SDOS (standard day of supply)

SDOS stands for standard days of supply, also written as standard day of supply in the singular. It is a NATO logistics term for the quantity of supplies required to support one day of operations under standard conditions. NATO's Logistics Handbook lists SDOS as "Standard Days of Supply" in its abbreviations, alongside DOS for "Days of Supply".

The term belongs to NATO logistics and stockpile planning. It gives planners a common unit for expressing how much stock is needed for an operational period. Because it is a NATO planning measure, SDOS is a term bid teams are most likely to meet in defence and allied logistics material rather than in general commercial procurement.

What SDOS stands for in NATO logistics terminology

The NATO Logistics Handbook lists two related abbreviations: DOS for "Days of Supply" and SDOS for "Standard Days of Supply". The first is the general idea of counting supplies in days. The second is the standard version of that count, based on one day under standard conditions.

A NATO glossary of abbreviations, AAP-15, gives "standard day of supply" with the French equivalent "jour standard d'approvisionnement". That bilingual entry is useful for Canadian teams that work in both official languages.

How SDOS differs from a combat day of supply

NATO separates the standard day from the combat day. The 1994 NATO Logistics Handbook defines a combat day of supply as the total amount of supplies required to support one day of combat. It is calculated by applying an intensity factor to a standard day of supply.

• Standard day of supply: the quantity needed to support one day under standard conditions.
• Combat day of supply: the standard day of supply adjusted by an intensity factor to reflect one day of combat.

In practice, the standard day is the baseline. The combat day is derived from it, so the standard figure sits underneath any combat-intensity calculation.

How NATO uses days of supply in stockpile planning

NATO logistics planning uses days of supply to express the stocks to be held in theatre. The count covers both the initial phase of a mission and the expected sustainment period. Stating requirements in days lets planners describe stock levels in terms of how long a force can be supported, not only in raw quantities.

NATO's terminology is maintained in NATOTerm, the official terminology database run by the NATO Terminology Office within the NATO Standardization Office. It is the reference point when a document's use of a logistics term needs to be checked.

What SDOS means for suppliers bidding on Canadian public contracts

SDOS is a planning unit, not a price term or a certification. It describes how much a force needs for a standard day and how many such days are held. A supplier that sees SDOS in a defence-related solicitation, a NATO-linked requirement or supporting logistics material should read it in the NATO sense set out above.

Bid teams should do three things when the term appears:

• Confirm whether the document means standard days of supply or the related combat day of supply.
• Check how many days the requirement covers, including any initial and sustainment periods.
• Match quantities and delivery commitments to the figures stated in the solicitation itself.