The sound-absorbing coefficient which shows decrease of acoustic, water absorption degree means it reveals coefficient of correlation of reverberation hour with the remainder acoustic diminishing fact from the sample in the reverberation room.
 
 
Freudenberg Forschungsdienste KG

Sound-absorbing measurement by DIN EN 20354 and NR
 

measurement by ASTM C 423-90a

Foot notes : NRC = Noise Reduction Coefficient)
 
 
 
   
 
Examination date : 2001.07.19
Examination material : JEIL PLANK CEILING
  (STL 0.6T, 400mm X 1200mm, powder coating)
Examination condition : Temperature 22℃, Relative humidity 75%
Examination result : NRC = 0.35
 
   
 
Examination date : 2001.06.08
Examination material : JEIL PLANK CEILING
  (STL 0.6T, 400mm X 1200mm, powder coating) w / Acoustic fabrics (0.2T)
Examination condition : Temperature 21℃, Relative humidity 68%
Examination result : NRC = 0.55

 
   
 
Examination date : 2001.06.13
Examination material : JEIL PLANK CEILING
  (STL 0.5T, 300mm X 1200mm, powder coating) w / Acoustic fabrics (0.2T)
Examination condition : Temperature 21℃, Relative humidity 66%
Examination result : NRC = 0.65

 
   
 
Examination date : 1999.02.01
Examination material : JEIL TILE CEILING
  (AL 0.8T, 600mm X 600mm, powder coating) w / Acoustic fabrics (0.2T)
Examination condition : Temperature 20℃, Relative humidity 30%
Examination result : NRC = 0.75

 
   
 
Examination date : 1999.02.08
Examination material : JEIL TILE CEILING
  (AL 0.8T, 600mm X 600mm, powder coating) w / Acoustic fabrics(0.2T), glass fiber(25T)
Examination condition : Temperature 20℃, Relative humidity 40%
Examination result : NRC = 0.80

 
   
 
Examination date : 2001.02.21
Examination material : JEIL PLANK CEILING
  (AL 1.0T, 450mm X 1700mm, powder coating) w / Acoustic fabrics (0.2T)
Examination condition : Temperature 21℃, Relative humidity 56%
Examination result : NRC = 0.70

 
   
 
Examination date : 1999.02.03
Examination material : JEIL PLANK CEILING
  (STL 0.7T, 300mm X 1200mm, powder coating) w / Acoustic fabrics (0.2T)
Examination condition : Temperature 20℃, Relative humidity 37%
Examination result : NRC = 0.75

 
   
 
Examination date : 1999.02.08
Examination material : JEIL PLANK CEILING
  (STL 0.7T, 300mm X 1200mm, powder coating) w / Acoustic fabrics (0.2T), glass fiber(25T)
Examination condition : Temperature 20℃, Relative humidity 40%
Examination result : NRC = 0.80

 
   
 
Examination date : 1999.02.03
Examination material : JEIL TARTAN CEILING
  (STL 0.7T, 1200mm X 1200mm, powder coating) w / Acoustic fabrics (0.2T)
Examination condition : Temperature 20℃, Relative humidity 37%
Examination result : NRC = 0.70

 
   
 
Examination date : 1999.02.08
Examination material : JEIL TARTAN CEILING
  (STL 0.7T, 1200mm X 1200mm, powder coating) w / Acoustic fabrics (0.2T), glass fiber (25T)
Examination condition : Temperature 20℃, Relative humidity 40%
Examination result : NRC = 0.75

 
NGC Testing Services Acoustical Testing Laboratory

NRC by ASTM C 423-99a and SAA measurement
(Foot notes : SAA = Sound Absorption Average)
 
   
Examination date : 2001.12.13
Examination material : JEIL PLANK CEILING (STL 0.7T, 300mm X 1200mm, powder coating (0.06T) w / Acoustic fabrics (0.2T)
Examination condition : Temperature 19℃, Relative humidity 46%
Examination result : NRC = 0.70 & SAA = 0.71

 
   
Examination date : 2001.12.13
Examination material : JEIL PLANK CEILING (STL 0.7T, 300mm X 1200mm, powder coating (0.06T) w/ Acoustic fabrics (0.2T), glass fiber (30T)
Examination condition : Temperature 19.1℃, Relative humidity 48%
Examination result : NRC = 0.90 & SAA = 0.87