Author: Jouth Zhao, Senior Engineer, Dengtai Staircase Manufacturing Co., Ltd.
Load testing verifies that a ladder can safely support the specified working load. This article explains the two types of load testing (proof load testing and type testing), when each is required, and what to expect from a load test report.
Two Types of Load Testing
| Test Type | Purpose | When Required |
|---|---|---|
| Type Testing | Validates the ladder design once. Performed on a representative sample. | New product development; regulatory certification |
| Proof Load Testing | Verifies individual production units. Each ladder or a statistical sample is tested. | Specified in purchase order; regulated industries |
Standard Load Test Values
| Standard | Proof Load (per rung) | Deflection Limit | Duration |
|---|---|---|---|
| OSHA 1910.23 | Test to 250 lbs (1,112 N) | No permanent deformation | Not specified (typically 1 minute) |
| EN ISO 14122-4 | 1.5 × rated load; minimum 1,500 N | Elastic deflection < 1/200 of span | 1 minute |
| AS 1657 | 1.5 × design live load | Deflection < span/250 | 1 minute |
Dengtai’s standard proof load: 2,000 N (450 lbs) applied to center of rung — exceeds all standard requirements.
Load Test Procedure
- Support the ladder section at the bracket positions (simulating installed condition)
- Apply the proof load at the center of a rung using calibrated weights or a hydraulic test frame
- Measure deflection under load
- Remove the load and check for permanent deformation
- Test a minimum of 10% of rungs per ladder (randomly selected)
- Record results in a load test report
Related Resources
FAQ
Q: Is load testing required for every ladder order?
No. Type testing validates the design; proof load testing is performed when specified in the purchase order or required by the project specification. For standard models, Dengtai provides the type test certificate. For custom or heavy-duty orders, proof load testing can be specified.
Q: What is the cost of proof load testing?
Approximately $50-100 per ladder tested, depending on the ladder size and the number of rungs to be tested. Statistical sampling (testing 10% of ladders in a batch) reduces cost while maintaining confidence.
Q: Can proof load testing damage the ladder?
No, if performed correctly. The proof load is within the elastic range of the material. If the ladder passes, it returns to its original shape. Only a design-defective or fabrication-defective ladder should show permanent deformation — which is exactly what the test is designed to detect.
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