Earth-moving machinery - Safety - Part 5: Requirements for hydraulic excavators; German version EN 474-5:2022+AC:2022

Standard Background and Purpose

DIN EN 474-5:2023 "Erdbaumaschinen – Sicherheit – Teil 5: Anforderungen an Hydraulikbagger" is a harmonized standard of the European Machinery Directive 2006/42/EG, applicable to hydraulic excavators first placed on the market in the European Economic Area. This standard was developed by Technical Committee CEN/TC 151, with DIN Germany serving as the secretariat, aiming to provide manufacturers with safety design guidelines and presumptions of conformity. The 2023 version replaces the 2013 version, reflecting industry technological advancements and accident statistics analysis, further strengthening protections for operators and those in the surrounding area.

Major Technical Changes (2013 to 2022 Versions)

Compared to the previous version, the 2022 version (adopted in Germany in 2023) introduces several important updates:

Key Safety Requirements Interpretation

Operator Protection Structures (ROPS/TOPS)

Based on machine weight and configuration, the standard classifies protection structures into three categories:

• Compact Excavators (1t : Must be equipped with TOPS (Tilt-Off Protection Structure), conforming to EN 13531. Medium-sized excavators (6t : If there is no lift cab or the fixed lift is ≤ 500mm, ROPS (Roll-Off Protection Structure) must be equipped according to ISO 12117-2. Overhead or mobile cabs>: If the fixed lift is > 500mm or the cab is mobile, a special ROPS/TOPS assessment is required, with the lateral load formula Us(J) = 6500 × (M/10000)^1.25. For example, a 20t hydraulic excavator equipped with a liftable cab needs to have its ROPS verified to meet energy absorption requirements under lateral forces, ensuring the operator's survival space in the event of a rollover.

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  Braking System

  The standard specifies the driving brake and swivel brake in detail. For swivel brake, Anhang C sets strict performance indicators:

  • The swivel service brake must be able to stop the upper frame within a specified deceleration angle (deceleration angle B ≤ 90° or calculated according to the formula).
  • The swivel parking brake must maintain its position for 30 minutes and automatically activate (when the engine stops). For machines weighing ≤ 6t, a hydraulic locking valve is permitted, but a swivel lock must be provided.
  • The swivel lock device must not produce permanent deformation under maximum torque.

  For example, in the test of a certain brand of hydraulic excavator, if the rotation speed is 12 r/min, the service brake must stop within 90°; if it exceeds this, it does not meet the standard.

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  Visibility and Auxiliary Systems

  The standard has made significant updates to the operator's visibility.

  • The reference to ISO 5006:2017 has been modified to require: When the direct field of view is insufficient, the camera image must be automatically displayed as the machine moves and automatically restored after manual cancellation. Imaging resolution requirements: For a test object 1.5m high at a distance of 1.2m from the visual aid, the image should be at least 10mm (except for panoramic cameras, which must comply with EN ISO 16001 G.4). Rearview mirrors must cover a specific area within a rectangular boundary (RB) and must not obstruct other fields of view. Lifting Operations and Stability The standard distinguishes between "lifting operations" and general excavation operations. When the machine is used for lifting, it must meet the following requirements: Lifting capacity is determined according to ISO 10567, taking into account the weight of the tooling. If the machine's maximum lifting capacity is ≥1000kg and its weight is ≤50t, an overload warning device (EN 474-1:2022 4.12.3) and a load diagram must be provided. For machines weighing >50t, the above devices are only required if the manufacturer specifies them for lifting. When using a timber grab, the overturning load limit for non-static lifting (loaded while traveling) is 60%. Example: A hydraulic excavator in lifting mode, if equipped with an extended boom, should have a load diagram showing the safe loads at different working radii, which the operator must strictly adhere to.

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    Quick Connectors

    The 2022 version adds clause 4.9 for hydraulic quick connectors (such as grab bucket quick-change devices), requiring:

    • Measures must be taken to prevent the tooling from accidentally falling, such as: automatically and mechanically locking the first contact pin; or preventing lifting until fully connected; or holding the tooling throughout the entire stroke (within the bucket cylinder stroke); or issuing an audible and visual alarm.
    • The above functions must be verified through functional testing using all expected tooling.

    For example, a quick-change system that does not fall even when the cylinder retracts in an incompletely locked state meets the "holding function" requirement.

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    Standard Framework Comparison Table

    Elements	EN 474-5:2023	ISO 20474-5:2021	AS 4773-2019 (Australia)
    Protective Structure	Based on quality classification, ROPS/TOPS rigorous testing	Similar, but performance equivalence is allowed	Refer to ISO, but with added falling object protection requirements
    Rotation Braking	Anhang C detailed specifications for deceleration angle and testing	No specific appendix, only performance requirements	Refer to EN, but no specific values
    Visibility	Modified ISO 5006, Add Automatic Camera Activation	Directly reference ISO 5006:2017	Reference ISO, no additional requirements
    Quick Connectors	Explicitly define 4 fall protection measures	Briefly mention connector safety	No dedicated section
    Lifting Operations	Distinguish between weight and application, mandatory load diagram	Similar, but different thresholds	Requires load diagram, but no weight threshold

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    Implementation Recommendations

    • Manufacturers: Risk analysis should be conducted based on the latest version of the standard, with particular attention to rotational braking testing and quick connector functional verification. It is recommended to integrate an automatic locking mechanism during the development phase. **Users:** When purchasing equipment, verify the CE marking and declaration of conformity, ensure the machine load diagram is complete, and regularly inspect the protective structure and braking system. **Testing Institutions:** Note the clause in the standard that "safety functions of the control system are not included." Independent verification in conjunction with EN ISO 13849 is required during evaluation. **Practical Application Case:** A European hydraulic excavator manufacturer redesigned its rotary braking system according to the new standard when upgrading its 20t model. In prototype testing, with a rotation speed of 12 r/min, the initial braking deceleration angle was 85°, meeting the formula requirement (B≤90°). However, after 10 consecutive braking cycles, the 10th deceleration angle increased to 102°, exceeding the 20% tolerance. Engineers optimized the brake pad material and hydraulic pressure compensation, stabilizing the maximum deceleration angle within 95°, ultimately achieving certification. This case demonstrates that not only single-cycle performance but also braking stability is crucial. Another case: A user of a hydraulic excavator reported that the quick-connect coupling occasionally failed to lock when changing the grab bucket. The manufacturer upgraded the self-locking mechanism according to clause 4.9, ensuring immediate mechanical locking after the first pin contact and preventing the hydraulic cylinder from lifting if not fully engaged. After 1500 cycle tests, there were zero failures, meeting the standard requirements.