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Explosion Panels

Bag Filters showing the effectiveness of proper explosion venting.

Explosions can be devastating and occur far more frequently than most people realize. They often result in loss of life, injury, damage to plant the equipment and loss of production.

Flowseal Explosion Vent Panels which conform to the requirements and specifications of NFPA68 (1998 edition), offer a safe and cost effective means of countering this catastrophe.

Our Engineers can assist in the application and sizing of explosion vent panels.

Detail of burst on Explosion Panel

Flowseal explosion vent panels are of the “composite slotted” type and are essentially maintenance free.

They can be manufactured for temperatures up to 500ºC and for rectangular, round or curved vents.

All Flowseal Explosion vent panels are certified and can be manufactured to burst at pressures as low as 5kPa.

Added Edit – De Wet

Flowseal Bursting Discs & Explosion Vent Panels are manufactured to comply with the requirements of the American NFPA 68, 2007 edition entitled Guide for Venting of Deflagrations and also the German VDI-3673, 1995 edition and are tested and certified in compliance with BS 2915 : 1990, the Specification for Bursting discs and bursting disc devices.

Flowseal Explosion vent panels can be of the multi ply composite slotted type or of the domed one piece construction type. The accuracy of response is within 10% of the certified burst pressure and the response is immediate.

General Design

Flowseal Explosion Vent Panels are manufactured with controlled opening patterns that ensure full opening on initial rupture and can be fabricated to any size, and can be circular, rectangular or curved. They can be supplied in a variety of different configurations depending on temperature, pressure, medium etc.


 All Flowseal Vent closures are designed to withstand natural forces such as wind loads and operating conditions such as pressure fluctuations and the effects of temperature, abrasion and corrosion.


Frames are designed to completely support the panels and to ensure that the panels can rupture as planned without any hindrances or distortion that may adversely affect the bursting pressure or the vent area.

The frames are generally drilled to suit customer requirements.

For composite slotted type panels, if the system is under negative pressure, the frame must incorporate vacuum support bars designed to support the panels under full negative pressure. In calculating vent areas, the area of the vacuum support frame is to be taken into account.

Panels (Support and Burst)

 All Flowseal multi ply composite panels incorporate a support panel on the inside, this is to prevent abrasion and or damage to the seal membrane as well as preventing the seal membrane being sucked inward due to negative pressure.

Multi ply composite slotted panels and single ply domed panels all conform to the NFPA 9-4.3.2 requirement relating to the inertia of vent closures, and that is that the mass must not exceed 12.2kg per square metre.

Vibration Damping

In all composite slotted type panels, a layer of ceramic fibre is inserted between the support panel and the seal membrane to minimise the effects of vibration brought about by the turbulence of passing air or the pulsing of a pulse type bag filter.

 Seal Membrane

 The seal membrane is generally made out of a ply of PTFE non permeable foil or other material suitable for the operating temperature and medium.


Flowseal Bursting discs and explosion panels are manufactured so that in the event of an explosion, all parts are retained, there will be no shrapnel or fragmentation.

Burst Detection

Burst detection can be provided if required simply by means of a break wire system or by means of encapsulated reed switch and magnet.

Burst Testing and Certification

Burst testing is done in the Flowseal factory and complies with the requirements of BS 2915:1990. At least one panel of every batch is tested in order to provide certification.

Tags and Signage

All panels supplied are fitted with tags which indicate the static burst pressure of the panel, and are equipped with a bold sign stating in large lettering “DANGER – EXPLOSION VENT – KEEP CLEAR”