In general, fs-40 tubes are required by many uv accelerated aging test customers.But in practice, uvb-313el is a better choice.The volume of uvb-313el is quite different from that of fs-40, so it has a significant price advantage.

As shown in figure 1, the spectral power distribution (SPD) curve of these two uv lamps is the same shape.The only difference is that the uvb-313el lamps in the QUV uv aging test chamber (QUV/basic) without irradiance control have a higher irradiance.

The fs-40 tube was mainly used in the trial of SAEJ2020. An earlier version of the standard required the use of the fs-40 uv lamp because the fs-40 was the only lamp available in the 1970s before the solar eye irradiance control function was developed.After 2002, however, this requirement was removed, and the subsequent standard required "UVB lamps using 313nm nanoscale peak as described in table 3 of ASTMG154".

The irradiance set value of SAEJ2020 was determined by studying a large number of old models of ultraviolet aging test chamber using fs-40 lamp tubes. In the updates to j2020 in 1995 and 2002, the average irradiance at 310nm was specified as 0.48w/m2.Unlike most standards, SAEJ2020 allows ±15% deviation for equipment without irradiance control function, but requires an additional irradiance test every 400 hours for equipment without irradiance control function to confirm irradiance.In the requirements of the standard, uvb-313el lamp is still unable to meet the requirements.

Many calibration committees referred to the SAEJ2020 test conditions, but with the SAEJ2020 standard updated iteratively, the relevant standards did not update the test requirements in a timely manner.

According to the standard requirements of SAEJ2020, there is no special preference for fs-40 uv lamp or uvb-313el uv lamp.The standard only requires test conditions -- UVB lamps that conform to ASTMG154 and irradiance control points of 0.48W/m2 at 310nm (which we can provide).

The irradiance control function of solar eye ensures the irradiance consistency of uv accelerated aging test chamber during the test process.Therefore, the irradiance control point was set at 0.48w /m2@310nm and these uv-accelerated aging test Chambers could be tested using UVB or fs-40 lamps.

If the user is using a uv accelerated aging test chamber with irradiance control, uvb-313el uv lamp is recommended.The irradiance control point during SAEJ2020 or test based on this standard is set at 0.48W/m2.Even if the standards are not updated and the use of UVB tubes is justified, we suggest that customers should not buy fs-40 tubes at a higher price for outdated standards.

If you are using a uv accelerated aging test chamber (QUV/se) without irradiance control, you should continue with the fs-40 uv lamp.To ensure a level of irradiance comparable to their standard or previous tests.This is because in the uv accelerated aging test chamber without irradiance control function, the irradiance level of UVB313 lamps is significantly higher than that of fs-40 lamps.

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