Ajak,
The butterfly valve you’re referring to can be a lug type with a through hole. This is common practice. However, also consider that the tapped hold provides some added stability for a simple valve like the butterfly, and the flanges surrounding the butterfly valve will address the pipeline integrity challenges, so long as the proper flange classes (and corresponding stud bolts) are properly selected for the pipeline medium and pressure. In case it is useful, I’ve attached a reference bolt chart for common flange sizes.
