How to Calculate L10 for Road Noise
- 1). Count the number of vehicles passing by the site during the interval for which L10 must be calculated. For example, to calculate L10(18 hr) count the number of vehicles during a given day, between 6 am and midnight. That is considered a representative 18-hour interval.
- 2). Adopt a decibel scale for your calculations by evaluating the following formula:
scaledQ = 10 x log(Q)
Replace "Q" by the vehicle count obtained in Step 1. "log()" denotes the logarithm in base 10. - 3). Apply a correction factor for the average amount of noise from a single vehicle, by evaluating the following formula:
L10 = 28.1 + scaledQ
The constant 28.1 in the formula above represents the 90th-percentile amount of noise attributed to a single vehicle in this method for estimating L10. Because L10 is computed in a logarithmic scale, adding 28.1 to the scaled vehicle count is equivalent to multiplying the non-scaled vehicle count by 28.1 in the original linear scale.
The result of this calculation is measured in dbA. It is a quite accurate estimation for the L10 parameter you need to design the building.
