Crane Test Load Requirements per ISO 14518:2015 Explained
ISO 14518:2015 "Cranes — Test Loads — Requirements" is the dedicated international standard governing test loads for cranes. It specifies load value determination, loading procedures, and acceptance criteria for type tests, routine (factory) tests, and periodic inspections, ensuring consistency and comparability across testing regimes.
Test Load Classification and Load Value Determination
ISO 14518:2015 classifies test loads into four categories: the rated load (the crane's design Rated Lifting Capacity), the static test load (1.25 multiples of rated load, used to verify structural strength and safety margin of the steel structure), the dynamic test load (1.1 multiples of rated load, used to verify mechanism functions and the reliability of safety devices), and the overload test load (1.25 to 1.5 multiples of rated load, applied during type tests or for special verification purposes).
Load values are determined as follows: the static test load is set at 1.25 times the rated load (verifying structural strength); the dynamic test load is set at 1.1 times the rated load (verifying mechanism functions including Hoisting/Lifting, Lowering, Slewing, and Luffing); and the overload test load for type tests ranges from 1.25 to 1.5 times the rated load, depending on the crane type and its Work Duty / Classification. Standard Weights used for testing must be metrologically calibrated, with a mass deviation of ≤±1%, and must remain within their calibration validity period. When substitute loads (e.g., water tanks or sandbags) are used, they must be mutually agreed upon by both parties, with the mass deviation clearly documented.
Static Load Test Procedure and Acceptance Criteria
The loading procedure for the static load test begins with positioning the crane at the test location and setting outriggers or supports fully in accordance with the working condition. The crane is first loaded to the rated load and held for 10 minutes while deformations are measured at various points (main girder deflection, outrigger deformation, boom tip sag, etc.). The load is then removed to no-load, and residual deformation is measured (residual deformation must not exceed 20% of total deformation). Next, the crane is loaded to 1.25 multiples of rated load and held for 15 minutes, followed by another round of deformation measurements. After unloading, all structural components are inspected for permanent deformation, cracks, and other damage.
Acceptance criteria for the static load test require that main girder deflection under rated load does not exceed L/400 (bridge cranes) or L/300 (gantry cranes), or that boom tip sag remains within allowable limits. Under the 1.25-times load, the structure must show no permanent deformation (at least 80% of deformation must recover after unloading), with no cracks in Weld Seams, no loosening of Bolts, and no damage to connecting elements. Temperature corrections may be applied for hot and cold ambient temperature conditions. All measurement data must be recorded and confirmed by the inspector's signature. Every crane shipped from Kelude Heavy Industry undergoes a 1.25-times static load test as part of its routine test.
| Test Type | Load Multiplicity | Pressure Holding Time | Test Purpose | acceptance criteria |
|---|---|---|---|---|
| Static load test | 1.25Times | 10~15min | structural strength | Nonepermanent deformation/Crack |
| Dynamic Load Test | 1.1Times | Fullstroke3Cycles | Mechanism Function | Smooth Operation/None Abnormal noise |
| Overload Test | 1.25~1.5Times | 3min | safety margin | Structural Integrity |
| routine test | 1.1~1.25Times | unit by unit | Quality Verification | All Passed |
| Type Test | 1.25~1.5Times | All | design verification | All Items Passed |
Dynamic Load Test Procedure
The dynamic load test follows a structured loading procedure: after loading to 1.1 times the rated load, combined motion tests are performed on all mechanisms—hoisting through the full stroke with at least 3 raising and 3 lowering cycles (checking brake slip distance ≤ 100 mm), luffing through the full working radius at least 3 times (for mobile and tower cranes), slewing at least 3 full rotations in each direction (checking slewing stability), and crane bridge/trolley travel across the full stroke at least 3 times (checking operating stability and synchronization). Each mechanism must operate smoothly and accurately, free from abnormal impacts or noise. The brakes must provide reliable braking—static braking (holding the rated load stationary with load drop ≤ 100 mm) and dynamic braking (emergency braking at rated rotational speed with braking distance within the specified limit).
Safety device functional checks are performed during the dynamic test to verify the operation of each device: the load moment limiter (LML) stops hoisting and radius increase when the rated load moment reaches 100%, while lowering and radius decrease remain operable; the lifting capacity limiter stops hoisting at 105% of rated load; and limit switches are individually triggered and inspected for height limit, working radius limit, and slewing limit. Safety device testing is conducted simultaneously with the dynamic load test to confirm the reliability of each device under dynamic operating conditions.
Test Safety and Documentation
Safety requirements for testing—a safetyCaution zone must be established around the test area (radius ≥ maximum working radius of the crane + 2 m), and unauthorized personnel are prohibited from entering. Test coordination is directed by an experienced, certified signaller, and all crane operations are performed by a certified operator. Test loads must use dedicated test weights securely fixed to prevent overturning or slipping. Outdoor testing is halted when wind speed exceeds 8.3 m/s. Test records must include the test date, load values, measurement data, safety device inspection results, and test conclusions, signed by both the inspector and the operator.
| Safety Precautions | requirements | Responsible Person |
|---|---|---|
| Caution Zone | Radius≥Maximum radius+2m | Safety Officer |
| Personnel | Certifiedoperator+Signaller | Test Team Leader |
| Load Fixing | Test Weight Fixing Secure | operator |
| wind speed limit | ≤8.3m/s | inspector |
| Record Signature | Both Parties | inspector+operator |
Frequently Asked Questions
Q: What test load multiples does ISO 14518:2015 specify?
A: The static load test uses 1.25 times the rated load to verify structural strength, while the dynamic load test applies 1.1 times the rated load to validate mechanism and safety device functions. Type tests require overloads ranging from 1.25 to 1.5 times the rated load. Test weights must have a mass deviation within ±1% and be used within their calibration validity period.
Q: What is the procedure and acceptance criteria for the static load test?
A: First, hold the rated load for 10 minutes, then release. Next, apply 1.25 times the rated load and hold for 15 minutes before releasing. Under the rated load, deflection must not exceed L/400. At 1.25 times the rated load, there must be no permanent deformation (recovery of at least 80% after unloading) and no cracks. Residual deformation must not exceed 20% of total deformation.
Q: What are the acceptance criteria for the dynamic load test?
A: At 1.1 times the rated load, each motion—hoisting, luffing, slewing, and traveling—must complete at least three full cycles. All movements must be smooth with no abnormal noise or impact. The brake must perform reliably, with braking deflection not exceeding 100 mm. Safety devices must be verified for proper function during the dynamic test.
Q: What safety requirements apply during testing?
A: The warning zone radius must be at least the maximum working radius plus 2 m. Only certified operators and signallers may participate. Wind speed must not exceed 8.3 m/s, and the test load must be securely fixed. Every crane shipped from Kelude's factory has undergone a 1.25-times static load test and a 1.1-times dynamic load test, with a test report issued for each unit.
