Source: TS EN 12845+A2:2026 (EN 12845:2015+A2:2026), Clauses 10.1, 10.7.5, 10.8, 10.9 and Annex I.
The A2:2026 revision split the pump subject in two. Clause 10.1 (TSE p.60 / EN p.57) has been reduced to a single sentence: water supplies consisting of pumps shall be in accordance with EN 17451. In other words, the hardware detail of the pump set and its controller now lives in EN 17451, not in EN 12845. What remains in EN 12845 is this: what starts the pump set (Clause 10.7.5), which conditions are to be monitored (Clauses 10.8.5 and 10.9.2), and where those signals go and with which alarm type (Annex I). This article deals only with those remaining provisions.
What starts the pump set: two pressure switches
Clause 10.7.5.1 (TSE p.66 / EN p.63) requires three things:
- Two pressure switches shall be provided to start each pump set.
- The pipe to the pressure switches shall be at least 15 mm.
- The switches shall be connected in such a way that either switch will start the pump set.
Clause 10.7.5.3 (TSE p.67 / EN p.64) requires this arrangement to be testable: means shall be provided for testing pump set starting with each pressure switch. If an isolating valve is installed on the connection between the trunk main and any pump set starting pressure switch, a non-return valve shall be installed in parallel with that isolating valve, so that a fall in pressure on the trunk main is transmitted to the switch even when the isolating valve is closed.
Clause 15.5.1 d) (TSE p.111 / EN p.108) requires a 15 mm test valve to be fitted for testing the automatic pump set starting device.
Starting thresholds and manual stopping
Clause 10.7.5.2 (TSE p.66 / EN p.63) defines p as the pressure at the closed valve condition and gives two thresholds:
| Event | Threshold | Clause |
|---|---|---|
| Automatic start of the first pump set | When the trunk main pressure falls to a value of no less than 0.8p | 10.7.5.2 |
| Start of the second pump set (where two sets are installed) | Before the pressure falls to a value of no less than 0.6p | 10.7.5.2 |
The last sentence of the same clause is the most decisive provision for the design: once the pump has started, it continues to run until it is stopped manually. There is no automatic stopping.
The thresholds are proportional, not fixed bar values. For a set with a closed valve pressure p = 8.0 bar, 0.8p = 6.4 bar and 0.6p = 4.8 bar; this is only the arithmetic of the clause, not a value given as an example in the standard.
The four conditions monitored on an electrical pump set
Clause 10.8.5.1 (TSE p.68 / EN p.65) lists four conditions and refers to Annex I:
- power available to the motor and, where AC, on all three phases,
- pump on demand,
- pump running,
- start failure.
Clause 10.8.5.2 splits the indication in two: all monitored conditions shall be visually indicated individually in the pump room; pump running and a fault alarm shall also be audibly and visually indicated at a location permanently attended by responsible personnel.
Four indications on a diesel pump set
Clause 10.9.1 (TSE p.68 / EN p.65): diesel driven pump sets and ancillaries shall be in accordance with EN 17451; there shall be enough fresh air available in the pump room at all times to keep the diesel pump set running within the manufacturer specified limits and EN 17451.
Clause 10.9.2 (TSE p.69 / EN p.66), headed "Starter alarm indication", lists four conditions. Each shall be indicated by warning lights, both locally and at a responsibly manned location:
- a) pump running,
- b) start failure,
- c) common faults,
- d) automatic mode off.
Clause 10.9.3 also delegates the commissioning test: the site commissioning test shall be performed in accordance with EN 17451.
Field note: the A2 text contains no controller internals such as the number of cranking attempts, a mute button, a lamp test or the colour of the warning lights. For these subjects the basis is EN 17451 and the manufacturer documentation, not EN 12845.
Labelling: the name under which the alarm appears
Clause 18.2.6.2 (TSE p.119-120 / EN p.116-117) requires the alarms specified in 10.8.5.1 and 10.9.2 to be suitably marked both at the pump set controller and at the responsibly manned location:
- a) diesel fire pump starter switch off,
- b) diesel fire pump failure to start,
- c) pump running,
- d) diesel controller fault.
A manually operated stopping mechanism shall be labelled "SPRINKLER PUMP SHUT-OFF".
On the electrical side, Clause 10.8.3.2 (TSE p.68 / EN p.65) requires the supply switch to be labelled: "SPRINKLER PUMP MOTOR SUPPLY - NOT TO BE SWITCHED OFF IN THE EVENT OF FIRE". The letters shall be at least 10 mm high and white on a red background, and the switch shall be locked to protect it against tampering.
Supply and cabling: the infrastructure the monitoring signal rests on
Clause 10.8.2 (TSE p.67 / EN p.64):
- The supply to the pump set shall be dedicated to the sprinkler system and separated from all other connections. Where the electricity authority permits, the supply shall be taken from the incoming side of the main switch of the building; where this is not permitted, it shall be taken by a connection from the main switch.
- Only one load shall be connected to each power cable.
- Power cables shall be flame retardant and shall show burning behaviour in accordance with EN 60332, test type B or C. The conductor cross-section shall be at least 2.5 mm² Cu.
- Flame retardant cables may be laid as follows without further requirements: a) buried with a covering of at least 70 cm; b) in floors and walls made of non-combustible materials with sufficient covering, e.g. in concrete with a covering of 10 cm; c) in sprinkler pump rooms; d) in main electrical switchboard operating rooms fitted with sprinklers or in accordance with 5.1.2 c).
- Otherwise, E 90 fire-resistant cables shall be used.
- Where sprinkler systems are powered by two electrical power sources, the cables to the pump set should be laid at least 3 m apart from each other.
Clause 10.8.4 (TSE p.68 / EN p.65) gives a single figure for the cable cross-section: the current for calculating the correct dimension shall be determined by taking 150 % of the largest possible full load current of the pump set.
Clause 10.8.1.3: the pump set shall run at its nominal capacity within 15 s of starting. Clause 10.8.1.2: up to date documentation, such as installation drawings, main supply and transformer diagrams, controller panel, motor, control alarm circuits and signal connections, shall be kept available in the sprinkler valve or pump compartment.
Annex I: where the signal goes, and with which type
Clause I.1 (TSE p.158 / EN p.155): alarms shall be connected to an alarm panel in the sprinkler control room or the pump room and forwarded according to their importance. Alarms shall be transmitted to a permanently manned location, inside or outside the premises; type B (technical) alarms may in addition be transmitted to a responsible person.
The pump related rows of Table I.1:
| Alarm | Clause | Alarm type |
|---|---|---|
| Water flow alarm | 16.1.1 | A |
| Low pressure in the town main | 9.2 | B |
| Water flow detector in the pump room | 10.3.2 | A |
| Priming tank low level | 10.6.2.4 | B |
| Electrical pump set: on demand | 10.8.5.1 | B |
| Electrical pump set: start failure | 10.8.5.1 | B |
| Electrical pump set: running | 10.8.5.1 | A |
| Electrical pump set: no electrical power | 10.8.5.1 | B |
| Diesel pump set: automatic mode off | 10.9.2 | B |
| Diesel pump set: start failure | 10.9.2 | B |
| Diesel pump set: running | 10.9.2 | A |
| Diesel pump set: common fault | 10.9.2 | B |
| Low pressure in dry pipe and pre-action systems | 16.2.3 | B |
Clause I.2 (TSE p.159 / EN p.156) defines the distinction: signals from water flow alarms and alarm valves shall be indicated as fire alarms (level A). Depending on local conditions, the signal indicating that the sprinkler pump set is running may alternatively be treated as a fault alarm. Technical faults such as a power failure, which might prevent the system from working correctly in a fire, shall be indicated as fault alarms (level B).
Periodic verification of the monitoring chain
Clause 20.2.2.4 (TSE p.122 / EN p.119) defines the weekly automatic pump set starting test: on diesel sets, the fuel and oil levels are checked; the automatic starting condition is simulated by reducing the water pressure at the starting device; when the pump set starts, the starting pressure is checked and recorded; on diesel sets, the oil pressure and, with open circuit cooling, the cooling water flow are checked.
Clause 20.2.2.5: immediately after this test, the diesel engine shall be run for 20 min, or for the period recommended by the manufacturer, stopped and immediately restarted using the manual start test button.
Clause 20.3.4.3 (TSE p.125 / EN p.122) requires, in the annual routine, a test of the failure of the diesel engine to start and says that the alarm shall be tested for compliance with 10.9.7.2. Since Clause 10.9 in A2:2026 consists only of subclauses 10.9.1, 10.9.2 and 10.9.3, this is a residual cross-reference left in the text; in practice the content of the test is defined through EN 17451. The second sentence of the clause remains valid: immediately after this test, the engine shall be started using the manual starting system.
Frequently Asked Questions
How many pressure switches start a pump set under EN 12845+A2:2026?
Clause 10.7.5.1 (TSE p.66 / EN p.63) requires two pressure switches to start each pump set. The pipe to the switches shall be at least 15 mm and the switches shall be connected in such a way that either switch will start the pump set.
At what pressure does the pump set cut in?
Clause 10.7.5.2 (TSE p.66 / EN p.63): the first pump set starts automatically when the pressure in the trunk main falls to a value of no less than 0.8p, where p is the closed valve pressure. Where two pump sets are installed, the second starts before the pressure falls to a value of no less than 0.6p. Once started, the pump runs until it is stopped manually.
Which conditions are monitored on an electrically driven pump set?
Clause 10.8.5.1 (TSE p.68 / EN p.65) lists four conditions: power available to the motor (where AC, on all three phases), pump on demand, pump running and start failure.
Which indications are mandatory on a diesel pump set?
Clause 10.9.2 (TSE p.69 / EN p.66): pump running, start failure, common faults and automatic mode off. These four conditions are indicated by warning lights both locally and at a location permanently attended by responsible personnel.
Which alarms are type A and which are type B?
Table I.1 (TSE p.158 / EN p.155): the water flow alarm and the flow detector in the pump room are type A. The demand, start failure and no electrical power signals of the electrical pump set are type B, while pump running is type A. Clause I.2 notes that, depending on local conditions, the pump running signal may alternatively be treated as a fault alarm.
Where did A2:2026 move the pump controller provisions?
Clause 10.1 (TSE p.60 / EN p.57) is now a single sentence: water supplies consisting of pumps shall be in accordance with EN 17451. The controller hardware detail is in EN 17451, not in EN 12845; what remains in EN 12845 is the starting logic (10.7.5), the conditions to be monitored (10.8.5, 10.9.2) and the alarm transmission (Annex I).
References
- TS EN 12845+A2:2026 Clause 10.1 (TSE p.60 / EN p.57)
- TS EN 12845+A2:2026 Clause 10.3.2 (TSE p.61 / EN p.58)
- TS EN 12845+A2:2026 Clause 10.6.2.4 (TSE p.63 / EN p.60)
- TS EN 12845+A2:2026 Clauses 10.7.5.1, 10.7.5.2 (TSE p.66 / EN p.63)
- TS EN 12845+A2:2026 Clauses 10.7.5.3, 10.8.1.2, 10.8.1.3, 10.8.2 (TSE p.67 / EN p.64)
- TS EN 12845+A2:2026 Clauses 10.8.3.2, 10.8.4, 10.8.5.1, 10.8.5.2, 10.9.1 (TSE p.68 / EN p.65)
- TS EN 12845+A2:2026 Clauses 10.9.2, 10.9.3 (TSE p.69 / EN p.66)
- TS EN 12845+A2:2026 Clause 15.5.1 (TSE p.111 / EN p.108)
- TS EN 12845+A2:2026 Clause 16.2.3 (TSE p.114 / EN p.111)
- TS EN 12845+A2:2026 Clause 18.2.6.2 (TSE p.119-120 / EN p.116-117)
- TS EN 12845+A2:2026 Clauses 20.2.2.4, 20.2.2.5 (TSE p.122 / EN p.119)
- TS EN 12845+A2:2026 Clause 20.3.4.3 (TSE p.125 / EN p.122)
- TS EN 12845+A2:2026 Annex I, Clause I.1 and Table I.1 (TSE p.158 / EN p.155), Clause I.2 (TSE p.159 / EN p.156)
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Download MEP Calc on the App StoreTS EN 12845+A2:2026 (EN 12845:2015+A2:2026) Fixed firefighting systems — Automatic sprinkler systems — Design, installation and maintenance; TS EN 12845-2:2025 (EN 12845-2:2024) ESFR and CMSA sprinkler systems. Every figure in this article is taken from the published standard text; clause, table and page references are listed under References. General information only, not a substitute for the standard or for a design review.