CEN/TS 14972:2011

SLOVENSKI STANDARD
01-oktober-2011
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SIST-TS CEN/TS 14972:2008
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Fixed firefighting systems - Watermist systems - Design and installation
Ortsfeste Brandbekämpfungsanlagen - Feinsprüh-Löschanlagen - Planung und Einbau
Installations fixes de lutte contre l'incendie - Systèmes à brouillard d'eau - Conception et
installation
Ta slovenski standard je istoveten z: CEN/TS 14972:2011
ICS:
13.220.10 Gašenje požara Fire-fighting
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION
CEN/TS 14972
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
June 2011
ICS 13.220.20 Supersedes CEN/TS 14972:2008
English Version
Fixed firefighting systems - Watermist systems - Design and
installation
Installations fixes de lutte contre l'incendie - Systèmes à Ortsfeste Brandbekämpfungsanlagen - Feinsprüh-
brouillard d'eau - Conception et installation Löschanlagen - Planung und Einbau
This Technical Specification (CEN/TS) was approved by CEN on 28 September 2010 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 14972:2011: E
worldwide for CEN national Members.

Contents Page
Foreword .4
Introduction .5
1 Scope .6
2 Normative references .6
3 Terms and definitions .7
4 Requirements . 11
4.1 General . 11
4.2 Exclusions . 11
4.3 Local applications. 12
4.4 Volume protection . 12
4.5 Other considerations . 13
5 Activation and control . 13
5.1 General . 13
5.2 Electrical activation and control . 14
5.3 Non-electrical activation . 16
6 Design and installation . 16
6.1 General . 16
6.2 Pipes and fittings . 17
6.3 Pipe supports . 17
6.4 Hydraulic and pneumatic circuits . 17
6.5 Non-return valves . 18
6.6 Drainage . 18
6.7 Pressure gauges/monitoring . 18
6.8 Electrical Design . 18
6.10 Nozzle . 19
6.11 Air velocity, openings and ventilation . 19
6.12 Hydraulic and pneumatic calculations . 19
6.13 Automatic shut-down . 20
6.14 Enclosure requirements . 20
7 Components . 20
7.1 Nozzles . 20
7.2 Piping and fittings. 21
7.3 Control valves . 22
7.4 Pressure regulating valves . 22
7.5 Shut-off valves . 22
7.6 Check valves . 22
7.7 Safety valves . 22
7.8 Strainers . 22
7.9 Water supply components . 23
8 Water supply, including additives. 23
8.1 General . 23
8.2 Water quality . 23
8.3 Additives . 24
8.4 Duration . 25
8.5 Continuity . 25
8.6 Maximum and minimum water pressure . 26
8.7 Test devices . 26
8.8 Type of water supply . 26
8.9 Pressurization systems . 27
9 Acceptance tests and maintenance . 30
9.1 Acceptance test . 30
9.2 Commissioning report . 31
9.3 Inspection, maintenance and training . 31
10 Documentation . 32
10.1 Documentation for system and type approval . 32
10.2 Documentation for acceptance of design, installation and commissioning . 32
Annex A (normative) Test protocols . 34
A.1 Test protocol for flammable liquids (control and suppression systems) . 34
A.2 Fire test protocol for cable tunnels (control and suppression systems) . 37
A.3 Fire test protocol for office occupancies of Ordinary Hazard Group 1 . 42
A.4 Test protocol for the firefighting performance in commercial kitchen of type deep fat
fryers . 52
Annex B (informative) Guidelines for developing representative fire test procedures for watermist
systems . 58
B.1 General . 58
B.2 Evaluation of the fire hazard . 58
B.3 Evaluation of the compartment conditions . 59
B.4 Determining the performance objective . 60
B.5 Setting up the fire test procedure . 60
B.6 Carrying out the test . 62
B.7 Documentation and interpretation of test results . 62
Annex C (informative) Determination of drop size distribution . 64
C.1 Parameters . 64
C.2 Test data . 64
C.3 Data processing . 65
Annex D (informative) Testing of nozzles . 68
Annex E (informative) Function tests for acceptance and maintenance . 73
E.1 Preliminary function tests . 73
E.2 System function operational test . 73
Annex F (normative) Fire test procedure for certain occupancies Ordinary hazard group OH3 . 75
F.1 Object of the test . 75
F.2 Fuel packages . 76
F.3 Determination of acceptance criteria . 79
F.4 Test procedure . 79
F.5 Evaluation of the test results . 81
Bibliography . 82

Foreword
This document (CEN/TS 14972:2011) has been prepared by Technical Committee CEN/TC 191 “Fixed
firefighting systems”, the secretariat of which is held by BSI.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes CEN/TS 14972:2008.
This Technical Specification (TS) was adopted by CEN for which there is the future possibility of agreement
on a European Standard, but for which at present:
 the required support for approval as a European Standard cannot be obtained;
 there is doubt on whether consensus has been achieved;
 the subject matter is still under technical development.
This Technical Specification is established with a view to serving, for instance, the purpose of:
 publishing aspects of a subject which may support the development and progress of the European
market;
 giving guidance to the market on or by specifications and related test methods;
 providing specifications in experimental circumstances and/or evolving technologies.
The CEN members are requested to submit their comments and experiences with the use of these
requirements and recommendations to the Secretariat of the responsible Technical Committee CEN/TC 191.
CEN/TC 14972:2008 was reviewed and replaced with this new edition.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Croatia, Cyprus,
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.

Introduction
The main purpose of this document is to provide information about the minimum requirements on watermist
systems.
This document describes a series of specific test conditions to set out criteria capable of verifying performance
claims of watermist systems, classify and determine the extent of their suitability for intended applications,
whilst setting a minimum level of acceptable performance and/or safety.
As individual watermist applications have varied requirements and duty, this document is intended to apply to
both skidded stand alone and pumped systems. It is the approving authority's responsibility to assess and
implement the design manual of specific watermist systems against the tests set out in this document.
1 Scope
This Technical Specification specifies minimum requirements and gives information on design, installation and
testing and gives criteria for the acceptance of fixed landbased watermist systems for specific hazards and
provides fire test protocols for a variety of hazard groups.
The requirements are not valid for watermist systems on ships, in aircraft, on vehicles and mobile fire
appliances or for below ground systems in the mining industry.
Aspects of watermist associated with explosion protection are beyond the scope of this document.
The fire tests in this document apply to the applications as described in Annex A. Extrapolation is not covered.
The document is not a universal design manual for watermist systems, as different systems have different
characteristics and hence follow different design criteria to satisfy their duty requirements.
In the absence of a generalized design method, it is the intent of this document that watermist systems are
full-scale fire tested and its system component evaluations are conducted by qualified testing laboratories.
The full system acceptance requires the relevant fire test report, the component test report(s) as well as
manufacturer's design, installation, operation and maintenance manual for the application.
If the gas in the system is a significant factor for extinguishment/suppression, the relevant parts of EN 12094
and EN 15004-1 are applicable.
Firefighting systems in accordance with EN 12845 and water spray systems are not covered.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 54 (all parts), Fire detection and fire alarm systems
EN 12094 (all parts), Fixed firefighting systems ― Components for gas extinguishing systems
EN 12259 (all parts), Fixed firefighting systems ― Components for sprinkler and water spray systems
EN 12845:2004+A2:2009, Fixed firefighting systems ― Automatic sprinkler systems ― Design, installation
and maintenance
EN 13501-1:2007, Fire classification of construction products and building elements ― Part 1: Classification
using test data from reaction to fire tests
EN 15004-1, Fixed firefighting systems ― Gas extinguishing systems ― Part 1: Design, installation and
maintenance (ISO 14520-1:2006, modified)
ISO 5660-1, Reaction-to-fire tests ― Heat release, smoke production and mass loss rate ― Part 1: Heat
release rate (cone calorimeter method)
ISO 6182-11, Fire protection ― Automatic sprinkler systems ― Part 11: Requirements and test methods for
pipe hangers
ISO 6182-12, Fire protection ― Automatic sprinkler systems ― Part 12: Requirements and test methods for
grooved-end components for steel pipe systems
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
additive
chemical or mixture of chemicals, intentionally introduced into the water mist system
NOTE The additive can have one ore more of the following purposes:
 enhancement of, or compliance with, fire protection requirements,
 corrosion protection,
 frost protection.
3.2
authority having jurisdiction
organization, office, or individual responsible for approving equipment, and installation, or a procedure
3.3
automatic nozzle
watermist nozzle held closed by an integral thermal release element
NOTE see 3.39.
3.4
cooking grease
vegetable shortening incorporating an antifoaming agent
NOTE Only new greases are used for the tests.
3.5
cooking oil
cooking oil available in market with flash point value of 230 °C to 280 °C and auto ignition point between
330 °C and 445 °C
3.6
deep fat fryer
commercially available cooking appliance in which cooking greases in depth are used
NOTE Requirements are specified in EN 60335-2-37:2002.
3.7
design pressure
maximum working pressure expected to be applied to a system component
NOTE 1 The design pressure is an important parameter for the determination of the strength of components.
NOTE 2 The systems are defined by the following values:
 for low pressure systems: up to 12,5 bar;
 for medium pressure systems: higher than 12,5 bar, but below 35 bar;
 for high pressure systems: 35 bar and higher.
3.8
discharge duration
accumulated time during which fire fighting medium is applied
NOTE The time is given in minutes.
3.9
discharge time
time interval between the first appearance of extinguishing agent at the nozzle and the time at which the
discharge becomes predominantly gaseous or ceases
NOTE The discharge time is expressed in seconds.
3.10
domestic occupancy
individual dwelling for occupation as a single family unit or constructed or adapted to be used wholly or
principally for human habitation
3.11
dry pipe system
watermist system using automatic nozzles attached to a piping system containing air, nitrogen, or inert gas
under pressure, the release of which (as from an opening of an automatic nozzle) allows the water to flow
NOTE The water flows into the piping system and out through any activated nozzles.
3.12
fire control
limitation of fire growth and prevention of structural damages (by cooling of the objects, adjacent gases and/or
by pre-wetting adjacent combustibles)
NOTE The heat release rate does not grow.
3.13
fire extinguishment
complete elimination of any flaming or smouldering fire
3.14
firefighting medium
substance which causes fire extinguishment, suppression or control
NOTE Media for use in watermist systems: demi water, potable and sweet industrial water, and water with additives
are relevant.
The terminology includes the following:
a) water only, i.e. potable water, natural sea water, deionized water;
b) water with antifreeze;
c) water with fire extinguishing enhancing additive;
d) combination of a),b) and c) with an inert gas or a blend of inert gases used primarily to atomize the water and/or to
reduce oxygen concentration at the fire (see 3.25).
3.15
fire suppression
sharp reduction in the heat release rate and prevention of re-growth of the fire
NOTE The heat release rate decreases.
3.16
flash-over prevention
reducing the average temperature inside the protected volume to a temperature where the smoke layer with
combustion products do not ignite
3.17
inspection
most frequent scheduled maintenance procedure
3.18
installation (watermist)
part of a watermist system comprising a control valve set, the associated downstream pipes and nozzles
3.19
local application system
watermist system designed to protect a particular object or hazard in an enclosed, unenclosed or outdoor
condition
3.20
maintenance
combination of all technical and administrative actions, including supervision actions, intended to retain an
item in, or restore it to, a state in which it can perform a required function
[EN 50126-1:1999]
3.21
manufacturer's design and installation manual
document containing design rules for all details of a water mist system based on successful fire tests
3.22
maximum discharge rate
ratio of the quantity of extinguishing agent discharged from a nozzle to the discharge time measured within
± 1 s
NOTE The ratio is expressed in litres per minute for the maximum pressure.
3.23
mean discharge rate
discharge rate calculated dividing the total water amount by the total discharge time
3.24
multiple vat deep fat fryer
multiple fryers which are mechanically joined together
NOTE Each vat incorporates a separately controlled heating source. The at least two fryers are separated by at least
5 cm from each other.
3.25
operating pressure
constant or time-dependent pressure at a component during discharge
3.26
preaction system
dry pipe system, in which an independent fire detection system in the protected area allows the firefighting
medium to flow into the pipework prior to the independent operation and subsequent operation of any
automatic nozzle
3.27
pump
device consisting of one or more pressurizing units directly connected to a suitable driver
3.28
preburn time
time from ignition of the fire source till the operating pressure or design flow is available at the hydraulically
most remote nozzle
3.29
qualified company
company registered by a national body or accepted by the authorities having jurisdiction for design, installation
and maintenance of fixed watermist systems and fully trained and authorized by the manufacturer
3.30
responsible person
person(s) responsible for or having effective control over fire safety provisions adopted in or appropriate to the
premises or the building
3.31
single fluid system
system which generates watermist by passage of water or water with additive through the nozzle
3.32
split vat deep fat fryer
fryer that incorporates a dividing partition which splits the fryer in sections
NOTE Each split vat fryer incorporates a separately controlled heating source. The at least two fryers are separated
by at least 5 cm from each other.
3.33
supplier
qualified company that is responsible for the product, process or service and is able to ensure that quality
assurance is exercised
3.34
system duration
total time for which the supply of fire fighting medium is designed to last
NOTE 1 The time is given in minutes.
NOTE 2 For systems with intermittent discharge it is the sum of the times of discharge and the times without discharge.
3.35
twin fluid system
system which generates watermist at the nozzle by mixing water with an atomizing gas fed from a separate
pipe(s) from the water supply
3.36
user
person or persons responsible for use and maintenance of the watermist system
3.37
volume protection system
watermist system designed to protect all hazards in an enclosed volumetric space
3.38
watermist
water spray for which the diameter D measured in a plane 1 m from the nozzle at its minimum operating
v0,90
pressure is less than 1 mm
3.39
watermist nozzle
component with one or more orifices which is designed to produce and discharge watermist
3.40
watermist system
entire means of a firefighting system connected to a water supply equipped with one or more nozzles capable
of delivering watermist to meet the requirements of this document
NOTE Watermist systems may discharge plain watermist or a mixture of watermist and some other agent or agents
like gases or additives.
3.41
wet pipe system
watermist system using automatic nozzles attached to a piping system containing water and connected to a
water supply so that water discharges immediately from nozzles operated by the heat from a fire
4 Requirements
4.1 General
Watermist systems shall only be designed, installed and maintained by qualified companies and shall comply
with the following requirements.
The safe use of a water mist system is limited to applications it has been tested for. Parameters used during
such tests define the limits of its application, unless methods being acceptable to the authorities having
jurisdiction to interpolate test results can be applied. Parameters include room geometry, ventilation
conditions, fire load, etc.
Watermist systems shall be tested in accordance with Annex A. For scenarios where Annex A is not
applicable, it is recommended to test watermist systems in accordance with Annex B by a recognized third
party laboratory. In this case, the results of the test protocol should be acceptable to the authority having
jurisdiction, responsible for the acceptance of the system.
Annex A describes fire test protocols for a variety of hazard groups. Watermist systems shall be successfully
tested in accordance with these test protocols.
Annex B provides guidelines for defining representative fire test protocols based on a proper fire protection
engineering evaluation of the fire hazard, the compartment conditions, and the performance objectives for the
system.
The full system evaluation also includes component testing. Annex D describes the testing of watermist
nozzles. For other components, a customized evaluation or review should be carried out based on existing
component standards. If no suitable component standard is available, case-by-case evaluations should be
conducted by qualified testing laboratories.
Water mist systems shall be certified in conformity to all requirements of this document by a recognized
authority.
Where a watermist system or an extension or alteration to a watermist system is being considered within new
or existing buildings, the relevant parties shall be consulted and, where necessary, their approval sought at an
early stage, e.g. the water supply authority, the fire authority; the insurer(s) of the building and building
contents.
4.2 Exclusions
4.2.1 General
Watermist systems shall be designed and installed in a way that in any case contact between water and the
following materials or substances is avoided.
4.2.2 Materials which react with water
Watermist systems shall not be used for direct application to materials that react with water to produce violent
reactions or significant amounts of hazardous products. These materials include:
a) reactive metals, such as lithium, sodium, potassium, magnesium, titanium, zirconium, uranium and
plutonium;
b) metal alkoxides, such as sodium methoxide;
c) metal amides, such as sodium amide;
d) carbides, such as calcium carbide;
e) halides, such as benzoyl chloride and aluminum chloride;
f) hydrides, such as lithium aluminum hydride;
g) oxyhalides, such as phosphorus oxybromide;
h) silanes, such as trichloromethylsilane;
i) sulfides, such as phosphorus pentasulfide;
j) cyanates, such as methylisocyanate.
NOTE These materials are allowed if stored in non-combustible containers.
4.2.3 Liquefied gases
Watermist systems shall not be used for direct application to liquefied gases at cryogenic temperatures (such
as liquefied natural gas), which boil violently when heated by water.
4.3 Local applications
Systems designed to be installed in local applications shall be tested for the associated hazard class selected
and for the main protection objective/objectives of the applications concerned.
Systems designed to be installed in multiple hazard local application areas, where protection for individual
objects is foreseen, shall be approved for all associated hazards present in the area.
If necessary additional systems/nozzles shall be installed to cover all hazards present in that area.
4.4 Volume protection
Volume protection systems shall be designed and installed for the hazards to be protected within the volume,
in accordance with the design parameters established through representative fire tests (see 6.1).
Systems designed to be installed in a multiple hazard application shall be tested and approved for all present
hazards in the volume. Where the spread of fire is likely to involve two or more enclosed volumetric spaces,
adjacent fire hazards shall be taken into account, and the watermist system shall be designed for the
combined hazard.
NOTE The installation of an automatic door closing mechanism is expected to improve the effectiveness of the
system by ensuring that any doors to the volume being protected are kept shut.
4.5 Other considerations
4.5.1 Discharge delay
For dry and preaction systems with automatic nozzles the firefighting medium shall exit from the nozzle within
60 s after activation, i.e. opening of the first nozzle. In application with open nozzles the firefighting medium
shall exit from all nozzles within 30 s after activation.
4.5.2 Selection of detection system
If a detection system is used for activation it shall be as specified in the manufacturer's design and installation
manual. The detection system shall be specified based on the results of the fire tests.
The detection system shall comply with the requirements of 6.8.3.
4.5.3 Oxygen depletion
Systems discharging into the protected volume a gas, different from air, shall comply with the safety
requirements of EN 15004-1.
The safety requirements effected by the gas concentration produced by the watermist system shall comply
with national regulations.
5 Activation and control
5.1 General
The detection and activation system can either be mechanical, hydraulic, pneumatic, or electrical. The
activation system should fulfil the following requirements, if applicable:
a) the detection system shall be installed in all zones protected by the watermist system and shall comply
with the data sheet given by the manufacturer of the activation device;
b) the temperature rating of detector shall be as close as possible to, but not less than 30 °C above, the
highest anticipated ambient temperature;
c) when air or inert gas is used, the working pressure in the system shall not exceed 3,5 bar, except if
otherwise specified by the deluge valve manufacturer;
d) detection lines shall be monitored.
Details of specific intermittent misting operations of systems and the associated modes of controls re-setting
are not specified in this European Standard, but such systems can be applied in design, as long as the above
agreed principles of system rationale are observed and followed.
Detection, actuation, alarm and control systems shall be installed, tested and maintained in accordance with
appropriate national standards.
Failure of the control panel shall not be able to stop the ongoing watermist discharge or the ongoing discharge
sequence.
Watermist systems relying on a control system for the entire discharge duration shall be fire performance
tested together with the control system.
Watermist systems shall be automatically activated, except where the authorities having jurisdiction allow only
manual activation.
The system shall be arranged so that there is no possibility of an alarm being produced in an adjacent
extinguishing zone by the fire fighting medium.
Watermist systems activated by fire detection shall be equipped with a manual triggering device.
The manual triggering device should be located near the exit, outside the protected rooms and should be
installed at normal operating height, at highly visible locations.
NOTE 1 Watermist systems with automatic nozzles do not require a manual activation.
In addition to any means of automatic operation, the system shall be provided with an emergency triggering
device of each individual triggered selector valve for providing direct mechanical actuation of the system.
NOTE 2 National standards may require the release to operate after the pre-discharge alarms and time delay.
NOTE 3 National standards may require a manual triggering device incorporating a double action or other safety
device to restrict accidental operation.
5.2 Electrical activation and control
5.2.1 General
For the design, installation and maintenance of electrically activated systems, and also for component
requirements in respect of these systems, see relevant parts of EN 54 and EN 12094.
Detection, control and activation systems shall be able to function either automatically or manually. In the case
of automatic activation, provision for manual triggering shall be provided. Detection, control and activation
systems shall be installed, commissioned and maintained in compliance with the relevant national standards.
5.2.2 Application of EN 54
The relevant part of the EN 54 series shall be applied to the detection part of watermist systems, with the
following additions:
a) In case the system is activated after the reception of two or more alarm signals, generated by automatic
fire detectors, the reception of the first signal should be indicated visibly and audibly. On the reception of
the first signal, outputs (e.g. for plant shut down) may be activated. The number of detectors compared to
standard rules for spacing of detectors to achieve a quick responding firefighting system shall be doubled.
NOTE 1 To reduce the probability of false activation, it is recommended to design the system on basis of a 2-detector
confirmation. After a "confirming" alarm from a second detector the system release starts on basis of the "programmed"
sequence of, for example, time delay on activation device, shut down protected processes, shut down of ventilation, etc.
When the water discharge of the system depends on detector signal after the first release, no flame
detectors or smoke detectors shall be used, unless the type of detector has proven its reliability in the
presence of watermist.
b) In the coverage area of the watermist system, the activation temperature of the heat detector shall be
close to but at least 30 °C above the maximum temperature to be expected during standard operation.
c) The signal from the (separate) detection system to activate the watermist control system shall be
monitored.
d) The output circuit from the watermist control system to the electrical activating device for the water
discharge shall be monitored.
e) If monitoring is required (see Table 2), in addition the following active elements of watermist systems shall
have their functions supervised for open line and/or short circuit and shall have its status signalled:
1) the system "discharged" device, i.e. pressure device or flow device;
2) the position of any valves which can inhibit the flow of the fire extinguishing media to the nozzle;
3) a maintenance isolate switch, if installed. It shall electrically isolate the electrical activating device;
4) the expellant gas pressure-switch, if installed, to monitor the operational status of the system;
5) a level-switch (in case of a water storage container) to monitor the operational status of the system;
6) the "double-action" manual release device to activate the watermist control system.
NOTE 2 Indicators for items 2, 3 and 4 may be combined in one "system-status-indicator".
The following minimum requirements for control and indicating equipment shall be implemented:
7) power supply including batteries in accordance with 6.8.3;
8) supervision of circuits of active elements;
9) a switch, to electrically isolate the circuitry of the system discharge device, shall be provided to allow
for proper testing and maintenance. The status of this switch shall be clearly indicated on the control
panel;
10) alarm functions in accordance with 5.2.4.
f) If networked ringmains (loops) are used, several actuators shall be connected within a maximum of
eight sections in one loop. Between adjacent section actuators short circuit isolators shall be installed.
5.2.3 Power supply
The electric power supply shall be independent of the supply for the hazard area and shall comply with
EN 54-4.
The emergency power supply shall be capable of keeping the system in operation for at least 24 h from first
loss of power. The electrical supply shall be exclusively for the detection and control system.
The electrical supply isolating switch for the detection and control system shall be clearly marked as follows:
DO NOT SWITCH OFF
AUTOMATIC
FIRE FIGHTING SYSTEM
The connection shall be made on the supply side of the main electrical distribution board.
5.2.4 Alarm indications
Alarms or indicators or both shall be used to indicate the operation of the system or failure of any supervised
device. The type (audible, visual), number, and location of the devices shall be such that their purpose is
satisfactorily accomplished.
The activation of a watermist system should generate an acoustic alarm and/or an optical alarm.
Alarms shall be in accordance with the requirements of the authority having jurisdiction. Audible alarms and
where appropriate visible warning signs shall be provided:
a) Fire alarm signal upon the first alarm from one of the installed detectors. The signal may be by means of
visible indication and/or an alert tone. The alarm for each installation shall be connected to a permanently
manned location.
NOTE In case of high noise levels it is advisable to install a "visual attention maker" by means of, for example, flashing
light instead of the alert sounder.
b) System Operational Status, any conditions that may effect either automatic operation, or the
effectiveness of the system installed shall cause a visual indication on the system control and indicating
device. Such conditions shall include but not be limited to the following:
1) operation of the maintenance override function;
2) failure in the fire detection system;
3) fault in the activation circuit;
4) failure in capacity of the firefighting media, i.e. low water level, low pressure expellant gas, fire
pumps;
5) status "manual" in case of a device being installed for selection of either automatic or manual
operation;
6) failure in power supply.
Fault indications shall be connected to a permanently manned location.
5.3 Non-electrical activation
Where pneumatic, hydraulic or mechanic control e
...