I got exposed to a handheld circular saw around 18-19 meters away from me

I got exposed to a handheld circular saw operated by a person around 18-19 meters away from me. I only got exposed for around 10 seconds while passing through to go inside a building. I haven’t noticed major ringing, but my left ear kind of hurts, This took place outside and the person was wearing ear muff hearing protection and I wasn’t wearing any protection at all. I’m I at risk for permanent hearing loss?

I would not think so for that short of time. Yes your ears may bother you for a while. Just monitor how things go. My dad and uncle did a lot of work building homes, and I am sure with hours of exposure you would have issues. My dad never had hearing loss and I cannot remember him wearing any type of hearing protection.

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We all get the odd loud noise exposure. You’re walking along the street and then a siren fires up near by. If you have normal hearing then you might get some short term ringing or as you say pain. And then you carry on with life. Horns honking. Planes nearing approach and particularly take-off. Construction jack-hammers. The list goes on. When those loud noises happen I whip my hands up to plug and cover my ears. That’s a challenge with hearing aids.
And then there’re the loud noises we choose to consume. Concerts, headphones, tv.

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If at all possible I would cup my hands over my ears if one anticipates a loud noise. If I ever have to pull over to the side of the road to let an emergency vehicle pass, I cup my hands over my ears as soon as I pull to a stop. Although one may not be able to completely block the sound, at least one can attenuate it.

Sorry you had this terrible experience but it is too late now. Your hearing is damaged for the rest of your life. At least you have discovered a support group where others will commiserate and recommend ways to adapt. I do hope you at least were wearing a face mask and gloves.

The intensity of sound falls off as the inverse square law, if I remember correctly. There is a maximum upper limit to the intensity of sound based on the physics of air, etc. Again, if memory serves me, it’s 190 dB (but I forget what the 0 dB reference point is). However, most determinations online show that a handheld circular saw operates in the range of 110 to 120 db. So I think if you apply the inverse square law, you will find at 18 to 19 meters away (18 meters is 59.1 feet!), you will find that the sound could not possibly have been been loud enough to permanently damage your hearing unless you stood around for a considerable period of time. There is one catch. The inverse square law only applies to point sources. But what one learns as a health physicist (and a CHP to boot!), is that when you are more than about 10 times away from the widest diameter of a source, a radioactive source behaves approximately like a point source (particle radiation and electromagnetic radiation follows the inverse square law, too). So unless the sawed area is more than about 6 feet in length, the sound was falling off by the inverse square law most likely.

If the circular saw were 120 dB above a quiet background and 85 dB is “safe” for 8 hours exposure, AT THE SAW, the noise is 35 dB above a “safe” exposure level. (here’s where an expert HCP could help me on what dB increment should be taken as the doubling factor to work with), actual sound pressure doubles for every 6 db increase. So 35 dB above a “safe” level is essentially 6 doublings and 2 raised to the 6th power is factor of 64x above a “safe” sound pressure level. However, if the 120 dB is experienced at 1 foot from the saw, then ~60 feet away by the inverse square law is going to be 1/3,600 (60^2) less exposure. If the circular saw were actually 190 dB, the inverse square law would not provide adequate protection - but if that were so, as soon as anyone fired up a circular saw, they would instantly go deaf. Carpenters and other folks who use power tools experience significant hearing loss by the time they are 30 if they don’t use hearing protection but they are not using these tools at a distance of 18 meters and they use them day in and day out and only gradually lose their hearing over a period of years.

Even if you take 3 db as the increment at which sound “intensity” doubles, the results come out pretty much the same. At 18 m away, you are not going to experience a hurtful level of sound exposure for any short period of exposure.

Edit_Update: According to the Wikipedia equation in my subsequent post below, I should have used 3 dB as the decibel sound level doubling/reduction factor, not 6 dB as I did in my calcuations above. Putting 1/59.1 for the distance ratio into the Wikipedia equation gives an ~35 dB sound level drop and 35 dB divided by 3 dB per doubling/reduction, depending on which way you’re going, gives 11.7 doublings. 2 raised to the 11.7th power is a ~3,300 reduction factor going by decibels, which agrees well with the reduction factor computed from the square of the distance 59.1 feet (~3,500) going by the inverse square law and just relative distances.

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Oooh! Sarcasm! I do love seeing a bit of sarcasm in a ‘support group’.

Actually, the Wikipedia article on sound pressure is quite good. And the article points out that reference sound levels without specifying distance and other conditions such as reflective surfaces present when a sound level determination is made make data not very good. The article says the standard reference distance is often ONE meter. And the article provides a handy formula to stay within the decibel scale and take account of distance while applying the inverse square law.

image

A handy web calculator to do the calculation for you is here:

https://www.easycalculation.com/physics/classical-physics/decibels-distance.php

So if instead of using 1 foot as the distance at which a circular saw is 120 dB in loudness you use 1 METER, the sound level would be about 25 decibels lower at 18 meters. If you use 0.33 meter as the reference distance for measuring sound level, you get 35 dB lower at 18 m as I previously calculated the long way round.

The other interesting stuff you find on the web (besides wearing ear protection) is how keeping the saw in good condition can make a big difference in noise level for the user. Two pointers were to have sharp saw teeth and to maintain the blade mount so that the blade wobbles as little as possible while rotating.

The Wikipedia article on sound pressure cited above also defines what the reference level 0 dB sound level is:

The commonly used reference sound pressure in air is[6]

image

which is often considered as the threshold of human hearing (roughly the sound of a mosquito flying 3 m away)(!!!).

I think it’s Martin and Clark’s Introduction to Audiology that says most of us, especially as we grow into adulthood don’t have hearing anymore quite this good, so as a tip of the hat to the mass of us, threshold hearing at 10 to 15 dB louder is still considered “normal.”

Criminal that NIOSH does have tables of power tools noise levels but they reference ANSI and ISO standards that you have to pay $$$ money to buy to find out that methodology (and distance) at which the sound levels in the NIOSH tables were measured. They should simply offer the methodology as appendix material to their tables. See spreadsheet The NIOSH Power Tools Sound Power referenced on following web page: CDC - Noise and Hearing Loss Prevention - NIOSH

In the NIOSH tables the median A-weighted sound level (see Wikipedia article on A, B, and C weighting) is 109 dB for with a max value of 113 dB for 38 circular saws that they tested from a variety of popular brands.

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Thanks for the research. This certainly fits my “gut” impression. Circular saws aren’t that crazy loud and at a distance of almost 60 feet and for a very short time, I wouldn’t expect much, if any long lasting effect.

This mirrors near exactly other first time posts up here that present an equally ludicrous one time exposure “story”, then vanish. This is a troll, stop feeding.

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I wouldn’t be so quick to dismiss the post. Many people worry about damaging their hearing by going to a rock concert or something like that. I agree with the science that a singular exposure is not likely to do much harm, but it may still be a cause of worry. I think we should remain a source of support, not criticism of our members

I’ve had the usual array of loud noise experiences, including walking on the tarmac as jet planes were starting up or going to a loud wedding. My ears would ring for a few minutes, but I never noted a real decrement in hearing. Of course, I would worry about it, and for all I know it may have had some effect.

My hearing loss started around 15 years ago (at least when I first noticed it) and has been on the typical downhill course of high frequency sensorineural hearing loss of aging since that time. I cannot point to anything that is the “cause” of it.

–Steve

OTH, the post motivated me to look up stuff on noise levels and I was particularly struck to find out how relatively dangerous popping a large balloon is right next to one’s ears. Since I have a couple of young grandkids who will undoubtedly try doing that sooner or later, the guy/gal’s post may have saved someone’s hearing in my family or someone else’s kid at a birthday party, etc. I’m letting my daughters know about balloons. I never considered them so relatively loud and dangerous (up to 160 to 170 dB).

The other interesting thing in the same Wikipedia table is how loud a stun grenade is. Perhaps after a SWAT team delivers such a charge, the perps are not too likely to be able to hear “put your hands up or we’ll shoot!”

Yeah I always get a kick out of gun fights in the movies/tv. You’re in an enclosed space and gun shots are LOUD and nobody flinches. A gun fight…fuggedaboudit. The survivors would all be deaf.