Hot saw

A mason was cutting concrete block (cinder block) with a Stihl cut off saw (aka hot saw) Measured sound level readings were found up to 113 dBA (decibels A-weighted).  Although full shift noise dosimetry was not performed, given the intensity of exposure, under OSHA rules he should limit his exposure to 0.33 hours (or 20 minutes).  (see chart below – or 1910.95 (b)(2)table G-16)

The mason was wearing hearing protection (ear muffs). With that exposure, and a noise reduction rating (NRR) of 26 NRR, the employee could have exposure to his ear of up to 100 decibels.  – because, you can only take a portion of the noise reduction rating (half of it, is easiest – making the 26 NRR only worth 13).  Therefore 113 minus 13 is 100 at the ear.

Now, to make you worry more. OSHA’s method for viewing noise exposure is antiquated.  Someday we’ll discuss the ACGIH and their TLVs and how they compute noise exposure.

The point: This guy is making some noise, has exposure, and might do this activity all day.

How many hot saws are there in construction? At least he was using a hose to wet the dust down…more of that later.