free available chlorine
The term free available chlorine means the value obtained using any of the chlorinefree available methods in Table IB in 40 CFR 136.3(a) where the method has the capability of measuring free available chlorine, or other methods approved by the permitting authority.
Source
40 CFR § 423.11
Scoping language
In addition to the definitions set forth in 40 CFR part 401, the following definitions apply to this part: