A data centre came out of a five-year insurance survey with a list of major recommendations: the dry pipe valve trip test had not been done for three years, weekly fire pump run records were incomplete, and gauge calibration status was unknown. The site had been following an annual flow test regime, but FM Global DS 2-81 expects considerably more. This article summarises the weekly, monthly, annual, three-year and five-year expectations.
Weekly Tasks
- Fire pump: a 10 minute no-flow run, churn pressure recorded, alarms logged
- Gauges: visual check that riser and pump room gauges read within range
- Control valves: all OS&Y and post indicator valves confirmed open and sealed
- Tank level: fire water tank full, pressure tank at correct pressure
Monthly Tasks
- Sprinkler riser: visual inspection of alarm and dry pipe valves for leakage, corrosion and mechanical damage
- Suction tank: external inspection and check of the heating system where fitted
- Hose stations: cabinet, hose and nozzle integrity
- Control panels: alarm panel and fire alarm controller
Annual Tasks
- Main drain test: the 2 inch main drain is opened and static and flowing pressures recorded, which diagnoses friction and obstruction
- Fire pump flow test: the curve at churn, 100% and 150% of rated flow, compared against the manufacturer curve
- Sprinkler sampling: representative heads removed and tested from older systems
- Backflow preventer: forward flow and reduced pressure testing
- Valve exercise: every OS&Y and post indicator valve fully closed and reopened
Three and Five Year Tasks
- Every three years: full trip test of dry pipe valves
- Every five years: internal inspection of sprinkler pipework, coordinated with the corrosion provisions of DS 2-1, using endoscopic inspection at several points
- Every five years: gauge calibration by a certified laboratory
- Every ten years: fire pump driver overhaul and motor winding insulation testing
Practical Differences From NFPA 25
| Task | FM DS 2-81 | NFPA 25 |
|---|---|---|
| Weekly pump run | 10 minutes no-flow with records | 10 minutes no-flow with records |
| Dry pipe trip test | Full trip every three years | Full trip every three years |
| Internal inspection | Five yearly at several defined points | Five yearly obstruction investigation |
| Sprinkler sampling | By age, earlier for dry sprinklers | By age across all types |
| External survey | Annual insurer survey | Owner responsibility |
Quick Checklist
- Weekly: pump run, gauges, valves, tank — recorded in a log
- Monthly: riser inspection, hose cabinets, alarm panel
- Annual: main drain, pump curve, valve exercise, backflow
- Three yearly: dry pipe full trip test
- Five yearly: internal inspection and gauge calibration
- All records kept digitally and in hard copy for the surveyor
Frequently Asked Questions
What does the main drain test actually tell you?
It compares static pressure with flowing pressure at the riser. A larger than expected drop indicates a restriction upstream - a partially closed valve, a blocked strainer or an obstructed main. It is the single most informative annual test because it checks the supply path that everything else depends on, and it takes minutes to perform.
Why does FM require a full dry pipe trip test rather than a partial one?
A partial trip proves the valve moves; a full trip proves that water actually reaches the most remote inspector's test connection within the required time. Only the full test verifies the water delivery time that the whole dry system design depends on, which is why it is required on a three year cycle.
Why is internal pipe inspection needed if there are no leaks?
Corrosion products accumulate internally long before a pinhole appears, and they obstruct sprinklers and branch lines while the system still looks sound from outside. Endoscopic inspection at several points every five years catches tuberculation and sludge while remediation is still straightforward.
How do FM expectations differ from NFPA 25 in practice?
The task list is broadly similar, but FM applies it more strictly and adds an annual insurer survey with formal recommendations attached to the policy. Sites that comply with NFPA 25 alone frequently still receive recommendations, most often for missing records rather than missing work.
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Download MEP Calc on the App StoreFM Global Property Loss Prevention Data Sheet DS 2-81 (Inspection, Testing and Maintenance of Fire Protection Systems); NFPA 25, Standard for the Inspection, Testing and Maintenance of Water-Based Fire Protection Systems.