Safety experts from TÜV know the scenario: pumps without sufficient stability can quickly overheat. This heat can lead to an explosion with devastating damage to production. The company may be left holding the bag for part of the damage if the liability insurance company can prove that the company was negligent. Unsecured pump units are therefore a high business risk. What's more, the management responsible is committing a criminal offense if it fails to comply with the legal requirements.

The jungle of standards

Only a few manufacturers cover the complete safety chain for measurement and control technology (MCR) with their products and solutions. However, safety in the production process is a top priority for companies. This is why there are numerous standards and regulations that must be interlinked. They all require consistent application of, for example, the Industrial Safety Ordinance and TRGS 725 (Technical Guideline for Hazardous Substances).

What sounds simple and logical at first glance becomes complex as soon as you enter the jungle of standards, directives, regulations, technical rules and manufacturer recommendations that must be observed when monitoring ignition sources: IEC/EN 60079-xx as a set of standards on explosion protection, DIN EN 50495 (safety devices for the safe operation of equipment with regard to explosion hazards) and DIN EN 14597 (temperature control and limiting devices for heat-generating systems) are relevant to this topic. The consideration of the DIN EN 14597 standard always includes a complete measuring, control and limiter system consisting of sensor, logic and actuators. For example, the following considerations are certified for the individual components:

• Response behavior of the sensor system
• Reactions (modes of action) of the evaluation electronics
• Reliability/lifetime of the actuators

In addition, IEC/EN 61508, EN/ISO 13849 as well as EN/IEC 62061 and EN/IEC 61511, TRGS 725 (technical rule) and possibly other product-specific standards are applied in the area of functional safety. While electrical explosion protection traditionally played a major role in safety precautions in the past, in recent years the focus has increasingly shifted to mechanical components as a potential source of ignition.

Different types of ignition protection

EN 50495, which was published in Europe in 2011, is central to the topic of ignition source monitoring. It stipulates that in explosion protection, potential ignition sources are eliminated or rendered ineffective by various types of ignition protection. It is necessary to effectively monitor unavoidable residual ignition sources using suitable safety devices. These devices must carry out the corresponding measures within the appropriate response time. EN 50495 distinguishes between simple type a safety devices (e.g. thermal switches, thermistors or temperature monitoring units) and complex type b safety devices - devices that are installed independently of the type of ignition protection equipment under control (EUC).

Examples include overload protection devices for electric motors with type of protection Ex(e) or external control devices for type of protection pressurized enclosure Ex(p). EN 14597 is also relevant; this European standard applies to electrical or non-electrical temperature control and limiting devices used to control and monitor the temperature in heat-generating systems by controlling the energy supply. It applies to ensure that the temperature in heat-generating installations does not exceed a predetermined limit (temperature class). The consideration of this standard always includes a complete measuring, control and limiter system consisting of sensor, logic and actuators. For example, the response behavior of the sensors, the reactions or switching behavior of the evaluation electronics and the reliability/lifetime of the actuators are certified for the individual components.