What is BS EN 61191-3 - Printed board assemblies about?  
BS EN 61191 is an international standard that discusses printed board assemblies. The main objective of the BS EN 61191 series is to provide manufacturers of printed board assemblies with best industry guidance on ensuring their products play a positive role in the functioning of electronic applications.
BS EN 61191-3 is the third part of the multi-series that provides requirements for lead and hole solder assemblies. The requirements pertain to those assemblies that totally use through-hole mounting technology (THT), or the THT portions of those assemblies that include other related technologies (i.e. surface mount, chip mounting, terminal mounting).
Who is BS EN 61191-3 - Printed board assemblies for? 
BS EN 61191-3 on requirements for through-hole mount soldered assemblies is useful for: 
- Manufacturers of electronic equipment and components
- Manufacturers of printed board circuits and semiconductors
- Manufacturers of automotive parts
- Manufacturers of surface mounting devices
- Electronic engineers
- Product design engineers
Why should you use BS EN 61191-3 - Printed board assemblies?  
A PCB works at the heart of every electronic device. However, for its optimal functioning, adopting best industry practices on attaching electrical components to the circuit board via soldering, is vital. In this regard, through-hole technology is one that permits an electrical connection of components to a conductive pattern by the use of plated or non-plated holes with annular rings in the mounting substrate.
BS EN 61191-3 provides you with best industry requirement and practices for designing and assembling these printed boards. BS EN 61191-3 covers the assembly of components with leads inserted into through-holes and soldered by machine and/or manual processes.
The requirements provided can also aid in better selection of insulation materials, that can withstand higher external stresses.
To ensure part retention during soldering operations, BS EN 61191-3 also covers configurations for lead terminations in printed board plated through-holes.
Thus, BS EN 61191-3 can be your guide on ensuring lead and hole solder assemblies that use THT, impart adequate level of bonding between layers, that can prevent damage from vibrational or shock forces. If you are a manufacturer, this can ultimately help ensure that the electrical functions are fully implemented, thus contributing to the overall quality, reliability and performance of the end-use application.
What’s changed since the last update?
BS EN 61191-3:2017 supersedes BS EN 61191‑3:1999, which is withdrawn. BS EN 61191-3:2017 includes the following technical change with respect to BS EN 61191‑3:1999:
- The requirements have been updated to be compliant with the acceptance criteria in IPC-A-610F
