UNI EN 12845 Fire Pumps: If you want to clarify “once and for all” which pump types can be used for fire protection water supply systems, the answer starts with the relevant standards and the preferred hydraulic layout.
Table of Contents
References: UNI EN 12845:2020 and T/R 11438:2016
When discussing pumps that can be used to supply fire protection systems, the applicable standard is UNI EN 12845:2020, specifically Section 10.6.1 andAppendix E.
In addition to this standard, reference is also made to T/R 11438:2016, section 8.4. In practice, to answer the question correctly, the Pump Types that are “acceptable” must be determined by considering these points together.
Acceptable Types: Summary List
Following the order of the references cited, the applicable types are listed as follows:
- Section 10.6.1 of UNI EN 12845
- Horizontal-axis centrifugal pumps
- Vertical Submersible Axial Flow Pumps (VTP)
- Submersible Pumps
- Appendix E to UNI EN 12845
- Horizontal multistage pumps
- Item 8.4 T/R 11438
- Split-case pumps (axial split case)
This list serves as a guide for making your selection: not all pumps are “interchangeable,” and, above all, the installation configuration and specific requirements also matter.
UNI EN 12845 Fire Pumps and Hydraulic Diagram: Why the Downpipe Configuration Is Preferred
For the hydraulic system, the SUBMERSIBLE configuration is “obviously preferred.” In practical terms, this means that, within the proposed decision-making process, the first pumps to be considered are horizontal-shaft centrifugal pumps installed in a submerged configuration.
UNI EN 12845 also classifies vertical submersible axial-flow pumps (VTP) as having the same level of reliability, and these are also considered to be BELOW THE THRESHOLD. The key point is that, when you can remain below the threshold, that configuration is considered the reference standard.
VTP: Advantages of the Design and Impact on Dimensions
A “major advantage” of the VTP system over the centrifugal pump system is highlighted: the water storage tank is located below ground level.
Consequently, the only external space occupied is that of the water treatment plant. This is useful when the goal is to streamline the footprint and create a “cleaner” exterior layout, without altering the reliability of the underlying design.
When the rules allow for a secondary floor (and why it is a “fallback” option)
The same result in terms of overall dimensions can also be achieved by using horizontal centrifugal pumps with an ABOVE-FLOW hydraulic configuration. However, this configuration is considered acceptable only if the two previous UNDERFLOW configurations (centrifugal pumps in underflow or VTP) could not be used.
The reasoning given is clear: the status of “SOPRABATTENTE” is described as “a source of countless problems.” The original text includes a reference to a link for further information, which is not available here: for the full article, it would be best to reinsert it (see the final section, “Missing Data / Questions”).
Water supplies: single and upper single, and engine coupling
Based on the diagrams we’ve looked at so far, it is shown that it is possible to create:
- Single-type water supply systems
- Single-point water supply systems
In both cases, it is stated that both electric and diesel engines can be paired with the main pumps. This point is important because it links the choice of pump and hydraulic system to the typical water supply configuration, without limiting the solution to a single type of engine.
Submersible Pumps: When to Use Them and How to Justify Their Use
The UNI EN 12845 standard requires that submersible pumps be used only when strictly necessary and, as indicated, requires that this choice be justified.
Specifically, the report must explain why it was not possible to use the templates with:
- centrifugal pumps (in preferred layouts)
- VTP
Therefore, submersible pumps are not presented as the “standard” first option, but rather as a solution to be considered when the most suitable bottom-mounted configurations are not feasible.
Multistage and Axial Split-Case Pumps: Recommended Applications
Horizontal multistage pumps are described as being designed for systems known as “high vertical head” systems (Appendix E). In these cases, the required head is such that the use of this type of pump is necessary.
Finally, axial split-case pumps are recommended for specific applications where the flow rates of horizontal centrifugal pumps “typically” fall short. Here, too, the idea is clear: they are not the “default” choice, but rather a solution to client requirements.
Conclusion
To correctly select the pump types for fire protection water supply systems, the recommended approach is as follows: start with the approved types (UNI EN 12845 and T/R 11438), prioritize below-head installation, consider above-head installation only as an approved alternative when preferable solutions are unavailable, and justify the use of submersible pumps only when absolutely necessary.
