A spare breathalyzer normally sits in storage and keeps on-site testing going when the main unit is out for calibration or repair. The fact that it powers on and shows a display does not mean it is ready for testing right away. You need to check together what calibration history the stored unit has, whether you have the mouthpieces and power supplies needed on site, and whether you can keep recording results the same way your current workflow does.
This matters most where results must be managed in a consistent way, such as testing before workers enter a worksite, because swapping the unit can itself break the record trail. Calibration here means the management procedure of checking how a breathalyzer's readings compare with reference values and making any needed adjustments. Manage spares not by stock count but by whether they can actually be deployed on the day you need them.
Even after a short storage period, review the management history separately
Because a spare unit is used less often, it is easy to assume it is in good condition. But if you do not know the environment it was stored in over a long period, whether it was moved, its battery condition, or its last calibration date, you cannot say for sure whether it can go into service. ILAC-G24:2022/OIML D 10:2022 advises that a recalibration interval be reviewed in light of not only the degree of use but also the conditions of use and risks from transport.
It is therefore better not to treat the unit as if its calibration clock stopped because it was not used. Confirm the calibration criteria for that model based on the manufacturer's user manual and your organization's management purpose. If a unit has no certificate or calibration history, or there is not enough basis to judge its next management date, classify it as "pending check" rather than "ready." That reduces rushed decisions during an urgent swap.
Once it is out of storage, match the physical unit to the documents first
Before taking the unit to the site, compare the serial number on the body with the asset register and the identification details on the calibration certificate. When you run several units of a similar model, it is easy to link a certificate or manual to a unit by appearance alone. The calibration date and the date you checked appearance and operation are not the same information, so record them separately.
| Check order | What to check and what to do | Deploy or hold |
|---|---|---|
| Identification match | Compare the serial number on the body, the asset register, and the certificate. | If all three match, move to the next check. |
| Visual check | Look for visible problems such as damage, contamination, or leakage on the body. | If you see an abnormality, do not assign it for on-site testing. |
| Management history check | Review the documents from the last calibration and the management criteria for that model. | If the basis is insufficient, classify it as pending check. |
| On-site kit check | Prepare the designated mouthpieces, power supplies, and the product-specific manual together. | The kit needed at the actual test location must be complete. |
The order in this table is not just a paperwork step. For example, if the certificate belongs to unit A but unit B was brought to the site, the certificate cannot describe the condition of unit B even though you have one. Conversely, if the unit looks fine but you cannot link it to its calibration documents, you lack the data to judge how its readings are being managed.
Do not confuse an operation check with calibration
Powering on, confirming the display, and checking the date and units are operation checks needed before on-site use. However, you cannot say you have confirmed calibration status just because a random person blew into it and got a result similar to usual. A person's test result is not a reference value for judging whether the unit meets its standard.
Consider a hypothetical example. A spare breathalyzer taken out of storage powered on and displayed normally, but the serial number on the linked certificate did not match the body. The observed fact here is that "the unit turns on, but its calibration documents cannot be confirmed." Rather than interpreting this as usable, you can classify it as pending check and either look again for the documents that match the body number or confirm the scope of inspection and calibration the manufacturer accepts. The completion criterion is not simply that the unit powers on; it is that the unit's identification is linked to its management records and the accessories needed on site are ready.
Organize differences from the main unit by task
Even if the spare provides the testing function, you cannot assume it handles automatic saving, printing, or computer connection the same way the main unit does. Before deployment, it is better to decide which tasks the spare will cover and what information must be recorded separately. For example, if the existing unit saved results automatically but the spare saves them differently, you need to decide in advance how to record the test time and the unit's identification during the backup period, so the records can be linked later.
For mouthpieces, also check in the product-specific manual whether a designated part is required for that model. It is better to avoid using consumables from another model just because they seem to fit physically. The DATECH official download center provides manuals by product, so keeping the spare unit's asset number together with its manual reduces the confusion of looking up the wrong model's guide on site.
Record the unit's movements after deployment and return
On the day you deploy a spare, write the actual place of use and the start date in the asset register instead of the storage location. If you keep the period the spare was used, rather than erasing it after the main unit returns, you can later trace which unit produced the test records for a given period. This is also necessary to avoid mixing up each unit's calibration history with its usage history.
Before putting a returned spare back in storage, record any abnormalities found during use, whether consumables were restocked, and any documents that need checking. If you separate ready units from pending-check units with distinct labels or lists, you can see how many units can actually be deployed immediately rather than just counting how many spares you have. The value of a spare lies not in the stored quantity but in being ready to keep testing going without interruption on the day a swap is needed.
