Protecting Cargo from Pressure Drops During Flight

Physics of the Process: Why Pressure Affects Cargo

When transporting goods by air to Kazakhstan from China, Europe, or the USA, items face sharp changes in atmospheric pressure. Although modern aircraft cargo holds are pressurized, the internal pressure during flight does not match sea level. Usually, it is maintained at a level equivalent to an altitude of 2000–2400 meters. This means that external pressure on the packaging drops, while the internal pressure inside hermetically sealed containers remains the same. KAZLOGIST.KZ specialists emphasize: if the packaging is not designed for such drops, it may deform, burst, or leak.

Risk Groups: Which Goods Suffer Most

Logisticians and procurement managers must understand that pressure protection is not required for all goods, but there are critical categories:

• Liquids and Gels: Cosmetics, chemicals, oils. When external pressure drops, the air inside the bottle expands, pushing the contents through the cap or tearing the seal.
• Hermetic Containers: Plastic canisters, drums, and even hard cases with equipment. The pressure difference can lead to "implosion" or bulging of the walls.
• Electronics with Air Gaps: Some types of high-precision instruments and displays can suffer if air is trapped inside the housing with no way out.
• Dangerous Goods (DGR): Aerosols, cylinders, and paints. For these, compliance with IATA DGR rules is mandatory, as depressurization can lead to fire or toxic contamination of the aircraft.

Practical Ways to Protect Cargo

To prevent losses, KAZLOGIST.KZ recommends using proven preparation methods. First, use specialized Pressure Relief Valves. They allow air to exit the container during ascent and re-enter during descent, maintaining the integrity of the shell. Second, when packaging liquids, it is necessary to leave "ullage" (headspace) — usually about 10% of the container volume. This allows the liquid and air to expand without the risk of rupturing the packaging. Third, use certified UN-packaging for dangerous goods, which undergoes tests for pressure differences up to 95 kPa.

The Role of KAZLOGIST.KZ in Ensuring Safety

We take on the packaging audit at the stage of picking up the cargo from the sender. If our warehouse in Europe or China sees that the container will not withstand the flight, we suggest repacking or palletizing. KAZLOGIST.KZ checks the availability of Safety Data Sheets (MSDS) for chemical goods, which specify pressure requirements. When booking space with partner airlines, we consider the aircraft type: on wide-body freighters, pressure and temperature control systems operate more stably than in the belly holds of small passenger planes.

Checklist for the Sender Before Flight

To minimize risks, check the following points:

• Does the container have a margin of safety for air expansion?
• Are the lids tightly closed and sealed with heat-shrink wrap?
• For electronics: are ventilation holes provided in the protective cases?
• Does the marking and packaging comply with IATA requirements if the cargo is classified as dangerous?

Remember that the responsibility for primary packaging lies with the sender, but KAZLOGIST.KZ is always ready to advise and adjust the process so that the cargo arrives in Almaty or another city in Kazakhstan in perfect condition. Delivery times from Europe are usually 3–5 days, and from China 3–6 days, allowing for timely stock replenishment.

To get an accurate calculation of the air freight cost for your cargo and advice on packaging requirements, please contact our managers.