UNI EN 12259-12 and EN 17451: What Really Changes

UNI EN 12259-12 is now a key standard for fire pumps used in sprinkler systems, and in Italy, it also applies to the water supply systems covered by UNI 10779. In this response, we clarify the rules, requirements, and practical checks related to design, construction, and certification.

Context: Why are these rules “necessary” under EN 12845 and UNI 10779?

In recent years, two European technical standards have been introduced that effectively change the way fire protection water supply systems are designed, constructed, and certified when working in accordance with UNI EN 12845:2020:

• UNI EN 12259-12:2023, product standard for fire pumps.
• UNI EN 17451:2025, standard governing the design and construction of fire pump-sets.

The key point is integration: EN 12845:2020 governs the design, installation, and maintenance of sprinkler systems, while EN 12259-12 specifies the requirements for the pumps that those systems must use.

UNI EN 12259-12: What It Covers (and Which RULES It Is Used With)

UNI EN 12259-12 is part of the series of standards on “Fixed Fire Protection Systems.” The text states that some parts of the series have already been harmonized (Parts 1 through 5) and that the others will be harmonized in accordance with the EU’s timeline and procedures.

In practice, the rules:

• specifies requirements for single-stage and multistage centrifugal pumps, with mechanical seals or soft packing, for use in automatic sprinkler systems;
• is intended to be used in conjunction with EN 12845 and EN 17451;
• It applies to various types (axial inlet, split-case, multistage, in-line, submersible well pumps, and vertical turbine pumps), regardless of the installation angle.

UNI EN 17451: What It Specifies Regarding the “Pump Set” in the Context of EN 12845:2020

UNI EN 17451 specifies requirements for:

• design and assembly of the pump unit in accordance with the requirements of EN 12845:2015+A1:2019 (UNI EN 12845:2020);
• installation and commissioning;
• characteristics of the essential components;
• performance tests for units powered by diesel and/or electric motors;
• testing, commissioning, delivery, and documentation.

The text explicitly states that EN 17451 may be applied in conjunction with the current edition of EN 12845 (UNI EN 12845:2020) and that any conflicting requirements arising from the application of other standards must be resolved through contracts and relevant specifications.

Practical Comparison of EN 12845, UNI 10779, UNI EN 12259-12, and UNI EN 17451

The “supply chain” link described is as follows:

• EN 12845:2020: establishes the framework for sprinkler systems (design, installation, and maintenance) and, to ensure proper implementation, requires pumps that meet requirements consistent with EN 12259-12.
• UNI EN 12259-12: specifies how pumps intended for use in these systems must be constructed and characterized.
• UNI EN 17451: specifies how the pump set used in sprinkler systems compliant with EN 12845 must be manufactured and commissioned.
• UNI 10779 (Italy): For water supply systems (including pressurization units), it refers to the requirements of EN 12845:2020. Consequently, the text states that UNI EN 12259-12:2023 must also be applied to fire hydrant systems, in addition to sprinkler systems.

Requirements for certification and the CE marking under EN 12845

The text states that it is not necessary to wait for updates to EN 12845:2020: the new rules directly affect the current requirements.

Specifically, for a fire-fighting pump-set installed in water supply systems designed and constructed in accordance with EN 12845, it is specified that it must:

1. be manufactured and certified in accordance with EN 17451;
2. Use pumps manufactured and certified by the manufacturer in accordance with EN 12259-12.

It is also stated that only by following these criteria can the groups be properly certified and the CE mark affixed.

Operational Updates to UNI EN 12259-12: Materials, QR, Curves, and Nameplate

This document outlines new developments and practical requirements that affect pump selection and verification.

Materials (as listed):

• Pump body: cast iron, cast steel, stainless steel, bronze, or aluminized bronze.
• Shafts: stainless steel.
• Protective sleeves, metal parts of mechanical seals, impellers, impeller fasteners, and wear rings (and their counterparts): bronze or stainless steel.

Performance and Definitions:

• Introduction to the concept of the pump’s nominal flow rate (Qr): defined as the flow rate corresponding to an NPSHr of 5 m.
• The curve must be capable of delivering 140% of Qr at a pressure of not less than 70% of the pressure at Qr.

Q/H curve tolerances:

• Requirement for compliance with EN ISO 9906:2012, Grade 2B (the text also notes that Grade 3B was previously specified, but is no longer permitted).

Nameplate:

• Requirement for a permanent metal nameplate bearing the required information.

Stated Practical Consequences (Quick Compliance Checklist)

The text lists immediate operational consequences. In terms of “document control,” this can be summarized as follows:

• Do not use Q/H curves without specifying Qr and without the point Qr × 140% (as a verification requirement);
• Verify that all curves meet Grade 2B tolerance;
• Check to see if the nameplate containing all the required information is present;
• consider that the introduction of these requirements leads to pumps:
  • made from the finest materials,
  • choices made by taking into account points on the curve near Qr,
  • with Hydraulic Performance specifications that have tighter tolerances than in the past,
  • immediately recognizable as fire pumps.

Technical example provided: what does it demonstrate (without “getting into theory”)

The example cited in the text (model ANX 50-315/8) shows how to verify compliance with the requirements:

• Specified materials: cast iron housing, stainless steel impeller and shaft, bronze wear rings;
• Qr as indicated and a curve containing 140% of Qr with H > 70% of Hr;
• reference to the NPSHr curve (head up to 16 m) used as the basis for verifying power consumption and for sizing the motor (electric or diesel);
• Performance data declared to be in compliance with EN ISO 9906:2012 Grade 2B.

The text concludes that the pump in the example meets the requirements of EN 12259-12.

Operational Conclusions (within the scope of EN 12845)

In summary, the text states that, within the scope of EN 12845, only fire pumps compliant with EN 12259-12 must be used, and fire pressurization systems must be designed in accordance with EN 17451, with direct implications for certification and the CE marking.

If you are designing or verifying a fire protection water supply system (sprinkler systems or, in Italy, hydrant networks as specified in the cross-reference to UNI 10779), consistency between the pump (EN 12259-12) and the unit (EN 17451) is the key point to ensure.