1. Applicable Standards and Design Basis
Our Stainless Steel Air Vent Heads are designed, manufactured, and tested in full compliance with:

• ISO 15364: Ships and marine technology — Pressure/vacuum valves and air pipe heads, covering performance requirements and type testing.

• SOLAS Chapter II-2: Mandatory fitting of corrosion-resistant flame screens at all vent openings.

• IACS UR F1/F2: Unified requirements for air pipe head strength, automatic closing function, and fire resistance considerations.

• Classification Society Rules: Type approval criteria from ABS, DNV, Lloyd’s Register, BV, CCS, NK, KR, RINA, and other IACS members.

• Flange Standards: Available to any international standard—ASME B16.5 (Class 150/300), EN 1092-1 (PN10/PN16/PN25), JIS B2220 (5K/10K/16K), or GB/T 2501—as specified.

2. Material Selection — The Stainless Steel Advantage
Every component is selected for lifelong corrosion resistance and compatibility:

• Body & Weatherhood: Fabricated or investment-cast from marine-grade austenitic stainless steel, typically AISI 316L (1.4404) for standard marine and chemical applications. For even higher corrosion resistance in warm, stagnant seawater or aggressive chemicals, duplex stainless steel (UNS S32205/1.4462) or super duplex (UNS S32750/1.4410) is offered. The naturally passive chromium-oxide surface requires no paint or galvanizing. The weatherhood is shaped to deflect solid water while allowing free drainage.

• Float & Closing Mechanism: Solid stainless steel (AISI 316L or duplex to match the body) non-collapsible float, with a fully stainless steel stem, guide, and sealing disc carrier. This ensures total immunity to corrosion, absolute buoyancy reliability, and smooth, jam-free operation over decades of use.

• Sealing Seat: Replaceable EPDM (standard for seawater, freshwater, ballast), NBR (for oil and fuel), or FKM/Viton® (for high-temperature, aromatic, and aggressive chemical cargoes). The soft seat provides a bubble-tight, maintenance-friendly seal.

• Flame Screen: Stainless steel (AISI 316L) woven wire mesh, compliant with SOLAS, easily removable for inspection and cleaning. The all-stainless assembly is inherently spark-proof and fire-resistant.

• Mounting Flange: Integrally fabricated stainless steel flange, with raised face or flat face as required, fully matching the specified piping class.

3. Key Technical Features and Performance Benefits

• Complete Corrosion Immunity: The use of 316L or duplex stainless steel throughout eliminates any possibility of body-through corrosion, even when continuously exposed to warm, aerated seawater, chlorinated water, or sour cargo vapors. There are no coatings to blister, crack, or require periodic renewal.

• Exceptional Mechanical and Fatigue Strength: Duplex grades offer twice the yield strength of standard 316L, allowing higher pressure ratings and resistance to deck-level impact, bending, and wave slap loading, while also permitting lighter designs than carbon steel equivalents.

• Wide Temperature Operating Range: With appropriate materials and seat selection, the vent head reliably operates from cryogenic temperatures (with LNG carriers) to over +200°C, making it suitable for steam-generating cargoes and hot oil tank vents.

• Fire-Safe and Non-Sparking: Stainless steel does not spark on impact and maintains its structural integrity far better than aluminum or coated steel in a fire. This is critical for flammable cargoes and hazardous zones.

• Automatic Positive Shut-Off: The buoyancy-driven float rises instantly on water entry, pressing the seat disc into a watertight closure. As soon as the water recedes, the float drops back, restoring full-bore ventilation without delay.

• Full Flow Capacity and Low Pressure Drop: The internal flow area is engineered to meet or exceed ISO 15364 requirements, ensuring tank pressure remains within safe limits during maximum loading and ballasting rates.

• Hygienic and Easy to Clean: The electropolished or smooth-passivated internal surfaces prevent bacterial growth and sediment adhesion, critical for potable water, pharmaceutical, and high-purity chemical tanks. The removable weatherhood provides full access for inspection and cleaning.

4. Typical Marine Applications
Stainless Steel Air Vent Heads are specified where other materials cannot perform reliably:

• Chemical and product tanker cargo tanks (high-sulfur, acidic, or chlorinated cargoes)

• Liquefied gas carrier (LNG/LPG) vent masts and tank vents

• Stainless steel chemical and clean product deepwell pump caissons and vent risers

• Potable water, demineralized water, and pharmaceutical-grade storage tanks

• Firewater foam concentrate tank vents

• Sewage treatment plant and gray water tank vents on cruise ships and ferries

• Offshore platform and FPSO process tank vents, firewater caissons

• Naval and coastguard vessel fuel and water tank vents requiring maximum survivability

5. Quality Assurance, Testing, and Certification

• Type Testing: Every design is type-tested according to ISO 15364 for automatic closing function under flooding, air flow capacity, and pressure drop. Additional fire testing is conducted for fire-safe certified variants where required.

• Production Testing: Each unit undergoes a complete dimensional check, float functional test, and seat leakage test (at 1.1 times the rated working pressure) before shipment. Test certificates are supplied with each unit.

• Material Traceability: Full EN 10204 Type 3.1 material certificates are provided for the stainless steel body, float, flame screen, and all pressure-retaining components. Every head is permanently laser-marked or stamped with the manufacturer’s name, size (DN/NPS), pressure rating (PN/Class), material grade (e.g., 316L/Duplex), heat number, and applicable standards.

• Class Approvals: Our Stainless Steel Air Vent Heads can be supplied with type approval certificates from all major IACS classification societies, ensuring immediate acceptance during newbuilding and repair surveys, and meeting the stringent requirements of major charterers and vetting inspections.