How magnets can be transported by air
Air transportation has certain particularities. In order to ensure safety, both people and goods need to be checked before boarding. If you bring magnetic materials, such as NdFeB magnets, or the customer is anxious for the goods and hopes that the manufacturer will deliver them by air, can we bring the magnets on the plane at this time?
Because the weak stray magnetic field interferes with the aircraft's navigation system and control signals, the International Air Transport Association (IATA for short) classifies magnetic cargo as Category 9 dangerous goods, which must be restricted when receiving and transporting. Therefore, some air cargoes with magnetic substances need to be magnetically tested in order to ensure the normal flight of the aircraft. Magnetic materials, audio materials and other instruments containing magnetic accessories are subject to magnetic testing.
Air Standard
According to the relevant provisions of IATA902: If the maximum magnetic field strength measured at a distance of 2.1m from the object to be measured does not exceed 0.159A/m (200nT, which is equal to 2mGs=0.002Gs), then the object is not restricted as a magnetic substance and can be used as a General cargo handling.
If the maximum magnetic field strength measured at a distance of 2.1m from the object to be measured exceeds 0.159A/m, but the strength of any magnetic field at a distance of 4.6m from the surface of the object to be measured is less than 0.418A/m, the goods can be accepted and transported as dangerous goods.
If the strength of any magnetic field at a distance of 4.6m from the surface of the object to be tested is greater than 0.418A/m, then the object is strictly prohibited to be transported by air.
How to Meet Air Freight Standards
In order to meet the above air transportation requirements, it is necessary to demagnetize the magnets shipped by air. Although it is called demagnetization, it is not actually demagnetizing the magnets, but through special shielding packaging, so that the magnetism displayed by the package to the outside world meets the specified air safety transportation requirements. For shielding and packaging, high magnetic permeability materials are generally used, such as cold-rolled sheets, galvanized sheets, etc. If the amount of magnetic materials is large, several layers should be packed. The magnetic permeability of high magnetic permeability materials is very high. According to the principle of Faraday electric cage, the magnetic field mainly circulates in the box after packaging, and there is very little leakage. Packed in a carton or wooden box outside the shielding package.
Magnetic detection
Airlines or logistics companies that carry magnetic materials will require customers to do magnetic testing and issue an "air transport condition identification report" in order to ensure the normal flight of the aircraft. Generally, the air transport appraisal can only be issued by a qualified professional appraisal company recognized by the civil aviation administration of the country, and it is generally necessary to send samples to the appraisal company for professional testing, and then issue an appraisal report. If it is inconvenient to send samples, the professionals of the appraisal company will conduct on-site inspection and then issue an appraisal report. The validity period of the appraisal report is generally used this year, and after the New Year, it is generally necessary to re-do it.
During magnetic inspection, the customer needs to pack the goods according to the requirements of air transportation, and the inspection will not damage the packaging of the goods. In principle, the inspection does not open the goods, but only detects the stray magnetic field on the 6 sides of each goods. If the magnetic inspection of the goods is unqualified, special attention should be paid. First, with the consent of the customer, the magnetic inspection staff will be entrusted to unpack the goods for inspection, and then put forward relevant reasonable suggestions according to the specific situation. If the shielding can meet the air transportation requirements, the goods will be shielded according to the customer's request, and the relevant fees will be charged.