Siren Decibel Loss Calculator

Model siren loudness changes for construction operations accurately. Compare scenarios with distance, air, and shielding. Export reports, validate audibility, and brief crews fast always.

Calculator

Typical sirens may range from 100–140 dB at 1 m.
Use the distance where the source level is specified.
Distance from siren to the listening point.
Use line model for long corridors or extended sources.
Higher at high frequencies, heat, or low humidity.
Use for walls, berms, containers, or partial enclosures.
Optional allowances for wind, clutter, reflections, etc.
Approximate equipment and ambient sound at the receiver.
Common planning margins are 5–15 dB above background.
Uses your same losses and model to solve distance.
Example: 85 dB for busy work zones.

Example Data Table

Use these sample values to verify calculations and understand typical outputs.

Source (dB @ m) Receiver (m) Model Air (dB/100m) Barrier (dB) Receiver Level (dB) Total Loss (dB)
120 @ 1 250 Point 0.8 0 ≈ 70.0 ≈ 50.0
130 @ 1 400 Point 1.0 10 ≈ 71.0 ≈ 59.0
120 @ 1 600 Line 0.5 5 ≈ 84.2 ≈ 35.8
Example outputs are rounded for readability. Your results depend on chosen losses.

Formula Used

Receiver level
L2 = L1 − Lossgeom − Lossair − Lossbarrier − Lossother

Geometric spreading
Point model: Lossgeom = 20 · log10(d / d0)
Line model: Lossgeom = 10 · log10(d / d0)

Air absorption (simple)
Lossair = α · (d − d0) / 100
where α is in dB per 100 m and distances are in meters.

Audibility check
Audible when L2 ≥ Background + Margin.
This is a planning model. Field conditions may vary with terrain, wind, and reflections.

How to Use This Calculator

  1. Enter the siren level at the stated reference distance.
  2. Set receiver distance to the work area or public location.
  3. Choose point or line spreading to match the situation.
  4. Add air absorption and any shielding or barrier allowances.
  5. Set background level and audibility margin for your site.
  6. Click Calculate and review receiver level and pass/fail.
  7. Use CSV or PDF to share the selected scenario.
If audibility fails, reduce distance, increase source level, or improve placement.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.