Plan usable shelf space, not litres
In a fridge used for temperature-sensitive medicines, some space should not hold stock at all: the door, the area directly in front of or touching the evaporator or air outlet, the bottom where air may be colder or warmer depending on design, and the gap needed against the back and side walls for air to circulate. What is left is your usable shelf area.
Purpose-built pharmaceutical refrigerators are designed with forced air circulation, no door storage and controlled shelves for this reason. Domestic fridges, with freezer compartments and door racks, usually have larger temperature differences between zones.
Work out peak stock
Peak stock is the most you hold at once, normally just after a delivery and before the previous stock has sold. Peak = stock left before the delivery + the delivery itself. List items by pack size, because pack dimensions decide shelf use far more than the count of units.
Seasonal demand, scheme campaigns and supplier minimum orders can all push peak stock up for a few weeks. Plan for those peaks, or agree split deliveries with the supplier.
Worked example
Assumptions: nominal shelf 520 × 420 mm; after keeping 50 mm clear at the back and 20 mm at each side, usable area is 480 × 360 mm; three pack types at peak, sizes measured from stock.
| Pack | Size (mm) | Peak quantity | Per shelf | Shelves needed |
|---|---|---|---|---|
| Small unit cartons, laid flat 3 high | 110 × 60 × 40 | 400 | 4 × 6 × 3 = 72 | 5.6, so 6 |
| Larger packs, 2 high | 200 × 150 × 100 | 30 | 2 × 2 × 2 = 8 | 3.75, so 4 |
| Outer cartons on delivery day | 300 × 200 × 200 | 4 | 1 | 4, so unpack them |
| Total if outers are unpacked | 10 shelf positions |
What to take from the example
Outer cartons waste space: one 300 × 200 mm carton occupies a whole shelf in this cabinet. Unpack into baskets on arrival if the product's instructions allow it.
Ten shelf positions plus an allowance for air space and peaks (a planning margin of 20 to 30%, not a rule) means about 12 to 13 shelf positions. That is a larger single cabinet or two smaller ones. Two cabinets give somewhere to move stock if one fails, which matters when the stock is valuable and hard to replace.
Good practice in the layout
- Use open baskets or perforated shelves so air passes around the packs.
- Do not store anything in the door, and keep stock off the floor of the cabinet unless the maker says that zone is in band.
- Keep food, drink and samples out of a medicines fridge.
- Place the temperature probe where the maker or your programme recommends, and leave space around it so it reads the air the stock sees.
- Arrange stock so the oldest is used first and staff can find items without holding the door open.
Indian site conditions
Many pharmacies are non-AC shops with afternoon temperatures well above 35 °C. Ask what ambient the fridge is rated to hold +2 to +8 °C in, and keep it out of direct sun and away from the shutter. Voltage swings and outages are a bigger risk to stock than capacity: plan monitoring with an alarm, a stabiliser or wide-voltage unit, and backup power for longer cuts.
Frequently asked questions
- Can I use a domestic fridge for medicines?
- Many health programmes advise against it because domestic fridges have larger temperature swings, door storage and freezer compartments that can freeze stock. Follow your regulator's or programme's guidance for your products.
- How full can a pharmacy fridge be?
- Full only to the usable area described by the maker, with gaps for air between packs and walls. If you find yourself pushing stock against the back wall or into the door, the cabinet is too small for your peak.
