At workplaces that run several breathalyzers, devices calibrated on the same day can still need different management priorities. A device used every day at the entrance and one taken out only for events or business trips are used at very different rates over time. If you record only the last calibration date, it is hard to spot heavily used devices. If you look only at the cumulative test count, you can miss how much time has passed for a device that has been in long-term storage.
An equipment log is a management document that links a single device's identification, calibration certificates, the cumulative test count shown on the unit, and repair history. Here, calibration means a procedure that checks, under defined conditions, the relationship between a reference value and the device's indication. It is distinct from adjustment, which changes the device so that it reads the specified value, and from repair, which fixes a fault or abnormality. Recording calibration dates and counts together gives you a basis for deciding what to review again on each device, and when.
What dates and counts each add
The last calibration date shows how much time has passed since calibration, but not how much the device was used in that time. If two devices were calibrated in the same month and only one was used every day for access control, it is hard to treat them as being in the same state based on date alone. Conversely, even if a device has a low usage count, if a long time has passed since calibration, you also need to look at the date standard.
When reviewing the recalibration interval, you can consider the manufacturer's recommendation, the degree of use, and the operating environment. However, this does not mean the same time or count standard applies to every breathalyzer. First check whether the user manual or manufacturer guidance for that model actually gives a time condition and a count condition. If both are given, you can mark whichever condition is reached first as the next calibration review point.
If you have not confirmed a condition in the documents, you must not write an arbitrary time or count in the log as if it were a fixed standard. In that case, record the document you consulted and the date you checked it, and list the manufacturer's guidance as an item to confirm further. The role of the log is not to apply one number to every device but to preserve the basis for decisions on each device.
Link the device and its certificate as a single record
The model name alone makes it hard to tell several units of the same product apart. Record both the asset number and the serial number on the unit, and make sure you can check that the device identification on the certificate matches the information in the log. This reduces the chance of mixing up another device's certificate or repair history.
| What to record | How to record it | Why it is needed |
|---|---|---|
| Device identification | Record the asset number and serial number together | Keeps histories of units of the same model from getting mixed |
| Last calibration information | Record the calibration date and certificate number shown on the certificate | Avoids confusing the receipt or shipping date with the calibration date |
| Cumulative count information | Record the number on screen together with the date it was read | Avoids mistaking a past number for current usage |
| Next review criterion | Record the reference document, date checked, and review condition | Lets you find the basis for the criterion even if the person in charge changes |
The calibration date on the certificate may differ from the date you received the device, so use the date stated on the certificate in the calibration date column. It is better to record repair or inspection dates in a separate column. Calibration, repair, and adjustment are not the same work, so combining them into one line of history makes it hard to interpret the device's condition later.
If you record the cumulative count shown on the unit at the time of calibration separately from the count currently shown, you can also see the change since the last calibration. However, whether that number counts only successful tests or also includes canceled or failed attempts can differ by model. If you have not confirmed the function, it is accurate to record it as "cumulative count shown on the unit," not "number of successful tests."
Record counts with the date they were checked
Keeping a separate ledger for every test adds to the workload at the site and invites omissions. If the cumulative count can be viewed on the unit, you can consider reading the number on screen on a set inspection day and transferring it to the log. A number on its own does not tell you when it applied, so always record the count and the check date as a pair.
If the cumulative count on the unit cannot be checked, or the way to view it is unclear, you can use data obtained during actual operation, such as access control records, as supporting data. However, multiplying the number of staff on duty or the number of people entering by the number of operating days does not reflect retests, visitor tests, or people who were not tested. Do not mix such values with the number shown on the unit. Keep them as a separate record that states the basis of the calculation, such as "estimated usage calculated from operating records."
If you used a manual or manufacturer guidance as the standard, also record the document name and the date you checked it in the log. For example, DATECH's official Downloads page posts "The New AF-50 / AF-50AD Korean-language manual." Keeping the reference document lets you check again which guidance the decision was based on, even after a model change, a document revision, or a change in the person in charge.
How to preserve records when the displayed count goes down
If the cumulative count display has been reset or the display method has changed after repair, do not overwrite the past number with the new one. Record the last count checked before the reset and its date, and separate the reset and the numbers after it as a new period. Simply joining numbers from different periods can lead to a wrong calculation of usage since the last calibration.
As a hypothetical example, suppose the log for Device A shows a cumulative 1,240 tests on June 1, but the screen shows 15 at the July routine inspection. First, recheck the serial number on the unit and the number on screen, and check whether there are any documents about repair, inspection, or setting changes in between. At this point, the fact actually observed is that the displayed number went down. A reset or a change in display method is only a possible interpretation until the documents are checked.
If a reset is confirmed, keep the existing record of 1,240 tests and note something like "Reset of cumulative display confirmed at July inspection; 15 tests in the following period." The standard for treating the record as complete is that the previous number, the new number, each check date, and the reason for the reset continue within the same device's history. If you could not confirm the cause, do not add the numbers together arbitrarily. Record the decrease and that the cause is unconfirmed.
When an adjustment has been made, record it separately from calibration as well. Adjustment is work that makes the device give a specified indication, and recalibration may usually be needed after adjustment. Recording the work date, the type of work, and whether the cumulative display changed after the work keeps you from confusing calibrations that require a certificate with repair history.
Manage transfers and the next review targets together
If you pass on only the number "800 cumulative tests" when sending a device to another location, the time that number was read is lost. Before the transfer, record the device identification, the count shown on the unit, the check date, and the purpose of the transfer. The receiving side records the date received and the screen number it checked again on a separate line. This is not for evaluating staff workload. It is a record that keeps track, without gaps, of where and for how long the device was used.
When you review the log regularly, look not only at the last calibration date but also at the date the cumulative count was last read and whether any reset, repair, or adjustment history is missing. The next scheduled calibration date is a planning value for preparing submission and budget. If test readings differ from usual or the device shows abnormal operation, rather than keeping the same management status just because the scheduled date has not arrived, you can record the symptom and when it occurred in the history and flag the device for further review.
An equipment log that records calibration dates and test counts together is not a document for collecting lots of numbers. It is a tool for choosing the next review targets by linking, in one place, the elapsed time for each device, changes in usage, the manufacturer documents consulted, and changes such as repairs or resets. If the conditions for a model are unclear, it is best to organize the device serial numbers, current log records, and certificates on hand so they can be checked against the manufacturer's guidance.
