How to Distinguish the Grade of Prefabricated Houses
The classification of the safety grades of prefabricated house components and the entire house is as follows:
The grading of prefabricated house components (such as prefabricated slabs) is mainly based on their current quality and degree of danger, referring to the classification standards for the assessment of concrete components. They are divided into Grade a, Grade b, Grade c, and Grade d.
Grade a: The surface of the component is flat, or there are only a few minor cracks or peeling in individual areas; there is no obvious exposure or corrosion of the steel bars; the end support of the prefabricated slab is stable, and enhanced connection measures have been taken. Such components are in good condition and can be used normally.
Grade b: There are slight cracks or local peeling on the surface of the component; exposure and corrosion of the steel bars occur in individual areas, but the degree of corrosion is light; the end support of the prefabricated slab is basically stable without obvious looseness. Such components have certain defects and require regular observation and maintenance.
Grade c: The protective layer of the component is severely peeled off, the steel bars are obviously exposed and corroded, and rust expansion cracks appear; obvious stress cracks and deformations occur in load-bearing components such as beams and slabs; the end support length of the prefabricated slab is insufficient, which may affect the structural safety. Such components already have potential safety hazards and need to be reinforced or replaced in a timely manner.
Grade d: The protective layer of the component is extremely severely peeled off, and some steel bars are exposed; serious stress cracks and deformations, or even fractures, occur in load-bearing components such as beams and slabs; the end support length of the prefabricated slab is severely insufficient, posing a risk of falling. Such components have lost their load-bearing capacity, and measures must be taken immediately to eliminate the danger.
The overall safety grade of a house is divided into four grades: A, B, C, and D according to the "House Safety Assessment Standards".
Grade A: The structure meets the safety requirements for use, no dangerous points are found in the load-bearing components, and the house can be used normally.
Grade B: Individual load-bearing components are in a dangerous state, but it does not affect the safety of the main structure. The dangerous components need to be reinforced or repaired.
Grade C: Some load-bearing structures no longer meet the safety requirements, local dangers occur, constituting a partially dangerous house. Immediate measures need to be taken to prevent the expansion of the danger, and overall reinforcement or renovation plans should be made.
Grade D: The load-bearing structure as a whole has problems, constituting a dangerous house for the entire building. The house can no longer be used safely and must be taken out of service and demolished or rebuilt.
It should be noted that the determination of the house safety grade must be carried out by a professional institution through on-site inspection, structural analysis, and other means to issue an assessment report. It should not be judged subjectively based solely on the age of the house or the structural form.
