ATP

The ATP is a United Nations convention that governs how perishable food moves across international borders. It establishes the technical requirements for insulated containers, refrigerated vehicles, and the testing procedures that prove they maintain safe temperatures during transport. Signed in 1970 and amended multiple times since, it functions as both a legal framework and a technical standard that shippers and carriers must follow to move chilled or frozen goods through most countries.

The agreement defines three main equipment categories: insulated vehicles (lorries and trailers with permanent insulation), insulated containers (portable boxes), and refrigerated vehicles equipped with active cooling systems. Each category has minimum insulation values measured in watts per cubic meter per kelvin (W/m³K), which determine how much heat leakage is acceptable. A refrigerated lorry might achieve 0.4 W/m³K, while a simple insulated container achieves 0.9 W/m³K. Testing involves placing the equipment in a controlled environment and measuring temperature rise over time to verify it meets the standard.

Certification and enforcement

ATP compliance is not optional for international trade in most European and North African countries, and many others have adopted it. Equipment must be tested by an approved laboratory and issued a certificate valid for five or six years depending on type. The certificate displays the equipment's thermal classification and is a condition of legal carriage. A vehicle without a valid ATP certificate cannot legally transport perishables across many borders, and loads can be rejected or seized at checkpoints if documentation is missing or expired.

The technical requirements are tighter for active refrigerated units than for passive insulation, reflecting that powered cooling can compensate for heat gain more reliably. However, the ATP also covers backup systems and contingency procedures, because a broken compressor on a five-day run poses real risk. The standard includes provisions for using ice or dry ice as supplementary cooling in certain configurations, and defines which combinations of active and passive systems are acceptable.

Food producers and logistics operators often treat ATP compliance as a basic hygiene and legal requirement rather than a quality advantage, though meeting the standard does provide assurance that temperature stability is physically possible within the equipment. The agreement has become the de facto global baseline for perishable transport infrastructure, and most cold chain operators maintain ATP-certified equipment as their starting point before adding their own monitoring, tracking, and contingency layers on top.