To ensure product quality, Chongqing Hi Sea Marine Equipment Co., Ltd. treats pre-shipment inspections as a critical acceptance criterion. This ensures no substandard products enter the marine supply system.

1. Requirements

1.1 Materials for the main components of the ventilator are listed in Table 1.

.2 The surface of the ventilator shall be flat and smooth, free of sharp edges, distortion, or skewing.

1.3 Diameter deviation for ventilator and vent head shall be ±3mm; verticality deviation shall be 2h/1000 (where h is the duct body height).

1.4 Welded surfaces of the ventilator shall be free of cracks, slag inclusions, burn-through, or lack of fusion defects.

1.5 Weatherproof covers of the ventilator shall open smoothly; moving parts shall be coated with neutral lubricating grease.

1.6 Steel components of ventilator shall achieve rust removal to Sa2 or St2 grade per GB/T 8923 on both inner and outer surfaces, followed by two coats of anti-rust primer.

1.7 After water immersion testing, inspected areas of Type A, B, and C ventilator shall show no water droplets or stains. Indentation width between sealing material and duct contact surface shall not be less than 0.5t (where t is duct wall thickness).

2. Test Methods

2.1 Air Tightness Test

2.1.1 Water Jet Test

Using a nozzle with a diameter of no less than 12.5 mm and water pressure of no less than 0.25 MPa, perform a water jet test at a distance not exceeding 1.5 mm from the ventilator. The test duration shall be 3 minutes, and the results shall comply with the requirements of Section 4.7.

2.1.2 Impression Test

Apply white powder evenly to the sealing compound at the weatherproof cover joint. Close the weatherproof cover tightly, then open it to inspect the width of the impression mark where the sealing compound contacts the duct edge. Results shall comply with the requirements of 1.7.

2.2 Appearance Inspection

Conduct visual inspection. Results shall comply with requirements 1.2, 1.4, 1.5, and 1.6.

2.3 Dimensional Inspection

Use measuring tools to inspect diameter and perpendicularity deviation of the ventilator and vent head. Results shall comply with requirement 4.3.

3. Inspection Rules

3.1 Ventilator inspections are categorized into type testing and factory inspections.

3.2 Type Testing

3.2.1 Type testing shall be conducted under any of the following circumstances:

a. First production batch of the product;

b. Significant changes in structure, materials, or manufacturing processes;

c. Non-continuous batch production;

d. Transfer of production to another factory;

e. Inspection by the ship inspection department.

3.2.2 Type testing items are specified in Table 2.

Table 2 Inspection Item List

3.2.3 The number of inspection samples shall be: For each specification of ventilator, one unit shall be selected from the first production batch for type testing. Airtightness testing shall be conducted per 2.1.1.

3.2.4 Acceptance criteria: If the type testing of the ventilator meets the requirements of Table 2, it shall be deemed as passing the type test. If nonconformities are found, the product may be reworked and retested. If the retest passes, the type test shall be considered passed.

3.3 Factory Inspection

3.3.1 Factory inspection items for ventilator shall follow Table 7.

3.3.2 Batch formation and sampling: Each ventilation duct shall undergo factory inspection. Airtightness testing shall be conducted per 2.1.2.

3.3.3 Acceptance Criteria: Ventilator meeting the requirements of Table 7 during factory inspection shall be deemed to have passed factory inspection. If nonconformities are found, the product may be re-inspected after rectification. Passing the re-inspection shall be deemed as passing the factory inspection.

3.3.4 After passing inspection, the inspection department shall issue a certificate of conformity for the ventilator