The criteria and methods for determining whether PV mounting bolts need to be replaced can be detailed in the following aspects:

1. Appearance inspection of bolts

l Rust and deformation: whether there is rust, rust or deformation on the surface of the bolt. If there is rust or deformation on the surface of

    the bolt, it should be replaced in time to ensure the reliability and safety of the connection

l Thread damage: check whether the thread of the bolt is intact. If the threads are seriously worn or cracked, it will affect the tightening

    effect of the bolt and need to be replaced in time.

2. Detection of tightening torque

l Torque value check: Use torque wrench to test the tightening torque of bolts. According to the design requirements and relevant

    standards (e.g. JGJ 82), check whether the tightening torque of bolts is in accordance with the regulations.

l Torque wrench records: Regularly check the calibration records and construction records of torque wrenches to ensure the accuracy and

    consistency of fastening operations.

3. Inspection of bolted parts

l Shims and Washers: Check that the shims and washers on the bolted joints are complete and in good condition. If shims or washers are

    damaged, missing, or not properly installed, they may cause the bolts to loosen and need to be replaced.

l Exposed length: Check whether the exposed length of the bolt meets the design requirements. In general, the exposed length of the bolt

    should be 2/3 of the thread diameter.

4. Impact of environmental factors

l Climatic conditions: In extreme climatic conditions (e.g., high winds, heavy rain, lightning, etc.), bolts may be loosened by shock loads.

    Therefore, bolts should be thoroughly inspected after inclement weather and tightened or replaced if necessary.

l Vibration effects: Solar mounts may be affected by vibration during operation, resulting in loose bolts. The tightening status of the bolts

    can be checked visually or by using vibration detection equipment.

5. Regular maintenance and inspection

l Regular inspection: PV operation and maintenance personnel should regularly rub and tighten the bolts to ensure the firmness of the

    connection. For the bolts that have been loosened, rusted or damaged, they should be replaced in time.

l Maintenance records: establish a bolt maintenance record system to record the time, content and results of each maintenance, in order to

    track the use of bolts and replacement history.

6. Construction quality control

l Installation specification: in the installation process, strictly in accordance with the design drawings and construction specifications for the

    operation, to ensure that the installation quality of the bolt and fastening effect.

l Anti-corrosion treatment: All exposed Solar metal parts (including bolts) should be treated with anti-corrosion treatment to extend their

    service life.

7. Handling of special cases

l Temporary substitutes: For non-standard bolts used temporarily for special reasons, they should be dealt with in a timely manner at the

    time of replacement, and records should be kept.

l Replacement of damaged parts: If the bracket assembly is found to be deformed, weld cracked or connecting parts damaged, the

    relevant parts should be replaced in time.r