Factor Filtro Ocular (FPFO) Description
The human eye can be damaged at work by three main types of risks present in work activities: mechanical, chemical and radiation.
Sometimes we cannot select the protection filters taking into account the recommendations of harmonized standards because the sources are not typified.
In these cases, it is necessary to evaluate if the exposure limit values (ELV) are exceeded based on the wavelength range emitted by the source. Depending on the emission spectrum of the source, we will calculate a series of values that comparing them with the limit values will allow us to know the risk index.
When the risk index is greater than 1, it indicates that the ELV is exceeded and it is necessary to protect the worker with a protection filter that must be selected according to the filter protection factor (FPF) for each wavelength range where they are exceeded. the corresponding VLEs, in order to mitigate the ocular risk that is intended to be avoided (thermal risk, risk of blue light, etc.).
In order to apply the evaluation carried out by this application, verify that the following conditions exist:
- Pulsed sources with pulse duration less than or equal to 0.25 seconds.
- The exposure limit values are calculated considering an exposure time equal to the duration of a pulse.
- Subtended angles in the following range: 1.7 mrad - Verify the subtended angle applying the following relation: [(x + y / 2)] / r (where x and y are the dimensions of the source and r the distance to it).
- Measure the spectral radiant exposure H (λ) at the exposure distance (when working with high intensity pulsed light sources, a distance of 0.2 m is considered as the most unfavorable if an accident occurs).
In future reviews of this application it is planned to expand to other exposure conditions
Sometimes we cannot select the protection filters taking into account the recommendations of harmonized standards because the sources are not typified.
In these cases, it is necessary to evaluate if the exposure limit values (ELV) are exceeded based on the wavelength range emitted by the source. Depending on the emission spectrum of the source, we will calculate a series of values that comparing them with the limit values will allow us to know the risk index.
When the risk index is greater than 1, it indicates that the ELV is exceeded and it is necessary to protect the worker with a protection filter that must be selected according to the filter protection factor (FPF) for each wavelength range where they are exceeded. the corresponding VLEs, in order to mitigate the ocular risk that is intended to be avoided (thermal risk, risk of blue light, etc.).
In order to apply the evaluation carried out by this application, verify that the following conditions exist:
- Pulsed sources with pulse duration less than or equal to 0.25 seconds.
- The exposure limit values are calculated considering an exposure time equal to the duration of a pulse.
- Subtended angles in the following range: 1.7 mrad - Verify the subtended angle applying the following relation: [(x + y / 2)] / r (where x and y are the dimensions of the source and r the distance to it).
- Measure the spectral radiant exposure H (λ) at the exposure distance (when working with high intensity pulsed light sources, a distance of 0.2 m is considered as the most unfavorable if an accident occurs).
In future reviews of this application it is planned to expand to other exposure conditions
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