Good day to all,

As per my research, the minimum slope of impulse line is 1:12

Can anyone here knows how to explain this, and how can we apply this in the actual scenario?

TIA

 

Historically it is imperial measurement based: 1 inch per foot (12 inches).

I suspect that ratio was chosen because it was an easy means for the installation contractors to remember. I seriously doubt any 'study' was ever done, it was just a convenient ratio in the in-use measurement system combined with common sense from experience in drainage, making sure that any condensate flows downhill towards a drop leg with a drain.