Abstract

This document specifies requirements and gives recommendations for the design, installation, water supplies and backflow prevention, commissioning, maintenance and testing of fixed residential fire sprinkler systems in buildings for residential occupancies.
This document is intended for use by those concerned with purchasing, designing, installing, testing, inspecting, approving, operating and maintaining automatic residential sprinkler systems, in order that such equipment will function as intended throughout its life.
This document identifies construction details of buildings which are the minimum necessary for satisfactory performance of residential sprinkler systems complying with this standard.
This document applies to any addition, extension, repair or other modification to the residential sprinkler system.
This document does not cover situations such as arson where fires of a malicious intent may be started in multiple locations simultaneously.

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Publication Date
24-Mar-2027

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FprEN 16925 is a draft European Standard from the European Committee for Standardization (CEN) for fixed firefighting systems, focused on automatic residential sprinkler systems in buildings for residential occupancies. It specifies requirements and recommendations for design, installation, water supplies, backflow prevention, commissioning, maintenance and testing so the system can function as intended throughout its life. It is intended for purchasers, designers, installers, testers, inspectors, approvers, operators and maintenance personnel.

What does FprEN 16925 specify?

FprEN 16925 specifies the technical rules for automatic residential sprinkler systems in residential buildings, including how they are planned, installed, supplied with water, commissioned, maintained and tested. It also sets out the building construction details needed for the sprinkler system to perform satisfactorily.

The document applies to additions, extensions, repairs and other modifications to an existing residential sprinkler system. It excludes malicious fires started in multiple locations at the same time, such as arson scenarios of that type.

The document is organized into clauses 1 to 18 and annexes A to J.

AnnexWhat it covers
ASprinkler system zoning
BSprinkler system monitoring
CTransmission of alarms
DHydraulic calculations
ELong-term inspection and testing of pipework and sprinklers
FSpecial circumstances
GTypical water supply arrangements
HPrecautions and procedures when a system is not fully operational
IHydraulic test
JNew technology

What are the key requirements of FprEN 16925?

FprEN 16925 ties together the building layout, hydraulic design, water supply, alarm functions and ongoing maintenance so the system remains usable over time. The most important requirements are the ones that affect protection extent, water availability, sprinkler placement and the checks needed before and after operation.

Planning, documentation and consultation

Clause 4 requires the user or owner to receive drawings and information that identify the premises, occupancies, designer, reviewer and issue details. For new work or changes to an existing system, the relevant parties should be consulted early, including the water undertaker, fire authority, building control body and insurers where relevant. In practice, this means the system is not designed in isolation - the building, water supply and approvals need to be aligned from the start.

Where the system must protect

Clause 5 requires residential sprinkler protection across the building, including covered balconies and communicating buildings, except for the permitted exceptions. Those exceptions include certain small bathrooms and toilets, unoccupied attics and roof voids in defined cases, shadow areas within a stated limit, concealed spaces with limited access, enclosed vertical shafts, rooms protected by other accepted automatic fire-fighting systems, and small built-in features such as cupboards. For the reader, this clause is where you decide what is and is not sprinklered, so it drives both scope and cost.

Hydraulic design and water supply

Clause 6 sets the design basis for the most demanding area of operation, the minimum design density, the number of design sprinklers and the duration of water supply. It also sets minimum and maximum operating pressure limits at the sprinkler. Clause 7 requires backflow prevention where potable water is used, control of maximum system pressure, protection against freezing and tampering, and accessible stop valves for Type 2 and Type 3 systems. Clause 8 then limits the water sources to water mains, storage tanks or pressure tanks, with storage-tank details including effective capacity and suction clearances. In practice, these clauses tell the designer what flow, pressure and duration the water supply must deliver, and how the water source must be protected and maintained.

Pumps, pipework and sprinkler installation

Clause 9 covers residential sprinkler system pumps, including power capability, housing, valves, suction conditions, priming and electrically driven pump sets. Clauses 10 to 12 cover wet, dry and pre-action installation types, sprinkler spacing and location, sprinkler types and uses, operating temperatures, and rosettes and cover plates. The practical effect is that the system must be arranged so the correct sprinklers operate, the pipework does not freeze or over-pressurize, and the sprinkler components are compatible with the installation conditions.

Valves, alarms, signs and maintenance

Clauses 13 to 16 require the control valve set, stop valves, drains, gauges, alarm devices, pipework identification and site notices needed to isolate, test, drain and monitor the system. Clause 17 requires commissioning tests, including hydrostatic testing of pipework and pneumatic testing of dry pipework, followed by a compliance certificate and as-built documents. Clause 18 requires inspection, testing and maintenance records, spare sprinklers for Type 2 and 3 systems, annual checks, anti-freeze testing where used, and long-term inspections after the stated service intervals. In practice, these clauses define what must be checked before handover and what the owner must keep doing throughout service life.

What terms does FprEN 16925 define?

  • A alarm - the system flow alarm that indicates a possible fire.
  • B alarm - an indication of a technical fault or abnormal condition.
  • Area of operation - the maximum area assumed for design purposes to have sprinklers operating in a fire.
  • Competent person - a person trained and qualified by knowledge, understanding and practical experience to carry out the required task correctly.
  • Design density - the discharge flow from each sprinkler divided by the area covered, expressed in mm/min.
  • K-factor - the constant that characterizes sprinkler hydraulic performance and links pressure to water flow.
  • Residential compartment - a space enclosed by walls and a ceiling with defined opening limits to adjacent rooms.
  • Response time index (RTI) - the response measure used for quick response spray sprinklers in EN 12259-1.

Who uses FprEN 16925?

FprEN 16925 is used by people who procure, design, install, approve, operate and maintain residential sprinkler systems. That includes fire protection engineers, sprinkler contractors, building owners, housing providers, building control bodies, fire authorities, insurers and maintenance providers.

It is especially relevant for residential buildings, apartment buildings, care homes, small hotels or hostels, student accommodation, bed and breakfast premises, and other occupancies listed in the system type table in clause 4.2. It also matters to water suppliers and pump/equipment providers because the standard addresses water supply arrangements, backflow prevention, pump sets and monitoring.

What changed in FprEN 16925 from the previous edition?

FprEN 16925:2026 will supersede EN 16925:2018 and EN 16925:2018/AC:2020.

Which standards are used with FprEN 16925?

FprEN 16925 cites several standards that supply component rules, test methods and supporting requirements:

  • EN 12845 - provides the base terms and definitions used by the standard, and is also used for Ordinary Hazard areas and for pressure tanks.
  • EN 12259-14 - defines residential sprinklers, and EN 12259-1 is used for quick response spray sprinklers and sprinklers used in non-residential areas within a residential building.
  • EN 12259-5 - covers water flow detectors used in alarm arrangements.
  • EN 1717 - provides the backflow prevention requirements for potable-water connections.
  • EN 54 (all parts) - supports fire detection and fire alarm system interfaces.
  • EN 806-5 - governs maintenance of backflow prevention devices in water installations.
  • EN IEC 60331-1 - provides the fire test for circuit integrity of electric cables used in the system.
  • EN 1057, EN 10205, EN 10216-1, EN 10217-1 and EN 10255 - support the pipe material choices used in sprinkler pipework.
  • EN 60529, EN 60730-1 and EN 60898-1 - support enclosure protection and electrical control/circuit-breaker requirements.

The foreword also places the document in the wider CEN fixed-firefighting series, including EN 12259, EN 14972, EN 12094, EN 15004, EN 12416, ISO 6184, EN 13565, EN 671 and EN 12101.

What does the FprEN 16925 document contain?

The document contains tables, figures, calculation methods, installation procedures and inspection guidance rather than just high-level rules. Table 1 links system types to building applications, Table 2 sets the minimum design criteria, and Table 3 gives suction pipe inlet clearances for storage tanks.

Annex D provides the hydraulic calculation methods, including the formulas for static pressure, sprinkler flow, pipe friction loss, fitting losses and velocity limits. Annex E gives the long-term inspection and test sampling for pipework and sprinklers, including what to inspect and how many sprinklers to remove and test.

Annex G shows typical water supply arrangements, including town-main-fed systems, boosted systems and stored-water systems. Annex H gives shutdown precautions and actions after sprinkler operation, while Annex I gives a worked hydraulic test method for checking as-fitted performance. Annex A, B and C support zoning, monitoring and alarm transmission, which are the main coordination tasks for design and approval.

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Effective Date
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Frequently Asked Questions

FprEN 16925 is a draft published by the European Committee for Standardization (CEN). Its full title is "Fixed firefighting systems - Automatic residential sprinkler systems - Design, installation and maintenance". This standard covers: This document specifies requirements and gives recommendations for the design, installation, water supplies and backflow prevention, commissioning, maintenance and testing of fixed residential fire sprinkler systems in buildings for residential occupancies. This document is intended for use by those concerned with purchasing, designing, installing, testing, inspecting, approving, operating and maintaining automatic residential sprinkler systems, in order that such equipment will function as intended throughout its life. This document identifies construction details of buildings which are the minimum necessary for satisfactory performance of residential sprinkler systems complying with this standard. This document applies to any addition, extension, repair or other modification to the residential sprinkler system. This document does not cover situations such as arson where fires of a malicious intent may be started in multiple locations simultaneously.

This document specifies requirements and gives recommendations for the design, installation, water supplies and backflow prevention, commissioning, maintenance and testing of fixed residential fire sprinkler systems in buildings for residential occupancies. This document is intended for use by those concerned with purchasing, designing, installing, testing, inspecting, approving, operating and maintaining automatic residential sprinkler systems, in order that such equipment will function as intended throughout its life. This document identifies construction details of buildings which are the minimum necessary for satisfactory performance of residential sprinkler systems complying with this standard. This document applies to any addition, extension, repair or other modification to the residential sprinkler system. This document does not cover situations such as arson where fires of a malicious intent may be started in multiple locations simultaneously.

FprEN 16925 is classified under the following ICS (International Classification for Standards) categories: 13.220.20 - Fire protection. The ICS classification helps identify the subject area and facilitates finding related standards.

FprEN 16925 has the following relationships with other standards: It is inter standard links to EN 16925:2018. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.

FprEN 16925 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.

Standards Content (Sample)


SLOVENSKI STANDARD
01-junij-2026
Vgrajeni gasilni sistemi - Avtomatski sprinklerski sistemi za bivalne površine -
Načrtovanje, vgradnja in vzdrževanje
Fixed firefighting systems - Automatic residential sprinkler systems - Design, installation
and maintenance
Ortsfeste Brandbekämpfungsanlagen - Automatische Sprinkleranlagen für
Wohnbereiche - Planung, Installation und Instandhaltung
Installations fixes de lutte contre l’incendie - Systèmes d’extinction automatiques du type
sprinkleur résidentiel - Conception, installation et maintenance
Ta slovenski standard je istoveten z: prEN 16925
ICS:
13.220.20 Požarna zaščita Fire protection
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
prEN 16925
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2026
ICS 13.220.20 Will supersede EN 16925:2018
English Version
Fixed firefighting systems - Automatic residential
sprinkler systems - Design, installation and maintenance
Installations fixes de lutte contre l'incendie - Systèmes Ortsfeste Brandbekämpfungsanlagen - Automatische
d'extinction automatiques du type sprinkleur Sprinkleranlagen für Wohnbereiche - Planung,
résidentiel - Conception, installation et maintenance Installation und Instandhaltung
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 191.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 16925:2026 E
worldwide for CEN national Members.

prEN 16925:2026 (E)
Contents Page
European foreword . 5
Introduction . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Contract planning and documentation. 11
4.1 General . 11
4.2 Preliminary stage . 12
4.3 Consultation . 12
4.4 Design stage . 13
5 Extent of residential sprinkler protection . 17
5.1 Buildings and areas to be protected . 17
5.2 Permitted exceptions . 17
5.3 Design Criteria - limited areas within the building that are not residential occupancies . 19
5.4 Fire resistant separation . 19
6 Hydraulic design and pipe layout . 20
6.1 Hydraulic design criteria . 20
6.2 Locations of the area of operation — Hydraulic demand . 20
6.3 Hydraulic Calculations . 20
6.4 Pipe layout . 21
6.5 Flexible Sprinkler Hose . 21
7 Water supplies . 22
7.1 Water supply . 22
7.2 Backflow prevention . 22
7.3 Maximum water pressure . 22
7.4 Housing of equipment for water supplies . 22
7.5 Test facility devices . 23
8 Type of water supply . 23
8.1 General . 23
8.2 Water main . 24
8.3 Storage tanks . 24
8.4 Pressure tanks . 26
9 Residential Sprinkler System Pumps . 26
9.1 General – All types of residential sprinkler systems . 26
9.2 Compartments for pump sets . 27
9.3 Temperature requirements . 27
9.4 Valves and accessories . 27
9.5 Suction conditions . 27
9.6 Performance characteristics . 29
9.7 Electrically driven pump set – All types of residential sprinkler systems . 31
10 Installation type and size . 32
10.1 Wet pipe installations . 32
10.2 Dry pipe installations . 37
10.3 Pre-action installations . 37
prEN 16925:2026 (E)
11 Spacing and location of sprinklers . 37
11.1 General . 37
11.2 Spacing of residential sprinklers . 38
11.3 Distance of residential sprinklers from walls . 39
11.4 Deflector position of residential sprinklers . 39
11.5 Obstructions in relation to residential sprinklers . 39
11.6 Small compartments . 46
12 Sprinkler design characteristics and uses . 46
12.1 General . 46
12.2 Sprinkler types and application . 46
12.3 Sprinkler nominal operating temperatures . 46
12.4 Sprinkler rosettes and cover plates . 47
13 Valves and gauges . 47
13.1 Control valve set . 47
13.2 Stop valves . 48
13.3 Drain requirements . 48
13.4 Test valves . 48
13.5 Pressure gauges . 48
14 Alarms and alarm devices . 49
14.1 System monitoring and alarm transmission . 49
14.2 Water flow A alarm . 49
14.3 Alarm connection . 49
15 Pipework . 50
15.1 Pipe system . 50
15.2 Pipe supports . 52
16 Signs, notices and information . 54
16.1 Block plan . 54
16.2 Signs and notices . 54
17 Commissioning tests . 56
17.1 General . 56
17.2 All pipework . 56
17.3 Dry pipework . 56
17.4 Completion certificate and documents . 56
18 Inspection, testing and maintenance. 56
18.1 General . 56
18.2 Spare sprinklers . 57
18.3 Precautions while carrying out work . 57
18.4 Annual inspection . 57
18.5 Long-term inspections . 58
Annex A (normative) Sprinkler system zoning . 59
A.1 General . 59
A.2 Guidance for zoned installations . 59
Annex B (normative) Sprinkler system monitoring. 60
B.1 Type 1 systems . 60
B.2 Type 2 and 3 systems . 60
B.3 Functions to be monitored . 60
Annex C (normative) Transmission of alarms. 62
prEN 16925:2026 (E)
C.1 Type 1 systems . 62
C.2 Type 2 and Type 3 systems . 62
Annex D (normative) Hydraulic calculations . 64
D.1 Static pressure . 64
D.2 Flow from a sprinkler . 64
D.3 Pipe friction loss . 64
D.4 Pressure loss through fittings and valves . 65
D.5 Velocity . 67
D.6 Accuracy of calculations . 67
Annex E (normative) Long term inspection and testing of pipework and sprinklers . 68
Annex F (informative) Special circumstances . 69
Annex G (informative) Typical water supply arrangements . 70
Annex H (informative) Precautions and procedures when a system is not fully operational . 73
H.1 Minimizing the fire safety risk when a sprinkler system is shut down . 73
H.2 Planned shut-down . 73
H.3 Unplanned shut-down . 73
H.4 Action following sprinkler operation . 74
Annex I (informative) Hydraulic test . 75
Annex J (informative) New technology . 77
Bibliography . 78

prEN 16925:2026 (E)
European foreword
This document (prEN 16925:2026) has been prepared by Technical Committee CEN/TC 191 “Fixed
firefighting systems”, the secretariat of which is held by BSI.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 16925:2018 and EN 16925:2018/AC:2020.
This document is part of a series of standards which includes the following:
— EN 12259 (all parts), Fixed firefighting systems – Components for sprinkler and water spray systems;
— EN 12845, Fixed firefighting systems – Automatic sprinkler systems;
— EN 14972 (all parts), Fixed firefighting systems – Water mist systems;
— EN 12094 (all parts), Fixed firefighting systems – Components for gas extinguishing systems;
— EN 15004 (all parts), Fixed firefighting systems – Gas extinguishing systems;
— EN 12416 (all parts), Fixed firefighting systems – Powder systems;
— ISO 6184 (all parts), Fixed firefighting systems – Explosion protection systems;
— EN 13565 (all parts), Fixed firefighting systems – Foam systems;
— EN 671 (all parts), Fixed firefighting systems – Hose systems;
— EN 12101 (all parts), Smoke and heat control systems.
prEN 16925:2026 (E)
Introduction
Sprinkler systems have demonstrated their value in protecting life and property in industrial and
commercial applications for over 100 years. The recognition that the largest number of deaths from fire
occur in the home has led to the introduction of sprinkler systems specifically designed for residential
occupancies.
A correctly designed and installed residential sprinkler system can detect and control a fire at an early stage
of development and activate a fire alarm. Operation of the system rapidly reduces the rate of production of
heat and smoke, allowing more time for occupants to escape to safety or be rescued.
Sprinklers operate at predetermined temperatures to discharge water over the area below. Only the
sprinklers near the fire, which are individually heated above their operating temperature, will operate. The
flow of water initiates a fire alarm signal to draw attention to the operation of the system. The operating
temperature is generally selected to suit ambient temperature conditions.
It is essential that residential sprinkler systems are properly maintained and regularly tested to ensure
correct operation in case of fire.
It should not be assumed that the provision of a residential sprinkler system eliminates the need for other
means of detecting and fighting fires and it is important to consider the fire precautions in the occupancy as
a whole. Structural fire resistance, escape routes, smoke alarms, fire alarm systems, provision of portable
extinguishers, training and information all need consideration.
It is assumed that the building design and construction will be in accordance with local building codes and
national requirements. If the residential sprinkler system is to be used to compensate for other fire
protection measures, such as walls or doors, building authorities may require the installation of a system
with additional measures to enhance performance and/or reliability.
Only a competent person should undertake the design, installation, inspection, testing and maintenance of
residential sprinkler systems. This standard does not necessarily cover all local or national legislative
requirements, which may take precedence over this standard.
prEN 16925:2026 (E)
1 Scope
This document specifies requirements and gives recommendations for the design, installation, water
supplies and backflow prevention, commissioning, maintenance and testing of fixed residential fire sprinkler
systems in buildings for residential occupancies.
This document is intended for use by those concerned with purchasing, designing, installing, testing,
inspecting, approving, operating and maintaining automatic residential sprinkler systems, in order that such
equipment will function as intended throughout its life.
This document identifies construction details of buildings which are the minimum necessary for satisfactory
performance of residential sprinkler systems complying with this standard.
This document applies to any addition, extension, repair or other modification to the residential sprinkler
system.
This document does not cover situations such as arson where fires of a malicious intent may be started in
multiple locations simultaneously.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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 1057, Copper and copper alloys — Seamless, round copper tubes for water and gas in sanitary and heating
applications
EN 10205, Cold reduced tinmill products - Blackplate
EN 10216-1, Seamless steel tubes for pressure purposes - Technical delivery conditions - Part 1: Non-alloy steel
tubes with specified room temperature properties
EN 10217-1, Welded steel tubes for pressure purposes - Technical delivery conditions - Part 1: Electric welded
and submerged arc welded non-alloy steel tubes with specified room temperature properties
EN 10255, Non-Alloy steel tubes suitable for welding and threading — Technical delivery conditions
EN 12259-1, Fixed firefighting systems — Components for sprinkler and water spray systems — Part 1:
Sprinklers
EN 12259-5, Fixed firefighting systems - Components for sprinkler and water spray systems - Part 5: Water flow
detectors
EN 12259-14, Fixed firefighting systems — Components for sprinkler and water spray systems — Part 14:
Sprinklers for residential applications
EN 12845, Fixed firefighting systems — Automatic sprinkler systems — Design, installation and maintenance
EN 1717, Protection against pollution of water intended for human consumption in potable water installations
and general requirements for devices to prevent pollution by backflow
EN 60529, Degrees of protection provided by enclosures (IP Code)
prEN 16925:2026 (E)
EN 60730-1, Automatic electrical controls for household and similar use — Part 1: General requirements
(IEC 60730-1)
EN 60898-1, Electrical accessories - Circuit-breakers for overcurrent protection for household and similar
installations - Part 1: Circuit-breakers for a.c. operation
EN 806-5, Specifications for installations inside buildings conveying water for human consumption - Part 5:
Operation and maintenance
EN IEC 60331-1, 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 0,6/1,0 kV and
with an overall diameter exceeding 20 mm
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 12845 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
A alarm
system flow alarm that indicates a possible fire
3.2
alarm receiving unit
control panel capable of initiating an alarm
3.3
area of operation
maximum area over which is it assumed, for design purposes, that sprinklers will operate in a fire
3.4
authority
organization or individual responsible for approving sprinkler systems, equipment and procedures
EXAMPLE Examples include the fire and building control authorities, the fire insurers, the local water authority
and other appropriate public authorities.
3.5
sprinkler (automatic)
nozzle with a thermally sensitive sealing device which opens to discharge water for fire-fighting
3.6
B alarm
indication of a technical fault or an abnormal condition
3.7
bed and breakfast
accommodation with up to four lettable rooms and up to three storeys, where the owner lives on the
premises and no meal other than breakfast is provided
prEN 16925:2026 (E)
3.8
competent person
person, suitably trained and qualified by knowledge, understanding and practical experience, and provided
with the necessary instructions, to enable the required task(s) to be carried out correctly
3.9
design area of coverage
floor area protected by a sprinkler
3.10
design density
discharge flow from each sprinkler, divided by the area covered
Note 1 to entry: Expressed in mm/min.
3.11
design sprinklers
individual sprinklers or groups of sprinklers within the same residential compartment located at the most
hydraulically favourable and unfavourable locations, and which are used to determine the hydraulic design
demand of the sprinkler system
3.12
dwelling
building that contains units intended to be used for habitation purposes
Note 1 to entry: The dwelling may be owned, rented, leased, let or hired out.
3.13
effective capacity
volume of stored water available, taking into account the air gap at the top and the unusable water at the
base of the tank
Note 1 to entry: the effective capacity is affected by a vortex letting air into the pump suction
3.14
flexible sprinkler hose
flexible device assembly and its supporting components used solely for connecting a single fire sprinkler to a
range pipe
3.15
horizontal ceiling
ceiling with a slope not exceeding 9,5°
3.16
K-factor
constant which characterises the hydraulic performance of a sprinkler and is used to calculate the water
flow through the sprinkler from the square root of the water pressure
3.17
manufacturer’s specification
document published by a manufacturer which is intended to supplement this standard with additional
technical information with regards to design, installation and maintenance
prEN 16925:2026 (E)
3.18
maximum flow demand
Q
max
flow at the point of intersection of the pressure-flow demand characteristic of the most favourable area of
operation of the sprinkler system and the water supply pressure-flow characteristic with the suction source
at its normal level
3.19
most favourable area
area of operation for which the water flow is at its maximum for a specified pressure, measured at the main
control valve or pump set
3.20
most unfavourable area
area of operation for which the system pressure, when measured at the main control valve or pump set, is
required to be at its maximum to achieve the specified design density
3.21
normal water level
water level at the water supply needed to give the required effective capacity in relation to the low water
level, including any necessary margins
3.22
premix anti-freeze solution
combination of an anti-freeze and water that is mixed, packaged and labelled by a manufacturer using a
quality controlled process that ensures product homogeneity and concentration as specified in order to
ensure localised concentrations do not arise in the pipe network
3.23
residential pump
pump dedicated to supply the sprinkler system only
3.24
sprinkler, quick response spray
½
sprinkler that gives a downward paraboloid pattern of water discharge and which has an RTI of 50 (m-s) or
less according to EN 12259-1, either upright, pendent or sidewall type
3.25
remote test valve
test facility incorporating a test valve with any associated fittings and pipework, delivering a flow equivalent
to the discharge from a single sprinkler with the smallest K-factor in the system, connected at the
hydraulically most remote location on a distribution pipe
prEN 16925:2026 (E)
3.26
residential compartment
space completely enclosed by walls and a ceiling, where
a) the total width of openings in a single wall to an adjacent room is not more than 2 500 mm and all
openings have a lintel depth of not less than 200 mm; or
b) there is a single opening without a lintel in a wall to an adjacent room of not more than 900 mm in width
and there are no other openings
3.27
residential occupancies
part of a building only containing dwellings
Note 1 to entry: This includes common areas such as separate small storage rooms up to 9 m used only by the
residents, the entrance area and boiler rooms.
3.28
residential sprinkler
type of sprinkler in accordance with EN 12259-14
3.29
shadow area
small area which is not wetted by the residential sprinkler due to an obstruction such as a wall or partition
3.30
sloped ceiling
ceiling with a slope exceeding 9,5°
3.31
small hotel
hotel or guest house with up to 14 lettable rooms and an occupied floor at a height of up to four storeys or
18 m above the lowest fire brigade access level, without a licence to sell alcohol
3.32
uoccupied attics
uppermost spaces that are empty and not being used for any purposes, including storage
4 Contract planning and documentation
4.1 General
The information specified in this clause shall be provided to the user or owner as appropriate. All drawings
and information documents shall carry the following information:
a) the name of the user and the owner, where known;
b) the address and location of premises;
c) the type of occupancies found in each part of the building;
d) the name of the designer;
e) the name of the person responsible for reviewing the design, who shall not be the designer and may be a
third party;
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f) date and number of issue.
4.2 Preliminary stage
The following information shall be provided:
a) a block plan of the premises showing:
1) the type of application (see Table 1);
2) the extent of the system with details of any unprotected areas;
3) location of control valve set(s);
4) location of zone stop valves (if applicable);
5) a cross-section of the full height of the building(s) showing the height of the highest sprinkler above
a stated datum level;
b) general information about the water demand, water main pressure and flow data if a water main
connection is to be used, and a plan of the test site;
c) description of any deviations from the requirements of this standard and the reasons why.
Table 1 — System types and applications
System Type Application
1 One or two-family dwelling / house
Pre-fabricated house
Bed and breakfast
a
2 Apartment building
a, b
House with multiple households sharing facilities
a, c
Care home
a, c
Child or adult day-care centre
a
Student accommodation
a
3 Care home
a
Small hotels or hostels
a
Limited to four storeys or 18 m height.
b
Shared facilities are bathrooms and/or kitchens and living rooms.
c
10 or fewer residents.
NOTE Some countries may have a national annex with guidance on the maximum height and any additional
requirements for apartment buildings higher than 18 m to be protected with a residential sprinkler system.
See Annex F for guidance on special circumstances for the applications in Table 1.
4.3 Consultation
Where a residential sprinkler system or an extension or alteration to a residential sprinkler system is being
considered for new or existing buildings, the following should be consulted where known and, where
necessary, their approval sought at an early stage:
a) the water undertaker (provider);
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b) the fire authority;
c) the building control body;
d) the insurer(s), where insurance is in place, of the dwelling and dwelling contents.
NOTE This list is not exhaustive and national regulations may require consultation with additional bodies.
4.4 Design stage
4.4.1 General
The information provided shall include a summary schedule (see 4.4.2), complete installation layout
drawings of the residential sprinkler installation(s) (see 4.4.3) and details of the water supplies (see 4.4.4).
4.4.2 Summary schedule
The summary schedule shall give the following information:
a) the name of project;
b) all drawings or document reference numbers;
c) the type(s) of installation(s) and the nominal diameter(s) of each control valve set;
d) the number or references of each control valve set in the system;
e) the number of sprinklers on each control valve set;
f) the pipework volume in the case of dry installations.
4.4.3 Installation layout drawings
4.4.3.1 General
Layout drawings shall include the following information:
a) the system type (see Table 1);
b) plan and cross sections showing construction details of floors, ceilings, roofs, exterior walls and walls
separating sprinklered and non-sprinklered areas;
c) the following information for each type of sprinkler:
1) nominal operating temperature;
2) K-factor;
3) response type;
4) orientation;
and for each type of residential sprinkler the maximum area of coverage;
d) the location of access to and the type of control valve sets;
e) the location and details of any water flow, and air or water pressure alarm switches;
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f) the location and size of any subsidiary valves, subsidiary stop valves and drain valves;
g) the location of all test valves;
h) the location and details of any alarm receiving unit;
i) the location of all concealed pipework;
j) a key to the symbols used.
4.4.3.2 Calculation
The following shall be given, with detailed calculations, either on purpose designed work sheets or as a
computer printout:
a) the hydraulic calculation program name and version number;
b) the date of the worksheet or print-out;
c) the actual internal diameters of all pipes used in the calculation;
d) for each design area of operation;
1) the area identification;
2) the system type;
3) the specified design density in millimetres per minute or the minimum flow and pressure according
to the instruction chart in EN 12259-14;
4) the number of sprinklers in the area of operation;
5) the sprinkler K-factor;
6) the maximum area covered per sprinkler in square metres;
7) detailed and dimensioned working drawings showing the following:
i) the node or pipe reference scheme used to identify pipes, junctions, sprinklers and fittings
which need hydraulic consideration;
ii) the position of the sprinkler or sprinklers requiring the greatest hydraulic demand;
iii) the sprinklers upon which the design density is based;
iv) the height above datum of each point of identified pressure value;
e) for each operating sprinkler:
1) the sprinkler node or reference number;
2) the nominal K factor;
3) the flow through the sprinkler in litres per minute;
4) the inlet pressure to the sprinkler or sprinkler assembly in bar;
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f) for each hydraulically significant pipe:
1) pipe node or other reference number;
2) nominal bore in millimetres;
3) the Hazen-Williams constant;
4) flow in litres per minute;
5) velocity in metres per second;
6) length in metres;
7) numbers, types and equivalent length in metres of fittings and components;
8) static head change in metres;
9) pressures at inlet and outlet in bar;
10) friction loss in bar;
11) indication of flow direction.
4.4.4 Water supply
4.4.4.1 Water supply drawings
The drawings shall show pipework from the water main or storage tank to the control valve set. A key to the
symbols shall be included. The position and type of stop and non-return valves and any pressure reducing
valves, water meters, back-flow preventers and any connections supplying water for other services, shall be
indicated. Examples of typical water supply arrangements are shown in Annex G.
For full holding capacity stored-water systems, the pipework from the tank should be detailed in the
drawings. For reduced capacity stored-water systems, the pipework should be detailed either from where
the inflow pipe connects to a shared supply or from where the dedicated inflow supply enters the building.
Systems supplied from the water main should have the pipework detailed from where it enters the building.
4.4.4.2 Hydraulic calculation
A hydraulic calculation shall show that the minimum water supply characteristics can provide the required
pressure and flow at the control valve set.
Where the water supply is from a water main it can be necessary to assume a supply flow and pressure at
the design stage, include an allowance for pressure loss from the water main and to confirm adequate supply
once the water main is installed. See Annex I for a method to conduct the hydraulic test.
4.4.4.3 Town main
Where a town main forms the supply or provides inflow to a reduced capacity tank, the following details
shall be given:
a) the nominal diameter of the main, where known;
b) the demand pressure and flow characteristics for the hydraulically most demanding area of operation,
with the pressure measured at the ‘C’ gauge;
c) when allowed by the water undertaker, a pressure and flow characteristic graph indicating the available
pressure at any flow up to the maximum flow demand.
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4.4.4.4 Automatic pump set
The following details of each automatic pump set shall be provided:
a) a pump characteristic curve for low water level 'X' (see Figure 3) showing the calculated performance of
the pump or pumps under installed conditions at the control valve 'C' gauge;
b) the pump manufacturer's data sheet showing the following:
1) the generated head graph;
2) the power absorption graph;
3) the net positive suction head (NPSH) graph;
c) the installer's data sheet showing the pump set installed performance pressure/flow characteristics, at
the control valve 'C' gauge for normal water level and for low water level 'X' and at the pump outlet
pressure gauge for normal water level;
d) the height difference between the control valve 'C' gauge and the pump delivery pressure gauge;
e) the available and the specified NPSH at maximum required flow;
f) for a submersible pump the minimum depth of water in accordance with the manufacturer’s
instructions;
g) the most demanding sprinkler pressure/flow characteristic for the hydraulically most unfavourable and
the most favourable area of operation calculated at the control valve 'C' gauge;
h) a schematic drawing of the electrical system.
4.4.4.5 Storage tank
The following details shall be provided:
a) the location;
b) the total volume of the tank;
c) the effective capacity of the tank and duration;
d) the inflow for reduced capacity tanks;
e) the vertical distance between the pump inlet centre line and the tank low water level 'X';
f) details of the tank and roof construction;
g) protection against freezing;
h) protection against backflow;
i) low and normal water levels X and N;
j) height of gravity tank above the highest sprinkler.
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4.4.4.6 Pressure tank
The following details shall be provided:
a) the location;
b) the total volume of the tank;
c) the volume of stored water;
d) the air pressure;
e) the height of the highest and/or hydraulically most remote
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