Quality Inspection Methods for Prefabricated Houses

Quality inspection methods for prefabricated houses mainly include inspections of prefabricated components, inspections of the load-bearing capacity of prefabricated floor slabs, and simple self-inspection methods, as detailed below:

Inspections of Prefabricated Components:

1. Dimensional Deviation Inspection: Strictly inspect the dimensional deviations of components in accordance with the 'Standard for Acceptance of Construction Quality of Steel Structures' (GB 50205 - 2020). For example, the allowable deviation for the local flatness of the flange plate of a steel beam is 2mm, and the deviation of the web centerline must not exceed 2mm.
2. Appearance Quality Inspection: Check for obvious defects such as honeycombing, pitting, and cracks on prefabricated concrete wall panels and floor slabs.
3. Concrete Compressive Strength Inspection: Use the core drilling method to inspect the concrete strength of beams and columns in accordance with the 'Technical Specification for Core Drilling Method for Testing Concrete Strength' (CECS03:2007).
4. Reinforcement Inspection: Use a magnetic induction meter to inspect the reinforcement configuration of beams, slabs, and columns in accordance with the 'Technical Specification for Inspection of Reinforcement in Concrete' (JGJ/T 152 - 2008).
5. Crack Inspection: Inspect the width, location, and distribution of cracks in accordance with the 'Regulations for Building Quality Inspection' (DG/TJ08 - 79 - 2008). Preliminary judgments can be made using the business card insertion method or the transparent tape method.
6. Material and Mechanical Property Inspection: Verify the material reports of steel to ensure that the yield strength, tensile strength, and elongation meet the lower limits specified in national standards. Also, inspect the section moment of inertia and the effective penetration depth of welds.
7. Weld Quality Inspection: Main load-bearing welds must undergo non-destructive testing, with the sampling ratio for ultrasonic testing not less than 20%. It is recommended to conduct 100% testing for key nodes.
8. Anti-corrosion and Coating Treatment Inspection: Ensure that the derusting grade reaches Sa2.5 and the total dry film thickness of the paint is between 70 and 90 micrometers in accordance with the 'Technical Specification for Anti-corrosion Coating of Steel Structures' (CECS 343:2013).

Inspections of the Load-bearing Capacity of Prefabricated Floor Slabs:
Conduct factory building load-bearing inspections on three combined projects: the load-bearing structural system, structural layout and support system, and enclosure structural system, to assess whether the load-bearing capacity of the floor slabs meets the design requirements.

Simple Self-inspection Methods:
Knocking on Walls to Listen for Sounds: Gently knock along the joints of prefabricated panels and the center of the floor slab using a small iron rod, screwdriver handle, or key. If the sound is a dull 'dong, dong', it indicates dense concrete; if a hollow 'bang, bang' sound is emitted, there may be hollowing, peeling, or reinforcement corrosion, and the location should be marked for further inspection.