Explosion Proof EPTFE Flame Arrestor Vent For Flammable Liquid Storage Tank

The explosion-proof ePTFE flame arrestor vent for flammable liquid storage tank breather is a critical safety component that combines the pressure equalization and waterproof breathing functions of an ePTFE vent with the flame-quenching protection of an integral flame arrestor element. This device is engineered for installation on the vent ports of above-ground and underground storage tanks containing flammable and combustible liquids—gasoline, diesel, ethanol, jet fuel, crude oil, and various chemical solvents. Under normal operation, the ePTFE membrane provides the necessary in-breathing and out-breathing to equalize tank pressure during filling, emptying, and thermal cycling, while preventing water, dust, and debris from entering the tank. In the event of an external fire or an ignition source near the tank vent, the integral flame arrestor element—typically a bank of precision-spaced metal plates or a corrugated metal ribbon—absorbs the heat from any flame that attempts to propagate into the tank, quenching it and preventing a catastrophic tank explosion. This single device satisfies the dual requirements of tank pressure management and explosion protection, simplifying tank design and ensuring compliance with NFPA, ATEX, and API safety standards.

Storage tanks for flammable liquids present a constant explosion hazard. The vapor space above the liquid is often within the flammable range. The tank must breathe to equalize pressure. The vent port is therefore a direct opening to this flammable atmosphere. If a lightning strike, a static discharge, or a nearby fire provides an ignition source at the vent, a flame could travel back into the tank, igniting the vapor space and causing a devastating explosion. Regulatory standards (NFPA 30, API 2000, ATEX) mandate that vents on flammable liquid storage tanks be protected by flame arrestors. Traditionally, the vent and the flame arrestor are separate components, adding complexity, cost, and multiple potential leak paths. An integrated explosion-proof breather vent provides both functions in a single, tested, and certified assembly.

The explosion-proof ePTFE flame arrestor vent integrates both functions. The outer layer is the ePTFE waterproof breathable membrane, providing the environmental barrier and pressure equalization. Directly behind or integral with the membrane is the flame arrestor element—a precision-engineered matrix of narrow, heat-absorbing channels. If an external flame contacts the vent, the flame arrestor quenches it, preventing it from propagating through the vent and into the tank. The ePTFE membrane remains functional as the primary weather barrier. The entire assembly is tested and certified to ATEX, IECEx, and/or NFPA standards. The device is installed on the tank's vent pipe, providing a single-point solution for both breathing and explosion protection.

• Gasoline and diesel fuel storage tank vents (filling stations, fuel depots)
• Ethanol and biofuel storage tank breathers
• Jet fuel and aviation gasoline tank vents
• Crude oil storage tank breathers (upstream and refinery)
• Chemical solvent storage tank vents (MEK)
• Underground storage tank (UST) vent pipes at retail fueling stations

The explosion-proof vent is installed on the tank's vent pipe or directly on a tank port. During normal tank breathing (filling, emptying, thermal cycling), air flows in and out through the ePTFE membrane, which provides waterproofing and dust protection. The flame arrestor element is in the flow path but presents minimal resistance to normal breathing airflow. If an external fire or an ignition source occurs near the vent, the flame front enters the vent. The flame arrestor's narrow, heat-absorbing channels rapidly cool the flame below its auto-ignition temperature, extinguishing it. The flame does not propagate past the arrestor element. The tank and its contents are protected from explosion.

1. Determine the tank volume, the maximum fill and empty rates, and the expected temperature range to calculate the required breathing capacity per API 2000.
2. Identify the flammable liquid and its explosion group (IIA, IIB, IIA1, etc.) to select the correctly rated flame arrestor element.
3. Choose the connection type and size to match the tank's vent pipe or port.
4. Specify the required safety certifications: ATEX/IECEx for international applications, NFPA for North American markets.
5. Ensure the vent is installed in a location where it can safely vent any flame (end-of-line deflagration arrestor) and is regularly inspected per the maintenance schedule.

• Q: Is the ePTFE membrane compatible with the flame arrestor function?
  A: Yes, the ePTFE membrane is upstream (external side) of the flame arrestor. It does not interfere with the flame-quenching mechanism, and the flame arrestor protects the membrane from direct flame exposure.
• Q: Will the flame arrestor element become clogged with dust or insect debris?
  A: The external ePTFE membrane acts as the primary filter, preventing dust, insects, and debris from reaching the flame arrestor element and keeping it clean.
• Q: How often does the flame arrestor need to be inspected or cleaned?
  A: The inspection and maintenance schedule is specified by the manufacturer and by the applicable safety regulations. The external ePTFE membrane significantly reduces the rate of contamination of the flame arrestor element, potentially extending the inspection interval.
• Q: Is the entire assembly certified as a single device?
  A: Yes, the combined breather and flame arrestor assembly is tested and certified as a single unit to the relevant ATEX, IECEx, or NFPA standards.
• Q: Can this vent be used on a tank that also has a nitrogen blanketing system?
  A: The vent provides breathing for normal pressure fluctuations. For a tank with a nitrogen blanket, the vent's set pressure must be coordinated with the nitrogen supply pressure to ensure proper system function.