Sprinkler Systems
QA inspection checklist

Installation

1. 1.

   Sprinkler heads match design — type, temperature, spacing
   What to look forHead type per design hazard category — pendant, upright, sidewall, recessed, concealed, or ESFR. Temperature rating typically 68°C (red) for general areas, 79°C (yellow) for warm areas, 93°C+ for plant rooms. K-factor and thread match the schedule. Spacing per BS EN 12845 hazard class.
   Acceptable whenPer BS EN 12845 / LPC Rules / FM Global: LH (Light Hazard) 21 m² coverage / 4.6 m max spacing; OH (Ordinary Hazard) 12 m² / 4.0 m; HHP (High Hazard Process) 9 m² / 3.7 m. Head 75-150 mm below ceiling typical. ESFR per FM Global Datasheet 8-9.
   StandardBS EN 12845:2015+A1:2019 — Fixed firefighting systems — Automatic sprinkler systems. LPC Rules for Automatic Sprinkler Installations (LPCB). FM Global Datasheets. BS 9251:2021 (residential).
   Common defectsSpacing exceeds hazard-class maximum — gaps in coverageWrong temperature head near skylights/heaters — premature operationPendant head installed upright (or vice versa) — distribution wrongRecessed head with cover plate temperature rating not matching headObstructions (beam, light fitting, ductwork) within head spray pattern
2. 2.

   Pipework material and size correct
   What to look forPipe material and class per design — typically galvanised steel BS EN 10255 medium-grade or threaded stainless / CPVC. Sizes verified against hydraulic calculation — main, distribution, range pipes all sized for design density at AMAO. Joints per system (threaded, grooved Victaulic, welded).
   Acceptable whenPer BS EN 12845 and hydraulic calc — pipe sized so AMAO sprinkler delivers design density (e.g. 7.5 mm/min OH3) at minimum design pressure (typically 0.7 bar). Pipework supported per BS EN 12845 Section 17. CPVC to BS EN 1452 / NSF-61 with system listing.
   StandardBS EN 12845:2015+A1:2019. BS EN 10255 (steel pipes). LPCB Loss Prevention Standards.
   Common defectsPipe undersized — design density not achieved at AMAOCPVC used in non-listed configuration — fittings/glue not approvedMixed grades (red-band & black-band) on same systemGalvanising broken at threads — corrosion pathWelded joints inside building — fire risk during installation, no LPCB approval
3. 3.

   Hangers and supports at correct centres
   What to look forHangers per BS EN 12845 — galvanised steel, fixed to structure (not to other services or ceiling). Spacing per pipe size: typically 3.5 m for ≤ 50 mm, 4.5 m for 65-100 mm. Hanger within 600 mm of every fitting and end of pipe. Bracing for seismic / wind where required.
   Acceptable whenPer BS EN 12845 Section 17.3: hanger spacing 4.0-4.5 m max for typical sizes. Hanger within 600 mm of pipe ends and fittings. Type per system listing. Sway bracing per FM Datasheet 2-8 if applicable. Hanger bolt grade min 4.6.
   StandardBS EN 12845:2015+A1:2019 Section 17. FM Global Datasheet 2-8 (earthquake bracing). LPCB hanger Loss Prevention Standard LPS 1192.
   Common defectsHanger spacing > 4.5 m — pipe sag, water poolingHangers fixed to ceiling tile grid or other services — collapse on activationNo hanger near fitting — joint stressWire / chain "temporary" hangers left in placePlastic-coated hanger with bare steel pipe — galvanic risk
4. 4.

   Flow switches and alarms installed
   What to look forFlow switch on each zone, electrically connected to fire alarm panel. Pressure-monitor or zone control valve assembly with monitoring switch for valve position. Local alarm bell (water motor gong or electric) operational. Test connection (≥ 25 mm) to allow flow test without spraying.
   Acceptable whenPer BS EN 12845: flow alarm signal within 90 seconds of activation. Each zone monitored. Valve tamper switches on every isolation valve. Test connection per Section 16. Alarm bell or sounder ≥ 90 dB at 3 m.
   StandardBS EN 12845:2015+A1:2019 Section 14-16. BS 5306-2 (older but still referenced). LPS 1233 (zone control valve).
   Common defectsFlow switch wired to alarm but not commissioned at panel — silent activationTamper switch missing — closed valve undetectedNo test connection — flow test impossible without dropping ceilingLocal alarm gong inaudible at fire panel positionZone valve in wrong location (after the zone) — no isolation

Testing

1. 5.

   Hydrostatic pressure test passed

   Record: Test pressure (bar)
   What to look forSystem hydrostatically tested at 1.5× design working pressure (or 15 bar minimum) for 2 hours. No pressure drop after thermal stabilisation. No visible leaks. Test pressure recorded with calibrated gauge. Air bled from system before test. CPVC tested per manufacturer (water only, no air).
   Acceptable whenPer BS EN 12845 Section 18.2: hydrostatic test at 1.5× design pressure or 15 bar min, held 2 hours, no measurable drop after temperature correction. CPVC: water-only test (BS EN 12845 prohibits air test on CPVC). Heat-treated steel pneumatic test only with risk assessment.
   StandardBS EN 12845:2015+A1:2019 Section 18 (testing). LPCB Rules. FM Global Datasheet 2-1.
   Common defectsPneumatic (air) test used on CPVC — explosion risk, prohibitedPressure drop > 0.5 bar — undetected leakTest duration cut short to < 2 hoursUncalibrated gauge — invalid testTest made before all heads fitted — system not as-installed
2. 6.

   Flow test completed

   Record: Flow rate (l/min)
   What to look forFlow test from test connection at remote AMAO position — verifies water delivery at design density and pressure. Static and residual pressures recorded. Pump start test (where applicable) — pump runs on flow demand. Flow rate measured with calibrated orifice or flow meter.
   Acceptable whenPer BS EN 12845 / LPC Rules: flow at AMAO test point ≥ design flow at design pressure. Pump test confirms design duty point. Town main capacity verified against required supply (where mains-fed). Records signed by commissioning engineer.
   StandardBS EN 12845:2015+A1:2019. LPC Rules Technical Bulletin TB203. NFPA 25 (US, sometimes referenced in inspection-test).
   Common defectsFlow short of design — pump duty wrong or pipe undersizedTest made through hose to drain — friction loss invalidates readingPump did not auto-start — pressure switch faultTown main pressure inadequate at demand — design assumed wrong mainNo record of flow vs pressure curve
3. 7.

   LPCB/FM commissioning certificate issued
   What to look forCommissioning certificate per BS EN 12845 Annex H or LPC Rules signed by competent installer and approved certificator. Identifies hazard category, design density, AMAO, water supplies, and as-built drawings. LPS 1048 or FM Global approved installer status verified. As-built and O&M provided.
   Acceptable whenPer BS EN 12845 Annex H / LPC Rules: Certificate of Conformity issued; system independently inspected by LPCB / FM (where insurance demands). Annual servicing schedule per BS EN 12845 Section 20. As-fitted drawings deposited with FRA holder.
   StandardBS EN 12845:2015+A1:2019 Annex H. LPS 1048 (LPCB approved sprinkler contractor). FM Global Approval Standard 2000.
   Common defectsInstaller not LPS 1048 / FM approved — insurance voidNo third-party witness to commissioning — disputedAnnex H certificate signed but key results missingNo annual service schedule handed overAs-built drawings not provided — future modifications risk

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