Thai law makes the fire pump test compulsory. NFPA 25 defines what a test is. The two are not the same document, they do not ask for the same things, and on the annual test the gap between them is wide enough to matter.
Running is not passing
Almost everything in a fire protection system proves itself by state. A valve is open or shut. A detector alarms or it does not. A fire pump is different: it has to prove a shape.
A pump that starts on demand, runs sweetly for half an hour and shuts down on command has demonstrated that the starting circuit and the engine work. It has demonstrated nothing about whether the pump will still deliver the flow and pressure your sprinkler, hydrant or deluge system was designed around.
The envelope: three points, not one
NFPA 20 defines the curve a listed fire pump has to sit inside. Three points, and the pump has to satisfy all three:
- At churn (no flow) — net pressure not more than 140% of rated (§6.2.2)
- At 100% of rated flow — at least 100% of rated pressure
- At 150% of rated flow — at least 65% of rated pressure (§6.2.1)
A 1,500 gpm pump rated at 85 m must therefore also make at least 55 m at 2,250 gpm, and must not exceed about 119 m at churn. Miss any one of the three and the curve is wrong, however well the engine sounds.
Churn matters as much as the overload point, and for a different reason. Excess churn pressure is not a performance problem, it is a pressure-containment problem: net churn head plus maximum static suction has to stay inside the pressure rating of the pipework, valves and fittings downstream. Bounding that is what the main relief valve is for.
What the annual test actually measures
NFPA 25 requires an annual flow test of every fire pump assembly at churn, 100% of rated flow and 150% of rated capacity (§8.3.3.1). Where the suction supply genuinely cannot deliver 150%, the standard allows the test to stop at 100% of rated flow plus the maximum flow available at the lowest permissible suction pressure (§8.3.3.4) — an allowance, not a default.
Then comes the part most sites get wrong. The results are acceptable only if all three of the following hold (§8.3.7.2.3):
- The pump meets the flow and pressure demand of the most demanding system it supplies, based on design information the owner provides.
- The pump supplies 100% of rated flow.
- The net pressure at each flow point is at least 95% of one of: the original manufacturer’s pump curve, the original unadjusted field test curve, or a curve generated from the pump nameplate.
Three things follow from that wording.
The 5% is a floor against a baseline, not a year-on-year drift allowance. The comparison is against the original curve, not against last year’s test. A pump losing 2% a year passes every comparison with its predecessor and fails in the third year against its baseline.
You may choose the baseline, but only from that list. The commissioning acceptance curve is the most common and usually the most honest choice, but the manufacturer’s curve and the nameplate curve are equally permitted. Say in the report which one you used.
Criterion 1 is independent of criterion 3. A pump can sit inside 95% of its own curve and still fail, because the curve was never big enough for the system demand. That is why the owner has to furnish the design demand before the test, not after it.
One more clause is worth knowing by name. Section 8.3.7.2.2 forbids raising engine speed above the pump’s rated speed as a way of meeting rated performance. If a contractor’s answer to a soft curve is to turn the governor up, the test is invalid.
When the test fails
NFPA 25 does not simply say “fix it”. It sorts the failure (§8.3.7.2.4):
- The owner is notified in writing.
- The cause is investigated.
- Failure to provide the maximum system demand is an impairment — with everything that follows from that.
- Degraded performance that still meets the maximum system demand is a deficiency — serious, but not an impairment.
- Excessive vibration, or excessively worn or loose components, is a deficiency.
The record of the investigation and the corrective action is kept by the owner (§8.3.7.2.10). That impairment/deficiency line is what decides whether you need a fire watch tonight or a work order this month.
Between annual tests: the no-flow test
The weekly or monthly run is not a small annual test. It is a start-and-run check, and its rules are separate:
- Diesel-driven pumps: weekly by default (§8.3.1.1.1). Another frequency is permitted only where an approved risk analysis supports it (§8.3.1.1.2).
- Electric motor-driven pumps: weekly where the pump serves buildings beyond fire-department pumping capacity, has a limited service controller, is a vertical turbine, or takes suction from a ground-level tank or a source without useful pressure (§8.3.1.2.1). Monthly is permitted for electric pumps outside those categories and for systems with a redundant pump (§8.3.1.2.2).
- Run time: electric at least 10 minutes, diesel at least 30 minutes (§8.3.2.3, §8.3.2.4).
- The pump is started automatically, not by pressing manual start (§8.3.2.2), and qualified personnel are present throughout (§8.3.2.7).
What Thai law requires
Four instruments matter, depending on the kind of site you run.
Factories — ประกาศกระทรวงอุตสาหกรรม เรื่อง การป้องกันและระงับอัคคีภัยในโรงงาน พ.ศ. 2552
Published in the Royal Gazette on 30 September 2552 (2009). Two clauses do the work. ข้อ 10 requires fire water in a quantity sufficient to supply the fire-fighting equipment continuously for not less than thirty minutes. ข้อ 11 requires the system to be installed to accepted international standards — and the Department of Industrial Works’ own implementation handbook names NFPA as the example, listing standpipes, automatic sprinklers and the fire pump as the three components of a water-based system.
The handbook goes further, and this is the part worth pinning to the pump room wall. Its fire pump inspection form sets:
- Weekly inspection — pump condition; pipework and supports; pump room and ventilation; battery voltage and electrolyte; coolant level; lubricating oil level; fuel level for diesel.
- Monthly — water level in the fire water tank. Six-monthly — condition of the tank itself.
- Weekly test — diesel engine pump run, 30 minutes.
- Monthly test — electric motor pump run, 30 minutes.
- Annual test — flow rate and operating pressure, recorded in gpm and psi.
- Annual maintenance — engine oil change for diesel.
High-rise and extra-large buildings — กฎกระทรวง ฉบับที่ 33 (พ.ศ. 2535)
Applies to buildings 23 m and over, and to extra-large buildings. Cite it as amended — ฉบับที่ 42 (2537), 50 (2540) and 64 (2564). ข้อ 20 requires an automatic extinguishing system covering every floor; ข้อ 21 requires fire water piping from the source, a fire department connection, hose outlets, standpipes and a water reserve. The pump is what makes those pressure requirements achievable.
Workplaces — กฎกระทรวง … การป้องกันและระงับอัคคีภัย พ.ศ. 2555
Made under the Occupational Safety and Health Act พ.ศ. 2554 and amended by ฉบับที่ 2 (พ.ศ. 2561). It reaches essentially every workplace regardless of building type, and requires inspection, testing and retained records, plus an annual drill. If a site somehow escapes both the factory notification and the building regulation, this one still applies.
LPG storage — ประกาศกระทรวงพลังงาน พ.ศ. 2567
For LPG depots the fire pump must sustain the cooling-water demand for at least thirty minutes, at least one pump must be engine-driven, and the system is subject to an annual trip test whose records the Department of Energy Business audits. The compliance window for existing depots closed on 18 February 2026 — covered in our separate article on Thailand’s LPG tank-cooling rule.
Where Thai practice and NFPA 25 diverge
They are not in conflict, but they are not the same, and the differences run both ways.
On the electric pump’s no-flow run, the Thai form is stricter. NFPA 25 requires a minimum of 10 minutes (§8.3.2.3). The DIW handbook form asks for 30. Run 30.
On frequency, NFPA 25 is stricter for a large group of electric pumps. The Thai form puts every electric pump on a monthly cycle. NFPA 25 puts four categories of electric pump on a weekly cycle — including any pump taking suction from a ground-level tank, which describes most Thai industrial installations. Run weekly.
On the annual test, the gap is not about numbers but about meaning. The Thai form records one flow figure and one pressure figure. That can be measured accurately, filed correctly and satisfy an inspector while telling you nothing about whether the pump has degraded — because a single point cannot be compared to a curve. NFPA 25 wants three points and a comparison against a baseline at 95%. A Thai-compliant annual record is not, on its own, an NFPA 25 annual test.
The rule we apply on every job: design and verify to whichever requirement is stricter, document both, and make the report say which standard each figure answers to.
Buying the pump: three listings, not one
A fire pump package is three separate listings:
- The pump — UL 448
- The diesel engine — UL 1247
- The controller — UL 218
An electric motor-driven pump with an alternate power supply adds a fourth listing — the transfer switch, UL 1008. A diesel set has none: it starts from two independent battery banks.
A listed pump bolted to an unlisted controller is not a listed package, and the acceptance test is where that surfaces — usually at the worst possible moment in a project. We find it on survey more often than we would like.
What the report has to contain
NFPA 25 sets a minimum (§8.4.1.1), and it makes a useful specification to write into a maintenance contract:
- All raw data — suction and discharge pressures, voltage and current readings, and pump speed at every flow point tested
- The fire protection system demand as furnished by the owner
- Whether pump performance was satisfactory or unsatisfactory
- Deficiencies found during testing and during analysis, with recommendations
- The manufacturer’s performance data, the actual performance, and the pump discharge curves
- Time delay intervals for starting, stopping and power transfer
- A comparison with previous test results, where applicable
If a maintenance quotation does not commit to items 1, 5 and 7, it is a run-and-record visit, not an annual test.
How SATU Innovative can help
SATU Innovative supplies fire pump packages and holds the NFPA 25 inspection, testing and maintenance contract that keeps the curve honest afterwards — both halves, one accountable party. If you would like a performance test before the year you need one, contact us.
Frequently asked questions
Does the weekly 30-minute diesel run satisfy the annual test?
No. The weekly run is a no-flow test under section 8.3.2; the annual test is a flow test at three points under section 8.3.3, evaluated against a baseline curve. They answer different questions.
Our pump read 6% below last year. Is that a failure?
Not necessarily — and that is the wrong comparison. The test is measured against the original manufacturer’s curve, the original unadjusted field test curve, or the nameplate curve, not against last year. Take the reading to the correct baseline first, then check it against system demand.
Can we test at less than 150% of rated flow?
Only where the available suction supply genuinely cannot deliver it (§8.3.3.4). You then test at 100% of rated flow and at the maximum flow available at the lowest permissible suction pressure — and you say so in the report.
Who may run the fire pump test?
NFPA 25 requires qualified personnel to conduct the test and qualified individuals to interpret the results (§8.3.7.1.2). Under Thai law the design and certification of fire protection systems fall to a licensed professional engineer; the LPG notification of พ.ศ. 2567 makes engineering certification explicit.
How long do we keep the records?
The owner retains the test report and the record of any investigation and corrective action. For LPG depots the Department of Energy Business expects at least the previous year’s records to be produced on inspection. In practice, keep the full history — the baseline curve is the one document you cannot recreate.
Related reading
- Thailand’s LPG Tank-Cooling Rule: Requirements and the Passed Deadline
- Oil Spill Response Equipment: What to Specify in Your TOR
A note on editions and sources
NFPA 20 clause references are to the 2025 edition; NFPA 25 clause references are to the 2020 edition. Clause numbering can move between editions — check the current edition before quoting a number in a specification. Thai requirements are cited from the Royal Gazette texts and from the Department of Industrial Works implementation handbook for the 2552 factory notification.
Image credits
Both photographs by SATU Innovative: a diesel fire pump engine instrument panel during an annual performance test, January 2026; and an installed diesel engine fire pump controller at an anonymised Thai manufacturing plant.