[TheForge] Acoustical baffling

[terry l. ridder]

hello;

comments intermixed below.

On Sun, 25 Jul 2004 PlumDon at aol.com wrote:

don>  
don> My 7.5 hp T-30 compressor is located outside my shop and under a roof but  
don> not enclosed. But it is close (100') to a neighbor. It comes on frequently when  
don> I am using the Old Blue hammer or sand blasting cabinet. I'm afraid it is  
don> beginning to irritate them and I would like to head off any problems. 
don>  

an inexpensive way to shield noise is to berm a structure which contains
the air compressor. this could be as simple as a section of corrugated
galvanized steel pipe set on a bed of crushed rock at grade and mound
with sand than top soil. the open ends can be easily capped with sheet
metal or wooded doors. 

another method would be to plant fast growing bushes or trees between
the air compressor structure and your neighbor. the foliage would act as
a sound break and look nice at the same time. would beat the look of
those concrete sound barriers that seem to be sprouting up everywhere
along the expressways ( oxymoron ) in northern illinois.

another example, which a company here used to isolate their backup
generator is given below in ascii art::

                  /\
                /    \
              /        \
            /            \
          /                \ <- simple gable roof
          [][            ][] <- 3ft high wall 
          [][            ][]
          [][            ][]
          [][            ][]<- railroad ties
     /----[][            ][]----\  <-- the actual slope is 
    /     [][            ][]     \     not this steep it is a more
   /      [][            ][]      \    gentle slope.
  /       [][            ][]       \
 / earth  [][            ][] earth  \
/         [][            ][]         \
----------------------------------------- <-- grade

the railroad ties were drilled so that rebar could be driven through
them and into the ground. also deadman anchors were used for every third
railroad tie. the deadman anchors were nothing more than 1 inch threaded
rod with a three foot section of 10 inch diameter concrete. the 1 inch
threaded rod goes through the railroad tie to 1/4 inch steel plate 6
inches heigh by 12 inches wide and tighten down with a lock washer and
nut. 

another company did something similar but used 12 ft i-beams spaced
vertically so that the railroad ties could be slid in between them.

        ---          ---         ---
         |[          ]|[         ]|  <- top view
        ---          ---         ---

        | |[        ]| |[       ]| |
        | |[        ]| |[       ]| |
        | |[        ]| |[       ]| |
        | |[        ]| |[       ]| | <- side view
        | |[        ]| |[       ]| |
        | |[        ]| |[       ]| |
        | |[        ]| |[       ]| |
------------------------------------ <- grade
        | |          | |         | | <- 4ft of i-beam below grade

my 2 cents.

don>  
don> I put up a 4' x 8' wall with T-111 and home insulation. Helps but still a  
don> lot of noise going to the neighbors. I was thinking some kind of convenient  
don> roll-up sound insulating blanket might be available that I could just drop down,  
don> like a shade or curtain when in use. Any one have any experience or 
don> suggestions?  They would be greatly appreciated. 
don>  
don>  
don> Don  Plummer
don> 

-- 
terry l. ridder ><>