prEN 12259-16

• Abstract:

  This document specifies requirements, test methods and performance criteria for factory-applied polymer coatings applied to the internal and external surfaces of steel pipes intended for use in fixed water-based fire-fighting systems designed in accordance with the EN 12845 series of standards.; This document specifies requirements for the polymer coating when used as a corrosion-protection system. The mechanical and functional characteristics of the steel pipes and pipe systems are outside the scope of this document and are as specified in the EN 12845 series.; NOTE Throughout this document, the term "coating" refers exclusively to factory-applied polymer coatings unless otherwise specified.

• Status: Not Published
• Publication Date: 30-Jan-2028
• ICS: 13.220.20 - Fire protection
• Technical Committee: CEN/TC 191 - Fixed firefighting systems
• Drafting Committee: CEN/TC 191/WG 5 - Sprinkler systems
• Current Stage: 4060 - Closure of enquiry - Enquiry
• Start Date: 24-Sep-2026
• Due Date: 06-Jan-2027
• Completion Date: 24-Sep-2026
• Ref Project: oSIST prEN 12259-16:2026 - Fixed firefighting systems - Components for sprinkler and water spray systems - Part 16: Polymer coated pipe systems

prEN 12259-16 is a CEN draft European Standard for factory-applied polymer coatings on steel pipes used in fixed water-based fire-fighting systems. It sets requirements, test methods and performance criteria for the coating when it is used as a corrosion-protection system in sprinkler and water spray pipework designed to the EN 12845 series. The document is aimed at coating and pipe manufacturers, test laboratories, and anyone verifying whether coated pipe is suitable for these systems.

What does prEN 12259-16 specify?

prEN 12259-16 specifies what factory-applied polymer coatings on the internal and external surfaces of steel pipes have to do, how they are tested, and how the results are judged. The mechanical and functional properties of the steel pipe and pipe system themselves remain under EN 12845.

The document is organized into:

• scope
• normative references
• terms and definitions
• assessment methods and criteria
• technical documentation, user documentation and marking
• Annex A for a normative corrosion evaluation option

Annex	What it covers
Annex A	Corrosion evaluation option 1, including coating thickness, adhesion, cyclic corrosion exposure and chemical compatibility testing

In practice, the standard is about the coating as a corrosion barrier, not about redesigning the pipework or sprinkler system.

What are the key requirements of prEN 12259-16?

prEN 12259-16 focuses on testable coating performance, traceable documentation, and durable marking. The main point is that a coated pipe has to prove it can keep its protective function after fire exposure, corrosion exposure and ageing.

General testing and sample control

Clause 4.1 sets the common test conditions and sample handling. Tests are run under controlled ambient conditions unless a specific test says otherwise, and the test samples have to match the submitted technical documentation. This matters because the laboratory result only counts if the tested pipe really represents the product being offered.

Flame resistance of the coated pipe

Clause 4.2 checks how the coating behaves in a flame test. The pipe sample is exposed in a defined rig, and the result has to show no residues or detachments that could interfere with downstream components such as a sprinkler. In practice, this is meant to prevent loose coating material from affecting water flow or component function after fire exposure.

Coating thickness

Clause 4.3 requires thickness measurement on both the inside and outside surfaces at several locations, without averaging the values. The coating must meet at least the manufacturer’s declared minimum thickness. For users, that means thickness is a direct acceptance check, not a nominal figure.

Optional hydraulic performance check

Clause 4.4 gives an optional C-value determination. It is only used when specifically requested and is based on multiple pipe samples, some of them preconditioned by salt spray exposure. The test shows whether the coated pipe keeps acceptable hydraulic behaviour, so it is relevant when flow performance needs to be documented alongside corrosion protection.

Corrosion resistance and ageing

Clauses 4.5 to 4.8 cover salt spray corrosion, ageing in warm air, ageing in warm water, and two corrosion evaluation options. The coated pipe must not show visible corrosion after these exposures, with limited minor corrosion allowed only in post-treatment areas. Option 1 uses the normative Annex A route for more detailed corrosion evaluation, while Option 2 uses a salt spray-based visual acceptance check.

Documentation and marking

Clause 5 requires technical documentation, user documentation and marking. The technical file has to include coating thickness information, ordering specifications and confirmation of corrosion-protective function. The user information has to include a data sheet, installation instructions and compatibility information. Marking must be permanent, clearly legible, non-combustible and undetachable.

What terms does prEN 12259-16 define?

• pipe end - the side of the pipe intended to receive a pipe joint element.
• post treatment - a method used to restore permanent corrosion protection after mechanical or thermal processing has damaged the coating.
• C-value - the pipe constant determined in the optional hydraulic test to show the pipe’s flow behaviour.
• NSS test - the neutral salt spray corrosion test used for corrosion exposure in the document.
• CRw - the corrosion rate used in Annex A to assess internally coated pipe samples.
• CPVC - chlorinated polyvinyl chloride, used in Annex A as the plastic pipe material for compatibility testing.

Who uses prEN 12259-16?

prEN 12259-16 is used by manufacturers of coated steel pipe, coating applicators, and test laboratories that prepare type tests and performance checks. It is also used by certification bodies, quality managers, and buyers who need a clear basis for accepting polymer-coated pipe for sprinkler or water spray systems.

Designers and installers use it when they need to specify coated pipe with documented corrosion protection. Procurement teams use it to check that the supplied pipe comes with the right technical documents and permanent marking.

Which standards are used with prEN 12259-16?

• EN 12845 (all parts) - provides the sprinkler-system framework, the referenced terms and the pipe-system characteristics that are outside the scope of this part.
• EN 12259-5:2002 - provides the ageing procedures used in warm air and warm water.
• EN ISO 9227:2022 - provides the neutral salt spray corrosion test method used for corrosion exposure.
• ASTM D638 - is used in Annex A as the basis for Type V tensile specimen geometry in the chemical compatibility work.

What does the prEN 12259-16 document contain?

The document contains a flame test setup, a coating-thickness method, an optional hydraulic C-value method, salt spray corrosion exposure, warm-air and warm-water ageing methods, and two corrosion evaluation routes. It also contains the technical documentation and marking requirements that link the laboratory result to the product being supplied.

Annex A adds detailed procedures for coating thickness measurement, adhesion strength measurement, cyclic corrosion chamber testing, and chemical compatibility testing against plastic pipe specimens. Figures in the body show the flame test and C-value test arrangements, and the text includes the calculation approach used for the pipe constant.

SLOVENSKI STANDARD
01-september-2026
Vgrajene naprave za gašenje - Sestavni deli sprinklerskih sistemov in sistemov s
pršečo vodo - 16. del: Cevni sistemi s polimernim premazom
Fixed firefighting systems - Components for sprinkler and water spray systems - Part 16:
Polymer coated pipe systems
Ortsfeste Löschanlagen - Bauteile für Sprinkler- und Sprühwasseranlagen - Teil 16:
Polymerbeschichtete Rohrsysteme
Installations fixes de lutte contre l’incendie - Composants des systèmes d’extinction du
type sprinkleur et à pulvérisation d’eau - Partie 16: Réseaux de tuyauteries revêtues de
polymère
Ta slovenski standard je istoveten z: prEN 12259-16
ICS:
13.220.10 Gašenje požara Fire-fighting
13.220.20 Požarna zaščita Fire protection
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2026
ICS 13.220.20
English Version
Fixed firefighting systems - Components for sprinkler and
water spray systems - Part 16: Polymer coated pipe
systems
Ortsfeste Löschanlagen - Bauteile für Sprinkler- und
Sprühwasseranlagen - Teil 16: Polymerbeschichtete
Rohrsysteme
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 12259-16:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Assessment methods and criteria . 4
4.1 General. 4
4.1.1 Test conditions . 4
4.1.2 Test modules and test samples . 5
4.1.3 Documentation . 5
4.2 Flame test . 5
4.2.1 Assessment method . 5
4.2.2 Criteria . 7
4.3 Layer thickness of polymer coating . 7
4.3.1 Assessment method . 7
4.3.2 Criteria . 7
4.4 C-value determination (optional) . 7
4.4.1 Assessment method . 7
4.4.2 Criteria . 8
4.5 Salt spray corrosion . 8
4.5.1 Assessment method . 8
4.5.2 Criteria . 9
4.6 Ageing in warm air . 9
4.6.1 Assessment method . 9
4.6.2 Criteria . 9
4.7 Ageing in warm water . 9
4.7.1 Assessment method . 9
4.7.2 Criteria . 9
4.8 Corrosion evaluation . 9
4.8.1 General. 9
4.8.2 Corrosion evaluation - Option 1 . 9
4.8.3 Corrosion evaluation - Option 2 . 10
5 Technical documentation, user documentation and marking . 10
5.1 Technical documentation . 10
5.2 User documentation . 11
5.3 Marking . 11
Annex A (normative) Corrosion evaluation option 1 . 12
Bibliography . 17

European foreword
This document (prEN 12259-16:2026) has been prepared by Technical Committee CEN/TC 191 “Fixed
fire fighting systems”, the secretariat of which is held by BSI.
This document is currently submitted to the CEN Enquiry.
1 Scope
This document specifies requirements, test methods and performance criteria for factory-applied
polymer coatings applied to the internal and external surfaces of steel pipes intended for use in fixed
water-based fire-fighting systems designed in accordance with the EN 12845 series of standards.
This document specifies requirements for the polymer coating when used as a corrosion-protection
system. The mechanical and functional characteristics of the steel pipes and pipe systems are outside the
scope of this document and are as specified in the EN 12845 series.
NOTE Throughout this document, the term “coating” refers exclusively to factory-applied polymer coatings
unless otherwise specified.
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 12259-5:2002, Fixed firefighting systems — Components for sprinkler and water spray systems —
Part 5: Water flow detectors
EN 12845 (all parts), Fixed firefighting systems — Automatic sprinkler systems title of series
EN ISO 9227:2022, Corrosion tests in artificial atmospheres - Salt spray tests (ISO 9227:2022)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in the EN 12845 series of standards
and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
ISO Online browsing platform: available at https://www.iso.org/obp/
IEC Electropedia: available at https://www.electropedia.org/
3.1
pipe end
side of the pipe intended to potentially receive the pipe joint element
3.2
post treatment
method of restoring a permanent corrosion protective property, for the treatment of defects in the
polymer coating due to mechanical/thermal processing of the already polymer coated pipelines
4 Assessment methods and criteria
4.1 General
4.1.1 Test conditions
The tests shall be conducted at a temperature of (25 ± 10) °C unless otherwise specified for a specific test.
The tolerance of all test parameters shall be ± 5 %, unless specified otherwise. The test conditions given
here shall be observed for each test unless otherwise specified.
4.1.2 Test modules and test samples
For the testing of polymer coated pipelines, the number and dimensions of the required test samples are
determined when the test schedule is drawn up. At least the following test samples shall be used for the
tests:
— 1 pipe;
— 1 pipe, which also has all the post-treatments specified in the documentation.
4.1.3 Documentation
4.1.3.1 General
The test samples shall comply with the documents according to Clause 5 and shall be within the scope of
this document.
4.1.3.2 Technical documentation
The technical documentation submitted by the manufacturer shall be checked whether the test samples
correspond to the description in the technical documentation and comply with the requirements of this
document, which can be verified in the process.
4.1.3.3 Marking
By visual inspection of the labelling, it shall be evaluated and checked for completeness and compliance
with the requirements according to 5.3.
4.1.3.4 Resistance to corrosion and ageing
By reviewing the documentation and examining the test samples, it shall be determined whether the
corrosion protective function of the coating (inside and outside) is given.
4.2 Flame test
4.2.1 Assessment method
In preparation for the test, the test sample shall be placed dry and open in the test device. The test sample
shall have a length of 800 mm to 1 000 mm.
Dimensions in millimetres
a) Side view
b) Top view
Key
1 test sample
2 pan 200 mm × 400 mm × 60 mm
Figure 1 — Test set-up flame test
The fuel pan, stainless steel with 2 mm wall thickness, dry and clean, shall be positioned centrally under
the pipe end with its longitudinal axis centrally perpendicular to the pipe axis as shown in Figure 1. The
fuel shall then be filled into the fuel pan and ignited.
Characteristic values of the test shall be:
— Fuel: methanol (concentration ≥ 99 %);
— Filling quantity:
— 0,5 l for nominal diameters < DN 100;
— 1 l for nominal diameters ≥ DN 100 (in the case of reducing joints, the dimension of the smaller
nominal diameter shall be used to determine the filling quantity);
— Burning time:
— until the fuel quantity burns off (naturally 5 min) for nominal diameter < DN 100;
— 8 min for nominal diameter ≥ DN 100 (for reducing sleeves, the dimension of smaller nominal
diameter shall be applied to determine the burning time).
After the burning time has expired, the flame shall be extinguished by filling the pan with water. The test
sample shall remain in the air to cool down.
4.2.2 Criteria
After completion of the test in accordance with 4.2.1 no residues/detachments, etc. shall form in the pipe
which could impair the function of downstream components (e.g. flow reduction of a sprinkler).
4.3 Layer thickness of polymer coating
4.3.1 Assessment method
The coating thickness shall be measured internally and externally at each of 5 different locations
distributed over the surface and checked for compliance with the requirements of 4.3.2. The
measured/determined values shall not be averaged.
4.3.2 Criteria
When tested in accordance with 4.3.1, the layer thickness shall be at least the value specified by the
manufacturer.
4.4 C-value determination (optional)
4.4.1 Assessment method
This test is optional and may only be performed if explicitly requested. For each nominal diameter, 12
test samples shall be submitted, all with the same length of 800 mm to 1000 mm. Four of the test samples
shall be cut into sections of approximately 200 to 250 mm length as shown in Figure 2, Key 2. The test
shall be carried out on at least two nominal sizes in the range DN 40 to DN 80.
For the measurement and evaluation of the real pipe constant, the pressure loss ∆p shall be determined
over a test section according to Figure 2. For this purpose, test samples in the unconditioned state as well
as in the preconditioned state shall be used.
For the preconditioning, the test samples are subjected to a salt spray corrosion test according to 4.5.1,
but with deviating test durations, so that the following results after the preconditioning phase:
— Test sample 1: unconditioned;
— Test sample 2: 240 h preconditioned;
— Test sample 3: 720 h preconditioned.
The complete set-up (test sample 1, 2 and 3) shall be built using couplings for smooth-ended pipes, which
shall be supplied by the manufacturer. The hydraulic effects of the connecting edges on the test samples
shall be minimized. For this purpose, the connections shall be deburred accordingly and joined together
in alignment and centrically in the longitudinal axis.
Named test samples shall be assembled into a test section as shown in Figure 2 using assembly equipment
supplied by the customer.
The test section shall then be supplemented by the inlet and outlet pieces with measuring points and
connected to the water supply. The measuring connections of the differential pressure transducer shall
be connected to the pressure measuring points (1/2“-welded-on sockets) in the inlet and outlet sections.
Key
1 outlet tube 5 flange
2 4 × test item 6 flow direction
3 inlet tube D diameter
4 pipe coupling
For 1/2” welded-on socket with a 3 mm bore sharply deburred on the inside of the pipe.
Figure 2 — Test section C-value measurement
Then the test section shall be flown through with an increasing flow rate until the maximum measuring
range of the differential pressure transducer (P = 500 mbar) or the flow meter (Q = 3000 l/min) is
reached. The real differential pressures between the measuring points of inlet and outlet shall be
recorded. To calculate the real pipe constant C, the Hazen-Williams formula is converted and shall be
applied as:
5 1,85
6, 05 ××1 0 Q ×L
1,85
C=
(1)
4,87
∆pD ×
where
C is the dimensionless pipe constant;
Q is the flow rate in l/min;
L is the pipe length in m;
∆p is the pressure loss in bar;
D is the inner pipe diameter in mm.
The measured values shall be averaged. For the final d
...