Common Questions About Construction Noise Measurement

• 1.Do I need a dosimeter or a sound level meter?

  Use a dosimeter when you need one worker's full-shift exposure (LEX,8h) as they move around the site. Use a handheld sound level meter when you need a spot reading at a fixed point — a machine, a work zone, or the site boundary. Many programs use both: dosimeters for the crew, a meter for everything else.

• 2. How often does the instrument need to be calibrated?

  Field-calibrate with an acoustic calibrator immediately before and after every measurement session — this only takes a minute and protects the whole data set from an undetected drift. Beyond that, most meters and calibrators also need a full laboratory calibration on a periodic cycle (commonly every 1–2 years); check the certificate that shipped with your instrument for the exact interval.

• 3. Is a Class 2 sound level meter accurate enough for a construction site?

  For general-purpose work — checking machinery, work-zone levels, and most occupational exposure surveys — a Class 2 meter is accurate enough and is what most site teams use. Class 1 becomes necessary when a specific regulation calls for it, or for precise low-level environmental measurements and narrowband frequency analysis.

• 4. What noise level triggers hearing protection requirements?

  85 dBA as an 8-hour time-weighted average is the commonly referenced action level (OSHA/NIOSH) at which hearing conservation measures — protection, monitoring, rotation — are expected to start. Many single pieces of construction equipment exceed this on their own, so protection is often required well before a full shift is logged.