Weight Rooms + Sound Transmission Problems

More and more gyms and athletic facilities are being put on higher stories.  Because ECORE manufactures leading brands in both athletic sports surfacing (everlastsportssurfacing.com) and acoustic underlayments (qtsoundcontrol.com), we’re a logical company to turn to for a solution when the dropping of free weights and rhythmic impacts of treadmills become bothersome to adjacent tenants.

Because lightweight construction is so prevalent, there are going to be instances in which there is a structural incompatibility and no superficial floor treatment will sufficiently mitigate the low frequency sound and vibration problems at hand.  (Click here for a list of professionals who can help).  

Historically, the ideal solution was to build a floating floor such as the one detailed below (from M. David Egan, Architectural Acoustics), but we work with a lot of customers who want another option whether it’s due to cost or other preferences.

floatingfloor-egan

We decided to run some field tests with our existing products.  One product that always had a lot of potential to handle significant impacts was our 2.5″ thick molded tile, so this is where our journey towards a better solution began.

IMG_1959

Results have been promising, but we couldn’t ignore the fact that these tiles were designed for lighter use- not the impact of a 100-lb kettle bell at a crossfit gym!  So we’ve been tweaking it and we’ve modified some accessories to help it handle more extreme impacts.  We are still in the process of field testing some test installations, but here is some data from a few field tests we’ve already conducted.

All field tests are conducted by independent, third-party acoustic consulting professionals.  Their participation in these field tests should not be taken as an endorsement of the product.

When interpreting the data below, keep in mind that while loudness is highly subjective, a general rule of thumb (per Egan book) follows:

Change in Sound Level (dB)Change in Apparent Loudness
1Imperceptible (except for tones)
3Just barely perceptible
6Clearly noticeable
10About twice (or half) as loud
20About 4 times (or one-fourth) as loud

Field Test #1 at a gym in Toronto, Canada.  Testing conducted by HGC Engineering.

  • FIIC test and 80-lb. dumbbell drops from approx. 3-ft. high
  • Assembly: 8″ hollow core concrete slab (FIIC 21, 128.5 dBI/95.6 dBAI)
  • Treatment: 2.5″ thick ECORE molded tiles (FIIC 60, 124.9 dBI/81.9 dBAI)

Field Test #1 Results

 Tapping Test80-lb Dumbbell Drop Test (from 36" high)
FIICdBAI (A-weighted, impulsive sound level)
Existing/Bare Slab2197-100
2.5" Treatment6053-56

Results: FIIC: 39 dB improvement; dumbbell drops: 44 dBA improvement

HGC1

 

Field Test #2 at a different gym in Toronto, Canada.  Testing conducted by HGC Engineering.

  • FIIC test and 80-lb. dumbbell drops from approx. 3-ft. high
  • Assembly: 10″ concrete slab (FIIC 34, 129.2 dBI/101.3 dBAI)
  • Treatment: 2.5″ thick ECORE molded tiles (FIIC 65, 127.5 dBI/81.2 dBAI)

Field Test #2 Results

 Tapping Test80-lb Dumbbell Drop Test (from 36" high)
FIICdBAI (A-weighted, impulsive sound level)
Existing/Bare Slab3496-100
2.5" Treatment6461-66

Results: FIIC: 30 dB improvement; dumbbell drops: 35 dBA improvement

HGC2

 

Field Test #3 at a gym in Omaha, Nebraska.  Testing conducted by The Sextant Group.

  • FIIC test and 50-lb. dumbbell drops from approx. 2.5-ft. high
  • Assembly: 8mm Everlast Flooring, QT4005 underlayment, 4″ concrete slab, 12″ ceiling plenum, GWB ceiling (no knowledge of resilient channels or insulation in ceiling cavity) (FIIC 67, 71.1 Leq (dB)/49.6 LAeq (dBA))
  • Treatment: 2.5″ thick ECORE molded tiles (FIIC 69, 66.4 Leq (dB)/35.7 LAeq (dBA))

Results: FIIC: 2 dB improvement; dumbbell drops: 4.7 Leq (dB)/13.9 LAeq (dBA) improvement

Sextant1

 

While the single number dB improvements are helpful, I find it particularly useful to see the entire sound spectrum in graphical form, as it allows one to better understand what is really happening to the sound energy.

In building acoustics, frequency ranges are generally classified as: low (50-200 Hz), mid (250-1000 Hz), and high (1250-5000 Hz).  Traditional ASTM sound transmission test procedures do not include all of the data in the low frequency range (they range from approx. 125-5000 Hz).  For most commercial and residential applications, this is acceptable, but in the case of gyms and weights being dropped you can see that the bulk of the sound energy occurs in the lower frequencies, below 125 Hz.  For this reason, the FIIC ratings are not as helpful in determining actual improvement as are the impulsive sound pressure levels or 1/3 octave band data gathered from dumbbell drops.  We also made sure to include data down to 20 Hz, which is generally considered the lowest threshold of human hearing.  As you can see even at 20 Hz, which is barely audible for most people, our 2.5″ tile makes some improvement

We hope you’ve found this information helpful.  If you’d like more information about this product, please click here to contact your nearest regional sales manager or leave a comment and I’ll get back to you myself.



'Weight Rooms + Sound Transmission Problems' have 5 comments

  1. December 13, 2014 @ 11:26 am Philip Greene

    Has this become a product yet? My business located next to a crossfit gym. We did not realize that crossfit involves dropping weights (shame on us). However, we are working with the building owner to find a solution and this looks ideal.

  2. December 16, 2014 @ 1:05 pm Philip Greene

    Has this testing resulted in a product yet?

  3. December 16, 2014 @ 1:49 pm Philip Greene

    I wanted to find out if this is a product that is available yet. Can samples of these tiles be ordered for testing?

  4. September 13, 2016 @ 1:20 pm Dave

    Please let me know if you are still pursuing this product development, or have developed it for sale.
    Thanks,
    Dave Wilson


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Sound Advice is a division of ECORE International designed to keep you informed with the latest and greatest in architectural acoustics. Contact us at 717.598.3335 or spaley@ecoreintl.com.