Deflagration and endurance burning proof ventilation hood - B 4.1 N | KITO Armaturen

KITO B4.1N – Vent Cap with Flame Arrester

The KITO® BEH-6-…-IIB3-K type B4.1N is a terminal flame arrester designed for storage tank vent openings. It is suitable for flammable liquids and vapors in explosion group IIB3, with MESG ≥ 0.65 mm and a maximum operating temperature of 60 °C. Installation is intended for tank roofs, manway covers, or vent lines. Use in enclosed spaces is not permitted.

Functional Role

This device enables venting of gases to atmosphere and air intake into the tank, while restricting flame transmission into the vessel. It does not function as a pressure/vacuum relief valve and is not equipped with an actuator. Selection does not replace overpressure or vacuum protection calculations.

Dimensions and Connection

• Nominal sizes: DN 80 and DN 100
• Flange pressure class: PN 16
• Connection: EN 1092-1 type B1 flange
• Main dimensions: D 353 mm, H 250 mm

Construction Materials

Standard body is cast steel 1.0619; optional version in stainless cast steel 1.4408. The flame arrester element is fully replaceable. Housing/mesh available in 1.4308/1.4310 or optionally 1.4408/1.4571. The metal weather hood includes a folding mechanism with thermal fuse element.

Sizing

Selection is based on required breathing capacity and allowable pressure drop. Flow curves refer to air at density ρ = 1.29 kg/m³ at 273 K and atmospheric pressure; correction for other gases is based on density.

Difference from B4N

B4.1N covers the stricter IIB3 group with MESG ≥ 0.65 mm. B4N is for IIB1 with MESG ≥ 0.85 mm and may be used for alcohols only after additional assessment and approval.

Standards

Includes type examination certificate per EN ISO 16852 and CE marking in accordance with ATEX 2014/34/EU.