In this project, the measurement of downtime according to EN ISO 13855 in industrial presses was carried out as part of an action of the ADEQUA area of PRODEN GROUP.

The intervention was carried out in an industrial facility in the province of Barcelona, where the implementation of safety barriers presented limitations due to the existing configuration of the machines.

In this context, the minimum safety distance obtained by theoretical calculation was excessive for the space available.

Technical context: retrofitting of existing machinery

Real limitations in industrial presses

In existing machinery, especially in presses, it is common to find geometrical and operational restrictions.

Therefore, the direct application of normative criteria may result in solutions that are difficult to implement.

In this case, the initial safety distances significantly conditioned the feasibility of the solution.

Need to validate by actual measurement

Faced with this situation, a strategy based on the actual measurement of machine behavior was proposed.

In this way, it was possible to adjust the calculation of distances based on data obtained under real operating conditions.

This approach is key in industrial retrofit projects.

Methodology applied according to EN ISO 13855

Measurement of downtime as a critical variable

The minimum safety distance depends directly on the total downtime of the system.

According to EN ISO 13855, this distance is determined by the following expression:

S = (K × T) + C

Where:

• S → minimum safety distance
• K → approach velocity of the human body
• T → total system downtime
• C → device intrusion distance

Therefore, the measurement of downtime becomes a decisive element in the design of the solution.

Downtime measurement on machines according to ISO 13855 with calibrated instrumentation

All measurements were performed with certified and calibrated equipment suitable for measuring machine downtime according to ISO 13855.

In addition, specific devices were used for tests on industrial safety systems, including:

• optoelectronic barriers
• double pushbutton systems
• safety stop functions

This type of measurements, developed by the ENGINEERING area of PRODEN GROUP, allows to obtain real data of the dynamic behavior of the machine.

This ensures the reliability of the results and the technical traceability of the process, especially in retrofit projects where the calculation depends directly on the actual response of the system.

Analysis of the machine-protection system

The measured downtime includes the contribution of different elements:

• press clutch-brake system
• valves and pneumatic elements
• control logic and safety relays
• barrier response time

In addition, the variability between equipment, derived from its condition and configuration, was considered.

Results obtained in the presses analyzed

Adjustment of distances in Press 1, 2 and 3

Based on the measurements taken, minimum safety distances were defined for each piece of equipment:

• Press 1 → distance optimized according to actual performance
• Press 2 → adjustment conditioned by longer stopping time.
• Press 3 → reduced distance due to lower inertia

These results made it possible to adapt the solution to each machine.

Safe reduction of distances

Without measurement, distances obtained by calculation tend to be conservative.

However, the use of real data allowed:

• justifiably reduce distances
• ensuring regulatory compliance
• adapting the implementation to the available space

This was a determining factor in the viability of the project.

Technical value within the ADEQUA project

Integration in safety adequacy

The measurement was not intended as an isolated study.

It was integrated within the adequacy project, allowing the correct definition of the implementation of barriers.

Thus, the final solution met both regulatory and operational criteria.

Balance between safety and operations

The approach adopted allowed:

• maintain the required level of security
• avoid oversized solutions
• optimize operator-machine interaction

In addition, the impact on productivity was minimized.

Economic optimization of the solution

Thanks to the measurement, complex structural modifications were avoided.

Therefore, a solution was achieved:

• technically justified
• economically viable
• consistent with the existing installation

Regulations applied

The project was developed in accordance with:

• EN ISO 13855
• EN ISO 12100
• EN ISO 13849-1
• IEC 60204-1

This framework makes it possible to relate the dynamic behavior of the machine to the safety of the solution.

Industrial adaptation based on actual data

In retrofit projects, especially on existing machinery, the theoretical calculation does not always reflect the operational reality.

Downtime measurement in accordance with EN ISO 13855 on industrial presses therefore enables you to make the right technical decisions.

This approach, applied by ADEQUA in PRODEN GROUP, facilitates viable, safe solutions aligned with the actual installation.

To learn more about this topic, you can consult the following article of our blog about: ISO 13855 downtime measurement: when to measure.