Enter Lamp and Distance Details
Formula Used
This calculator estimates delivered fluence from a measured reference irradiance. It applies distance loss, angle loss, lamp count, fixture losses, aging, surface acceptance, overlap, and design allowance.
Effective irradiance:
E = Eref × N × (Dref / D)n × cos(θ) × T × F × A × S × O × M
Delivered fluence:
H = E × t
E is effective irradiance. H is fluence. N is lamp count. D is working distance. n is the distance exponent. θ is the incidence angle. T, F, A, S, O, and M are correction factors.
How to Use This Calculator
- Enter the lamp name and application type.
- Add measured reference irradiance and its measured distance.
- Enter the planned working distance and exposure time.
- Use exponent 2 for inverse square behavior.
- Adjust angle, lens, fixture, aging, surface, and overlap factors.
- Add a target fluence when a required dose is known.
- Press calculate and review pass status.
- Download the CSV or PDF report for records.
Example Data Table
| Application | Reference Irradiance | Reference Distance | Work Distance | Time | Target Fluence |
|---|---|---|---|---|---|
| UV coating cure | 120 W/m² | 0.50 m | 1.20 m | 90 s | 0.75 J/cm² |
| Infrared drying | 250 W/m² | 0.40 m | 0.90 m | 120 s | 1.50 J/cm² |
| Inspection exposure | 80 W/m² | 0.60 m | 1.00 m | 60 s | 0.25 J/cm² |
Construction Lamp Fluence Planning
Why Fluence Matters
Lamp fluence is the delivered energy per area. It matters during curing, drying, inspection, and temporary treatment work. A lamp may look bright, but distance can reduce useful energy very quickly. This makes field spacing important. It also makes measured data better than guesswork.
Distance Control
Many lamp checks use inverse square behavior. That means doubling distance can cut irradiance to one quarter. Real sites may differ. Reflectors, guards, lenses, dust, surface angle, and lamp age can change the result. This calculator lets you include those losses. It also allows a custom exponent. That helps when a lamp has a shaped beam or a measured falloff curve.
Field Use
Start with a reliable irradiance reading. Record the reference distance. Then enter the actual work distance. Add exposure time from the planned process. If the lamp is angled, add the incidence angle. A large angle lowers the normal dose on the surface. Add transmission, fixture efficiency, lamp aging, and surface factors. These values help create a conservative site estimate.
Target Checks
A target fluence gives the page a pass check. The result shows delivered fluence, required time, and the farthest distance that can still meet the target. This is useful for planning repeat work. It also helps crews compare several lamp positions before setup. Use the design allowance when conditions are uncertain. Keep notes for the job record. Export the results when documentation is needed.
FAQs
1. What is lamp fluence?
Lamp fluence is energy delivered per surface area. It is usually calculated from irradiance multiplied by exposure time.
2. Why does distance affect fluence?
Distance spreads lamp energy over a larger area. With inverse square behavior, irradiance falls sharply as distance increases.
3. What distance exponent should I use?
Use 2 for normal inverse square estimates. Use measured lamp data when the beam is focused, shielded, or highly directional.
4. What is reference irradiance?
It is the measured lamp irradiance at a known distance. The calculator uses it as the starting point for distance adjustment.
5. Why include angle loss?
An angled beam delivers less normal energy to the surface. The calculator applies a cosine correction for that condition.
6. What does design allowance mean?
Design allowance reduces the credited dose. It adds conservatism for dust, measurement uncertainty, lamp drift, and field variation.
7. Can I use this for UV curing?
Yes. Enter UV irradiance, distance, exposure time, and target fluence. Always confirm critical curing work with approved field measurements.
8. Does this replace a site meter?
No. It supports planning and documentation. Important jobs should still use calibrated meters and project-specific acceptance requirements.