What photobiological safety covers
Photobiological safety is the assessment of whether a light source can harm the eye or the skin through exposure. The hazard depends on the spectrum, the radiance, the distance, the duration and the aperture of the exposure, and the classification is made under a defined method for a defined product. A portable lantern is a product where the distance and the aperture change in use: a lantern that sits on a table is a different exposure from one that hangs at eye level, and a wide beam is a different exposure from a narrow one.
The method behind a classification is a laboratory procedure, not a sentence on a specification sheet. A buyer who reads a classification and nothing else is reading a conclusion without the conditions that produced it. The conditions include the source as tested, the distance and aperture used, the spectral measurement behind the classification, and the product configuration as it will ship.
A useful habit is to treat any photobiological safety statement as a document request rather than a claim to be accepted. The document names the classification, the method, the sample and the scope. A supplier who can produce all four has run the assessment; a supplier who can only say the product is safe has not.
What a buyer should request
The first request is the classification statement itself, written in the terms the method uses rather than in marketing language. A classification is a category under a defined method, and a buyer should not accept a restatement of it in different words, because the restatement may drop the boundary that the classification carries.
The second request is the scope of the statement: which product, which configuration, which modes and which accessory set. A lantern with a diffuser in place is not the same exposure as the same lantern without it, and a lantern fitted with an optional lens is not the same as the bare model. The statement should say which configuration it covers.
The third request is the measurement behind the classification: the spectral distribution, the radiance or irradiance values, the distance and the aperture. These are the numbers a laboratory would check, and they are the numbers that let a buyer see whether the classification is consistent with the product.
The fourth request is the applicability statement: which limit the assessment applied and whether that limit is the one that applies in the intended market. A buyer should never fill in a standard number or a laboratory name on their own, because the classification belongs to the document and the document belongs to the holder.
The four checks on a photobiological safety file
| Check | What it should give | What it means if it is missing |
|---|---|---|
| Classification | The category under the stated method | The claim has no defined meaning |
| Scope | The model, configuration and modes covered | The claim may not describe the product |
| Measurement | Spectral data plus radiance and distance | The classification cannot be checked |
| Applicability | Which limit was applied, and for which market | The claim may not be the applicable one |
| Holder | Who holds the statement | Accountability is unknown |
| Sample identity | Golden sample or production batch | The claim may not describe what ships |
Ask for the six checks, not the conclusion. A supplier who can fill six rows has run the assessment and kept the record. A supplier who can only repeat that the product is safe has not run it, or has decided that the buyer does not need the method.
Why portable lighting is a special case
A portable lantern is a product where the user controls the exposure. The same lantern can be set on a table two hand-spans away or hung above a seated person, and the two are different exposures under the same classification. A classification performed at a defined distance and aperture is a statement about that distance and that aperture, and it should not be read as a statement about every distance the product can reach.
Glare is the second special case. A lantern that is bright in the centre and sharp at the edge can be uncomfortable to look at directly, even when the hazard classification is low, and the discomfort is a usability issue before it is a safety issue. A diffuser that softens the patch reduces the discomfort, and a beam that concentrates it increases it. This is the link between the photometric article on beam angle and illuminance and the safety discussion.
The third special case is the battery. A lantern that holds a high output for a long time is a lantern that sustains the exposure, and the runtime question and the safety question meet in the same firmware decision. A driver that derates early shortens the high-output exposure and lengthens the low-output one.
Classification ≠ eye safety in every situation
The boundary to state plainly: a classification under a defined method is not a promise that the product is safe at every distance, in every mode and with every accessory. It is a statement about the configuration and the conditions that were assessed, and it carries a boundary that the marketing language usually drops.
A second boundary: a low classification is not a license to stare into the source. The classification describes the hazard under the method, and it does not describe the discomfort of a bright light in a dark tent. Glare can be unpleasant and disruptive without being a hazard under the method.
A third boundary: a classification is not a substitute for the photometric document. The beam and colour figures are needed to understand how the light falls, and the classification is needed to understand the exposure, and neither replaces the other. This is the same discipline that emergency backup lighting applies to its documentation, and the same one that a private-label lantern run carries when a brand changes the diffuser.
Five questions for the supplier
- What classification does the assessment state, and under which method was it performed? Ask for the terms the method uses, not a restatement.
- Which product configuration, modes and accessory set does the statement cover? A diffuser or a lens changes the exposure.
- What were the spectral data, the radiance or irradiance values, the distance and the aperture used? These are the numbers a laboratory would check.
- Which limit was applied, and is that the limit that applies in the intended market? Applicability belongs in the file.
- Which sample and batch does the statement describe, and can you send the full statement with the quotation rather than after the order? The document is the point of the exercise.
Next step
Request the classification statement with its scope, measurement, applicability and holder, and file it by model and revision. Do not accept a restatement in marketing language, and do not fill in any standard number or laboratory name yourself. Related reading: tent camping lighting for the documentation a retail buyer expects. To apply this to a live sourcing project, start at contact.
Part of the Lumizuno outdoor-lighting notes. Illustrative values only; lumens and ingress ratings must be read with their test conditions.