Each turbidity calibration mode has a default unit:
Nephelometric Mode: NTU (2020t) or FNU (2020i)
Ratiometric Mode: NTRU (2020t) or FNRU (2020i)
Attenuation Mode: AU (2020t) or FAU (2020i)
The meter will permit the user to choose to report results in any of the other available
calibration units (NTU, FNU, AU, FAU, NTRU or FNRU) other than the default unit. It also
allows the brewing industry to check process water in the nephelometric mode and choose
to have results reported in American Society of Brewing Chemists (ASBC) or European
Brewery Convention (EBC) units.
Acronyms
Defi nitions
NTU
Nephelometric
Turbidity Units
FNU
Formazin
Nephelometric Units
AU
Attenuation Units
FAU
Formazin Attenuation
Units
NTRU
Nephelometric
Turbidity Ratio Units
FNRU
Formazin
Nephelometric Ratio
Units
ASBC
American Society of
Brewing Chemists
EBC
European Brewery
Convention
For more information see ASTM 07726-4 Standard Guide for the Use of Various Turbidimeter Technologies for the
Measurement of Turbidity in Water.
TAKING TURBIDITY WATER SAMPLES
Clean plastic or glass containers may be used for turbidity samples. Ideally, samples should
be tested soon after collection and at the same temperature as when collected.
Notes
Incandescent white light between
400 and 600 nm, 90° detection,
2020t
IR LED (usually) 860 nm, bandwidth
less than 60 nm, 90° detection,
2020i
Incandescent white light between
400 and 600 nm, 180° detection,
2020t
IR LED (usually) 860 nm, bandwidth
less than 60 nm, 180° detection,
2020i
Incandescent white light between
400 and 600 nm, 90° and 180°
detection, 2020t
IR LED (usually) 860 nm, bandwidth
less than 60 nm, 90° and 180°
detection, 2020i
2020t/i
2020t/i
12
Regulatory
Method
EPA 180.1
ISO 7027
Not applicable
ISO 7027
EPA 180.1
Not applicable
Not applicable
Not applicable