A mouthpiece used with a breathalyzer is a consumable through which the person being tested blows their breath. Individuals and workplace purchasing staff buying a device for the first time often receive separate quotes for the main unit and for consumables. If the mouthpieces included with the main unit are not subtracted from the additional order quantity, you can end up buying the same item twice before you even start using it.
What matters in a first order is not predicting long-term usage, but securing enough for training and actual testing right after delivery without running out. So rather than calculating only the "total quantity needed," compare on the same basis which mouthpiece it is and which model it fits, along with the quantity already secured. Separating the included set, separately ordered quantities, and stock that can actually be received reduces both double purchasing and shortfalls at the start.
First confirm the included items from the main unit's package contents
Whether mouthpieces come with the main unit, and if so which item and how many, must be confirmed in the order specification. Do not estimate the included quantity from consumables shown in product photos or from a general description of contents in a quote. It is safer to write down the main unit model name and the item name and quantity of the included mouthpieces separately on the main unit purchase order.
"The same item" here means not a consumable with a similar name but a mouthpiece that matches the actual device model and purpose. Different testing methods or device models may use different mouthpieces, so do not count quantities meant for another device as a substitute for the included set. If you also note the applicable device and mouthpiece item on the quote for additional purchases, the purchasing and inspection staff can look at quantities on the same basis.
Split the required quantity into operating use and training use
A first order may need quantities for learning how to use the device right after installation or for explaining procedures, in addition to what will be used in actual operation. If mouthpieces for training are mixed into the quantity for actual testing, it is hard to tell how many remain after training, and the basis for additional orders becomes unclear. If you plan to run training, it is better to keep the training quantity as a separate line.
That said, there is no need to set a large spare quantity just because it is for training. Define the range needed based on the number of people attending training, the number who will actually try the device, and whether operation starts right after training. Avoid reducing quantities on the assumption of a reuse count or usable period the manufacturer has not specified.
| Line to separate | What to record when calculating | Rule that prevents duplication |
|---|---|---|
| Quantity to start actual testing | Number of mouthpieces per model to use when operation starts | Keep it separate from the training quantity |
| Training and demonstration quantity | Number actually to be used in training | Mark whether it is included in the operating quantity |
| Included with the main unit | Item and quantity stated in the order specification | Compare whether the model and purpose match the additional purchase |
| Separately ordered or on hand | Order number, expected arrival date, whether usable | Subtract only quantities secured before the start date |
Deduct only "secured, identical items"
Determine the additional order quantity by adding the quantity to start actual testing and the training and demonstration quantity, and then subtracting the quantity of the same item already secured. Subtract both the included set and separately ordered quantities, but do not subtract quantities not yet confirmed as receivable as if they were confirmed stock. If the result does not match the pack size, record both the number of individual pieces needed and the number of packs to order.
As a hypothetical example, suppose mouthpieces for a particular device are needed: 24 for actual operation and 6 for training. If the main unit's package contents include 10 of the same item, and an additional 5 already ordered are confirmed to arrive before the operation start date, the additional number of individual pieces needed is 15. What to observe is not the fact that "30 are needed in total," but whether the 10 and the 5 really fit the same device, and whether they can be received before the start date. The completion criterion is that if both conditions are met, you order 15 rounded to the pack size, and if not, you do not subtract the unconfirmed quantity.
Look at incoming items and existing stock separately
The fact that an order has been accepted is different from having usable stock. Quantities without a confirmed delivery date, or being handled for exchange or return, may not be immediately usable for initial operation. For mouthpieces already left over, first confirm that the applicable model and item match the current order, rather than counting them just because packages are left.
You can suggest separating "confirmed secured" and "awaiting confirmation" quantities in the purchase documents. Subtract the confirmed secured quantity from the additional order, and include the awaiting-confirmation quantity only after it is settled whether it can be delivered. This way, if the delivery date changes, you can quickly recalculate where the shortfall arises.
Compare the main unit order and the consumables order at once
Double purchasing tends to happen when the person buying the main unit and the person buying consumables each look only at their own documents. Before approval, compare the two documents on one screen or in one summary sheet to check whether items included with the main unit were put on the additional order list again. Compare not only quantities but also item names, applicable models, pack sizes, and expected arrival dates.
After delivery, record the included quantity on the order separately from the quantity actually received. If some items did not arrive or an exchange occurred, do not keep the original calculation as is. Recalculate the additional quantity needed based on what has actually been secured. It is appropriate to judge a first order complete not when the quote is received, but when the mouthpieces of the same item needed to start operation have arrived without duplication.
