Aging Test Calculator

Accelerated Aging Test Calculator

Calculation Results

Accelerated Aging Factor (AAF): –

Required Test Duration: – Days

Equivalent to – hours in the stability chamber.

function calculateAging() { var tAmbient = parseFloat(document.getElementById('ambientTemp').value); var tAccel = parseFloat(document.getElementById('testTemp').value); var q10 = parseFloat(document.getElementById('q10Factor').value); var realTimeDays = parseFloat(document.getElementById('realTime').value); if (isNaN(tAmbient) || isNaN(tAccel) || isNaN(q10) || isNaN(realTimeDays)) { alert("Please enter valid numeric values."); return; } if (tAccel <= tAmbient) { alert("Accelerated temperature must be higher than ambient temperature."); return; } // Formula: AAF = Q10 ^ [(T_accel – T_ambient) / 10] var exponent = (tAccel – tAmbient) / 10; var aaf = Math.pow(q10, exponent); // Test Duration = Real Time / AAF var testDuration = realTimeDays / aaf; var testHours = testDuration * 24; document.getElementById('aafResult').innerText = aaf.toFixed(3); document.getElementById('testDurationDays').innerText = testDuration.toFixed(2); document.getElementById('testDurationHours').innerText = testHours.toFixed(1); document.getElementById('aging-results').style.display = 'block'; }

Understanding Accelerated Aging Tests

In product development, particularly for medical devices, pharmaceuticals, and electronics, determining the shelf life of a product is critical. However, waiting for two or three years to see how a product degrades is often not feasible. This is where the Accelerated Aging Test comes in.

Accelerated aging is a method that uses increased temperatures to speed up the chemical degradation of materials. By exposing a product to higher temperatures for a shorter period, manufacturers can simulate the effects of long-term storage at ambient temperatures.

The Arrhenius Equation Logic

Most accelerated aging calculations are based on the Arrhenius equation. In practical quality assurance, we use the simplified Q₁₀ factor approach (often referenced in ASTM F1980 for medical device packaging):

• AAF = Q₁₀^{[(T_AA – T_RT) / 10]}

Where:

• AAF: Accelerated Aging Factor.
• Q₁₀: An aging factor, typically 2.0 for most polymers and medical supplies (meaning the reaction rate doubles for every 10°C increase).
• T_AA: Accelerated aging temperature (the temperature in the oven).
• T_RT: Real-time storage temperature (usually 20°C or 25°C).

Example Calculation

Suppose you want to validate a 1-year (365 days) shelf life for a product stored at 25°C, and you plan to run your test at 55°C using a Q₁₀ of 2.0.

1. Calculate the Temperature Difference: 55°C – 25°C = 30°C.
2. Calculate the Exponent: 30 / 10 = 3.
3. Calculate the AAF: 2.0³ = 8.
4. Calculate Test Time: 365 days / 8 = 45.63 days.

This means that keeping the product at 55°C for roughly 46 days is theoretically equivalent to keeping it at 25°C for a full year.

Why is the Q₁₀ Factor Important?

The choice of Q₁₀ is vital for accuracy. While 2.0 is the industry standard for many materials, some chemicals or specialized polymers may have a Q₁₀ ranging from 1.8 to 2.5. Using a factor that is too high may lead to under-testing, while a factor too low results in unnecessarily long testing cycles. Always consult material data sheets or industry standards like ASTM F1980 before finalizing test protocols.