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Explosion protection

Scope of works

  • concept development and implementation of the explosion protection system based on explosion suppression, relief or uncoupling,
  • limiting the range of the explosion hazard zones by the design and introduction of a dedusting and/or central cleaning systems (ATEX-compliant),
  • development of the Explosion Risk Assessment (also on the design stage),
  • classification of type and range of explosion hazard zones (also on the design stage),
  • development of the Explosion Protection Document,
  • ATEX training for safety and process safety,
  • providing audits for explosion safety in industrial facilities.

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Explosion safety expert

The ATEX137 directive, implemented in Poland by way of regulation of the Minister of Economy, obliged companies working with combustible substances in the form of dusts, gases, vapours and hybrid mixtures to provide appropriate protection of he equipment, installations and personnel against uncontrolled explosion.

The requirements related to the ATEX directive can be divided into preventive measures – trying to not allow the explosion to happen and effects minimisation to safe and acceptable levels. The last aspect is implemented by the introduction of explosion protection.

The WOLFF GROUP, of which ATEX is a part, is one of the few companies in Europe able to provide such comprehensive adaptations of process installations and complete production facilities to the applicable explosion and process safety regulations.

Explosion protection

One of the most elements of the explosion safety system are explosion protections. Their task is to limit the effects of the explosion to a level that is safe for equipment, instruments and – first and foremost – the personnel.

​​The employer is obliged to use explosion protection by the ATEX137 directive (implemented in Poland by the Regulation of the Minister of Economy of 8 July 2010 on minimum requirements for the occupational safety and hygiene, related to the possible occurrence of explosive atmosphere in the workplace – Dz. U. 2010 no. 138, item. 931).

Explosion suppression

The explosion suppression system is the most effective and versatile method for equipment and system protection against the effects of an uncontrolled explosion. Its primary task is detecting the explosion at the very beginning, i.e. immediately after the ignition sources occur. In order for that to be possible, the suppression system must have a very short reaction time. In the case of our solutions, the time from the moment of detection to the moment of explosion suppression is very short (0.0075 – 0.0300 s).

The most important advantages of the explosion suppression system are:

  • complete elimination of the effects of explosion (including product burn),
  • possibility of use for most products and equipment,
  • possibility to use inside halls and buildings,
  • possibility to use with noxious and toxic substances,
  • no requirement for explosion hazard zones to be determined.

Explosion suppression system components

Explosion suppression system cylinders – HRD

Explosion suppression system cylinders appear similar to traditional fire extinguishers but their design is quite different. For example, the delay of a typical extinguisher is several to a few dozens of seconds. In the case of the HRD, this time is measured in one thousandths of a second.

HRD system IR and pressure sensor

The task of both types of the sensors is the detection of the earlies stage of the explosion. In most cases, the use of just pressure sensors is sufficient. Their location is, in fact, key to the effective operation of the system.

Explosion suppression system central control unit

Due to the use of a multi-zone central control unit, it is possible to activate individual sections of the explosion suppression system (activation of the section, where the explosion happened).

Explosion relief (venting)

The relief (venting) systems are the weakest construction elements of the protected equipment, which “opens” in the case of explosion to provide a venting passage for the explosion wave. This protects the equipment against excessive internal pressure increase resulting in damage.

Explosion relief systems

Flameless explosion relief

The flameless explosion relief system for use in closed areas and in tightly built-up systems. The system also reduces the risk of fire after the explosion.

Self-closing explosion relief flaps

Explosion protection flaps with self-closing after explosion. This solution limits the chance of fire after the explosion (by cutting off air supply).

Standard explosion relief panels

Standard explosion relief panels. An economical solution with many limitations. Special care should be taken in its use.


Explosion relief panes are an economical alternative for other explosion protection systems. This is why this solution is often overused. Incorrectly used panels can be a serious threat to the process installation and its personnel. Special care should be taken when selecting panels.​​

Serious mistakes made in relation to the use of relief panels: 

  • using the panels in closed rooms without any further protective measures,
  • lack of safety zone markings near the protected device, instrument,
  • facing the panels towards other equipment, buildings, roads and footpaths,
  • asymmetrical distribution of panels against the axis of the protected equipment (reaction force),
  • using with noxious, harmful, toxic or corrosive substances.

Explosion decoupling (cutoff)

In practice, explosion decoupling (cutoff) is an integral element of the relief to suppression systems. Its purpose is to physically close all channels and transfer stations connecting the device in which the explosion took place with the rest of the system. This solution prevents explosion spreading due to propagation into other equipment and instruments.

Explosion decoupling systems

HRD decoupling systems

Highly versatile solution commonly used in the food, chemical, pharmaceutical, power and wood industries.

VENTEX relief systems

Passive, multiple use protection – acting due to the strength of the explosion wave.

Q-flap, reverse stopping flap

A reverse flap is an economical solution, which, due to its limitations (e.g. only horizontal installation, minimum gas speed, maximum gas contamination) is useful in a number of dedusting systems.

Explosion insulation by a certified cell valve

Certified cell valves are usually applied under tanks, silos, filters and cyclones. Their main advantage is that they provide the isolation of bulk materials feeding and explosion isolation.

Explosion isolation by quick-active slide gates

The solution is intended for use in especially difficult cases, where using other systems is not possible (e.g. high maximum explosion pressure or explosiveness constant).

Explosion isolation by a diverter

The solution was developed and used only in dedusting systems. The main issue with the diverters is that they generate high flow resistance in the system.


Explosion protection methods, such as suppression or relief do not provide effective protection in case they are not integrated with solutions preventing the spread of the explosion. The employer is obliged to use explosion protection with solutions preventing explosion propagation by the ATEX137 directive (implemented in Poland by the Regulation of the Minister of Economy of 8 July 2010 on minimum requirements for the occupational safety and hygiene, related to the possible occurrence of explosive atmosphere in the workplace – Dz. U. 2010 no. 138, item. 931).

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