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Explosion isolation is a form of explosion protection used most commonly in industrial processes.

 When an explosion occurs, it can quickly propagate towards connected parts of a process, via ductwork for example. The result is several secondary explosions occurring in other parts of the factory, posing an immediate threat to the lives of personnel and destruction of assets & property.

 With explosion isolation however, this risk is mitigated. There are several forms of explosion isolation. There are passive techniques such as flap valves or barrier valves, or there are active systems such as rapid acting valves or chemical isolation. Explosion isolation systems work as a barrier so the explosion is blocked from entering neighbouring equipment. Explosion isolation should be designed specifically for the individual application by a professional, taking into account a variety of factors.

 Flap valves or barrier valves are entirely mechanical. A flap valve is installed in the ductwork, and when an explosion occurs, a durable metal flap inside the valve will slam shut upon the initial pressure wave of the explosion, forming a barrier. This barrier will block propagation from the explosion source, removing the potential for a secondary explosion. After an explosion, a quick inspection of the valve and the repositioning of the flap is usually all that’s needed to get the equipment back up and running and protected once again. Using the B FLAP explosion isolation barrier valve, the user can clearly see from the outside of the valve the position of the flap as it is indicated by a small tab on the valve housing. However, there is an additional, optional, position indicator accessory that can be connected to a control panel in order to alert the user when the valve is closed.



Isolating an explosion is the best way to protect surrounding equipment and in turn, protect on site personnel. When an explosion builds momentum, it will propagate into any connecting applications or vessels, spreading to other parts of the process and causing a major risk to life. To prevent this, we can supply explosion isolation valves and rapid acting slide gate valves to stop the explosion in its tracks. 


The B-Flap I explosion isolation flap valve can stop the propagation of an explosion caused by processed organic, melting, coarse, and metal dusts up to explosion class St 3 and dusts with very low values of minimum initiation energy (MIE) and temperature (MIT). This new design of the B-FLAP I explosion isolation flap valve makes it easier to handle during the installation and operational maintenance. Now, the all new BFV can be used in piping systems inclusive of elbows and obstacles with vertical and horizontal installation orientations.

Optional accessories available include:

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

explosion isolation flap valve


The BFV features capabilities for push and pull systems, with the possibility of installation on horizontal and vertical pipes. The mechanical functionality of the BFV isolation valve means there is no need for electrical energy for the mechanism to function. The BFV can handle low pressure losses and high pressure resistance. There is the possibility of equipping the equipment with additional accessories such as a position indicator that shows from the outside of the valve the status of the flap (whether it is opened or closed). The inspection hatch means servicing is quick, easy and effortless.

explosion isolation valve
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In the above visualisation of explosion protection design for a dust filtration unit, we can see two B-FLAP explosion isolation flap valves used, paired with a FLEX flameless venting device. This partnership can be used indoors where personnel and surrounding equipment are present as the explosion will be completely contained given the protection devices are designed accordingly with the applications parameters in mind.

The explosion starts and the initial pressure wave blasts open the VMP explosion venting device that is housed within the FLEX unit. The FLEX flame quenching membrane stops flames and harsh fumes from exiting the housing – all that can be seen from the outside of the application is a puff of smoke. As the explosion intends to propagate through the ductwork to connecting applications and processes, the B-FLAP valve is also triggered by the initial pressure wave of the explosion, causing the inside flap mechanism to slam shut into place,blocking propagation of the explosion. 

After the explosion is finished, a quick inspection of the B-FLAP is needed to ensure it is safe to return to operation, and the VMP explosion vent panel inside the FLEX must be replaced. That is why we always recommend spare panels are kept on site for easy reinstatement so the process can get back to work as quickly as possible after an initiation.

Thanks to the new B-FLAP design, you can see installation of the B-FLAP is acheived on a variety of bends and obstructions. The B-FLAP isolation valve to the right of the application is also installed vertically, making for even more flexibility when it comes to the design parameters of any application. 




HRD Suppression system, explosion isolation barrier



GatEx rapid acting slidegate valve system, explosion isolation barrier


We are waiting to discuss your explosion safety requirements, so don’t hesitate to get in touch. Whether you would like to receive a quotation or you are just looking for more information, we are here to help.




0208 243 8914