Tower Crane Reliability Test Standard GB/T 17806-1999
GB/T 17806-1999, "Tower Cranes — Reliability Test Methods," is the dedicated standard for reliability testing of tower cranes. It specifies the test procedures, load spectrum, fault classification rules, and reliability assessment indicators used to verify a tower crane's ability to operate without failure under defined conditions.
Test Methods and Key Reliability Indicators
The standard requires a cumulative operating time of ≥500 hours for the reliability test. The test load is set at 100% of the rated lifting capacity and covers all crane motions, including hoisting, lowering, slewing, luffing, and traveling. The reliability assessment indicators require a mean time between failures (MTBF) of ≥150 hours and an operation success rate of ≥90%. Faults are classified into three categories: essential faults (caused by design or manufacturing defects, counted in the MTBF calculation), misuse faults (resulting from improper operation, not counted), and secondary faults (triggered by other faults, also not counted).
The load spectrum for the reliability test is designed to simulate real-world operating conditions of tower cranes. Light loads (≤30% of rated load) account for 40% of the test time, medium loads (30%–70%) for 35%, and heavy loads (70%–100%) for the remaining 25%. Each test cycle includes hoisting, lowering, slewing, luffing, and traveling motions. A complete cycle starts with lifting the test load and ends when the load is set down, with each cycle lasting approximately 5 to 10 minutes.
The MTBF calculation method depends on the nature of the fault. Essential faults, which stem from design defects or manufacturing quality issues, are included in the MTBF calculation. Misuse faults, caused by operator error or failure to follow prescribed maintenance procedures, are excluded from the calculation but must be recorded and analyzed. Secondary faults, which occur as a consequence of another fault, are also excluded from the MTBF calculation.
Fault Data Recording and Analysis
Fault analysis must be initiated within 2 hours of each fault occurrence, with details recorded in the fault record table (time, location, mode, cause, and classification). The MTBF is calculated after 500 hours of cumulative operation. No more than 3 essential faults are permitted per 500 hours. If the same component fails 3 or more times consecutively, it is deemed a design defect and the test is terminated. Upon completion of the test, non-destructive testing is performed on the main structural components.
Essential faults
All motions
Full cycles
Design defects
Heavy 25%
& verdict
| reliability Indicator | requirements | test method | Determination |
|---|---|---|---|
| MTBF | ≥150h | Cumulative Operation | Inherent Fault Count |
| Completion Power | ≥90% | Complete Cycle | Completion Rate |
| Number of Faults | ≤3Occurrences | Record Statistics | Inherent Fault |
| Structural Condition | None Crack/Deformation | Non-destructive testing | Test Before/After |
The fault record table must be completed in a standardized and thorough manner, documenting the exact time of each fault, the affected component (tower mast, boom, slewing mechanism, hoisting mechanism, luffing mechanism, travel system, etc.), the fault mode (crack, deformation, leakage, wear, electrical fault, etc.), the root cause analysis, and the fault classification. All entries must be signed by both the test operator and the recording personnel. Data analysis is performed after 500 cumulative operating hours.
Test Report
The Test Report covers product information, test conditions (temperature, humidity, wind speed, Load spectrum), test data (operating hours, duty cycles, fault record table), MTBF calculation procedures, fault analysis (fault tree or root cause analysis), improvement recommendations, and the final acceptance conclusion. The report is signed by the test supervisor and stamped with the official seal of the testing institution.
| Fault Classification | Definition | Inclusion Criterion | Example |
|---|---|---|---|
| Inherent Fault | design Defect | Yes | Crack/Leakage |
| Misuse Fault | Improper Operation | No | overload/Collision |
| Secondary Fault | Secondary Inducement | No | Chain Reaction |
Kelude Heavy Industry provides tower crane reliability testing services in accordance with the standard.
FAQ
Q: How is MTBF calculated?
A: MTBF = total test time / number of inherent failures. The requirement is ≥150h. For example, if 3 inherent failures occur over 600h of operation, MTBF = 200h, which passes. An inherent failure is a defect caused by design or manufacturing flaws. Misuse and secondary failures are not counted.
Q: What is the load spectrum for reliability testing?
A: Light load (≤30% of rated capacity) for 40% of the time, medium load (30%–70%) for 35%, and heavy load (70%–100%) for 25%. Each cycle includes all motions: hoisting, lowering, slewing, and luffing. Minimum test duration: ≥500h.
Q: How are failures handled during testing?
A: Record the time, location, mode, and cause of each failure. Testing may resume after the faulty part is replaced; replacement time is not counted toward test duration. If the same component fails three or more times consecutively, the test is terminated and the unit is deemed non-compliant.
Q: What must the test report include?
A: Product model, test conditions and load spectrum, total test time, MTBF calculation steps, fault record table, failure analysis conclusions, and improvement recommendations. A final verdict of compliant or non-compliant with supporting rationale.
