Acoustic & Noise Barrier Calculators

Source Characteristics
Propagation & Ground
Ground Attenuation
dB loss
Atmospheric Absorption
dB loss
Receiver Level
dB(A)
WHO Residential Daytime — 53 dBA
ISO 9613-2: Point sources decay approximately 6 dB per doubling of distance (spherical divergence). Line sources approximately 3 dB (cylindrical divergence). Ground attenuation adds up to 4 to 6 dB over soft ground at mid-range frequencies.
Geometry — Maekawa Method
Spectrum & Barrier
Overall Source Level
dBA
Receiver Level (with barrier)
dBA
Octave Band Analysis
Band (Hz)Source (dB)δ (m)Fresnel NIL (dB)Receiver (dB)
Maekawa (1968): IL = 10 log10(3 + 20N) where N = 2δ/λ (Fresnel number). Practical barriers rarely exceed 20 to 24 dB globally due to atmospheric scattering and lateral flanking paths.
Traffic Flow
Propagation & Site
Basic Noise Level
dB
Speed & HGV Correction
dB
Distance Correction
dB
Surface + Angle Correction
dB
Est. LAeq,16h Daytime
dBA
Est. LAeq,8h Night
dBA
Est. Lden (EU END)
dB
WHO Residential Daytime <= 53 dBA
WHO Night-time <= 45 dBA
EU END Action Threshold <= 55 Lden
CRTN (DoT 1988): L10(18h) predicted from traffic parameters. LAeq,16h approximately equals L10(18h) minus 2 dB for free-flowing traffic. Lden applies EU END evening (+5 dB) and night (+10 dB) weighting.
Mechanical Plant Inventory
Assessment Criteria — BS 4142:2014+A1
Plant Inventory Summary
EquipmentLw (dB)QtyDist (m)Contribution (dBA)
Combined Specific Level
dBA
BS 4142 Assessment
BS 4142:2014+A1:2019: Rating level at or below background = positive/low impact. Approximately 5 dB above = likely adverse. Approximately 10 dB above = significant adverse. Always consider context.
Room Dimensions
Surface Materials
Room Use Type
Room Volume
Total Surface Area
Total Absorption ΣAα
Sabins
Target Range
seconds
RT60 vs target range
RT60 by Room Use
Room TypeTarget RT60 (s)Status
Sabine’s formula: RT60 = 0.161 x V / ΣAα. Valid for diffuse fields. For non-diffuse rooms, Eyring’s formula is more accurate.
External Noise Source
Building Configuration
Facade Composition
Remaining fraction = opaque wall
Composite Facade Rw
dB
Effective Attenuation (weakest link)
dB
Compliance Status
Per-Storey Analysis
StoreyHeight (m)Slant Dist (m)External (dBA)Internal (dBA)TargetStatus
BS 8233:2014: Living rooms <= 35 dBA daytime; bedrooms <= 30 dBA night. Composite Rw uses area-weighted energy combination. Weakest link = min(composite Rw, ventilation attenuation).
Vibration Source
Receiver & Assessment
Vibration Dose Value (VDV)
m/s^1.75
Wm Frequency Weighting
BS 6472-1:2008 — Human Comfort (VDV)
BS 5228-2:2009 — Construction Vibration (PPV)
DIN 4150-3 — Cosmetic Damage Limit (PPV)
BS 6472 VDV Criteria Reference
Building UseLow Probability (m/s^1.75)Adverse Possible
Residential day0.2-0.40.4-0.8
Residential night0.1-0.20.2-0.4
Office0.4-0.80.8-1.6
Workshop0.8-1.61.6-3.2
PPV attenuation: PPV2 = PPV1 x (10/d)^n. n depends on ground type. VDV (simplified BS 6472): 1.4 x aw x sqrt(T) where aw = PPV x 2 pi f x Wm / 1000 m/s^2. Specialist monitoring recommended for detailed assessment.