A foam suppression system for a paint booth using an ILP solenoid valve is an engineered fixed fire-suppression installation that detects a fire in the booth and discharges a foam concentrate and water proportioned mixture through the booth’s nozzle/riser network. The system uses detectors (typically linear heat or smoke + spot detectors), a control panel and, for discharge actuation, a high-reliability main valve whose pilot is controlled by an ILP solenoid. The ILP acts as the fast-acting pilot that triggers main valve opening (and can be latching to prevent reclosure), enabling fast foam application while allowing reliable electrical control, manual release, and interlocks (e.g., HVAC shutoff, conveyor stop).

2) Main components

• Detection & control

  • Detector(s): linear heat detector or optical smoke detectors (paint booths often use temp/aspiration for false alarm resistance).

  • Fire control panel with foam system logic, manual release, status lights, event logging, and outputs for building interlocks.

• Actuation

  • Main discharge valve (deluge / solenoid-pilot actuated valve or motorized ball valve) sized for required flow.

  • ILP solenoid valve (pilot solenoid / latching pilot): electrically driven pilot that opens the main valve. May be latching (stays open when energized) or non-latching depending on design.

  • Manual release (e.g., pull station, mechanical actuator).

• Foam generation

  • Foam concentrate storage & pump (proportioning pump or bladder tank depending on system type).

  • Proportioner: inductor (simple systems) or balanced pressure proportioner / bladder tank / introduce pump with venturi for accurate %.

  • Foam mixing manifold and piping to nozzles.

• Delivery

  • Foam/water delivery piping, risers, nozzles / spray heads selected for foam type (low expansion / medium expansion as required by the hazard).

• Ancillary

  • Pressure gauges, flow switch, test connections, check valves, drain valves.

  • Electrical interlocks: HVAC shutdown, conveyor/door stop, exhaust fans, power kill, operator alarms.

  • Alarms: local horn/strobe and remote supervisory signals.

3) Typical operating logic & sequence (stepwise)

1. Detect: Detector(s) in booth sense an alarm condition (heat/smoke).

2. Alarm: Fire control panel enters pre-alarm/alarm and starts local alarms; if automatic, it initiates delay (if configured) for confirmation or immediate action.

3. Interlock: Panel triggers building interlocks — stop conveyor, shut down HVAC/exhaust fans, isolate flammable material sources.

4. Pilot energize: Panel energizes ILP solenoid (or sends latching pulse). The ILP opens the pilot port of the main valve.

5. Main valve opens: Main deluge/discharge valve opens, allowing water into the foam proportioner.

6. Foam proportioning: Foam concentrate pump or proportioner injects concentrate at specified % (e.g., 3%, 6% depending on foam used).

7. Discharge: Foam/water mixture discharged through nozzles covering the booth — operator panel logs events.

8. Hold/latch: If ILP is latching, it holds pilot open until manual reset. System can be configured to require manual inspect/reset before rearming.

4) Why use an ILP solenoid pilot?

• Fast, reliable actuation of main valve with low current draw (especially latching types).

• Failsafe options: pilot can be configured normally closed (NC) so valve stays closed without power; or latching to maintain open without continuous coil power (useful if power is lost after actuation).

• Remote and local control: allows electrical signal from panel to control hydraulic main valve while keeping mechanical robustness.

• Integration with interlocks and supervisory circuits: coil monitored by panel for continuity, health checks and fault annunciation.

• Maintenance & testing: easier to test pilot circuits without cycling main valve repeatedly.

5) Design considerations & sizing (high-level)

• Design discharge density & run-off time: follow the foam manufacturer and local fire code (NFPA 33 for spray finishing operations in many jurisdictions, NFPA 11 for foam). Example: choose application rate (L/min·m² or gpm/ft²) and duration (e.g., 10–30 minutes) and size water/foam accordingly.

• Main valve sizing: pressure drop, required flow at required nozzle K values. Valve Cv should exceed peak flow requirements.

• Pilot sizing: ILP pilot must supply sufficient pilot flow/pressure to operate the main valve under static system conditions — consult valve vendor for pilot orifice and coil specs.

• Power / electrical: ensure correct coil voltage (24 VDC/110 VAC/230 VAC common options), make coil supervision available to panel (fault dry contacts).

• Foam type: choose appropriate concentrate (AR-AFFF, protein, synthetic) for paint solvents used and compatible with proportioner.

• Nozzle type & placement: ensure foam spreads properly and doesn’t overspray sensitive electricals; often low expansion spray nozzles or foam aspirators are used.

6) Typical technical specification 

System: Automatic foam suppression system for paint booth — deluge/discharge system actuated via pilot-operated main valve controlled by ILP solenoid.

Detection & Control: Addressable/analog fire control panel with event logging, manual release, pre-alarm, remote monitoring outputs, detector loop for linear heat/spot detectors and supervised circuits for ILP coil and flow switch.

Main Valve: Pilot-operated deluge valve rated for working pressure up to X bar (specify), end connections flanged to ANSI/IS/DIN standards, epoxy coated internal parts.

ILP Solenoid: In-line latching/pilot solenoid valve suitable for pilot port of main valve; coil voltage: 24 VDC (or specify 110/230 VAC), coil class F insulation, latching option available. Valve body brass/stainless steel rated to pilot pressure of Y bar. Include manual override and visual indicator of pilot position.

Foam Proportioning: Balanced pressure proportioner (or inline inductor) providing accurate injection at specified % (e.g., 3–6%). Foam concentrate storage tank (SS304) with pump sized for design flow.

Nozzles: Low-expansion foam nozzles with K values as per hydraulic design. All piping per approved hydraulic calculation.

Supervision & Alarms: Coil supervision relay, flow switch, pressure supervision, local horn/strobe. Panel outputs for HVAC shutdown and conveyor stop.

Standards & Codes: Comply with applicable local regulations and internationally recognized standards (e.g., NFPA 11, NFPA 33 or the local authority having jurisdiction). Provide manufacturer data sheets and third-party certification where applicable.

7) Sample Bill of Materials (BOM) — small booth example

• 1 × Fire control panel with foam module

• 1 × Pilot-operated deluge main valve (size e.g., 2½" or 4" depending on flow)

• 1 × ILP solenoid (24 VDC latching coil)

• 1 × Manual release station

• 1 × Foam concentrate storage tank (200 L) + foam pump (per design flow)

• 1 × Balanced proportioner or inductor

• 6 × Foam nozzles (low expansion)

• 1 × Flow switch (supervised)

• Pressure gauges, check valves, strainers, test header, alarms (horn/strobe)

• Piping, fittings, hangers, paint/labeling

(Quantities and sizes must be calculated by hydraulic design.)

8) Installation notes & good practices

• Mount the ILP solenoid pilot near the main valve pilot port with shortest practicable pilot tubing to minimize response lag.

• Use shielded/terminated wiring for solenoid coil back to panel; provide coil supervision circuit.

• Fit a local manual override lever at the main valve for emergency actuation if electrical system fails.

• Provide a test header and sample point to test proportioning without fully discharging system.

• Locate foam concentrate tank in a ventilated area and ensure secondary containment for spills.

• Make piping accessible for inspection; paint/label all valves and include “do not tamper” tags where required.

• Ensure grounding/bonding of metallic piping when flammable paints/solvents are used.

9) Commissioning & testing checklist

• Visual inspection of all components and piping for leaks and fitment.

• Verify ILP coil voltage at the coil terminals and coil polarity/earth.

• Functional test: energize ILP from panel in test mode and verify main valve pilot opens and main valve strokes open.

• Flow & proportioning test: operate system in test mode to confirm foam concentrate % and coverage (sample foam/water ratio).

• Interlocks: test HVAC shutdown, conveyor stop, door locks and alarm outputs.

• Supervision: verify supervision circuits report open/short faults (e.g., remove coil connect to confirm fault annunciation).

• Documentation: As-built drawings, hydraulic calculation, operation & maintenance manuals, spares list.

• Certificate: issue commissioning certificate and log test results.

10) Maintenance & service schedule (recommended)

• Monthly: panel self-test, verify detector status, check coil supervision LED, check pressure gauges.

• Quarterly: inspect nozzles for blockages; confirm manual release operation.

• Annually: full functional test including proportioner calibration and foam concentrate quality check (pour test or lab test).

• After any discharge: full inspection, replace used concentrate, re-calibrate proportioner, functional test of ILP and main valve.

11) Safety, regulatory & selection cautions

• Codes: Paint booths are hazardous (flammable vapors). Design must follow the local authority having jurisdiction and recognized standards (example: NFPA 33 for spray finishing and NFPA 11 for foam systems). Always obtain AHJ approval.

• Compatibility: Ensure foam concentrate is compatible with paints/solvents and with pipe materials and proportioner.

• Electric spark mitigation: Provide bonding/grounding and prevent electrical sources of ignition during and after foam discharge.

• False alarm risk: Paint booths often have contaminants; choose detectors and alarm verification schemes to reduce false trips while preserving safety.

12) Quick trouble-shooting (ILP-main valve)

• Coil not energizing: check power supply, fuses, panel output, wiring continuity, coil resistance.

• Pilot not moving but coil energized: check pilot orifices for debris, verify pilot piping not blocked, check correct pilot pressure at main valve.

• Main valve fails to open: verify pilot seat is sealed or stuck — apply manual pilot/cup test. Check main valve actuator spring, pressure differential requirement.

• Latching coil failed to latch: test coil pulse duration — latching coils often require a short high-current pulse then low-hold or mechanical latch.

13) Short comparison vs direct-electric motorized main valve

• ILP + main deluge valve: robust hydraulic actuation, smaller power requirement at coil, proven for high flows and harsh environments. Allows fail-safe pneumatic/hydraulic behavior.

• Direct electric actuated valve: may offer simpler wiring and direct control but often needs larger actuators for large flows, may be slower or require larger electrical power and more maintenance.