I wouldn’t be able to give you an exact answer, but I’ve helped introduce two or three, and analysed maybe around ten. I’ve spent around 6 months in total doing some work for a guideline to help the safe design of pipelines though – so I may indirectly help introduce many many more in the future!
This is a good question though – sometimes people tell you what they do (e.g. design pipelines!) and you think “Ok… but how many? 1, 10, 100, 1000?” So to give you an idea, a project usually takes in the region of weeks to months, so that’s why the number of pipes is around the 10-15ish number.
Comments