IEC 61757-1-1:2016

Overview

IEC 61757-1-1:2016 - “Fibre optic sensors - Part 1-1: Strain measurement - Strain sensors based on fibre Bragg gratings (FBG)” defines detailed specifications for fibre optic strain sensors that use one or more fibre Bragg gratings (FBG) as the sensing element. Read together with IEC 61757-1:2012 (generic fibre optic sensor specifications), this part specifies the most important features and characteristics of FBG-based strain sensors and the procedures to determine them, including basic performance parameters for the corresponding optical readout instruments. The standard covers measurement of both static and dynamic strain across relevant frequencies and provides a blank detail specification in Annex B.

Key topics and technical requirements

• FBG element and spectral properties: definition and measurement of Bragg wavelength, spectral width, reflectivity and side-lobe behavior.
• Sensor configuration and installation: FBG strain sensor configurations, measuring point, gauge length, attachment and production/series identification.
• Performance characteristics to be measured and reported: strain sensitivity, gauge factor, maximum strain range, fatigue behaviour, minimum operating radius, temperature- and humidity-related ranges, temperature-induced strain response, stability (drift, creep, hysteresis).
• Test methods and sampling: procedures for tensile tests, bending (gauge factor) tests, fatigue tests, proof tests and environmental conditioning; sampling plans (random, type, series and individual testing) and statistical reporting.
• Measuring instrument guidance: basic performance parameters and recommendations for FBG readout instruments used to convert optical signals into strain values.
• Documentation: blank detail specification (Annex B) and guidance on what construction, operational and limiting parameters must be reported.

Applications and who uses this standard

IEC 61757-1-1 is intended for:

• Sensor manufacturers developing and documenting FBG strain sensors and production test regimes.
• Test and calibration laboratories performing type and acceptance testing of FBG strain sensors.
• System integrators and instrumentation engineers selecting sensors and readout instruments for structural health monitoring, civil and aerospace structures, energy infrastructure, rail and transport systems, and industrial process monitoring.
• Procurement, certification and quality assurance teams that require standardized performance data and specification templates for FBG strain sensors.

Practical benefits include consistent performance characterization, comparable supplier data, reliable instrument-sensor pairing, and standardized test methods to support long-term structural monitoring projects.

Related standards

• IEC 61757-1:2012 - Generic specifications for fibre optic sensors (to be read in conjunction with IEC 61757-1-1).

Keywords: fibre Bragg gratings (FBG), strain measurement of fibre optic sensors, FBG strain sensor, FBG measuring instrument, structural health monitoring.