EN 12845 Diesel Pump Batteries, Chargers and Starters

The most common misconception on site is the assumption that EN 12845 contains detailed numerical provisions for diesel fire pump batteries, such as cell voltage, charging current or the number of start attempts. In TS EN 12845+A2:2026 this is not the case. Clause 10.9, headed "Diesel engine driven pump sets", consists of only three subclauses, and those three clauses take up less than half a page on EN p.65-66 (TS p.68-69). Source: TS EN 12845+A2:2026, Clause 10.9, EN p.65-66.

This article reports in full what the standard actually says on this subject and states clearly what it no longer says. The gap has not been filled with figures compiled from other sources.

What Clause 10.9 covers today

Clause 10.1 points the same way: water supplies consisting of pumps shall conform to EN 17451 (EN p.57). The technical reason for the A2 revision is stated explicitly in the European foreword: integration of the references to and use of EN 17451, EN 12845-2 and EN 12845-3 into this document (EN p.10).

In the text there are "deleted text" markers immediately before 10.9.1, between 10.9.1 and 10.9.2, and between 10.9.2 and 10.9.3. The battery, charger, starter motor and spare parts provisions that occupied those positions in earlier editions have been removed by A2.

The four alarm conditions of 10.9.2

Clause 10.9.2 (EN p.66) lists the following four conditions:

• a) pump running;
• b) start failure;
• c) common faults;
• d) auto position off.

All four are indicated in two places at once: locally and at a location permanently attended by responsible personnel. The means of indication is a warning lamp.

Alarm transmission level: Annex I, Table I.1

Annex I (normative, EN p.155-156) determines the level at which alarms are transmitted. The diesel pump set row refers to 10.9.2:

Type A is a fire alarm and type B is a technical (fault) alarm. Clause I.2 states that the signal reporting that the pump set is running may, depending on local conditions, also be treated as a fault alarm. Alarms are connected to an alarm panel in the sprinkler control room or in the pump room and transmitted to a permanently attended location. Type B technical alarms may in addition be transmitted to the responsible person designated in accordance with 20.1.

Marking: Clause 18.2.6.2

Clause 18.2.6.2 (EN p.116-117) requires that the alarms specified in 10.8.5.1 and 10.9.2 be suitably marked both at the pump set control panel and at the location attended by responsible personnel:

• a) diesel fire pump start switch off;
• b) diesel fire pump start failure;
• c) pump running;
• d) diesel control panel fault.

The manually operated stopping mechanism is labelled "SPRINKLER PUMP SHUT-OFF".

Battery maintenance: the only direct provision left in the standard

The only direct maintenance provision concerning batteries is in Clause 20.2.3 (monthly routine, EN p.120): the electrolyte level and density of all lead acid cells, including the diesel engine starter batteries and the control panel power supply batteries, are checked. If the density is low, the charger is checked; if the charger is working normally, the affected battery or batteries are replaced.

This provision is in the monthly routine, not in the half yearly routine. Clause 20.3.3.2 (EN p.121) governs the exercising of the moving parts of dry alarm valves, accelerators and exhausters in the half yearly routine in accordance with the supplier's instructions; it has nothing to do with batteries.

Three documents that address the battery side still appear in the list of normative references (EN p.15):

• EN 50342-1, Lead acid starter batteries, Part 1: General requirements and methods of test;
• EN 50342-2, Lead acid starter batteries, Part 2: Dimensions of batteries and marking of terminals;
• EN 60623, Secondary cells and batteries containing alkaline or other non acid electrolytes, vented nickel cadmium prismatic rechargeable single cells.

The classification references for battery types have been retained, but the numerical requirements for the voltage, capacity and charging characteristic of those batteries have been taken out of the EN 12845 text.

The parts of the weekly and annual tests that concern the starting circuit

Clause 20.2.2.4 (EN p.119) requires that, in the automatic pump set starting test, the fuel and engine lubricating oil levels of diesel engines be checked, the automatic start condition be simulated by reducing the water pressure at the starting device, the starting pressure be checked and recorded when the pump runs, and the oil pressure and the cooling water flow in open circuit cooling systems be checked.

Clause 20.2.2.5 (EN p.119-120) requires, immediately after that, that the engine be run for 20 minutes or for the period recommended by the supplier, then stopped and immediately restarted using the manual start test button. The water level in the primary circuit of closed circuit cooling systems is also checked. Throughout the test the oil pressure (if a gauge is fitted), engine temperatures and coolant flow are monitored; the oil hoses are checked and a general inspection is made for leakage of fuel, coolant or exhaust gas.

Clause 20.3.4.3 (annual routine, EN p.122) requires the start failure alarm to be tested and describes that test as being "in accordance with 10.9.7.2". Subclause 10.9.7 does not exist in the A2:2026 text; this is a dangling cross reference. Immediately after the test the engine is started using the manual starting system.

The pump room side

• Clause 10.3.1 (EN p.57): pump sets are located in a compartment with at least 60 minutes fire resistance that is not used for any purpose other than fire protection. Order of preference: a) a separate building, b) a building adjoining the sprinkler protected building with direct access from outside, c) a compartment inside the sprinkler protected building with direct access from outside.
• Clause 10.3.3 (EN p.58): the pump set compartment is maintained at a minimum of 10 °C for diesel driven sets (4 °C for electric sets).
• Clause 10.3.4 (EN p.58): compartments for diesel pump sets are provided with adequate ventilation in accordance with the supplier's recommendations. No numerical air flow rate is given.
• Clause 10.2 (EN p.57): where a superior or duplicate water supply contains more than one pump, only one of them may be driven by an electric motor. In a three pump arrangement each pump shall be able to deliver at least 50 % of the specified flow at the specified pressure.

Documentation

Clause 4.4.4.4 (EN p.28) requires that pump set documentation be provided in accordance with EN 17451. Clause 18.2.5.2 (EN p.116) requires that, in fully calculated installations, installer data conforming to EN 17451 be displayed at the pump, and that this comprise a) the pump supplier data sheets, b) a schedule listing the technical data specified in 4.4.4.4, and c) a copy of the installer's pump characteristic sheet.

Provisions no longer in the standard

The following topics do not appear in the text of TS EN 12845+A2:2026. Writing a value against these topics in a technical specification with a reference to EN 12845 would be a reference with nothing behind it:

• float and boost charging voltage per battery cell;
• the ratio of the charger output current to the C10 or C5 capacity;
• the number of start attempts, the duration of each attempt and the rest period between attempts;
• a requirement for a separating relay or diode group between two battery sets;
• a requirement to keep a hydrometer in the pump room (the hydrometer appears in the standard only in 11.1.2.2, for checking the specific gravity of the antifreeze solution, EN p.66);
• a diesel engine spare parts list (numbers of filters, belts, gaskets, injectors);
• how many hours of running the fuel tank must cover.

Field note: the removal of these provisions from the text does not mean that these topics have become unimportant on site; only the reference chain has changed. When these topics are written into a specification, EN 17451 and the pump set manufacturer's documentation should be cited as the source.

Frequently Asked Questions

Does EN 12845+A2:2026 give a cell voltage or a number of start attempts for the diesel pump battery?

No. TS EN 12845+A2:2026 Clause 10.9 (EN p.65-66) consists of only three subclauses: 10.9.1 states that diesel pump sets and their ancillary equipment shall conform to EN 17451, 10.9.2 that four conditions shall be indicated, and 10.9.3 that the site commissioning test shall be carried out in accordance with EN 17451. Provisions such as cell voltage, number of start attempts, attempt duration, charging current and spare parts lists are no longer part of this standard.

Which four conditions does Clause 10.9.2 require to be indicated?

TS EN 12845+A2:2026 Clause 10.9.2 (EN p.66): a) pump running, b) start failure, c) common faults, d) auto position off. All four are indicated by warning lamps both locally and at a location permanently attended by responsible personnel.

At what interval is the battery electrolyte checked, and in which clause?

In the monthly routine, Clause 20.2.3 (EN p.120). The electrolyte level and density of all lead acid cells, including the diesel engine starter batteries and the control panel supply batteries, are checked. If the density is low, the charger is checked first; if the charger is working normally, the affected battery or batteries are replaced.

What is done to the starting circuit of the diesel pump during the weekly test?

Clauses 20.2.2.4 and 20.2.2.5 (EN p.119-120): the fuel and engine oil levels are checked, the automatic start condition is simulated by reducing the water pressure at the starting device, the engine is run for 20 minutes or for the period recommended by the supplier, then stopped and immediately restarted using the manual start test button.

Which clause does the annual start failure test refer to?

Clause 20.3.4.3 (EN p.122) states that the start failure alarm shall be tested in accordance with 10.9.7.2. However, subclause 10.9.7 does not exist in the A2:2026 text; 10.9 consists only of 10.9.1, 10.9.2 and 10.9.3. This is a dangling cross reference.

References

• TS EN 12845+A2:2026 Clause 2, Normative references (EN p.15)
• TS EN 12845+A2:2026 Clause 4.4.4.4 (EN p.28)
• TS EN 12845+A2:2026 Clauses 10.1, 10.2 (EN p.57)
• TS EN 12845+A2:2026 Clauses 10.3.1, 10.3.3, 10.3.4 (EN p.57-58)
• TS EN 12845+A2:2026 Clauses 10.9.1, 10.9.2, 10.9.3 (EN p.65-66)
• TS EN 12845+A2:2026 Clause 11.1.2.2 (EN p.66)
• TS EN 12845+A2:2026 Clauses 18.2.5.2, 18.2.6.2 (EN p.116-117)
• TS EN 12845+A2:2026 Clauses 20.2.2.4, 20.2.2.5 (EN p.119-120)
• TS EN 12845+A2:2026 Clause 20.2.3 (EN p.120)
• TS EN 12845+A2:2026 Clause 20.3.3.2 (EN p.121)
• TS EN 12845+A2:2026 Clause 20.3.4.3 (EN p.122)
• TS EN 12845+A2:2026 Annex I, Table I.1 and Clause I.2 (EN p.155-156)
• TS EN 12845+A2:2026 European foreword (EN p.10)

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