Pressure Switches – Testing According to Pressure Equipment Directive 2014/68/EU
Pressure switches, pressure monitors and pressure limiters tested according to the Pressure Equipment Directive 2014/68/EU are used in systems where pressure must be monitored safely and inadmissible operating conditions must be detected reliably. Depending on the version, they are used for monitoring maximum pressure, minimum pressure or differential pressure and can trigger shutdown, alarm or lockout functions when a defined limit value is reached.
The Pressure Equipment Directive 2014/68/EU, also known as PED, applies to pressure equipment and assemblies with a maximum allowable pressure of more than 0.5 bar. It covers, among other things, pressure vessels, piping, safety accessories and pressure accessories. The objective of the directive is to ensure a high level of safety for pressure equipment placed on the European market.
In this category, you will find mechanical pressure switches and pressure limiters designed for applications with increased safety requirements. They are used, for example, in hot water systems, steam systems, LPG systems, burner controls, refrigeration systems, pressure vessels, piping systems and industrial process plants. Depending on the device type, they are suitable for liquids, gases, steam, fuel gases or liquid fuels.
Tested pressure switches are particularly important wherever a pressure limit value must not only be indicated, but monitored safely. Pressure limiters can be designed so that they do not automatically reset after triggering. Manual reset or lockout prevents a system from restarting unintentionally after a safety-relevant pressure exceedance.
Typical Applications
- Maximum pressure monitoring in pressure systems
- Minimum pressure monitoring in supply and burner systems
- Pressure monitoring in hot water and steam systems
- Safety shutdown in case of inadmissible pressure increase
- Monitoring of LPG systems and fuel gas lines
- Pressure monitoring in refrigeration, energy and process plants
- Protection of piping, vessels, pumps, heat generators and assemblies
Advantages of Tested Pressure Switches According to 2014/68/EU
- For safety-related applications: suitable for monitoring critical pressure limits
- Tested design: for systems where requirements of the Pressure Equipment Directive must be considered
- Mechanical switching principle: robust operation without auxiliary power for pressure detection
- Limit monitoring: suitable for maximum pressure, minimum pressure or differential pressure
- Lockout possible: depending on the version, available with manual reset or restart lockout
- Various media: depending on the series, suitable for liquids, gases, steam, fuel gases or liquid fuels
- Industrial design: suitable for demanding systems in mechanical engineering, plant engineering and process technology
Pressure Switches for Safety-Related Pressure Monitoring
A pressure switch detects a defined pressure value and provides an electrical signal when this switching point is reached. In simple applications, this signal is used for control or alarm functions. In safety-related applications, it can be part of a safety chain that shuts down a system or locks it against restart.
The Pressure Equipment Directive distinguishes, among other things, between pressure accessories and safety accessories. Safety accessories are devices designed to protect pressure equipment against exceeding allowable limits. These may include limiting devices that trigger corrective action, shutdown or shutdown with lockout.
Selecting the Right Pressure Switch
To select a suitable pressure switch or pressure limiter, the technical operating data of the system must be known precisely. This includes the medium, pressure range, maximum allowable pressure, required switching point, temperature, process connection, electrical switching capacity, protection rating, installation situation and requirements regarding lockout, approval or safety function.
For applications according to the Pressure Equipment Directive, it should also be checked which function the device performs in the system. If the pressure switch is used only as an operational device, different requirements may apply than if it performs a safety-related limiting function. In safety-critical applications, the design should always be based on the specific system, applicable standards and the required conformity assessment.
FAQ – Frequently Asked Questions about Pressure Switches According to Pressure Equipment Directive 2014/68/EU
1. What does Pressure Equipment Directive 2014/68/EU mean?
The Pressure Equipment Directive 2014/68/EU is a European directive for pressure equipment and assemblies. It defines requirements for the design, manufacture and conformity assessment of stationary pressure equipment with a maximum allowable pressure of more than 0.5 bar.
2. When is a pressure switch according to 2014/68/EU required?
A tested pressure switch or pressure limiter is required when it performs a safety-related function in a pressurised system or is part of a protective function against inadmissible pressure conditions.
3. What is the difference between a pressure switch, pressure monitor and pressure limiter?
A pressure switch provides an electrical signal when a switching point is reached. A pressure monitor supervises a pressure limit and can be used for control or shutdown. A pressure limiter is used for safety functions and may, depending on the version, include manual reset or lockout.
4. Which media can be monitored?
Depending on the device version, liquids, gases, steam, fuel gases, LPG or liquid fuels can be monitored. Exact suitability depends on the materials, pressure range, temperature and approval of the respective device.
5. What does maximum pressure monitoring mean?
Maximum pressure monitoring means that the device switches as soon as a defined upper pressure limit is reached or exceeded. This can shut down a system or trigger a safety function.
6. What does minimum pressure monitoring mean?
Minimum pressure monitoring means that the device switches when the pressure falls below a defined minimum value. This is important, for example, in burner systems, pump systems or supply lines.
7. What does lockout mean for a pressure limiter?
Lockout means that the triggered switching state is maintained and the system does not restart automatically. Operation can only be released again after the cause has been eliminated and the device has been manually reset.
8. Do mechanical pressure switches require a supply voltage?
No supply voltage is required for pressure detection itself. The pressure acts on a mechanical measuring element, which actuates a microswitch. Electrical connections are only required for the switching signal.
9. What information is important for selecting the right device?
Important information includes the medium, pressure range, maximum allowable pressure, required switching point, temperature, process connection, electrical switching capacity, protection rating, switching differential, installation situation and whether a safety-related limiting function is required.
10. Are tested pressure switches also suitable for steam systems?
Yes, depending on the series and approval, tested pressure switches and pressure limiters can also be used in steam systems. Pressure, temperature, medium and system requirements must be considered.
11. Can pressure switches according to 2014/68/EU be used in LPG systems?
Yes, special pressure limiters and pressure monitors are available for LPG systems. The decisive factor is that the respective device version is suitable for the medium, pressure range and safety function.
12. Why is correct selection important for safety-related pressure switches?
An incorrectly selected pressure switch may switch too late, too early or not at all in a critical situation. Pressure range, medium, temperature, electrical integration, reset function and approval must therefore be carefully matched to the system.