What is an explosion?

An explosion is the sudden chemical reaction of a combustible with oxygen involving the simultaneous release of high energy. An explosion can take place if and only if there are three factors: a combustible, oxygen (air) and a source of ignition.

Combustibles may be present in the form of gases, vapours, mists or dusts. The parameters relating to technical safety must be taken into account in the risk assessment.

You can find further information in our "Essential Explosion Protection" brochure.

Integrated explosion protection

The principle of integrated explosion protection requires all measures for explosion protection to be considered in a specific order. The three distinctive protection measures are: primary, secondary and tertiary (construction design-related).

Measures for primary explosion protection prevent the formation of a hazardous explosive atmosphere. This includes avoiding the use of combustibles (alternative technologies), inerting (adding nitrogen, carbon dioxide, etc.) and limiting the concentration via natural or technical ventilation.

Measures for secondary explosion protection prevent the ignition of a hazardous explosive atmosphere. The level of safety required for these precautions depends on the risk potential at the operating location.

Measures for tertiary or construction-design-related explosion protection limit the effects of an explosion to such a degree that they are not hazardous. This includes the following options: explosion-proof or explosion-shock-proof construction design, pressure relief and pressure equalising equipment as well as explosion suppression using fire-extinguishing equipment.

We provide more detailed information on the topic of integrated explosion protection and the relevant measures in our "Essential Explosion Protection" brochure.

Dust – the underestimated risk of explosion

In many industrial sectors, powdered and dust-like products are processed or formed during the production process. 80% of all dusts which are found in industry are combustible, in a closed space, even a layer of dust less than 1 mm is sufficient to trigger an explosion, after dust is stirred up and ignited.

Dust explosions present a particular risk for the food industry, the woodworking industry, the paper and plastics industry and pharmaceutical industries. The observations above are confirmed by German property insurers. According to the latter, an average of one dust explosion per day occurs in Germany, wherein around every fourth explosion is caused by food or animal feed dusts.

Dust explosions – conditions and effects

As with combustible fluids and the explosive gas-air mixtures that are formed by these, so too must certain conditions exist for combustible dusts in order to ensure that a dust-air mixture is not ignited by a suitable source of ignition and thus an explosion triggered as a result.

However, in comparison to gas explosions, dust explosions take a different course and, under certain circumstances, can have significantly more serious consequences. This is because the resulting wave of pressure causes further layers of dust to be stirred up, which then in turn ignite. This process continues and, in unfavourable circumstances, these type of chain reactions move through all parts of the plants or even through an entire building, destroying it.

R. STAHL – Your partner for dust explosion protection

Most companies are aware of the topic of gas explosion protection, whereas not many are informed about dust explosion protection. At R. STAHL,we treat dust explosion protection and gas explosion protection with equal importance. We help you to assess the risk of a dust explosion in your plants and to take the necessary technical measures to minimise this risk.

R. STAHL providesyou with a fullcertified range of products for potentially explosive dust atmospheres and can develop a customer-specific solution togetherwith you for virtually anyapplication. Take advantage of our extensive specialist knowledge in preventing dust explosions and use it to protect your people, plant and machinery.

We provide further information related to the topic of dust as a risk factor as well as technical safety parameters (including grain size, explosion limits, minimum ignition energy, glow temperature), types of protection, legislative mandates and suitable protection measures in our "Essential Explosion Protection" brochure.

Functional safety and explosion protection

Automation technology systems are increasingly taking over safety-relevant tasks in processes which represent a risk for people and the environment. In the event of an incident, they intervene in the process and can reduce the risk of a hazardous situation occurring. The functional safety of a plant is safeguarded if every safety function is executed in accordance with specifications. Here, the SIL (Safety Integrity Level) unit of measurementquantifies the risk reduction of a safety-relatedsystem in four separate levels.

Relevant standards IEC 61508 and 61511

Since August 2002, the IEC/EN 61508 standard has comprehensively defined the safety requirements in automation technology and primarily addresses the manufacturers of components for protective equipment. The IEC 61511 standard "Functional safety – Safety instrumented systems for the process industry sector" addresses the operators and designers of protective equipment. It provides recommendations and specifications on assessing the damage risk of plants and helps in selecting suitable, safety-related components.

The term SIL

SIL is the abbreviation for "Safety Integrity Level" and is defined as a measurement of the safety-related performance or reliability of an electronic or electrical control device.

Products and solutions for functional safety

Functional safety is often applied in plants with potentially explosive atmospheres. In accordance with the requirements of the IEC/EN 61508 standard, appropriate protection systems are therefore essential. R. STAHL recognised this link early on, and has the necessary specialist knowledge in this area. We offer you support and advice on the risk assessment, the implementation of measures for risk reduction and the assessment of the functional safety of your plant. In addition to our explosion-protected equipment, we also offer specific components and systems for functional safety.