Nominal Ocular Hazard Distance
Estimate nominal ocular hazard distance with a simple expanding circular-beam irradiance model.
Description
A simple ocular-hazard-distance estimate compares an expanding circular beam’s average irradiance with a supplied permissible value.
A simple ocular-hazard-distance estimate compares an expanding circular beam’s average irradiance with a supplied permissible value. The model expands radius linearly with distance.1
Estimate nominal ocular hazard distance with a simple expanding circular-beam irradiance model.
When to use Nominal Ocular Hazard Distance
Use this tool to estimate nominal ocular hazard distance with a simple expanding circular-beam irradiance model.
Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
How to use Nominal Ocular Hazard Distance and understand its results
- Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
- Enter beamPowerWatts, beamDiameterMeters, divergenceRadians, permissibleIrradianceWPerM2 using the field table and calculation rules, then run the tool.
- Read nohdMeters. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| beamPowerWatts | Beam power (W) | number; minimum: 0 | Required |
| beamDiameterMeters | Exit beam diameter (m) | number; minimum: 0 | Required |
| divergenceRadians | Full-angle divergence (rad) | number; minimum: 0 | Required |
| permissibleIrradianceWPerM2 | Permissible irradiance (W/m²) | number; minimum: 0 | Required |
Enter nonnegative power/diameter, positive divergence and positive permissible irradiance. Treat divergence as the radius-growth angle used by this formula. Return meters.
hazardRadius=sqrt(P/(πlimit)); distance=max(0,(hazardRadius−initialDiameter/2)/divergence) Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| nohdMeters | Nominal ocular hazard distance (m) | number; minimum: 0 |
{
"input": {
"beamPowerWatts": 1,
"beamDiameterMeters": 0.001,
"divergenceRadians": 0.001,
"permissibleIrradianceWPerM2": 10
},
"output": {
"nohdMeters": 177.9124116152771
}
}Limitations and assumptions
The limit is not derived. No Gaussian peak factor, pulsed exposure, optical aids, reflections or certified safety assessment is included.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Required Optical Density: Calculate required optical density from unprotected and permissible exposure values in matching units. For a complementary task, use Laser Safety Audit: Compare required laser-safety controls with documented controls.
References
-
Nominal Ocular Hazard Distance — tool.io
Similar or alternative tools
- Required Optical Density
Calculate required optical density from unprotected and permissible exposure values in matching units.
- Laser Safety Audit
Compare required laser-safety controls with documented controls.