ISO 7027-1-2016 PDF

Full title and description

ISO 7027-1:2016 — Water quality — Determination of turbidity — Part 1: Quantitative methods. This International Standard specifies quantitative optical methods (nephelometry and turbidimetry) for determining the turbidity of water using optical turbidimeters or nephelometers.

Abstract

ISO 7027-1:2016 defines two quantitative measurement procedures: (a) nephelometry for measurement of diffuse (scattered) radiation, suitable for low-turbidity waters (for example drinking water), and (b) turbidimetry for measurement of attenuation of a radiant flux, more applicable to highly turbid waters (for example wastewater). Nephelometric results are expressed in nephelometric turbidity units (NTU) — numerically equivalent to formazin nephelometric units (FNU) — with typical ranges from below 0.05 NTU up to about 400 NTU. Turbidimetric results are expressed in formazin attenuation units (FAU), typically from about 40 FAU to 4 000 FAU.

General information

• Status: Published (International Standard, confirmed).
• Publication date: June 2016 (confirmed in review 2021).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 13.060.60 (Examination of physical properties of water).
• Edition / version: Edition 1 (ISO 7027-1:2016).
• Number of pages: 9 (ISO publication length).

These bibliographic details are those given on the ISO record for ISO 7027-1:2016.

Scope

ISO 7027-1:2016 applies to quantitative optical determination of turbidity in water using calibrated turbidimeters or nephelometers. It covers measurement principles, expression of results (NTU, FNU, FAU), applicable measurement ranges for each method, and reference/primary materials (formazin) used for calibration and verification of instruments. The standard is intended to address both low-turbidity (drinking) waters and higher-turbidity waste or surface waters by using the appropriate optical technique.

Key topics and requirements

• Definition of two quantitative methods: nephelometry (measurement of scattered light) and turbidimetry (measurement of attenuation).
• Units and equivalence: nephelometric turbidity units (NTU) ≈ formazin nephelometric units (FNU); turbidimetry in formazin attenuation units (FAU).
• Typical measurement ranges provided for each method (nephelometry: ≲0.05 to ~400 NTU; turbidimetry: ~40 to 4 000 FAU) and guidance on instrument applicability.
• Requirements for calibration, verification and use of formazin (or equivalent) reference material for instrument checks.
• Measurement geometry and procedural guidance (e.g., recommended detection angles and instrument configuration for nephelometric and turbidimetric determinations).

Typical use and users

ISO 7027-1:2016 is used by water quality laboratories, public water suppliers, wastewater treatment operators, environmental monitoring organizations, instrument manufacturers and testing laboratories that perform routine and compliance turbidity measurements. It is also referenced by national bodies and laboratories when specifying test methods, instrument procurement, calibration and quality control procedures.

Related standards

ISO 7027-1:2016 replaced and superseded the earlier ISO 7027:1999 (withdrawn). The ISO 7027 series also includes Part 2 (ISO 7027-2:2019), which covers semi-quantitative/visual assessment methods (and related regional/adopted versions such as BS EN ISO 7027-2:2019). Users should consult the full ISO 7027 series for other parts and national/adopted editions.

Keywords

turbidity, nephelometry, turbidimetry, NTU, FNU, FAU, formazin, water quality, turbidimeter, nephelometer, calibration, ISO 7027.

FAQ

Q: What is this standard?

A: ISO 7027-1:2016 is the International Standard that specifies quantitative optical methods (nephelometry and turbidimetry) for measuring turbidity in water.

Q: What does it cover?

A: It covers measurement principles, units (NTU, FNU, FAU), typical measurement ranges, instrument calibration/verification (including use of formazin reference material), and procedural guidance for nephelometric and turbidimetric determinations of turbidity.

Q: Who typically uses it?

A: Laboratories performing drinking-water and environmental monitoring, water and wastewater utilities, instrument manufacturers, and conformity assessment bodies use this standard for routine and compliance turbidity measurement.

Q: Is it current or superseded?

A: ISO 7027-1:2016 is the current published Part 1 of the ISO 7027 series; it superseded ISO 7027:1999. The Part 1:2016 edition was reviewed and confirmed in 2021. Users should check for any newer revisions or related parts in the ISO 7027 series.

Q: Is it part of a series?

A: Yes — ISO 7027 is a multi-part series. Part 1 (this document) covers quantitative methods; Part 2 (ISO 7027-2:2019) covers semi‑quantitative/visual assessment methods and related guidance. National adoptions (for example BS EN ISO versions) also exist.

Q: What are the key keywords?

A: turbidity, nephelometry, turbidimetry, NTU, FAU, FNU, formazin, water quality, turbidimeter, nephelometer.