Standards Development

Scope

The proposed International Standard defines the terminology, structure, and measurement methods of distributed fibre optic sensors for static strain measurements based on Rayleigh scattering in optical fibres, where the fibre is the distributed strain sensing element. This standard also specifies the most important features and performance parameters of these distributed fibre optic strain sensors and defines procedures for measuring these features and parameters. If approved, this standard will be part of the IEC 61757 series, which is dedicated to fibre optic sensors. The individual parts of the IEC 61757 series are numbered as IEC 61757-M-T, where M denotes the measurand and T the technology of the fibre optic sensor. The sub-series IEC 617575-1-T is concerned with strain measurements. It should be noted that distributed fibre optic sensors based on Rayleigh scattering exhibit significantly different features than those based on Brillouin scattering, which are already covered by the companion standard IEC 61757-1-2.

Purpose

Specific aims and reasons for this standardization activity
The proposed International Standard provides manufacturers and applicants of distributed strain sensing systems (DSS) with technical specifications and related measurement procedures, which will improve the confidence in this new technology and accelerate its acceptance in the market, especially for safety relevant applications. The proposed standard defines harmonized and technically accurate specifications as well as corresponding test methods to determine the performances and the reliability of DSS based on Rayleigh scattering in optical fibres.
Main interest and timeliness of the activity
Fibre optic DSSs are already used in various fields of application, but still on a relatively small scale. This standard will accelerate DSS deployments in a variety of fields, including structural health monitoring (SHM) in civil engineering (e.g. piles, walls, dams, and bridges), geotechnology (e.g. ground movements and landslides), oil and gas (e.g. pipeline deformation and material fatigue monitoring) and electrical power cables (e.g. deformation and installation). Rayleigh-based (and Brillouin-based) DSS offer the advantage that they employ just a single optical fibre to detect signs and progress of localized structural defects over fairly large distances. However, broader acceptance of this sensor technology is hindered by the lack of internationally harmonized standards in this field.
Feasibility of the activity
There are no factors (e.g. patents, principal regulations from regulatory bodies) known, which could hinderthe successful establishment or general application of the standard. Moreover, WG 2 of SC 86C has 69 expert members from 17 countries, representing a wealth of expertise and knowledge in the field of fibre optic sensing.

Benefits
Equipment vendors and users both will benefit from this standard, which provides well-defined guidelines to manufacturers for specifying measurement performance and reliability of their products and, in addition helps users to select, install and operate fibre optic DSS systems based on widely recognized procedures.