19515.5. Chemical Composition 
Tolerance
(+ or -
Oxides
Percentage Weight
Percentage Range)
Silicon Dioxide
66-75
1.00
Aluminum Oxide
 0-7 
0.50
Calcium Oxide
 5-15
0.50
Magnesium Oxide
 0-5 
0.50
Sodium Oxide
 8-18
0.50
Potassium Oxide
 0-4 
0.50
Iron Oxide
 less than 0.5
0.05
Chromium Oxide
 less than 0.1
0.02
Sulfur Trioxide
 less than 0.2
0.02
All other oxides
 less than 0.1
0.02
Organic Carbon
 less than 0.1
0.02
Moisture Content
 less than 0.5
0.05
(No caking with free-flowing fiberglass)
Loss on Ignition
 less than 1.0
0.10
(Added by Stats. 1991, Ch. 706, Sec. 1.)