Whether a bulletproof vest insert needs replacement is primarily determined by four factors: service life, visual inspection, impact history, and storage condition. Even if it appears intact, an expired or impact-damaged insert may lose its protective capability and should be handled with caution.
1. Has it exceeded its recommended service life? Most bulletproof inserts are designed for a lifespan of approximately 5 years. Prolonged exposure to UV radiation, moisture, or extreme temperatures will accelerate material aging.
Ceramic-based inserts (such as alumina and silicon carbide) will experience reduced ballistic performance due to the accumulation of microcracks; UHMWPE (ultra-high molecular weight polyethylene) materials may experience a decrease in fiber strength due to oxidation.
It is recommended to proactively replace inserts older than 5 years from the manufacturing date, even if they have never been used.
2. Appearance and Structural Integrity Inspection: Regularly inspect the following items; if any abnormalities are found, the device must be taken out of service immediately:
Surface Damage: Cracks, missing corners, bulges, or delamination in the ceramic panel;
Edge Damage: Obvious scratches, deformation, or corrosion on the edges of metal or composite inserts;
Backing Abnormalities: Softening, discoloration, blistering, or loosening of fibers in the UHMWPE or aramid inserts;
Clear Labeling: Wear and tear on labels indicating protection level, production information, etc., making it impossible to confirm performance parameters.
3. Impact from Bullets or Sharp Objects:
After any bullet impact, regardless of whether it penetrates, the insert must be replaced. The ceramic layer will "break in one go" when absorbing energy and cannot withstand secondary impacts.
Even if it does not penetrate, a back dent depth (BFS) exceeding 25mm is considered a failure.
After a stab-resistant insert is attacked with a knife, the fiber layer may be cut, which is not visible to the naked eye, and it must also be scrapped.
