Explosion Isolation Flap Valve B-Flap I

Features and Benefits

  • In case of explosion in the downstream equipment (e.g.  a dust
    collector) a pressure wave will force the Flap plate  to close and
    lock in position.
  • When the Flap plate is closed it makes a barrier against the approaching flame front.
  • Inside valve, zone 20
  • Full name: Explosion Isolation Flap “B-Flap I”
  • Outside valve, zone 21,22 or no zone

Contact Envirox today about this system for your specific needs.


The B-Flap I is a mechanical explosion isolation flap valve designed to prevent the transfer of flame and pressure between technologies during a dangerous explosion.

This explosion isolation flap is certified according to EN 16447 and EN 15089.

During normal operation, the explosion isolation flap is kept open using the RPD (Reducer of Pressure Drop) mechanism. This solution significantly reduces pressure loss in the piping system due to airflow in the pipeline. During an explosion the protected pipe will be closed and locked.

Used in case of an explosion in the downstream equipment (e.g.  a dust collector) where a flame front may reach upstream areas and cause damage to staff and equipment. The flap plate is activated and closed thereby creating a barrier to the approaching flame front

This flap valve is suitable for all types of dusts, including metal dust, up to St 3. Installed on either horizontal or vertical pipes with its reverse flow application, its certified for dusts with extremely low values of MIE and MIT. It is also suitable for push and pull systems.

Other Advantages:

  • low pressure losses, high pressure resistance
  • easy installation, inspection, and maintenance
  • explosion isolation flap is locked when closed
  • possibility of application on pipes with elbows and / or obstacles
  • standardly equipped with an RPD mechanism
  • optional possibility to produce in a stainless steel version

Optional Accessories:

  • inductive sensor
  • dust sensor
  • J-Box (junction box)
  • intrinsically safe relay
  • counter-flanges