EN 12845 Annual, Three-Year and Ten-Year Routines

The annual pump flow test against the nameplate curve, the diesel failed-to-start scenario, suction strainer cleaning; the three-yearly tank and valve overhaul; the ten-yearly documented tank clean. This is where the real service-life items of a sprinkler system live.

At a polyethylene sheet manufacturer, the year-eleven tank clean produced 4 cm of sediment, sheets of rust scale and a bird skeleton. This was a site where gauges were read every week, batteries checked every month and hazard reviews done every quarter. But the ten-year tank inspection had been skipped, because "it's a closed system, the water won't rust". The long-interval clauses exist precisely to break that illusion.

The annual routine (12 months)

Automatic pump flow test

Every water supply pump is tested at full load. The test connection is made downstream of the non-return valve on the pump discharge. The pump must meet the pressure and flow figures on its nameplate, with an allowance for losses up to the supply pipe and valve set.

In practice, four measurement points: shutoff, 50 %, 100 % and 140 % of rated flow. The characteristic curve is compared with the nameplate:

• Shutoff no more than 140 % of duty head
• 100 % flow equals the nameplate pressure
• 140 % flow at least 70 % of duty head (EN 12845 is slightly more relaxed than NFPA 20, which asks for 65 %)

Deviation from the curve points to a worn impeller, internal recirculation, low motor speed or suction cavitation from inadequate NPSH. All measurements are recorded.

Flow test on systems without pumps

Where the supply is a town main or gravity tank only, the test connection is made upstream of the control valve set, and the design flow and pressure must be achieved.

Diesel failed-to-start test

Simulated to the standard's requirements: six consecutive cranking attempts — two groups of three, each attempt 5–10 s with 10–15 s between — must end with a failed-to-start alarm. The engine is then started manually straight afterwards, so the system is never left dead.

Float valve

The tank fill float valve is verified as operating correctly.

Suction strainer and settling chamber

Inspected at least annually and cleaned where required.

The three-yearly routine (36 months)

Storage and pressure tanks

Except for tanks designed not to require ten-year maintenance, all tanks undergo internal inspection, with draining and cleaning where necessary. Corrosion is assessed against the manufacturer's recommendations, and every tank is repainted or has its corrosion protection renewed.

Water supply stop, alarm and check valves

All water supply stop, alarm and non-return valves are inspected and replaced or overhauled as needed. On site that means partial or full stripping and visual inspection of the internals — spool seals, how the clapper seats, and spring load.

The ten-yearly routine (120 months)

At intervals no greater than ten years, all storage tanks are cleaned, internally inspected, and the shell repaired where required.

Draining the tank may be necessary, but alternative approaches can be accepted for water conservation — remotely operated or diver inspection, or internal photography by drone.

Field error — "70 % wasn't reached" on the annual flow test

At a chemical plant, the annual flow test produced only 58 % of nameplate pressure at 140 % flow, against a 70 % threshold. The control panel and flow meter were suspected first; a repeat measurement gave the same result. Opening the pump revealed a worn impeller — it had been running dry at low pressure because the jockey pump cut-in was miscalibrated and starting every thirty seconds. The symptom was wear; the root cause was the jockey calibration. Impeller and wear ring replacement took eight weeks including import lead time, during which the impairment measures applied.

The ten-year tank clean — practical choreography

1. Preparation: formal impairment notification to the authority and insurer. A temporary hose line or tanker water supply plan.
2. Draining: 24–72 hours for 50–500 m³.
3. Ventilation: confined space risk; force-ventilate for at least four hours.
4. Entry permit: confined space procedure, standby watcher, gas meter, lifeline.
5. Internal inspection: corrosion map, photographs of coating damage, analysis of a bottom sediment sample.
6. Repair: grit blasting and epoxy renewal where present, weld repairs, surface making good.
7. Refilling: chlorination at 10–25 ppm for 24 hours, then a clean water flush and microbiological test.
8. Return to service: system repressurised, alarms tested, logbook completed.

Typical duration is three to seven days. Where there is a single supply and a single tank, the building must be kept under fire watch throughout.

Pump curve acceptance

Test point	EN 12845 acceptance	NFPA 20 acceptance
Shutoff	≤ 140 % duty	≤ 140 % duty
100 % flow	Nameplate	Nameplate
140 % flow	≥ 70 % duty	≥ 65 % duty

Comparison with NFPA 25

The NFPA 25 annual pump flow test is essentially the same, with three-point curve verification as standard. Internal tank inspection is five-yearly for closed tanks and three-yearly for open ones under NFPA 25, against three-yearly plus a full ten-year clean under EN 12845. The diesel failed-to-start test uses ten attempts on the NFPA side against six in EN 12845. In practice the two standards complement each other closely.

Link to Turkish regulation

BYKHY refers the maintenance calendar to TS EN 12845. The ten-year tank clean is rarely scheduled in Turkey, because most installations are five to eight years old. But if an external insurance audit asks "when was the tank last inspected internally?" and there is no record, the consequence runs from a premium increase to a rejected claim. This line must not be left blank in the periodic inspection report.

Quick check list

• Annual pump flow test on a three-point curve, recorded.
• Diesel failed-to-start test followed by manual start.
• Float valve function verified.
• Suction strainer cleaned.
• Three years: tank internal inspection and corrosion protection renewed.
• Three years: stop, alarm and non-return valves overhauled.
• Ten years: full tank clean under impairment measures.
• All reports signed, photographed and appended to the periodic inspection report.

Frequently Asked Questions

What does the annual pump flow test check?

The characteristic curve against the nameplate at four points: shutoff no more than 140 % of duty head, nameplate pressure at 100 % flow, and at least 70 % of duty head at 140 % flow.

How is the diesel failed-to-start test carried out?

Six consecutive cranking attempts in two groups of three must produce a failed-to-start alarm, immediately followed by a manual start so the system is never left dead.

What happens at three years?

Internal inspection of all tanks, with cleaning and corrosion protection renewed, plus overhaul or replacement of all water supply stop, alarm and non-return valves.

Must the tank be drained for the ten-year clean?

Usually, but alternatives are accepted for water conservation — remote or diver inspection, or internal photography by drone. Entry requires a full confined space procedure.

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