How do you calculate nitrogen inerting cost for a UV line?

Multiply the curtain flow rate (SCFH) by the fraction of the hour the lamps are actually on, then multiply by your delivered nitrogen price per scf. At 180 SCFH, full runtime and $0.008/scf that is 180 × 1 × $0.008 = $1.44 per hour.

Why is nitrogen used in UV curing at all?

Free-radical UV chemistries are inhibited by atmospheric oxygen at the surface, leaving a tacky, undercured skin. A nitrogen curtain drops surface O₂ below a few hundred ppm so the top layer cures fully, letting you lower photoinitiator load or lamp power.

Is 180 SCFH a lot of nitrogen for a cure zone?

It is a typical mid-range curtain for a narrow-web or coating line. Wide lines and leaky enclosures can run 400-1000+ SCFH. The point of this calc is that even 180 SCFH costs $1.44/hr, or roughly $10,000/yr on a 24/5 schedule.

Should I buy an on-site nitrogen generator?

Compare the hourly cost this calculator returns against the amortized cost of a PSA or membrane generator plus its power. Generators usually win above a few hundred SCFH of steady demand, but only if your purity requirement (often 99.5-99.9%) is achievable.

How do I lower nitrogen consumption without hurting cure?

Tighten the enclosure and reduce leakage, optimize curtain geometry so N₂ sits where the film is, and dial flow to the minimum that keeps residual O₂ under target. Every SCFH you cut drops this hourly number proportionally.

Does lamp on-time really matter for gas cost?

Yes if you gate the curtain to lamp state. If N₂ flows continuously regardless of lamp status, set the on-time fraction to 1; if the curtain shuts off during gaps, use the true duty cycle and the hourly cost falls in the same proportion.

UV Curing calculator

UV Nitrogen Consumption Calculator

When a UV line runs an oxygen-sensitive chemistry, converters flood the cure zone with a nitrogen curtain to push O₂ inhibition out of the surface. That inert gas is a real consumable, and at high SCFH it can quietly become one of the most expensive line inputs. This calculator turns curtain flow, lamp duty cycle and your delivered nitrogen price into a straight dollars-per-hour figure so a process engineer or plant manager can see exactly what inerting adds to a job. It is the number you need before you argue for a curtain redesign, a lower flow setpoint, or an on-site N₂ generator.

What this calculator does

Calculate nitrogen consumption (SCFH) and hourly cost for inerted UV cure tunnels - the alternative to oxygen inhibition on surface-cure-sensitive chemistries.
Use it when costing inerted vs non-inerted cure on a new line, or when nitrogen cost is a meaningful share of cure operating cost.
It multiplies your nitrogen curtain flow by the lamp on-time fraction and your gas unit cost to give the hourly cost of inerting.

Formula used

Hourly consumption (scf/hr) = flow rate × runtime fraction
Hourly cost = consumption × $/scf

Inputs explained

Nitrogen curtain flow rate:
UV lamp on-time fraction per hour:
Delivered nitrogen price:

How to use the result

Use it when quoting or cost-modeling any nitrogen-inerted UV or EB job, or when comparing bottled/bulk N₂ against an on-site generator.
It assumes a steady curtain flow; real lines purge and ramp, and box leakage or an oversized curtain can push actual consumption well above the setpoint you enter.

Common questions

How do you calculate nitrogen inerting cost for a UV line? Multiply the curtain flow rate (SCFH) by the fraction of the hour the lamps are actually on, then multiply by your delivered nitrogen price per scf. At 180 SCFH, full runtime and $0.008/scf that is 180 × 1 × $0.008 = $1.44 per hour.
Why is nitrogen used in UV curing at all? Free-radical UV chemistries are inhibited by atmospheric oxygen at the surface, leaving a tacky, undercured skin. A nitrogen curtain drops surface O₂ below a few hundred ppm so the top layer cures fully, letting you lower photoinitiator load or lamp power.
Is 180 SCFH a lot of nitrogen for a cure zone? It is a typical mid-range curtain for a narrow-web or coating line. Wide lines and leaky enclosures can run 400-1000+ SCFH. The point of this calc is that even 180 SCFH costs $1.44/hr, or roughly $10,000/yr on a 24/5 schedule.
Should I buy an on-site nitrogen generator? Compare the hourly cost this calculator returns against the amortized cost of a PSA or membrane generator plus its power. Generators usually win above a few hundred SCFH of steady demand, but only if your purity requirement (often 99.5-99.9%) is achievable.
How do I lower nitrogen consumption without hurting cure? Tighten the enclosure and reduce leakage, optimize curtain geometry so N₂ sits where the film is, and dial flow to the minimum that keeps residual O₂ under target. Every SCFH you cut drops this hourly number proportionally.

Last reviewed 2026-05-12.