The European sprinkler standard was overhauled in 2026: the main standard became EN 12845:2015+A2:2026, ESFR and CMSA sprinklers moved into a separate part as EN 12845-2:2024, and pump sets were handed over to EN 17451. This article summarises what the new version brings and what it means on site.
EN 12845 is now a family
As of 2026 it is no longer sufficient to speak of a single "EN 12845" document. The standard has become modular, in a way comparable to NFPA 13 splitting storage into separate chapters. The current structure:
| Document | Turkish adoption | Scope |
|---|---|---|
| EN 12845:2015+A2:2026 | TS EN 12845+A2:2026-05 | The main standard (Part 1) — CMDA density-area systems, general design, installation and maintenance. Supersedes A1:2019/2020. |
| EN 12845-2:2024 | TS EN 12845-2:2025-12 | ESFR and CMSA sprinklers for high hazard storage |
| EN 17451 | — | Sprinkler pump sets — design, assembly, installation and commissioning |
| EN 12845-3 | — | A complementary part of the series |
As the European foreword to A2:2026 states, the technical changes against A1:2019 centre on integrating the references to and use of EN 17451, EN 12845-2 and EN 12845-3 into the main text. This version also consolidates the 2016 corrigendum and amendment.
Dates and the transition
- EN 12845:2015+A2:2026 — approved by CEN on 19 January 2026 and adopted by TSE on 21 May 2026. It must have national standard status by October 2026 at the latest, by which date conflicting national standards are withdrawn.
- EN 12845-2:2024 — approved by CEN on 11 November 2024, adopted by TSE in December 2025.
- In Turkey, TS EN 12845+A1:2020 is replaced by the new version on publication of A2.
Part 2: ESFR and CMSA go their own way
The new Part 2 covers only ESFR (Early Suppression Fast Response) and CMSA (Control Mode Specific Application) sprinklers, and is applied together with the main standard. Its notable technical rules:
- ESFR is used only on wet installations; CMSA works on both wet and dry, with dry systems restricted to dry pendent and upright types.
- ESFR sprinklers must comply with EN 12259-13, CMSA sprinklers with the corresponding component standard.
- Maximum ceiling or roof slope 10° (about 17.6 %).
- At least 1 m clearance between the ceiling sprinkler deflector and the top of storage.
- Skylights must withstand 300 °C for at least 5 minutes; those over 1 m³ require sprinkler protection under defined conditions.
- Open-top containers should not be used in sprinklered storage hazards.
Pump sets now sit in EN 17451
With A2, pump room design refers to EN 17451. Pump set selection, assembly and commissioning requirements must now be read from that separate document alongside the main standard. It is one of the most practical changes, breaking the habit of sizing a pump from a single source.
What to watch on site
- Name the version in the contract: "EN 12845" now points at more than one document; state the year, amendment and part number.
- Obtain Part 2 separately for ESFR and CMSA: the ESFR design curves are no longer in the main standard.
- Add EN 17451 for the pump: write the reference into the pump room specification.
- The mixed-standard trap: sizing sprinklers to EN and the pump to NFPA creates a mismatch in water supply duration.
Questions and answers
What is the new version of EN 12845 and when was it published?
Two new documents came into force. The current main standard is EN 12845:2015+A2:2026, approved by CEN in January 2026 and adopted in Turkey in May 2026, replacing TS EN 12845+A1:2020. In parallel, the ESFR and CMSA rules moved into EN 12845-2:2024.
What is the fundamental difference from A1:2019?
A2's biggest structural change is turning the standard from a single document into a family. It integrates the references to EN 17451 (pump sets), EN 12845-2 (ESFR/CMSA) and EN 12845-3 into the main text. The main standard now focuses on CMDA density-area systems, with specialist subjects delegated to separate parts. The 2016 corrigendum and amendment are also consolidated here.
Why was EN 12845 split into parts?
As the standard grew, specialist subjects such as ESFR, CMSA and pump sets were inflating the main text. CEN/TC 191 chose modularity comparable to the NFPA 13 restructuring of storage: Part 1 handles general design, installation and maintenance, Part 2 covers ESFR and CMSA for high hazard storage, and EN 17451 handles pump sets. Each part can now be updated independently.
What exactly does Part 2 cover?
Only the design and installation of ESFR and CMSA sprinklers, typically used in high hazard storage. It is applied together with the EN 12845 series — Part 2 is read alongside the main standard, never on its own.
What is the difference between ESFR, CMSA and CMDA?
They are three operating modes. ESFR works in suppression mode, materially reducing the heat release rate of the fire; it is defined by K-factor, number of operating sprinklers and head pressure, and usually provides ceiling protection only. CMSA works in control mode and is specified by sprinkler count plus head pressure for specific storage challenges. CMDA is the classic approach remaining in Part 1, where protection is defined by a density in mm/min over an area of operation in m².
What is EN 17451?
A separate European standard, Automatic sprinkler systems — Design, assembly, installation and commissioning of pump sets. With A2:2026, the EN 12845 main text refers to it for pump set requirements, so pump room designers must now use two documents together.
What is EN 12845-3?
A complementary part of the series, referenced in the A2:2026 text. The main standard integrates its use and references, and the series as a whole — Part 1, Part 2, EN 17451 and the related parts — is designed to be applied together.
Can ESFR sprinklers be used on a dry system?
No. Part 2 requires ESFR sprinklers to be used only on wet installations. CMSA sprinklers can be used on both wet and dry systems, though dry CMSA systems are limited to dry pendent and upright types. That directly affects sprinkler selection in cold stores at risk of freezing.
Which sprinkler types are valid for ESFR and CMSA?
Pendent, dry pendent or upright sprinklers complying with the relevant component standard — EN 12259-13 for ESFR, and the corresponding part for CMSA. Compliance with those component standards, and CE marking, is required in product selection.
What is the ceiling slope limit?
Ceiling or roof slope must not exceed 10°, about 17.6 %, under ESFR and CMSA protection. Steeper slopes require additional design measures. The deflector is preferably mounted parallel to the floor; parallel to the ceiling is also permitted within the 10° limit.
What clearance is required above storage?
At least 1 metre of clear space between the ceiling sprinkler deflectors and the top of the stack. That clearance is critical for even water distribution and suppression performance, and must be deducted when planning storage height.
How are skylights treated?
Skylights must withstand 300 °C for at least 5 minutes. Those with a volume above 1 m³ sitting more than 0.3 m above ceiling level, without a tightly fitted frame and glazing, must be protected by sprinklers of the same type as those around them.
Can open-top containers be used in storage?
Part 2 states they should not be used in sprinklered storage hazards. Non-combustible open-top containers can accelerate horizontal fire spread when combustible containers sit below them. Where they appear in a rack arrangement, additional assessment is required.
What is IRAS and when is it required?
In-rack automatic sprinklers. Although ESFR usually targets ceiling-only protection, in-rack sprinklers can be required for certain stack heights and commodity classes. In CMSA and high storage configurations, the decision follows commodity class, stack height and rack type.
How is plastic commodity classification abbreviated?
Part 2 classifies plastic commodities with detailed abbreviations covering uncartoned and exposed plastics, cartoned unexpanded and cartoned expanded plastics, and their uncartoned equivalents. That classification governs the ESFR and CMSA design criteria and the required head pressure.
Did A2:2026 change the maintenance requirements?
A2 keeps the maintenance regime and makes periodic system inspection and system monitoring more explicit. The routines remain layered — weekly, quarterly, half-yearly, annual, three-yearly and ten-yearly. Running that schedule with records is asked about increasingly often in insurance and third-party inspections.
When does A2:2026 become mandatory?
Under CEN rules it must have national standard status by October 2026 at the latest, and conflicting national standards must be withdrawn by the same date. In Turkey, TS EN 12845+A2:2026-05 has been published and replaces the earlier version. Designing new projects to the current version avoids problems in approval and insurance.
Can I finish an ongoing project to the earlier A1:2019?
If your contract references a specific version, it can be treated as valid through the transition; but the approving authority or the insurer may ask for the current version. The safest course is to state the year and amendment explicitly in the contract, and to set up new designs starting after 2026 to A2:2026 together with Part 2.
What should I watch when moving from NFPA 13?
The unit system, the density-area definition and the K-factor notation all differ. Under the new structure, Part 2 applies for ESFR and CMSA and EN 17451 for pump sets; looking for everything in the main standard, as NFPA habits suggest, leads to errors. Sizing sprinklers to EN and the pump to NFPA creates a water supply duration mismatch.
Where are the new versions obtained in Turkey, and are they mandatory?
TS EN 12845+A2:2026 and TS EN 12845-2:2025 are published by the Turkish Standards Institution. BYKHY accepts NFPA 13 and EN 12845 as alternatives, and which version applies is usually decided by the investor, the insurer and the third-party inspector. EU-owned facilities, CE-marked export buildings and European-insured logistics warehouses effectively expect the current EN 12845 version.
Frequently Asked Questions
What is the current version of EN 12845?
EN 12845:2015+A2:2026, approved by CEN in January 2026, superseding A1:2019/2020, alongside EN 12845-2:2024 for ESFR and CMSA.
Why was the standard split into parts?
So that specialist subjects — ESFR and CMSA, and pump sets — could live in separate documents and be updated independently of the main standard.
Can ESFR be used on a dry system?
No. ESFR is restricted to wet installations. CMSA works on wet and dry, with dry systems limited to dry pendent and upright types.
Where do pump set requirements now sit?
In EN 17451, referenced from the main text. Pump room design now needs both documents together.
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Download MEP Calc on the App StoreBS EN 12845:2015+A1:2019 Fixed firefighting systems — Automatic sprinkler systems. EN 12845-2:2024 (CMSA & ESFR sprinkler systems). NFPA 13 Standard for the Installation of Sprinkler Systems. Turkish Regulation on Fire Protection of Buildings (BYKHY). FM Global Property Loss Prevention Data Sheet 2-0.