Can an old safety helmet still be used?

1. Internal structure may have degraded
The exterior may look intact, but due to prolonged sun exposure and temperature changes, the polymer layer inside the safety helmet may have aged, developed micro-cracks, or become brittle. Even if there is no visible external damage, the protective performance will be significantly reduced.
2. External damage is difficult to identify
If the safety helmet has been subjected to impact (such as being hit by a falling object), even if there are no cracks or deformation, the internal energy-absorbing layer (EPS) may develop micro-cracks due to the force. This "invisible damage" can only be detected by professional testing equipment. If the replacement is delayed, the protective effect will be compromised.
3. Non-compliance risk
Many international and regional standards (such as EN 397, ANSI Z89.1) stipulate that the design lifespan of a safety helmet is usually 2-3 years. If it is not replaced after this period, it may not meet the compliance requirements for certain high-risk projects.
How to determine if a safety helmet needs to be replaced?