Why Not Every Deviation Constitutes a Violation

During the inspection of cargo, equipment, or industrial products, actual values do not always match the nominal values stated in the documentation. Dimensions may differ slightly from design specifications, weight may differ from the calculated figure, and certain characteristics may deviate from the product’s typical parameters. Such a difference alone does not mean that the product fails to meet requirements.

The key question is which criteria apply to the item being inspected. If the contract, drawing, or applicable standard specifies an acceptable range, a result within the established limits may be considered compliant. If a value falls outside the applicable tolerance, this provides grounds for further assessment and recording a nonconformity.

It is important to distinguish three concepts: a deviation, meaning the difference between the actual and specified values; a nonconformity, meaning failure to meet a specific requirement; and a violation, a broader assessment that may concern contractual or regulatory obligations. These concepts are related, but they are not interchangeable.

For a surveyor, this distinction has practical significance. An inspection is not only about identifying differences, but also about determining how significant they are in relation to the established criteria. Conclusions must be based on measurement results, applicable requirements, and the conditions under which the inspection was performed, rather than on a subjective impression of the item’s condition.

What Is a Tolerance and How Is It Applied

A tolerance establishes the permissible limits of deviation from a specified value or defines the range within which a parameter must fall. It may apply to dimensions, weight, geometry, physical material properties, and other characteristics. The specific form of tolerance depends on the parameter being checked and the product requirements.

For example, if a drawing specifies a dimension of 100 mm with a tolerance of ±1 mm, the acceptable range is 99 to 101 mm inclusive, unless the documentation provides another method for assessing boundary values. A measurement of 100.6 mm falls within this range, whereas 101.4 mm is outside it. However, the final assessment also depends on the measurement method used and the rules for determining conformity.

When preparing for an inspection, it is important to understand exactly which parameter is being checked and where its limit values come from. A nominal value does not always mean that only one result is acceptable, and reference product characteristics are not necessarily mandatory acceptance criteria.

In practice, several key distinctions should be taken into account:

• Nominal value — the specified or calculated parameter against which the result is assessed.
• Permissible deviation — the established limit for the difference between the actual and nominal values.
• Limit values — the minimum and maximum boundaries that the parameter must meet.
• Actual value — the measurement or inspection result obtained during the inspection.
• Acceptance criterion — the rule used to determine whether the item meets the stated requirements.

These concepts must not be applied arbitrarily. A tolerance for one product should not automatically be applied to a similar model, and a range established for production control may not be suitable for acceptance of a delivery. If permissible limits have not been defined, the inspector must determine which documents and requirements apply to the specific item.

Where Do Requirements for Permissible Deviations Come From?

The basis for assessing conformity depends on the type of product, the contract terms, and applicable regulatory requirements. For industrial equipment, criteria may be specified in a technical specification, drawings, standards, the manufacturer’s documentation, or an agreed acceptance procedure. Cargo inspections may also take into account requirements for quantity, weight, packaging condition, and other delivery characteristics.

The contract and documents defining the item’s technical parameters should be checked first. If the contract explicitly establishes acceptable values or refers to a specific standard, the assessment must take these conditions into account. It is also important to verify that the cited edition of the document applies to the product being inspected and to the relevant stage of control.

If documents contradict one another, the most convenient criterion must not be selected without justification. For example, a specification may state one value while the drawing states another. In such cases, it is necessary to establish how the documents relate to one another, their status, and the procedure for resolving conflicts provided for in the contract or applicable requirements.

Before the inspection, it is advisable to establish several basic conditions. This helps avoid a situation in which a measurement is performed correctly but the result is compared against an unsuitable standard.

In particular, establish:

• which document specifies the parameter being checked;
• which value or range is considered acceptable;
• which measurement method is prescribed;
• which inspection conditions may affect the result;
• which acceptance rules apply to borderline or disputed values.

If the documentation does not contain an unambiguous criterion, this limitation should be stated before the final conclusion is prepared. The inspector can record the actual result and describe the deviation found, but classifying it as a breach of a specific requirement requires an established basis. The absence of a criterion cannot be remedied by arbitrarily selecting a tolerance.

How to Measure and Assess Deviations Correctly

Even when the acceptance criterion is clearly defined, the inspection result depends on the measurement method. Different instruments, methods, and inspection conditions can produce slightly different values. Therefore, comparing an actual value with a tolerance requires consideration not only of the figure obtained, but also of how it was determined.

For example, when checking equipment geometry, it is important to consider the item’s position, measurement points, temperature, and surface condition if these factors affect the result. When weighing, the characteristics of the weighing equipment, installation conditions, and compliance with the established procedure matter. If the method does not meet requirements or the instrument cannot provide the necessary accuracy, the data obtained may be insufficient to support a reliable conclusion.

Measurement uncertainty is also important. It describes the range of values that can reasonably be attributed to the measured quantity. If a result is close to a tolerance limit, uncertainty may affect the conformity decision. The decision rule should preferably be established in advance, especially if the inspection result will be used for acceptance or to support a claim.

Before assessing the results, the inspector should check several points:

• whether the measuring instrument has the required range and resolution;
• whether the measurement conditions prescribed by the method were observed;
• whether the measurement points and inspection method were selected correctly;
• whether calibration, verification, or other applicable requirements for measuring equipment have been taken into account;
• whether repeat measurements and special rules for assessing borderline results are provided for.

A repeat inspection may be useful if the result is in doubt, but it must not become selective remeasurement until a desired value is obtained. The original results must be retained, and the reasons for repeating the inspection documented. This approach helps distinguish an actual deviation from possible problems with the measurement procedure.

Typical Deviations Found During Cargo and Equipment Inspections

The nature of a deviation depends on the item and the purpose of the inspection. Industrial equipment inspections commonly assess dimensions, surface condition, the position of components, and technical parameters. Cargo inspections may check weight, quantity, markings, packaging condition, and other characteristics specified in the inspection assignment.

Not all differences found can be assessed in the same way. A dimension can be compared with a drawing, weight with an established range or agreed weighing method, while surface damage may require a separate assessment criterion. If a requirement is qualitative—for example, if it prohibits a certain type of damage—it is necessary to clarify which characteristics are considered unacceptable.

Consider the following illustrative examples. They show why identifying a deviation and concluding that there is a nonconformity are separate stages of analysis.

• Part dimensions. If the tolerance specified in the drawing is ±0.5 mm, a result outside this range indicates a deviation from the specified dimension. The measurement method and applicable rule for assessing the result must also be taken into account.
• Cargo weight. A difference between the actual weight and the weight stated in the documents requires checking how the weight was determined, the weighing conditions, and the applicable acceptable range. The discrepancy alone does not prove a shortage.
• Surface condition. A scratch or dent may be a cosmetic defect or may affect the product’s functionality. The assessment depends on the technical requirements, the location of the damage, and its characteristics.
• Equipment completeness. The absence of a component specified in the specification may indicate that the delivery is incomplete. Before reaching a final conclusion, it is necessary to check whether the component is in another package or is being supplied separately.
• Position of mounting components. A deviation from the drawing may make assembly difficult or exceed the established limits. Assessment requires determining the permissible values and checking the actual dimensions using the prescribed method.

These examples show that there is no universal approach to assessing all deviations. Some parameters can be compared quantitatively, while others require inspection against established criteria. In each case, the report should state what was checked, which requirement was applied, and what results were obtained.

When Does a Deviation Become a Confirmed Nonconformity?

Recording a difference between the nominal and actual values is not enough to confirm a nonconformity. The applicable requirement must be identified, and it must be demonstrated that the inspection result does not meet it. The inspection method, measurement conditions, and limitations that could affect the conclusion must also be clear.

If the actual value falls outside the established tolerance, this usually provides grounds for recording a nonconformity, provided that the measurement was performed correctly and the appropriate decision rule was applied. However, further classification depends on the context. A technical nonconformity does not always constitute a major defect, grounds for rejecting the delivery, or a proven breach of contractual obligations.

When assessing the result, it is important to answer three questions in sequence. Which specific requirement applies to the item? How was the actual result obtained? Do the available data confirm that the permissible limits have been exceeded under the established decision rules?

If there is no reliable answer to any of these questions, the conclusion should be worded cautiously. For example, the inspector may state that the measured value differs from the nominal value, but that a final conformity assessment is not possible because no agreed tolerance has been specified. This is more accurate than declaring the product defective without sufficient grounds.

It is also necessary to distinguish the technical result from its legal consequences. An inspection may confirm that a parameter exceeds an established requirement, but whether this constitutes a breach of contract, grounds for rejecting the delivery, or a basis for holding a particular party liable must be determined in light of the contract terms and other circumstances.

Borderline Values and Disputed Measurement Results

The greatest difficulties in assessing conformity arise when a measured value is close to a tolerance limit. In such cases, even a small difference caused by instrument resolution, inspection conditions, or rounding can affect the final decision. Borderline results therefore require careful analysis rather than automatic classification of the product as compliant or noncompliant.

Consider an illustrative example. The acceptable dimension of a part is 49.5 to 50.5 mm, and the instrument shows 50.5 mm. If the measurement method and acceptance rule include the boundary value, the result falls within the range. However, where measurement uncertainty or special decision rules apply, the displayed figure alone may not be enough to reach an unambiguous conclusion.

Rounding must also be taken into account. If the actual result is rounded to fewer decimal places, the displayed value may conceal a difference between the original result and the limit value. The original data should therefore be retained at the precision required by the method, and rounding should be performed according to the established procedure.

When results are disputed, it is advisable to check the measurement conditions, the instrument’s condition and characteristics, the selection of inspection points, and the decision rule being applied. If the procedure allows, measurements may be repeated or a competent laboratory engaged. Original results must not be excluded from the report simply because a repeat check produced a different value.

How to Document Deviations in an Inspection Report

An inspection report should enable another specialist to understand what was checked and the basis for the conclusion. It is not enough to state that a parameter “does not comply with the standard.” The applicable requirement must be identified, the inspection result presented, and any circumstances relevant to its interpretation described.

The report should distinguish observed facts from technical assessments and assumptions about the causes of a deviation. For example, a measured dimension can be recorded directly, whereas a conclusion about how the deviation affects equipment operation may require additional calculations or an opinion from a specialist in the relevant field.

To ensure traceability, it is recommended that the report include the key details of the inspection. The information required depends on the item, method, and purpose of the inspection, but generally includes:

• identification of the item, inspected component, or batch;
• the requirement, drawing, specification, or other document against which the result was compared;
• actual values, units of measurement, and established tolerance limits;
• the method used, measuring equipment, and material inspection conditions;
• photographs, measurement tables, and other materials supporting the result;
• inspection limitations, disputed circumstances, and the need for further checks.

If a nonconformity is confirmed, the report should clearly state which parameter exceeded the permissible limits and by how much. If the available data are insufficient, it should specify what could not be established. This approach helps avoid categorical conclusions that are not supported by the inspection results.

It is important to remember that the report records the results of the inspection within the scope of the assignment performed. It may be used when considering a claim, but does not in itself always establish the cause of a defect, the responsible party, or the legal consequences of the deviation found.

Common Mistakes When Assessing Tolerances

Errors in conformity assessment often occur before the measurement itself, at the stage of selecting the criterion. If the inspector uses an unsuitable standard, relies on reference data instead of contractual requirements, or sets permissible limits independently, even a technically accurate measurement may lead to an incorrect conclusion.

Errors in processing results are equally significant. Incorrect rounding, disregarding uncertainty, and a lack of original data make conclusions harder to verify. In a dispute, this may reduce the evidentiary value of the report and make it more difficult for the parties to agree on further action.

The most common mistakes include:

• applying a tolerance that does not relate to the model or parameter being inspected;
• comparing results obtained using different methods or under incomparable conditions;
• treating any difference from the nominal value as a defect without checking the acceptable range;
• ignoring measurement uncertainty near a tolerance limit;
• selectively using repeat measurements without retaining the original results;
• concluding that a contract has been breached solely on the basis of a technical deviation;
• failing to cite the specific requirement and describe the inspection method in the report.

These errors can be avoided by systematically checking the basis, method, and result. If the criterion is unclear, it should be clarified before the final assessment. If the result is disputed, the original data should be retained and limitations stated. If a technical nonconformity is confirmed, its implications for acceptance and performance of contractual obligations must be assessed separately.

What to Do When a Nonconformity Is Identified

After a deviation is detected, it is important not to rush to a final conclusion, but to verify the reliability of the result and record the inspection circumstances. If a measurement is in doubt, consider whether a repeat check is needed, inspect the equipment, and make sure the criterion used applies to the specific item. The original results and inspection conditions must be retained.

Further action depends on the nature of the nonconformity, the contract terms, and the acceptance procedure. If the deviation is confirmed, the interested parties should be notified promptly in accordance with the prescribed procedure. If necessary, an additional inspection, technical assessment, or joint measurement can be arranged.

A practical sequence of actions may include the following steps:

• Record the actual value, the location and conditions of measurement, and the identity of the item inspected.
• Compare the result with the applicable requirement and verify that the inspection method was appropriate.
• Retain the original data, photographs, measurement records, and other supporting materials.
• Notify the interested parties in accordance with the contract and applicable procedure.
• Agree on further action: additional inspection, sorting, repair, replacement, acceptance subject to reservations, or another agreed method of resolution.

Not every deviation requires rejection of the entire batch or equipment. The possibility of further use, the need for correction, and whether acceptance with comments is permissible depend on the nature of the nonconformity and the applicable requirements. Such decisions should not be made solely on the basis of a visual impression or a single measurement when further technical assessment is needed.

The Surveyor’s Role in Assessing Deviations

An independent surveyor helps objectively record the actual condition of cargo or equipment and compare inspection results with the criteria provided. Depending on the assignment, we may conduct visual inspections, perform or witness measurements, check markings and documentation, record damage, and analyse identified deviations.

The measurement procedure itself is not the only important factor; selecting the correct criterion is equally important. If requirements contradict one another or do not specify an unambiguous tolerance, this must be noted. A surveyor can describe the actual result and indicate that the requirements need clarification, but should not arbitrarily establish contractual rules that are absent.

A high-quality inspection report makes it possible to trace the relationship between the requirement, the inspection method, and the result obtained. It should include identified nonconformities, supporting materials, and limitations that may have affected the conclusions. If the cause of a deviation has not been established, it must not be replaced with an assumption.

The limits of independent inspection should be borne in mind. A technical opinion may confirm that a parameter exceeds the established tolerance, but it does not always determine the cause of the defect, the responsible party, or the amount of loss. These issues require separate analysis taking into account the contract, delivery circumstances, and other evidence.

During inspections, we compare the actual characteristics of cargo or equipment with the available technical requirements and delivery documents. Depending on the assignment, we record dimensions, quantity, condition, and other parameters, check markings, and document identified deviations. If you need an assessment of inspection results, please contact us — the specialists at LVS Global will be happy to help.