The NFPA 25 five-year inspection, often sold as a 5-year sprinkler inspection, is the group of inspections and tests that come due every five years on a water-based fire protection system. The main one is an assessment of the internal condition of the piping, which looks for foreign material before it blocks a sprinkler. The same cycle covers valve internals, gauges, standpipe flow and hydrostatic tests, a hydrostatic test of the fire department connection (FDC) piping, full flow tests of pressure-reducing valves, and sprinklers in harsh environments.
NFPA 25 is the Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems. Every section number below is from the 2023 edition. The edition your jurisdiction has adopted and the Authority Having Jurisdiction (AHJ) decide what applies to a building, so check the numbers against that edition.
What comes due at five years
| Item | What the 2023 edition asks for | Section |
|---|---|---|
| Internal condition of piping | An assessment at least every 5 years, or at the frequency set by an approved risk analysis | 14.2.1.1, 14.2.1.2 |
| Alarm valves | Internal inspection of the valve and its strainers, filters, and restriction orifices every 5 years, or sooner if tests indicate | 13.4.1.2 |
| Check valves | Internal inspection, including the check valve at the FDC | 13.4.2.1, 13.8.6 |
| Backflow prevention assemblies | Internal inspection | 13.7.1.3 |
| Dry pipe valves | Strainers, filters, and restricted orifices inspected internally. The valve interior is an annual item | 13.4.5.1.4 |
| Preaction and deluge valves | Strainers, filters, and restricted orifices inspected internally every 5 years, plus diaphragm chambers on deluge valves. Valve interiors are annual unless the valve resets without removing a faceplate, when 5 years is permitted | 13.4.3.1.2.1, 13.4.3.1.3, 13.4.4.1.2.1, 13.4.4.1.3 |
| Gauges | Replaced, or tested against a calibrated gauge | 13.2.4.2 |
| Automatic air vents | Their strainers, filters, and screens are removed and inspected | 13.11.1 |
| Pressure-reducing valves | Full flow test on sprinkler pressure-reducing valves and on hose connection and hose rack pressure-regulating devices | 13.5.1.2, 13.5.2.2, 13.5.3.2 |
| Standpipe flow test | Automatic standpipes, at the hydraulically most remote hose valve outlets | 6.3.1.1 |
| Standpipe hydrostatic test | Manual standpipes and semiautomatic dry standpipes, including the FDC piping. Manual wet standpipes in combined sprinkler and standpipe systems are exempt | 6.3.2.1, 6.3.2.1.1 |
| FDC piping | Hydrostatic test from the connection to the fire department check valve | 13.8.5 |
| Private fire service mains | Flow test of underground and exposed piping | 7.3.1 |
| Sprinklers in harsh environments | Replacement or a sample test at 5 years, then retests every 5 years. Listed corrosion-resistant sprinklers may first be tested at 10 years | 5.3.1.1.2, 5.3.1.1.3 |
| Extra high temperature solder sprinklers | The same, where exposure to the maximum allowable ambient temperature is semi-continuous to continuous | 5.3.1.1.1.3 |
| Uncorrected obstruction | The system is examined again every 5 years while the cause remains | 14.3.2.1 |
Fire pumps have their own chapter and schedule, covered in fire pump testing requirements under NFPA 25. For the weekly through annual items, see NFPA 25 and NFPA 72 inspection frequencies.
The internal assessment of piping
Section 14.2 requires an assessment of the internal condition of piping at least every 5 years, or at a frequency set by an approved risk analysis, to look for foreign organic and inorganic material. The annex states the intent as reasonable assurance that corrosion and obstruction problems are found. It does not ask for proof that every piece of pipe is clean.
The body of the standard does not say how many points to open. The annex describes the usual method for sprinkler systems: open a flushing connection at the end of one main, and remove the end fitting, a piece of branch line, or a sprinkler. The branch line checked on dry pipe and preaction systems should be the most remote one from the water source that does not have the inspector's test connection. A sprinkler taken out for the look is replaced with a new one that matches it.
The annex also lists other methods: a video camera pushed into the system, laboratory analysis of water samples and the solids flushed out at a drain, and laboratory analysis of a pipe sample. It mentions ultrasonic testing too, but says it would not normally be used for this assessment, because it measures the pipe wall and can miss wood, plastic, or other debris inside. The annex suggests focusing on the places most prone to corrosion: high points of wet systems where air collects, low points of dry and preaction systems where water sits, and bulk piping near a fire pump.
The technician is looking for microbiologically influenced corrosion (MIC), zebra mussels, rust, scale, and debris. Tubercules or slime are tested for MIC (14.2.1.3). Material with the potential to obstruct pipe or sprinklers sends the job to an obstruction investigation (14.2.1.4). The annex notes that most piping holds some foreign material that is not enough to trigger one.
Three rules decide which systems get opened:
- Buildings with several wet pipe systems. Every other system is assessed in one cycle and the alternate systems in the next (14.2.2, 14.2.2.1). If foreign material turns up in any system in the building, all of them are assessed (14.2.2.2).
- Dry pipe and preaction systems. The every-other-system allowance is written for wet pipe systems, so it does not cover them.
- Nonmetallic pipe. It does not have to meet Section 14.2 (14.2.1.5).
An obstruction investigation is a different job
An obstruction investigation has no set frequency. It is required on system or yard main piping when any of the 16 conditions listed in 14.3.1 exists. They include:
- Obstructive material discharged during routine water tests
- Foreign material in a fire pump, a dry pipe valve, or a check valve
- Foreign material in drain test water, or a plugged inspector's test connection
- Plugged sprinklers
- Foreign material found in the pipe that could obstruct pipe or sprinklers
- Abnormally frequent false tripping of a dry pipe valve
- A system returned to service after a shutdown of more than 1 year
- Raw water supplied through the fire department connection
- Leakage caused by internal corrosion
- On dry pipe and double interlock preaction systems, total water delivery time 25 percent longer than at the acceptance test, or 5 seconds longer for parts protecting dwelling units
- On dry pipe and preaction systems designed with a Hazen-Williams C value of 120 because of nitrogen, failure to maintain the nitrogen supply, except during preplanned impairments
The investigation opens more of the system than the assessment does. Section 14.3.2.2 sets a minimum of five examination points: the system valve or water control valve, the far end of the most remote cross main, the branch line nearest the most remote line at both its cross main connection and its end, and the branch line piping tied to the most remote low point drain. The annex adds that more points can be examined where the findings call for it, and the body permits alternative nondestructive methods (14.3.2.3).
If the investigation finds enough material to obstruct pipe or sprinklers, qualified personnel carry out a complete flushing program (14.3.3). Tubercules or slime found during the investigation are tested for MIC (14.3.4). Where the condition behind the obstruction has not been corrected, or could still cause one after flushing, the system is examined again every 5 years (14.3.2.1). Annex D covers investigation and flushing procedures in more detail.
Quotes sometimes call the internal assessment a "five-year obstruction investigation." The investigation follows only when the assessment or another listed condition calls for it, so the two are separate scopes of work on a quote and on a report.
The other five-year items
Valve internals
Alarm valves and their strainers, filters, and restriction orifices are inspected internally every 5 years unless tests show a shorter interval is needed (13.4.1.2). Check valves are inspected internally every 5 years (13.4.2.1), and that includes the check valve at the FDC (13.8.6). Backflow prevention assemblies are inspected internally every 5 years (13.7.1.3), and for them the annex accepts annual maintenance that includes an internal inspection by qualified personnel.
Dry pipe valve interiors are inspected every year at the trip test, with strainers, filters, and restricted orifices on the five-year cycle (13.4.5.1.3, 13.4.5.1.4). Preaction and deluge valve interiors are annual too, but a valve that can be reset without removing a faceplate may be inspected internally every 5 years (13.4.3.1.2.1, 13.4.4.1.2.1). Their strainers, filters, and restricted orifices are a five-year item, and on deluge valves so are the diaphragm chambers (13.4.3.1.3, 13.4.4.1.3).
Gauges and air vents
Gauges are replaced every 5 years or tested every 5 years by comparison with a calibrated gauge (13.2.4.2). A gauge that is not accurate to within 3 percent of full scale is recalibrated or replaced (13.2.4.3). Automatic air vents are checked from the floor every year (13.11), and their strainers, filters, and screens are removed and inspected every 5 years (13.11.1).
Standpipes and the fire department connection
Automatic standpipe systems get a flow test every 5 years to confirm the required flow and pressure at the hydraulically most remote hose valve outlets while the system demand flows (6.3.1.1). Where that outlet is impractical to test, the AHJ is consulted on the location.
Manual standpipes and semiautomatic dry standpipes get a hydrostatic test every 5 years, including the FDC piping (6.3.2.1). The test pressure is at least 200 psi for 2 hours, or 50 psi above the maximum pressure where that pressure is over 150 psi. It is measured at the low point of the system or zone, and a gauge drop of 5 psi or less is not a failure. Manual wet standpipes that are part of a combined sprinkler and standpipe system are exempt (6.3.2.1.1).
The piping from the FDC to the fire department check valve is hydrostatically tested at 150 psi for 2 hours at least once every 5 years (13.8.5). It passes with a pressure loss under 5 psi and no visible leakage (13.8.5.1). The annex ties this test to the five-year check valve inspection: with the check valve out, the FDC piping can be capped and tested.
Pressure-reducing valves
Sprinkler pressure-reducing valves, hose connection pressure-regulating devices, and hose rack pressure-regulating devices each get a full flow test at 5-year intervals, compared with previous results, and a partial flow test every year (13.5.1.2, 13.5.2.2, 13.5.3.2). For the hose connection and hose rack devices, a tag on the valve records the test date, the flow, the inlet pressure, and the outlet pressure.
Sprinklers on a five-year cycle
Sprinklers exposed to harsh environments, including corrosive atmospheres, are replaced after 5 years in service or representative samples are tested and then retested every 5 years (5.3.1.1.2). The annex examples include paper mills, packing houses, steam rooms, storage battery rooms, and areas exposed to weather. Listed corrosion-resistant sprinklers in those environments may be tested first at 10 years and then every 5 (5.3.1.1.3). Solder-type sprinklers rated extra high, 325°F or more, and exposed to semi-continuous to continuous maximum allowable ambient temperatures follow the same 5-year rule (5.3.1.1.1.3). For sprinklers manufactured in 1920 or later, reaching 75 years in service brings a 5-year retest interval (5.3.1.1.1.4).
A representative sample is at least four sprinklers or 1 percent of the sprinklers in the sample area, whichever is greater (5.3.1.2). If one sprinkler in the sample fails, every sprinkler in the area that sample represents is replaced (5.3.1.3).
Private fire service mains
Underground and exposed piping is flow tested at least every 5 years (7.3.1).
The wider 2023 changes are in changes to NFPA 25 in the 2023 edition.
What the visit involves for the building
The traditional assessment drains the system, which takes it out of service. Chapter 15 impairment procedures apply while sprinkler protection is impaired (5.1.4). Before a test or shutdown, the owner notifies the AHJ, the fire department if required, and the alarm-receiving facility, and tells them again when the system is back in service (4.1.4).
The practical way to keep the cost down is to drain once: do the internal assessment in the same shutdown as the check valve and alarm valve internals. The annex points the same way. It suggests capping and testing the FDC piping while the check valve is out, and pushing a camera through the check valve during its five-year inspection. A system drained for a renovation or a repair can have its assessment done then, and the annex says the five-year interval restarts from that date.
The building owner is responsible for the inspection, testing, and maintenance (4.1.1), and qualified personnel perform it (4.1.1.3). The 2023 edition gives three ways to qualify: training the AHJ accepts, certification from a national organization the AHJ accepts, or registration, a license, or certification from a state or local authority (4.1.1.3.1).
How findings are classified
NFPA 25 sorts findings into noncritical deficiencies, critical deficiencies, and impairments. The annex table of example findings, Table A.3.3.8, places the five-year items like this:
| Finding | Class in the annex table | Reference |
|---|---|---|
| Internal assessment shows MIC, zebra mussels, rust, or scale | Critical deficiency | 14.2.1 |
| Gauge not replaced or calibrated in 5 years, or not accurate within 3 percent of scale | Noncritical deficiency | 13.2.4.2, 13.2.4.3 |
| Standpipe flow test does not give design pressure at the required flow | Impairment or critical deficiency | 6.3.1 |
| Leakage during the standpipe hydrostatic test | Noncritical deficiency | 6.3.2.1 |
| Pressure-reducing valve results not comparable to previous results | Impairment, critical, or noncritical | 13.5.1.2, 13.5.2.2, 13.5.3.2 |
| Sprinkler sample fails laboratory testing | Impairment or critical deficiency | 5.3.1 |
For gauges, Section 13.2.4.2 allows comparison testing in place of replacement. A gauge within 3 percent of full scale stays in service; one outside that tolerance is recalibrated or replaced (13.2.4.3).
Annex material is guidance only. Where the table shows more than one class, the class depends on the context and the effect on the system, and the AHJ may need to weigh in. The definitions and the Chapter 15 procedures are in critical deficiencies, noncritical deficiencies, and impairments under NFPA 25.
What the record has to show
Section 4.3 requires records of all inspections, tests, and maintenance. The owner keeps them, they may be stored electronically, and they are made available to the AHJ on request. Under 4.3.2, each record shows five things: the activity performed, the organization that performed it, its required frequency, its results and date, and the name and contact information of the qualified contractor or owner, including the person who did the work.
Records are kept for at least one year after the next inspection, test, or maintenance of that type (4.3.5). A five-year record therefore stays on file until a year after the next five-year visit. As-built drawings, hydraulic calculations, original acceptance test records, and device data sheets are kept for the life of the system (4.3.4).
For the five-year work, a report that holds up names which systems were opened and where, the method used, what was found, photographs of the pipe interior, and any samples sent for MIC testing. In a building that alternates its wet systems, the record of which half was assessed tells the next contractor where to start.
How Inspect Point fits five-year work
Inspect Point lets a contractor select the NFPA 25 code year, as a company default with an override for each building, which matters when one item carries a different rule by edition. Recurring inspections are scheduled as an inspection series. A finding is recorded as a deficiency with the severity the standard uses, Non-Critical, Critical, or Impairment. Technicians annotate photos in the app, and sprinkler records are kept by building. See the fire sprinkler page and the deficiencies page.
Common questions
Is the five-year internal inspection the same as an obstruction investigation?
No. The assessment in 14.2 is periodic. The obstruction investigation in 14.3 happens only when a listed condition exists, and it examines at least five points.
Does every sprinkler system in the building have to be opened?
Not always. Wet pipe systems in the same building can alternate between cycles until foreign material turns up in one of them.
Do sprinkler gauges have to be replaced every 5 years?
Replaced or tested. A gauge that reads within 3 percent of full scale against a calibrated gauge can stay in service.
How late can a five-year inspection be?
The 2023 edition defines a five-year frequency as once every 60 months, with a minimum of 54 months and a maximum of 66 (3.7.1.8). Check that the edition your AHJ has adopted uses the same window before leaning on it.
What does a 5-year sprinkler inspection cost?
The scope drives the cost: the number of systems to drain, the valves to open, and whether the building has standpipes, pressure-reducing valves, or a long list of gauges.
Code references
All numbers are from the 2023 edition of NFPA 25. Confirm them against the edition your AHJ has adopted.
- Frequencies and records: 3.7.1.8, 4.1.1, 4.1.1.3, 4.1.1.3.1, 4.1.4, 4.3.2, 4.3.4, 4.3.5.
- Sprinklers: 5.1.4, 5.3.1.1.1.3, 5.3.1.1.1.4, 5.3.1.1.2, 5.3.1.1.3, 5.3.1.2, 5.3.1.3.
- Standpipes: 6.3.1.1, 6.3.2.1, 6.3.2.1.1.
- Private fire service mains: 7.3.1.
- Components and valves: 13.2.4.2, 13.2.4.3, 13.4.1.2, 13.4.2.1, 13.4.3.1.2.1, 13.4.3.1.3, 13.4.4.1.2.1, 13.4.4.1.3, 13.4.5.1.3, 13.4.5.1.4, 13.5.1.2, 13.5.2.2, 13.5.3.2, 13.7.1.3, 13.8.5, 13.8.6, 13.11.1.
- Internal piping and obstruction: 14.2.1.1 through 14.2.1.5, 14.2.2 through 14.2.2.2, 14.3.1, 14.3.2.1 through 14.3.2.3, 14.3.3, 14.3.4.
- Annex A: Table A.3.3.8, A.14.2.1, A.14.2.2, A.13.7.1.3, A.13.8.5, A.5.3.1.1.2.
See Inspect Point run on your own inspections. A 30-minute demo, no commitment.