EN 12845 Annex H — System Monitoring

A sprinkler system is not installed and forgotten; it must sit under continuous supervision. Supervised valves, pressure, flow, level, pump status — without the Annex H signal list the system is effectively a closed door with nobody watching it.

At a furniture factory, the pump room electrical panel was opened during a weekly routine, the control circuit was briefly worked on, and the panel was closed again. The selector was left in "MAN" — the pump was out of the automatic start circuit. Nobody noticed, because there was no remote supervision signal. Eleven days later a fire started, the sprinklers operated, pressure fell, and the pump never started. A four-sprinkler fire spread to 600 m². Had the Annex H pump controller mode signal been monitored, the alarm would have arrived eleven days earlier. Supervision is the cheapest insurance there is.

Annex H — signals to be monitored

Water supply side

• Tank water level, with a low-level alarm
• Tank fill float valve status
• Town main pressure, where relevant
• Suction valve position (supervised)

Pump side

• Pump controller mode (Auto / Manual / Off) — critical
• Pump running signal
• Pump fault (motor overload, phase failure)
• Loss of main power
• Standby power (generator or diesel) status
• Diesel battery voltage, both batteries
• Diesel fuel level
• Pump room temperature, for freezing risk

System side

• System pressure, with a low alarm
• Flow alarm for each zone
• Stop valve position, for every supervised valve
• Drain valve position
• Air pressure on dry systems, with a low alarm
• Pre-action detection activation

Environment

• Pump room temperature, alarming at 4 °C
• Tank temperature, for freezing
• Fire detection panel status, integrated

Three layers of monitoring

Layer	Destination	Response time
1. Local alarm panel	Pump room, control valve set	Immediate, visual and audible
2. Site 24/7 control room	Watchman, security, BMS	1–5 min
3. Central monitoring or fire service	Per the alarm transmission annex	5–30 min

Field error — a miscalibrated tank level signal

At a logistics facility the ultrasonic tank level sensor was miscalibrated, reading an actual 320 cm as 410 cm. The float valve had also stuck and the tank was not refilling. Six months later a weekly visual check found the tank half full. Had a fire occurred in that period, the water would have run out at half the design duration. Annex H suggests a double check — an ultrasonic sensor plus a mechanical float alarm — with an alarm raised if the two disagree. A single sensor is not trustworthy.

Alarm panel design rules

• Signals grouped as Fire, Fault and Disabled
• Fire signals red, with a continuous audible tone
• Fault signals amber, with an intermittent tone
• Disabled signals steady amber, showing a deliberate bypass
• Every signal logged, with at least a year of event history
• The silence button mutes the tone but does not clear the signal
• The reset button works only once the condition has cleared

Pump controller mode — the single most important signal

The controller has three modes: Auto, Manual and Off. EN 12845 requires Auto; it is switched to Manual for maintenance and must be returned to Auto afterwards. Failing to return it is the single most common field error.

• A permanent "not in Auto" indication on the alarm panel
• A separate signal for every pump
• Transmission to the monitoring centre
• "Auto confirmed" as the first line of the monthly routine check list

Supervised valve detail

Valve type	Supervision method
OS&Y stop valve	Auxiliary contact switch on the stem position
Butterfly valve	Limit switch on the disc position
Drain valve	Limit switch on the handle position
Alarm test valve	Limit switch
Check valves	Usually not supervised, monitored indirectly by flow signal

Commissioning the monitoring system

1. The signal list is fixed at design stage — the Annex H minimum plus site-specific additions
2. Wired or wireless is chosen — wired for life safety, wireless as secondary
3. Alarm panel configured with zone names and signal labels
4. Each signal tested individually by forced triggering
5. System verification recorded, with the event log checked
6. Operators trained on the alarm response procedure
7. Monitoring centre contract put in place, where used
8. Monthly functional testing added to the calendar

Managing false alarms

A monitoring system that cries wolf overloads the operator and real alarms get missed. To reduce false alarms:

• A 30 s retard on the flow alarm, filtering short pressure surges
• A 60 s average on the pressure signal
• Hysteresis on temperature signals, for example alarm at 4 °C and reset at 6 °C
• Signals during testing marked as "test" and separated from the normal log
• Signal sensitivity checked at each periodic maintenance visit

Comparison with NFPA 25 and NFPA 72

NFPA 72 provides a detailed standard for supervised sprinkler signals. NFPA 13 requires control valves to be supervised electrically or visually. NFPA 20 gives the most comprehensive treatment of pump controller Auto/Manual/Off monitoring. Annex H condenses all three into a single annex — less detail, the same principles. NFPA is stricter in requiring audible and visual alarms, where EN accepts audible or visual.

Link to Turkish regulation

BYKHY has no separate clause for sprinkler supervision, but it is applied through EN 12845 and EN 54. Fire service inspections check the alarm panel zone map, the signal list and the event log. The items most commonly missing in Turkey are the pump controller mode signal, diesel battery voltage and drain valve position. Insurers compare the installation against the Annex H minimum list at the annual audit, and gaps go onto the deviation list.

Quick check list

• The signal list is defined in the design documents.
• Every stop valve is supervised.
• Pump Auto/Manual/Off signal is active.
• Tank level on two sensors (ultrasonic plus float).
• Air pressure monitored on dry systems.
• Local, on-site and central monitoring layers in place.
• Event log retained for a year.
• Monthly functional test in the calendar.
• Operators trained on the alarm response procedure.

Frequently Asked Questions

Which is the single most important supervision signal?

Pump controller mode. A controller left in Manual after maintenance is the most common way a system is silently disabled, and only an "not in Auto" signal catches it.

Why monitor tank level with two sensors?

Because a single miscalibrated sensor reads normally while the tank empties. Annex H suggests an ultrasonic sensor plus a mechanical float, alarming when the two disagree.

How are stop valves supervised?

OS&Y valves by an auxiliary contact on the stem, butterfly and drain valves by a limit switch on the disc or handle. Check valves are generally monitored indirectly through flow.

How do you keep false alarms down?

A 30 s retard on flow alarms, a 60 s average on pressure, hysteresis on temperature signals, and marking test-generated signals separately in the event log.

SprinkCalc — Fire Sprinkler Design Across Three Standards

SprinkCalc covers hazard classification, design density and area, K-factor selection, water demand and hydraulic calculations for NFPA 13, FM Global and BS EN 12845 in a single iOS app, and exports a professional PDF report.

Download SprinkCalc on the App Store

MEP Calc — 86+ Engineering Calculators

MEP Calc bundles 86+ engineering modules in one iOS app: 21 fire calculations plus heating, cooling, HVAC, plumbing, steam and natural gas.

Download MEP Calc on the App Store