Damage Classes under DIN EN 15635: Assessing Green, Yellow and Red Correctly

Impact damage to a rack upright often looks inconspicuous – a slight dent, a few millimetres of deformation. Statistically, precisely this situation is critical: the BGHW registers around 245,000 reported occupational accidents per year in retail and goods logistics, 57 of which are fatal. When racking installations fail, the consequences are often catastrophic – frequently involving personal injury, always involving business interruption and claims for damages. DIN EN 15635 therefore makes the assessment binding: every instance of damage must be assigned to one of the three hazard levels Green, Yellow (Orange) or Red. The key insight up front: what matters is not gut feeling, but measurement to the millimetre and correct classification – because this assessment determines whether the rack may continue to be operated, must be repaired within four weeks, or must be cleared immediately.

Why the traffic-light system? The legal basis

The three-level assessment system is not an internal administrative instrument, but a normative obligation. DIN EN 15635:2009-08 “Steel static storage systems – Application and maintenance of storage equipment” anchors damage classification in Section 9 “Safety of storage equipment in use and assessment of damaged components”. Specifically, Section 9.4 (inspection of the storage equipment) and Section 9.7 (damage handling procedure) regulate the obligation to assign a colour. Annex D of the standard provides the associated tolerance values and measuring methods.

This standard does not stand in isolation. It is embedded in a national framework of obligations:

• German Ordinance on Industrial Safety and Health (BetrSichV) § 14: Work equipment – and racking is work equipment within the meaning of this ordinance – must be inspected by a competent person before commissioning and at recurring intervals. Type of inspection, scope of inspection, findings and the signature of the competent person must be documented.
• TRBS 1203 “Persons competent to carry out inspections” of the Federal Institute for Occupational Safety and Health (BAuA) specifies who is allowed to inspect: the prerequisites are relevant vocational training, professional experience in the racking and warehouse sector, recent professional activity and specific further training as a rack inspector with examination and certificate.
• DGUV Information 208-043 “Sicherheit von Regalen” (formerly DGUV Regel 108-007, now partly superseded by DGUV Information 208-061 “Lagereinrichtungen und Ladungsträger”) links the European standard with German prevention practice and contains guidance on visual inspection, damage assessment and inspection documentation.

The consequence: anyone who assigns the damage classes incorrectly not only violates the standard, but also breaches national occupational health and safety law. In the event of an accident, the public prosecutor's office and the employers' liability insurance association examine closely whether the classification was carried out properly. Documented “Green” assessments of obviously critical damage regularly lead, in criminal proceedings, to the personal liability of the competent person and the employer.

Who classifies? Allocation of roles within the company

Three roles interlock: the weekly visual inspection is carried out by instructed employees – usually the warehouse or shift management. They report anomalies but do not make a final classification. The safety officer for storage equipment (PRSES – Person Responsible for Storage Equipment Safety) coordinates the inspection system, keeps the inspection log and ensures that repairs are carried out on time. The final damage classification – in particular the decision between Yellow and Red – is the responsibility of the competent person in accordance with TRBS 1203, who carries out the expert inspection at least annually.

Green: minor damage without immediate action

The green hazard level marks damage whose deformations lie within the tolerance limits of DIN EN 15635. The component is considered safe and operational – but this expressly does not mean that it may be ignored.

Tolerances: what exactly does the standard measure?

The authoritative measuring method is described in Annex D of the standard: a measuring rod or ruler 1,000 mm (1 m) long is placed against the damaged component in such a way that the point of damage is exactly in the middle. The maximum gap between ruler and component is measured. This yields the limit values:

• Vertical uprights (posts), transverse to the aisle direction: maximum 3 mm deformation – this corresponds to the weak axis of the upright, where the risk of buckling is greatest
• Vertical uprights, in the aisle direction: maximum 5 mm deformation – in the strong axis with a greater moment of inertia
• Diagonal and horizontal braces (bracing): maximum 10 mm deformation
• Beams: slight deformations without visible cracking, without impairment of the load carrier's support, without loosening of the safety locking pins

If these values are not exceeded, the damage is Green. Typical examples: superficial scratches from pallet contact, slight paint abrasion on the base plate, minimal dents without deformation of the load-bearing cross-section, soiling without corrosive effect, slight bending of the impact protection without functional impairment.

Documentation obligation despite a Green assessment

Green damage also belongs in the inspection report. The background: damage accumulates. A component documented today with 2 mm deformation can jump to 4 mm at the next impact – and then the tolerance limit is exceeded. Without earlier documentation, this progression cannot be proven. DIN EN 15635 therefore requires in Section 9.4 the complete recording of all findings, including the non-critical ones.

Deadlines and follow-up measures

Green assessments do not require repair, but a renewed check at the next regular visual inspection (weekly or at the interval determined by the risk assessment). Colour marking is recommended – for example with a marking label including the date – so that shift changes and external inspectors can also trace the history. The retention period for inspection reports under the BetrSichV is at least until the next inspection; in practice, a period of five years has proven effective in order to be able to demonstrate the damage history over the longer term.

Yellow: damage requiring action within 4 weeks

The yellow (officially “orange” in the standard) hazard level applies as soon as the tolerance values are exceeded but there is not yet an acute risk of collapse. The standard defines this range as “hazardous damage requiring action as soon as possible”.

What qualifies as Yellow?

Yellow damage is generally present when the tolerances from Section 9.7 of DIN EN 15635 are exceeded but not yet doubled:

• Deformation of the upright transverse to the aisle direction between 3 mm and 6 mm
• Deformation of the upright in the aisle direction between 5 mm and 10 mm
• Deformation of bracing between 10 mm and 20 mm
• Bent beams with measurable deflection but without incipient cracks
• Damaged but still load-bearing base plates
• Missing or loose safety locking pins on beams
• Loose, bent or missing anchors
• First spots of corrosion attacking the load-bearing material

May operation be continued?

There is often uncertainty about this in practice. The standard's answer is differentiated: the directly affected rack section (usually the affected bay) must be unloaded. Reloading before completion of the repair is not permitted. The adjacent, undamaged bays may continue to be operated, provided there is no structural interaction – which, in the case of installations with continuous bracing, must be checked in the individual case by the competent person.

A blanket load reduction (“we will only store half the weight”) is not a permissible substitute for the repair. The standard has no concept of reduced load capacity for damaged components, since the residual load capacity of a deformed profile cannot be reliably predicted.

Repair options and the 4-week deadline

For Yellow damage, a repair deadline of a maximum of four weeks applies. This deadline is the industry standard and is anchored in DGUV Information 208-043 as well as in the inspection practice of experts. Two options come into consideration for remediation:

1. Component replacement with original spare parts: always permissible, provided the manufacturer and type are identical and the connection details can be installed. The manufacturer documents the suitability; a renewed structural assessment is not required.
2. Repair by welding or reinforcement: only by certified specialist companies that verifiably restore the former load capacity. DIN EN 15635 expressly permits repairs even without the consent of the original manufacturer, but requires written proof of equivalent load capacity.

What is not permissible is the “straightening out” of deformed uprights by in-house personnel. Steel components undergo plastic deformation during an impact, which changes the material structure. Bending them back merely hides the damage visually and further reduces the load capacity.

Red: immediate taking out of service

The red hazard level is the escalation level. It demands immediate action because failure of the component – and thus a rack collapse – can no longer be ruled out.

What qualifies as Red?

The following in particular counts as Red damage:

• Deformation of the upright transverse to the aisle direction > 6 mm (more than double the Green limit value)
• Deformation of the upright in the aisle direction > 10 mm
• Deformation of bracing > 20 mm
• Cracks in load-bearing components, in weld seams or on the base plate – regardless of size
• Cracked or detached diagonal or horizontal braces
• Floor anchors loosened or torn out of their anchorage
• Beams that have jumped out of their connectors or whose safety locking pins are completely missing
• Massive corrosion with loss of cross-section
• Deformation of the impact or corner protection with additional deformation of the upright behind it
• Visible lean of the entire rack beyond the permissible installation tolerances

Barrier measures and clearing rules

As soon as Red damage is identified, a clear sequence applies:

1. Immediate cordoning-off of the danger zone – a sufficiently large safety distance from the installation, at least one rack height plus 1 m, ideally with a physical barrier (barrier tape is insufficient if forklifts could drive into the area).
2. Attachment of unambiguous prohibition signage in accordance with ASR A1.3 (prohibition sign, such as “No entry”). Mere marking with red adhesive tape does not meet the requirements of occupational health and safety law.
3. Controlled unloading of the affected bay – by trained personnel, with the installation structurally supported if necessary. In the event of an acute risk of collapse, unloading must be carried out from outside with longer aids or by a specialist company, not by the regular warehouse staff.
4. Notification of the supervisor, the safety officer and the competent person. In the event of serious damage, the manufacturer must also be involved.
5. Written blocking with an entry in the inspection log, including date, time, damage pattern and the person imposing the block.

Return to service

A rack assessed as Red may only be released again once the damage has been fully remedied and the repair has been re-inspected by a competent person. A new inspection certificate with an inspection report and release note is required. For components that have been subjected to severe deformation or an impact accident, replacement is usually the only safe option – a purely visual check is not sufficient. After exceptional events such as accidents, the BetrSichV requires an extraordinary inspection of the entire section of the installation.

Damage class overview (table)

Common assessment errors in practice

Experience from several thousand rack inspections shows: most misjudgements arise not from a lack of knowledge of the standard, but from typical cognitive and methodological errors.

“I can't see any deformation, so it's green”

Visual estimation of deformations is notoriously unreliable. A 4 mm deformation on a 2.5 m upright is practically impossible to detect with the naked eye, but exceeds the Green tolerance of 3 mm and qualifies as Yellow. Without applying a straight measuring rod or a gauge, a valid damage classification is not possible. It is not without reason that the standard requires metric measurement.

Disregarded cumulative damage

Two individual instances of damage just below the tolerance limit must be considered together as soon as they structurally influence each other. A 2.8 mm deformation transverse to the aisle plus a 4.5 mm deformation in the aisle direction on the same upright results in a combined load that can endanger buckling stability even if each individual value is formally “green”. Competent persons should round up in such cases – when in doubt, in favour of the higher damage class.

Confusing impact protection with the load-bearing upright

A severely deformed but separately installed impact protector is frequently harmless – it has fulfilled its purpose. If, however, the impact protection is bolted or welded directly to the upright, an impact has almost always also affected the load-bearing upright. In practice, only the visibly deformed protector is then replaced, while the damage to the upright hidden behind it remains undetected. The standard practice should be: for every deformed upright protector, measure the upright behind it and, if necessary, dismantle the protector.

Incorrect measuring methods

Popular sources of error are measuring with a ruler that is too short (300 mm or 500 mm instead of the prescribed 1,000 mm), placing it off-centre relative to the damage, “reading by eye” without a feeler gauge, and measuring on the wrong axis (longitudinal instead of transverse). Each of these errors can wrongly shift a genuine Yellow assessment into the Green range.

Ignoring secondary findings

Loose anchors, missing safety locking pins, defective load notices or incipient cracks on the beam connectors appear minor individually, but are safety-critical. In particular, missing beam safety locking pins do not qualify as “damage to a component”, but as a safety-relevant defect that must be remedied without delay – effectively a Yellow or Red assessment depending on the load condition.

Pressure from above: “Just make it grey”

Competent persons carry out inspections free from instructions. § 14 BetrSichV expressly assures them that they are not subject to any technical instructions from the employer during the inspection. Attempts to “argue” a Red assessment into Yellow or even Green are not only impermissible, but constitute shared responsibility on the part of the intervening person in the event of damage.

Measuring and documenting: tools and templates

Valid damage classification starts with the equipment. For regular inspection, the following are recommended:

Mechanical measuring equipment

• Steel measuring rod or steel ruler 1,000 mm, at least accuracy class II, with unprotected edges for flush application.
• Feeler gauge set (0.1–3 mm) for measuring narrow gaps between ruler and component.
• Callipers for material thickness measurements, for example to check corrosion losses.
• Spirit level and plumb line for checking the lean of the entire installation.
• Torque wrench for random checks of anchor bolt torques.

Special rack inspection gauges

Inspection gauges that physically reproduce the DIN tolerances are available from specialist dealers: a 1 m ruler with an integrated stop of 3 mm and 5 mm. If the gauge can be applied flush and the stop still touches the component, you are in the Green range. If a gap remains, the tolerance has been exceeded. These gauges considerably speed up the inspection and reduce measurement errors.

Digital tools

Mobile inspection apps and digital inspection logs integrate photo, damage description, GPS or location tag, damage class and repair order in a single record. Advantages: legally sound documentation, automatic resubmission for repairs with an expiring 4-week deadline, a continuous history per rack bay. Pay attention to compliance with the GDPR (photo recordings) and to audit-proof storage in accordance with GoBD if the inspection log serves as compliance evidence.

Templates for inspection reports

A complete inspection report contains at least: date, time, inspector with proof of qualification (TRBS 1203), location and designation of the racking installation, affected bay/level, damage description with measured values, photo, damage class, measure initiated, repair deadline, signature. Templates from the DGUV and the BGHW are available free of charge and meet the requirements of the BetrSichV.

Frequently asked questions

Is photo documentation without measured values sufficient?

No. Photos prove the existence of damage, but not its classification. DIN EN 15635 requires metric assessment; an inspection report without measured values is incomplete and not evidentially conclusive in the event of a dispute. Photos are a useful supplement, not a substitute.

Who decides between Yellow and Red when the measurement is borderline?

The competent person. If a measured value lies in the transition range (for example 6 mm transverse deformation), the higher damage class must be chosen in case of doubt. The standard expressly requires a conservative assessment. Consultation with the original manufacturer can support the decision.

What happens if the 4-week deadline cannot be met?

If the repair is not carried out within four weeks, the assessment automatically escalates towards Red. The competent person and the employer must then decide whether the affected bay is taken out of service completely. An extension of the deadline “due to component availability” is not provided for – in practice, however, the risk can be mitigated by temporary load reduction and close monitoring if this is documented and approved by the competent person.

Does the traffic-light system also apply to shelving and cantilever racking?

Yes. DIN EN 15635 is applicable to all static steel racking systems. For special designs (cantilever racking, flow racking, automated high-bay installations, mobile racking), supplementary inspection guidance applies in the respective product standards (e.g. EN 15512, EN 15620, EN 15629). The three-level assessment scheme remains the same, however.

What if several instances of Green damage occur on one upright?

The standard has no rigid rule for cumulative Green damage, but the professional assessment should take into account that several non-critical instances of damage consume the structural reserve. Inspectors of high-quality installations frequently choose to upgrade to Yellow where there are three or more instances of Green damage in the same cross-section area (e.g. the lower third of the upright) – not out of excessive caution, but because the safety reserve can no longer be demonstrated.

May weekly visual checks be carried out by non-competent employees?

Yes, with restrictions. According to the view of the DGUV and statements by KomNet NRW, the weekly visual inspection is an internal check that can be carried out by instructed employees, provided they have demonstrably been trained by a competent person. Responsibility for the inspection system remains with the employer or with the competent person who carries out the annual main inspection.

Conclusion

The traffic-light system of DIN EN 15635 is not a bureaucratic construct, but a proven tool with which rack damage can be assessed quickly, uniformly and in a legally sound manner. What is decisive is the separation between three levels: the metric measurement with the 1 m ruler, the classification according to the limit values 3 mm / 5 mm / 10 mm (with doubling as the threshold to Red) and the binding response – observation, repair within four weeks or immediate taking out of service.

Anyone who establishes this discipline in the warehouse not only protects employees from serious accidents, but also reduces business interruptions, insurance risks and liability issues. Investments in simple tools such as a steel ruler, feeler gauge and a digital inspection log pay for themselves through a single correctly identified Red assessment that prevents a rack collapse. When in doubt: better to round up one level, better to spend an hour more measuring, better to repair today than to clear out tomorrow. The standard specifies clear limit values – and that is exactly what makes it the safest ally of every competent person in the warehouse.