NWK-HF650
NK NWK-HF650 — High Expansion Foam Generator - Marine.
Inspector Detail
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Common issues
- Foam concentrate strainer/screen blockage reducing output
- Fan/impeller fouling or bearing wear reducing air throughput
- Foam concentrate degraded or wrong type used, reducing expansion ratio
- Orifice/nozzle blockage from debris in the concentrate line
- Corrosion of the generator casing in the humid/saline machinery space environment
Inspection checklist
- Visual inspection of casing, screen and nozzle for corrosion or blockage
- Check foam concentrate quality, expiry and correct type for the system design
- Test fan/motor start and running current against baseline
- Verify foam discharge test (partial or full) per PMS/class requirement
- Check associated isolating valves and piping for leaks or corrosion
- Verify local and remote (if fitted) activation
Service intervals
| Foam concentrate quality/sample test | annually, per SOLAS/class requirements for fixed foam systems |
| Foam generator functional test | typically annually as part of fire-fighting system testing |
| Screen/strainer cleaning | at each functional test or when reduced output is observed |
| Fan bearing lubrication | per the manufacturer's schedule, commonly annually, where applicable |
Critical spares
- Foam concentrate screen/strainer element
- Fan/motor assembly or bearing set
- Spray/orifice nozzle
- Foam concentrate - correct type and quantity per system design
- Casing gasket/seal set
Safety
- High-expansion foam floods the space and displaces oxygen - never enter a space during or after a foam release without enclosed-space entry procedure and gas testing
- Foam concentrate can be an eye/skin irritant
- Moving fan blades present a mechanical hazard during testing or maintenance
Class survey
Fixed high-expansion foam systems are surveyed under SOLAS II-2 fixed fire-extinguishing requirements. Class wants annual functional test records, foam concentrate sample test certificates, and evidence the system covers its designated space per the approved fire control plan.
Components & Design
Component data being added…
Technical Data
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Common failures & inspection points
Annual visual inspection of foam concentrate in storage tanks for excessive sludging, discoloration, or crystallization; laboratory quality testing of foam samples for viscosity, surface tension, and emulsion stability per ISO/IEC standards
Annual functional test of foam proportioning generators at rated operating pressure (4 bar); measure actual foam output capacity (m³/min) against nameplate specifications; verify proportioning ratio accuracy (1-3% injection)
Visual inspection of all piping, connections, and nozzles for corrosion, scaling, or blockage; pressure testing at 1.5x operating pressure; verify water connections (100A/150A) are clear and functional
Test foam expansion ratio (target 1:670 for NK.D-101M, 960+ for system discharge) using standardized test nozzles; measure drainage time and foam stability per EN 1568-3 or equivalent maritime standards
Verify MED (Marine Equipment Directive) B+D and IMO Rules certifications are current; confirm PFAS restrictions compliance (PFOS <10 mg/kg effective from 1 January 2026); review maintenance log and maker's declarations for approved foam batch numbers
Type-general inspection and maintenance points for this equipment category — not model-specific.
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