IP codes are defined by the IEC 60529 standard. The first digit ranges from 0 to 6 and indicates protection against solid objects (including fingers, tools, and dust). The second digit ranges from 0 to 9 and indicates protection against liquids (including dripping water, splashing, immersion, and high-pressure washing). For example, IP65 means fully dust-tight and protected against low-pressure water jets from any direction. When a digit is marked as X, it means that particular test was not performed, not that there is zero protection.

First, confirm the complete unit's protection rating, not just the housing: smart locks contain Bluetooth, NFC, RFID modules, and circuit boards, so the sealing design must cover the entire structure. Second, distinguish between static and dynamic water protection: IP rating tests are mostly conducted under static conditions. If the lock is installed on vibrating or continuously operating equipment, additional verification is required. Third, request the corresponding test report from the manufacturer and verify that the product model listed in the report matches the actual purchased specification, to avoid using a single certificate to cover an entire product series.

IP protection only covers the ingress of dust and water; it does not cover salt spray corrosion, UV aging, or high/low temperature cycling. For coastal, outdoor, or high-temperature-differential environments, separately request ASTM B117 salt spray testing or related weathering certifications, and evaluate them independently from the dust and water protection rating. Before purchasing, list the IP rating, weathering tests, and material specifications as separate items to avoid a single indicator misleading the overall protection assessment.