Safety managers and equipment staff who operate breathalyzers request calibration when they suspect an accuracy problem or when an outside body asks for a certificate. What you put in the request depends on whether you simply need a result on "whether the device can be used now," or data that compares the test results from when the device arrived with those after the work was finished.
Calibration is the work of confirming the relationship between the value a measuring device displays and a reference value. Adjustment is the work of changing values to bring the device's measuring performance into line, and repair is the work of restoring parts or functions in response to a fault or damage. If you need results both before and after calibration, rather than just writing "before-and-after results needed" on the request form, you should specify before submission which point in time's values you need and for what purpose.
Results from before the work cannot be recreated later
The as-received result is the result confirmed in the condition the device was in when it arrived at the calibration body. If adjustment or repair follows, the device's condition may change, so the post-work result alone cannot tell you the pre-work condition as it was. Even if you newly request measurements of the past condition after the work is done, there are limits to what can be provided if those measurements were not performed and recorded at the time.
This difference matters less for whether the result is good or bad and more for the purpose of the comparison. For example, if you need to review whether values changed compared with a previous certificate, you may need the pre-work result. Conversely, if the purpose is routine equipment management, the post-work calibration result and certificate may take priority. Deciding first what judgment you need reduces the chance of asking for unnecessary documents or missing the result from the point in time you actually need.
Calibration and adjustment are not the same thing. ILAC-G24:2022/OIML D 10:2022 distinguishes the two activities and explains that recalibration is generally needed after adjustment. So if adjustment or repair may be needed during the request process, it is best to decide at the same time which stage's results will be recorded and how to proceed if follow-up work arises.
State both the purpose and the point in time in the request
The wording of a request is the starting point for the calibration body to understand the scope of the work. Rather than naming only the deliverable, as in "request for before-and-after certificates," write separately why you need the as-received condition confirmed and why you need confirmation after the work. The scope of measurements and documents the body can actually provide should also be confirmed at this stage.
For example, you could write: "We need the as-received results to compare with the device's previous calibration data. If adjustment or repair is carried out, please let us know to what extent we can receive the work performed and the post-work results separately. We would also like to agree in advance on the name and contents of the document for external submission." This wording does not set a particular result in advance. It is a request to confirm the facts and document scope needed.
| Item to decide before submission | What to write on the request form | What to check on receipt |
|---|---|---|
| Purpose of the pre-work result | Why it is needed, such as comparison with earlier data or reviewing when a problem began | Whether the as-received result is shown separately in the document |
| Possibility of changes during work | How approval is obtained if adjustment or repair is needed | Whether the work actually performed is distinguished alongside the results |
| Use of the post-work result | Decision on continued use, internal management, external submission, etc. | Whether the document name and contents match what was requested |
| Existing data for comparison | Previous certificate, device identification, date the problem was noticed | Whether the data is for the same device under the same conditions |
The items in the table are not a mandatory form but a checklist to keep the request from missing anything. In particular, if the purpose is external submission, what documents the receiving body requires and the scope of documents the calibration body can issue are separate matters. If you lump the recipient's required format and the actual measurement and calibration scope into one sentence, you may have to rework the documents after receiving the results.
If adjustment or repair is involved, do not compare results on one line
If adjustment or repair took place between the two results, it is hard to place the numbers side by side and conclude that things "improved." You need to look at when the device's condition changed and what work was done. Separating the pre-work result, the work performed, and the post-work result in time order lets another person reviewing the data later understand the premises of the comparison.
As a hypothetical case, suppose a workplace's breathalyzer showed a measurement trend different from its previous certificate, so the device was sent in. The person in charge requested both the as-received and post-work results, and wrote that whether repair is needed would be decided after being contacted first. In this case, the thing observed is "a trend different from earlier data," and that alone does not confirm a sensor fault or any particular cause.
A possible action is to receive the as-received check results, whether adjustment or repair was actually done, and the post-work results separately. The completion criterion is not concluding a cause, but a state in which each requested stage can be identified in the documents and the internal records link what work took place between the results. If the as-received result was not provided, do not fill the gap with an estimated value. Record the fact that the data is not available separately from the results obtained afterward.
Send existing certificates and device information together
To compare pre- and post-work results, you must first make clear that the comparison involves the same device. When submitting the request, gathering the device's model name and identification, the previous certificate, and when and in what situation the problem was noticed makes it easier to explain the purpose of the request. The product specifications in a general user manual do not replace the results an individual device showed when it was received.
DATECH's official Downloads center posts product manuals and information on applying for KOLAS calibration. It is best to check the materials for the model you currently use and compare whether the device information in existing documents matches the device being sent. However, having a manual or past certificates does not automatically confirm the actual measurement results for the device's condition on arrival this time.
In internal management documents, rather than repeating only headings like "before calibration" and "after calibration," record the stages and document numbers shown on the original documents and link them. For example, if you keep the as-received check data, any information on adjustment or repair, and the post-work calibration results separately, you are less likely to treat values from different conditions as the same result.
After receiving results, check that the requested separation was kept
When you receive the results, first check whether the documents distinguish the device identification and the measurement stages. Then check whether any change, such as adjustment or repair, took place between the pre-work and post-work data. If only part of the requested before-and-after results was provided, it is important to record the scope that can be confirmed from the data provided, and not to interpret a past condition that has no data as if it were a result.
When another department asks for data on the past condition, there is no need to decide on a conclusion first and pass that on. Just explain what you want to compare or review, and which data you need: the as-received condition or the post-work condition. The key to a request that needs both before-and-after calibration results is not receiving two documents, but clearly recording what point in the device's condition each result shows.
