid gas concentration and b) the pH of the solution, in which case the lower the value the higher the acid gas concentration.

VDE 0472 part 813

BS 6425-part2

UNE 21-147 P2

Toxicity Index

LSZH

NES 713

A analysis of the gases evolved when the test specimen is burned and a toxicity index is calculated from the analysis, being weighted according to the known toxicity of the gas present.

CEI 2037-2

UNE 21-174

UITP vol 1

NFF 63808 NFF 16101

Oxygen Index

LSZH

BS 2782-1Method 141

This test gives a measure of the polymers flammability characteristics. It measures the minimum concentration of oxygen in an atmosphere of oxygen and nitrogen which will just sustain combustion of the test specimen.

ASTM S-2863

ISO 4589-2

Flammability Temperature Index

LSZH

BS 2782-1 Method 143

With the oxygen concentration kept constant at 21% in the oxygen index test, the test temperature is varied until the combustion is just sustained.

NES 715

ISO 4589-3