How do you calculate UV guarding area?

Multiply the open emission face area by the number of exposed sides to get theoretical area, then divide by coverage efficiency. With a 12 ft² face, 3 exposed sides, and 80% efficiency, you get 36 ft² theoretical and 45 ft² of guard material required.

Why is the required area larger than the theoretical area?

Coverage efficiency below 100% accounts for overlap at seams, cutouts for conveyor entry/exit, mounting flanges, and off-cuts. At 80% efficiency the 36 ft² theoretical need becomes 45 ft², a 9 ft² loss allowance.

What coverage efficiency should I assume for UV curtains vs sheet metal?

Rigid sheet-metal shrouds with clean cutouts run 85-92%. Flexible UV welding curtains with overlap seams and pass-through slots run lower, often 70-80%, because you overlap panels to block line-of-sight leaks.

Do I count the conveyor entry and exit as exposed sides?

Only if they leak line-of-sight UV. Most tunnels use labyrinth baffles at entry/exit so those faces are partially self-shielding; count them as exposed only if a person can see the arc from the opening.

Is this the same as sizing for UV dose or intensity?

No. This sizes physical barrier area for containment. Dose and intensity at the part are separate calculations — use the UV Multi-Lamp Tunnel Total Dose and UV LED Array Power Density tools for those.

What is a good coverage efficiency target?

Design to 80-85% for planning so you buy enough material, then verify with a UV meter that leakage at operator positions is below the ACGIH TLV. Efficiency is a material-buying factor, not a safety pass/fail.

UV Curing calculator

UV Shielding Coverage Calculator

UV shielding and guarding coverage sizes the amount of opaque barrier material — sheet metal shrouds, black anodized panels, welding-grade UV curtains — needed to enclose a UV curing source so stray UVC/UVB does not reach operators. EHS engineers and cure-cell integrators use it during machine guarding design and TCLV (threshold limit value) compliance checks. It matters because unshielded UV causes photokeratitis and skin erythema in minutes, and OSHA/ACGIH exposure limits are unforgiving. Sizing guard area early avoids scrambling for material mid-install when a lamp housing turns out to leak from three faces instead of one.

What this calculator does

Estimate total guard / curtain / enclosure area needed to contain stray UV from a cure station, given the open-face area, number of sides, and a coverage allowance.
Use it during cell design or safety retrofits when bidding out UV curtains, side panels, or a tunnel enclosure for an open conveyor cure cell.
It computes the total guard area required to shield a UV source by multiplying the open emission face area by the number of exposed sides, then dividing by the achievable coverage efficiency.

Formula used

Theoretical shield area = open face area × exposed sides
Total shielding required = theoretical area ÷ coverage efficiency

Inputs explained

Open UV emission face area to enclose:
Number of operator-exposed sides:
Guard coverage efficiency after overlap and cutouts:

How to use the result

Use it when specifying UV guarding for a new cure cell, retrofitting an open conveyor tunnel, or documenting an EHS containment plan before a lamp goes live.
It assumes each exposed side needs a full face-area barrier and does not model reflected/scattered UV off nearby stainless surfaces, which can require additional interlocked shrouding beyond the flat-area estimate.

Common questions

How do you calculate UV guarding area? Multiply the open emission face area by the number of exposed sides to get theoretical area, then divide by coverage efficiency. With a 12 ft² face, 3 exposed sides, and 80% efficiency, you get 36 ft² theoretical and 45 ft² of guard material required.
Why is the required area larger than the theoretical area? Coverage efficiency below 100% accounts for overlap at seams, cutouts for conveyor entry/exit, mounting flanges, and off-cuts. At 80% efficiency the 36 ft² theoretical need becomes 45 ft², a 9 ft² loss allowance.
What coverage efficiency should I assume for UV curtains vs sheet metal? Rigid sheet-metal shrouds with clean cutouts run 85-92%. Flexible UV welding curtains with overlap seams and pass-through slots run lower, often 70-80%, because you overlap panels to block line-of-sight leaks.
Do I count the conveyor entry and exit as exposed sides? Only if they leak line-of-sight UV. Most tunnels use labyrinth baffles at entry/exit so those faces are partially self-shielding; count them as exposed only if a person can see the arc from the opening.
Is this the same as sizing for UV dose or intensity? No. This sizes physical barrier area for containment. Dose and intensity at the part are separate calculations — use the UV Multi-Lamp Tunnel Total Dose and UV LED Array Power Density tools for those.

Last reviewed 2026-05-12.