C, minimum requirements

Written by Amadeus Lederle | 22.5.2026

Anyone who assembles bolted joints in safety-relevant applications cannot ignore VDI/VDE 2862. The guideline defines which monitoring requirements apply to tightening processes in series assembly - differentiated according to three tightening classes (A, B, C) with fundamentally different requirements for tools, logging, calibration and process capability.

The problem in practice: Many companies know the class designations, but not the specific minimum requirements for each class. Or they systematically classify their screwdriving cases incorrectly - typically downwards, i.e. as class B or C, although safety relevance would require a class A classification. They only notice the result in the IATF audit.

This article explains VDI/VDE 2862 in detail: what the three classes mean, which minimum requirements apply to each class, which tools are suitable for which class - and which audit findings most frequently arise if the guideline is not implemented consistently.

THE MOST IMPORTANT FACTS IN BRIEF

VDI/VDE 2862 classifies bolting cases into three classes: A (safety-relevant, highest requirements), B (function-relevant, medium requirements) and C (not safety- or function-critical, lowest requirements). The classification determines all further requirements.
Class A requires: 100% monitoring of each tightening, machine-supported protocol for each unit, calibration in accordance with VDI/VDE 2645 Part 2, Cpk ≥ 1.67 for torque and angle of rotation, unchangeable result storage.
Class B requires: Process monitoring (not necessarily 100%), logging, calibration according to VDI/VDE 2645, Cpk ≥ 1.33.
Class C: Simplest requirements - but the following also applies here: if the classification is incorrect and a Class C tightening case is safety-relevant, a Major NC is created in the IATF audit.

BRIEFLY SUMMARIZED

VDI/VDE 2862 is not an optional best practice - it is de facto mandatory for IATF 16949-certified companies in the automotive sector, as IATF 8.5.1 requires process monitoring for critical characteristics.
The most common mistake in classification: safety relevance is assessed according to internal judgment instead of OEM CSR and system function. BMW, Volkswagen and Mercedes-Benz explicitly define safety-critical screens in their CSRs - these must be class A.
Tool suitability and classification are directly related: A simple torque wrench with a cracking noise is not suitable for class A. Only a screwdriver with its own measuring and logging system fulfills Class A requirements.

CONTENT OF THIS ARTICLE

What VDI/VDE 2862 regulates - and why it is relevant
Screwdriving classification: How class A/B/C is determined
The three classes in detail
Complete requirements matrix: A/B/C at a glance
Tool suitability per class
Mandatory content of the tightening data protocol for each class
Audit check: What inspectors check for each class
Frequent errors and misclassifications
VDI/VDE 2862-compliant screwdriving data acquisition
Frequently asked questions

What VDI/VDE 2862 regulates - and why it is relevant

VDI/VDE 2862 'Minimum requirements for screwdriving systems' is a guideline from the Association of German Engineers (VDI) that defines the minimum requirements for the monitoring system for screwdriving processes in series assembly. It is considered a technical consensus for the automotive industry and is de facto mandatory for IATF 16949-certified suppliers - not because IATF 16949 refers directly to VDI/VDE 2862, but because IATF 8.5.1 requires the monitoring of important process parameters, and screws in safety-relevant applications are considered as such.

The current edition of VDI/VDE 2862 Part 1 (Sheet 1, 2012) defines the basic principles of screw joint classification. Part 2 (Sheet 2, 2015) specifies the calibration requirements. In addition, VDI/VDE 2645 applies to the calibration of testing and measuring equipment for bolted joints.

3 classes

A (safety), B (function), C (non-critical)

VDI/VDE 2862 Sheet 1

IATF 8.5.1

Standard basis for VDI/VDE 2862 as a de facto obligation

IATF 16949:2016

100 %

Class A: Every tightening must be monitored and recorded

VDI/VDE 2862 minimum requirements

Major NC

Most frequent audit consequence for misclassification class A

CSP audit analyses 2024/25

Bolted joint classification: How class A/B/C is determined

The classification of a bolted joint is the most critical decision in the entire process. All subsequent requirements - tool, monitoring, protocol, calibration, Cpk - are consequences of the class assignment. A downward misclassification is not only an audit risk, but also a liability risk.

The classification criteria according to VDI/VDE 2862

Class A: The bolted joint has a direct impact on the safety of persons (drivers, passengers, other road users) or on the environment. Failure or incorrect tightening has the potential to lead to personal injury. Examples: Brake system, steering, suspension, airbag system, fuel system.
Class B: The screw connection is important for the function of the product, but has no direct safety relevance. Failure leads to functional impairment or loss of comfort, not to personal injury. Examples: Engine assembly (not relevant to the safety system), body attachments, interior structures.
Class C: The screw connection is neither safety-relevant nor functionally relevant in the sense that its failure would render the product unusable. Examples: Trim clips, interior covers, aesthetic add-on parts.

WHEN MUST THE OEM OR CUSTOMER BE CONSULTED?

If it is unclear whether a screw connection is safety-relevant: check the OEM design documentation and Customer Specific Requirements (CSR). BMW, VW and Mercedes-Benz explicitly list safety-critical joints.

System consideration: A bolted joint may appear to be 'non-critical' internally, but may be safety-relevant in the system context. Example: Fastening screw for a sensor that controls a safety system.

In case of doubt: if in doubt, classify higher. An incorrectly low classification (e.g. class B instead of A) generates a major NC in the audit and, in the event of damage, a liability situation that is massively worsened by the misclassification.

Changes in the product development process: If a component is subsequently given a safety-relevant function, the fastener classification must be checked and adjusted if necessary.

The three fastener classes in detail

VDI/VDE 2862	Class A	Class B	Class C
Classification	Highest safety relevance	Functionally critical, not safety-relevant	Neither safety-critical nor function-critical
Bolting class	Safety-relevant connection	Functionally relevant connection	Non-critical connection
Typical applications	Brake, steering, wheel suspension, airbag, fuel line, seat belt fastening, electric drive systems	Engine block fastening without safety system, transmission housing, body structures, chassis components without safety function	Trim clips, trim strips, aesthetic covers, wiring harness attachments without safety function
Minimum monitoring	100% - every suit must be monitored. No statistical sampling acceptable.	Process monitoring - statistical or 100%. At least random testing with defined scope and reaction plan.	No minimum monitoring required according to VDI/VDE 2862. General quality assurance according to QM system.
Protocol obligation	Machine-supported log per unit and screw position. Stored unalterably, with time stamp and tool ID.	Logging recommended. Manual recording acceptable for simple tools if a valid system is available.	No logging obligation according to VDI/VDE 2862. Good practice: Random sampling log.
Calibration	VDI/VDE 2645 Sheet 2 - controlled tools with their own measuring system. Calibration interval according to risk analysis.	Calibration in accordance with VDI/VDE 2645 Sheet 1. Regular calibration of the tool required.	Not mandatory according to VDI/VDE 2862. Regular tool testing according to internal plan recommended.
Cpk requirement	Cpk ≥ 1.67 for torque and angle of rotation. Both to be verified separately.	Cpk ≥ 1.33 for torque. Rotation angle monitoring recommended, mandatory for controlled tools.	No Cpk obligation according to VDI/VDE 2862. Internal targets useful.
NC risk in case of violation	Major NC IATF 8.5.1 - in practice often associated with OEM escalation.	Minor NC in the absence of logging, major NC if safety relevance is proven.	Audit risk low - but misclassification, e.g. C instead of A, is a major NC.

Complete requirements matrix: A/B/C at a glance

The following matrix summarizes all relevant requirement fields for the three classes - as a compact reference for operational practice.

Requirement	Class A	Class B	Class C	Standard reference
Torque monitoring	100 % - each tightening	Random sample or 100 %	Not mandatory	VDI/VDE 2862 Sheet 1, Section 4
Monitoring angle of rotation	Mandatory (100 %)	Recommended for controlled heat exchanger	Not required	VDI/VDE 2862 Sheet 1
Storage of results	Mandatory - unchangeable	Mandatory - protocol	Not required	VDI/VDE 2862 Sheet 1, Section 5
Storage per unit (SN)	Mandatory	Recommended	Not required	VDI/VDE 2862 / IATF 8.5.2
Tool calibration	VDI/VDE 2645 Sheet 2	VDI/VDE 2645 Sheet 1	Internal testing	VDI/VDE 2645
Minimum Cpk torque	≥ 1,67	≥ 1,33	Not mandatory	VDI/VDE 2862 / IATF
Minimum Cpk angle of rotation	≥ 1,67	Recommended ≥ 1.33	Not mandatory	VDI/VDE 2862
Response plan for NOK	Mandatory - defined and documented	Mandatory	Recommended	IATF 8.5.1
Screwdriving case documentation	Mandatory - incl. classification justification	Mandatory	Recommended	VDI/VDE 2862 Section 3
Tool traceability	Mandatory - ID in the protocol	Mandatory	Not required	VDI/VDE 2862 / IATF 7.1.5
Statistical process verification	Mandatory - Cpk report per characteristic	Recommended	Not mandatory	IATF 16949 section 9.1

Tool suitability per screwdriving class

Not every fastening tool is suitable for every class. Suitability depends on whether the tool can measure and record torque and angle of rotation and store the result in an unalterable form.

Tool type	Class A	Class B	Class C	Note
Torque wrench (controlled, integrated transducer)	✓	✓	✓	Standard for class A/B. Own measuring system, direct protocol.
Pneumatic screwdriver with torque measurement (external)	(✓)	✓	✓	For class A: only if external measurement 100% per tightening, not statistical.
Electric screwdriver with own logging system	✓	✓	✓	Best solution: integrated measuring and logging system per tightening.
Click torque wrench (manual)	✗	(✓)	✓	Unsuitable for cl. A: no automatic protocol. Cl. B: only with manual documentation and valid random sample.
Impact wrench (without measuring system)	✗	✗	(✓)	Unsuitable for cl. A+B: no torque value measurable. Cl. C: only if random sample tested afterwards.
Cordless screwdriver without measuring system	✗	✗	✓	No torque verification possible. Only acceptable for non-critical class C connections.
Robotic screwdriver with integrated measuring system	✓	✓	✓	Optimal solution for all classes: fully automatic protocol per screw position and SN.
*✓ suitable (G90) - (✓) conditionally suitable with conditions (G50) - ✗ not suitable (G20)*

Mandatory content of the fastening data protocol per class

A screwdriving data log is only suitable for auditing if it contains all relevant mandatory fields for each class. The following matrix shows what is mandatory, what is recommended and what is optional.

Protocol field	Class A	Class B	Class C	Content / Format / Example
Serial number / unit identity	Mandatory	Mandatory	Recommended	Unique SN of the workpiece - link suit ↔ unit
Screw position / joint number	Mandatory	Mandatory	Recommended	Clear identification of which screw position was approached
Actual torque (Nm)	Mandatory	Mandatory	-	Measured actual torque value per tightening in Nm
Target torque + tolerance	Mandatory	Mandatory	-	Reference value from work instruction - Comparison target/actual
Actual rotation angle (degrees)	Mandatory	Recommended	-	Measured angle of rotation - especially for angle-controlled connections
IO/NIO result	Mandatory	Mandatory	-	Clear release/blocking decision per suit
Tool ID	Mandatory	Mandatory	Recommended	Identification of the screwdriver - prerequisite for calibration verification
Calibration status of tool	Mandatory	Recommended	-	Proof that the tool was calibrated at the time of tightening
Time stamp (ISO 8601)	Mandatory	Mandatory	Recommended	Machine-set unchangeable time stamp per suit
Worker ID / machine program	Mandatory	Recommended	-	Identification of the person or the automation program
Post-suit identification	Mandatory	Mandatory	-	Was this a first suit or rework? Different assessment!
Parameter set / work instruction	Mandatory	Mandatory	-	Reference to the released parameter set - Version and date

VDI/VDE 2862 is not bureaucracy. It is the answer to the question that a public prosecutor asks when three people die after a steering failure: 'Did you prove that the steering bolts were tightened correctly? Without VDI/VDE 2862-compliant documentation, this question cannot be answered.
- Amadeus Lederle CTE, CSP Intelligence GmbH

Audit check: What inspectors check per class

Class A - safety-relevant bolting cases

Range	Test points
Mandatory test points	☑ Classification documentation with justification of safety relevance ☑ 100% monitoring: each individual suit in the protocol log ☑ Complete log fields: SN, screw position, actual torque, IO/NIO, tool ID, time stamp ☑ Tool calibration certificate in accordance with VDI/VDE 2645 Sheet 2 ☑ Cpk torque ≥ 1.67 from current production data ☑ Cpk angle of rotation ≥ 1.67, if controlled by angle of rotation ☑ Reaction plan for NOK suits
Target test points	SPC control chart for class A screw position parameters MSA / Gage R&R for the screwdriver's measuring system ☐ Proof of unalterable logging ☐ Worker training certificate for class A screwdriving position handling
Frequent audit findings	→ 100% monitoring only implemented on a random basis → Protocol without tool ID → Cpk torque present, Cpk rotation angle missing → Reaction plan exists, but is not documented or implemented

Class B - function-critical screwdriving cases

Range	Test points
Mandatory test points	☑ Classification documentation with justification: why class B and not A? ☑ Torque values documented, sample size defined ☑ IO/NIO decision for each recorded suit ☑ Calibration certificate for tool in accordance with VDI/VDE 2645 Sheet 1 ☑ Cpk torque ≥ 1.33
Target test points	☐ 100% monitoring instead of random sampling ☐ Rotation angle monitoring for process validation ☐ Tool ID in the log for complete calibration chain
Frequent audit findings	→ Class B, although failure severely impairs product function → Sample size not justified or too small → Cpk from too few measured values, e.g. < 25 subgroups

Class C - uncritical tightening cases

Range	Test points
Mandatory test points	☑ Classification documentation: why neither safety-critical nor function-critical? ☑ No direct protocol obligation, but classification justification must be comprehensible
Target test points	☐ Sampling protocol of the suits ☐ Tool inspection documented according to internal plan
Frequent audit findings	→ Class C, although safety-relevant in system analysis → No classification documentation available

Frequent errors and misclassifications

In auditing practice, the same errors emerge time and again. They usually do not arise intentionally, but through ignorance of the classification criteria or through historically grown practices.

Error	Why it occurs	Audit consequence	Correct procedure
Class B instead of A for chassis screws	Internal assessment: 'Drives even without this screw'	Major NC - direct safety relevance chassis not recognized	Check OEM-CSR. System consideration: Failure = vehicle control impaired = class A
Click screwdriver for class A screwdriving cases	Existing tools continue to be used without suitability check	Major NC IATF 8.5.1 - no automatic protocol possible	Class A requires a controlled tool with its own measuring system and protocol
Cpk only for torque, not angle of rotation	Rotation angle monitoring misunderstood as optional	Minor/Major NC - both parameters mandatory for class A	Class A: Prove Cpk ≥ 1.67 for torque AND rotation angle separately in each case
Protocol without tool ID	Protocol contains tightening data, but not which screwdriver was used	Finding - calibration adjustment not possible, IATF 7.1.5.1	Tool ID as a mandatory field in the log; automatic with controlled screwdriver
No classification documentation	Class assignment known verbally, not specified in writing	Finding - inspector cannot verify assignment	Screwdriving case register: each screwdriving position with class, reason, date, person responsible
NOK response plan exists, but is not implemented	Response plan exists on paper, but workers do not know what to do	Finding IATF 8.5.1 - Process not mastered	Integrate response plan into work instructions, train workers, provide evidence

VDI/VDE 2862-compliant screwdriving data acquisition and logging

PRACTICAL TIP

CSP IPM automatically records all mandatory fields of the VDI/VDE 2862-compliant screwdriving data protocol - for class A, B and C. Screwdrivers are connected via OPC UA, REST or direct IO. The log contains SN, screw position, actual torque, rotation angle, IO/NIO, tool ID and timestamp - stored unchangeably, linked per serial number.

Class A-compliant: 100% protocol per tightening, automatic, no manual intervention possible
Protocol fields: all VDI/VDE 2862 mandatory fields automatically filled - no mandatory field can be forgotten
Calibration status: tool ID linked to calibration database - expired calibration = warning before tightening
SN link: Tightening data can be retrieved per serial number - complete traceability chain
Cpk automatic: Cpk torque and rotation angle from production data - per tightening position and time period
Reaction plan digital: in case of NOK tightening, automatic locking workflow + worker note + CAPA trigger

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Frequently asked questions

Is VDI/VDE 2862 required by law?

VDI/VDE 2862 is not legislation - it is a technical guideline (VDI recommendation). However, it is de facto mandatory for IATF 16949-certified companies because IATF 8.5.1 prescribes the monitoring of critical process characteristics and VDI/VDE 2862 is a recognized technical rule. OEM-CSRs (BMW, VW, Mercedes) can specify VDI/VDE 2862 directly as a requirement - it is then contractually binding. In the event of a claim, the following also applies: anyone who has not applied VDI/VDE 2862 must prove under civil law that their own method was equivalent or better.

How does VDI/VDE 2862 differ from IATF 16949 section 8.5.1?

IATF 16949 section 8.5.1 is the general standard requirement: 'Manufacturing and service processes shall be carried out under controlled conditions, including the monitoring of characteristic process features'. VDI/VDE 2862 is the technical specification of this requirement for bolting processes: It defines what 'controlled conditions' for bolted joints actually mean - which class, which monitoring, which protocol. IATF 8.5.1 is the 'what', VDI/VDE 2862 is the 'how'.

Can I downgrade a Class A bolted joint to Class B at a later date?

Technically yes - but only through a formal change process with complete documentation: justification of the reassessment, system analysis (proof that there is no safety relevance), approval by a qualified person responsible and, if necessary, customer approval. If the OEM has specified the original Class A classification or requires it in its CSRs, downgrading is not possible without OEM approval. The change history must be fully traceable in the audit.

What is the difference between torque-controlled and angle-controlled tightening?

With torque-controlled tightening (torque method), the tightening process is ended when a defined target torque is reached. The torque is the control variable. In the case of angle-controlled tightening (angle-controlled tightening method), a pre-tightening torque is set first and then a defined angle of rotation is continued. This angle is the control variable. Angle-controlled tightening generally generates more uniform preload forces because it is less dependent on the effects of friction. VDI/VDE 2862 requires the monitoring of both parameters for class A.

How often do screwdrivers have to be calibrated for class A screwdriving applications?

VDI/VDE 2645 Sheet 2 does not specify a fixed calibration interval. The interval must be determined and documented on a risk basis. Factors: Frequency of use, environmental conditions, significance of the screwdriving case, results of the last calibration. Intervals commonly used in automotive practice: daily self-test (reference suit on test equipment), weekly or monthly calibration by laboratory, annual calibration by accredited laboratory. The decisive factor is that the calibration status must be documented in the log and be verifiable for each suit.

What is an NIO response plan and what must it contain?

An NOK response plan (also: response plan for faulty suits) describes what happens to a unit if a suit is assessed as NOK (not OK). Mandatory content: Identification and blocking of the affected unit (so that it cannot be delivered), who makes the rework decision (quality manager), what rework is permitted and how the rework process is documented, and under what conditions a unit is released or scrapped. The response plan must be known (worker training) and practiced - a written plan that the workers do not know is not a functioning response plan.

Does VDI/VDE 2862 also apply to manual tightening work without a tool logging system?

For class C screwdriving cases: yes, manual tools without automatic logging are permissible. For class B screwdriving cases: conditionally - manual logging is possible, but it must be valid and consistent. For class A screwdriving cases: no - manual tools without an automatic measuring system are not suitable for class A. The class A requirement (100% monitoring + machine-supported log) cannot be fulfilled with hand tools without a measuring system. In these cases, either the tool must be replaced by a controlled system or the process must be redesigned in such a way that no Class A tightening operation is performed manually.

Do all tightening cases of a product have to be classified - even class C?

Yes - all tightening operations carried out in an IATF-certified production environment should be classified and documented. Not because VDI/VDE 2862 explicitly requires this for class C, but because the auditor asks the question: "Why is this screw class C?" and requires a documented justification. A bolt register with all bolt position designations, classes and reasons is the best preparation for this audit point. It also prevents subsequent misclassifications if product functions change due to design modifications.

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