Sprinkler types
Anyone who regularly deals with sprinkler systems will certainly have heard of ESFR sprinklers. However, CMDA and CMSA are abbreviations that are rarely used, at least in Germany. Therefore, the three sprinkler types are explained first.
CMDA
The classic sprinkler, which has just celebrated its 150th birthday, is based on the fact that it limits the heat release of the fire by releasing water and thus stops the fire from spreading. When designing this sprinkler system, the water coverage is specified for a certain effective area. This is where the name comes from: CM = "control mode", D = density (water coverage); A = area (effective area).
In other words, a sprinkler that stops the spread of fire by applying a certain amount of water over a defined effective area. As a harmonized construction product, the sprinkler heads must comply with DIN EN 12259-1 and bear a CE mark. The design is carried out on the shelf in accordance with VdS CEA 4001 or DIN EN 12845. The area of application covers the entire range from offices and underground car parks to industrial and logistics buildings.
ESFR
This type of sprinkler is based on very early triggering (FR = fast response) and then rapid suppression (ES = early suppression) of the fire. The suppression of a fire is understood to mean the reduction of the heat release rate. Figure 1 shows a suspended K360 ESFR sprinkler. In Europe, DIN EN 12259-13 describes the requirements for the ESFR sprinkler component.
ESFR sprinklers are often used in buildings with a high fire risk (e.g. warehouses). When using ESFR sprinklers, it is often possible to dispense with the installation of rack sprinklers. When designing this sprinkler system, the sprinkler type (incl. K-factor), the minimum pressure at the sprinkler and the number of sprinklers to be supplied simultaneously are specified.
CMSA
This type of sprinkler has not yet been widely used in Germany. It is also a sprinkler that controls a fire by limiting the rate of heat release (CM = control mode). In contrast to the CMDA sprinkler, the CMSA sprinkler is designed for use in special storage situations (SA = specific application). Figure 2 shows an upright K360 CMSA sprinkler. (Converted from the US units, it is actually a K368 sprinkler. However, it is used as a K360 in the design).
When designing this sprinkler system, the sprinkler type (incl. K-factor), the minimum pressure at the sprinkler and the number of sprinklers to be supplied simultaneously are specified. The CMSA sprinkler component is described in prEN 12259-15. ESFR sprinklers can generally only be used in wet systems; there are also concepts for CMSA sprinklers in dry systems. In simple terms, DIN EN 12845-2 therefore deals with sprinklers with large K-factors.
Development of standards
The development of this standard has a long history. Over ten years ago, the responsible European committee for automatic firefighting systems (TC 191) discussed whether they wanted to continue with a European standard that had a shadowy existence (at least in Germany, DIN EN 12845 was practically never applied) because it was technically very outdated, or whether a new standard should be developed using the expertise of European experts. The latter was decided.
The best solutions from various regulations (FM data sheets, NFPA and (VdS) CEA 4001) were to be combined in order to provide users with an up-to-date and practicable standard that also meets the high requirements for risk transfer of insurers.
In order to be able to handle such a large set of rules, the standard has currently been divided into three parts:
Part 1 - Basics and classic sprinklers (CMDA)
Part 2 - ESFR and CMSA sprinklers
Part 3 - Earthquake safety requirements
Part 1, with its more than 600 pages and correspondingly many comments and discussions, will take a few more years before it is published. Part 2 - which actually builds on Part 1 - could be completed more quickly simply because of its length (a good 60 pages). There is also a direct problem here: the current sprinkler standard (DIN EN 12845 : 2020-11) uses a different risk classification than the new Part 2 of DIN EN 12845. Table 1 shows the changed classification for non-storage risks
The classification of storage classes (HHS) is not quite so simple. In DIN EN 12845-1 and thus also in DIN EN 12845-2, the standard international classifications have been used, according to which plastics are differentiated according to their density (foamed/unfoamed) and the pre-wettability of their packaging (cardboard/uncardboard) (see Table 2).
The application of DIN EN 12845-2 is also currently somewhat stuck in other areas, as Part 1 still lacks the foundation on which Part 2 is based. In order to correct the biggest contradictions, it is planned to write an amendment to DIN EN 12845: 2015+A1:2019 at in the near future. However, an all-round coherent concept will only be available when DIN EN 12845-1 is published.
Storage categories according to DIN EN 12845-1 and -2 (Table 2)
Brandgefahrenklasse | Beschreibung |
HHS 1 | nichtbrennbareProdukteauf Holzpalette |
HHS 2 | z. B. Granulat in Kartonage |
HHS 3 | ungeschäumter,kartonierter Kunststoff |
HHS 4 | geschäumter,kartonierter Kunststoff ungeschäumter,unkartonierter Kunststoff |
HHS 5 | geschäumter,unkartonierter Kunststoff |
Focus on warehouse fires
Both ESFR and CMSA sprinklers were developed for warehouse fires. The ESFR sprinkler concept is a technical innovation that was developed on the basis of CMSA sprinklers. CMSA and especially ESFR sprinklers have become an integral part of modern logistics. They have their useful justification and often give operators the desired flexibility. However, every user must be aware that these types of system are less robust than classic sprinkler systems with rack sprinklers.
The official introduction to DIN EN 12845-2 states: "ESFR and CMSA sprinklers are less able to cope with unfavorable boundary conditions and deviations (e.g. those caused by incorrect design or a change in practice in the protected premises over time). Attention is drawn to the risk that deviations from this standard in design and installation usually lead to total failure of the fire protection system, which is why compliance with all requirements of this standard, without exceptions, is of paramount importance."
Examples include the consideration of spray obstructions or the need for cross and, above all, longitudinal shafts. VdS CEA 4001, for example, also requires shafts in the racking concepts in accordance with 11.6. However, we have a certain degree of robustness due to the arrangement of the rack sprinklers. If individual shafts are partially blocked, major damage can occur. The fire spreads a little more, additional sprinklers open, but as a rule this will not mean a total loss.
This is not the case with ESFR concepts. If shafts are blocked here, this can lead to a complete loss of the building, especially with high storage heights. Planners, installers and experts are therefore obliged to take particular care to ensure that all requirements of DIN EN 12845-2 are fully implemented and that deviations are only accepted in very justified individual cases.
When reading DIN EN 12845-2, the experienced sprinkler planner will quickly realize that many design parameters originate from NFPA 13. This is the basis for the classic ESFR concepts with 12 sprinklers to be calculated hydraulically. However, the latest findings from FM have also been incorporated, providing additional options for the protection of storage risks and, in particular, the so-called "retrofit design" with ESFR sprinklers in the rack.
Spray obstructions are a decisive criterion in the planning of ESFR and CMSA sprinkler systems. EN 12845-2 now offers simplified and standardized regulations for this (see Figure 3).
In recent years, research has been carried out as part of a project by the Property Insurers Research Group, supported by the NFPA Research Foundation. It was found that the original criteria for classification as a spray hazard could be relaxed in many situations. These findings were taken into account when drawing up the standard.
When applying DIN EN 12845-2, it is important to note that although the translation was carried out and checked carefully, it cannot be ruled out that there may be errors that distort the meaning. For example, there were a large number of passages in the final version that were translated literally correctly but do not technically correspond to the meaning of the English original. The national working committee NA 03- 03-03 at DIN is working on optimizing the German version accordingly. If in doubt, however, it is advisable to consult the English version of EN 12845-2.
Further problems and their solution
In addition to the problems described above due to the limited compatibility between DIN EN 12845-2 and the currently valid DIN EN 12845, there are three further problems:
Firstly, Part 2 does not require the use of tested and certified products. Although ESFR sprinklers must comply with EN 12259-13 and CMSA with EN 12259-15, these are not harmonized component standards. This means that there is no CE marking of these products by independent, accredited certification bodies. The same applies to almost all other components. The only exceptions are alarm valves, flow detectors, CMDA sprinklers and the important water-powered alarm gong. There are harmonized component standards for these components (DIN EN 12259-1 to -5) and independent CE certification (e.g. by the laboratories of VdS Schadenverhütung GmbH) is mandatory. It is strongly recommended to use components that have been independently tested and certified by VdS or FM Approvals.
Secondly, there are no requirements for installers. The company should employ competent, experienced and trained personnel. This is not checked independently. However, the quality of the installer is crucial, because even the most intensive acceptance test by experts cannot find all the defects that may have been made during installation. Installer companies with external quality control, such as the VdS 2132 installer approval procedure, are recommended (see QR code on the right).
Thirdly, no information is provided on the characteristics of the water supply. This would not be part of Part 2 anyway, so we have to fall back on DIN EN 12845. Although this describes different types of water supply, it does not specify which type is to be provided. For example, the largest industrial site could be supplied exclusively by a pump, which is definitely not recommended for reasons of availability and redundancy. DIN EN 12845-1 will contain corresponding tables (similar to those in VdS CEA 4001); until it is published, the draft can be used as a guide or the redundancy considerations from VdS CEA 4001, Table 8.04 can be adopted.
A solution to all three problems is Annex T of VdS CEA 4001. This annex describes an interface between systems according to VdS - with proven installers, components and redundancies - and other regulations, including DIN EN 12845-2. This means that a highly available water supply system can be built according to VdS and the design within the protected areas corresponds to the new protection concepts according to DIN EN 12845-2.
During the final vote on DIN EN 12845-2, it became apparent that, despite great care, some errors, contradictions and inaccuracies had crept in. As technical comments may no longer be taken into account in the context of final votes, it was decided to draw up a correction shortly after publication.
One example is the requirement that all shafts in a rack must have a width of 150 mm. This requirement is familiar from other regulations for longitudinal shafts. Transverse shafts with a width of 150 mm will generally not be found, which strictly speaking rules out the application of the standard. The correction is expected to be published in the second half of 2025.
Applicability in Germany
Finally, we come to the question of whether DIN EN 12845-2 can be applied in Germany at all. According to MVV TB Annex 14 Paragraph 10.4.2, sprinkler systems should be planned, dimensioned and installed in accordance with DIN EN 12845:2020-11. However, other regulations are explicitly permitted, but the application must be shown in the fire protection certificate.
However, the information required in the fire protection certificate or generally in the building documents goes beyond this information.
The MVV TB states: "All necessary information [on planning, dimensioning and execution] must be presented [in the building documents, if necessary] in the fire protection certificate." In this quote, the text in the square brackets is a planned change to the MVV TB for 2025. However, even without the planned changes, it is clear that the necessary information for planning the sprinkler system must be provided in the fire protection certificate. This applies in particular to information that cannot be found in the selected technical regulations. Thus - at least in the opinion of the author - the concept creator must comment on the three problems/gaps in DIN EN 12845-2 mentioned above:
- Which components of which quality should be used?
- What requirements are placed on the planning and construction company?
- How should the water supply be organized?
It is known from discussions that those preparing fire protection certificates are often not technically capable of making these determinations. This is not intended as a criticism of these people. The field of fire protection is complex and it is therefore not possible to be familiar with every area in detail. Be that as it may, the MVV TB requires the information.
Now you could have an extinguishing system concept drawn up by a specialist planner and refer to this concept in the fire protection certificate. In individual cases - especially in the case of complex properties - this may be the right approach. Another option would be to refer to Appendix T of VdS CEA 4001, specifying that the system should be planned and installed in accordance with the VdS regulations and that the design criteria of DIN EN 12845-2 should be used via Appendix T.
If the sprinkler systems - which is usually the case - are also required by building regulations, the VdS Technical Inspection Body can also carry out the prescribed expert inspections on the basis of DIN EN 12845-2. For several years, an internal project team has been working on the developments relating to the DIN EN 12845 series, so that testing readiness is available. Our experts can also use the FM or NFPA regulations as a basis for testing. We are also happy to evaluate the system for the insurer.