If you have followed today's news of Chandigarh getting flooded with floating cars only within 3 hours of rains, you will realise that we are seeing a change in weather pattern and metros are also affected by it.
Normally, metros are designed for highest flood level recorded and average rain fall of a particular place.
Architects in most cases leave all this to plumbing designer. But this year itself reports from various metros in country established that all is not right. Across the country many stations were flooded and leakages damaged critical installations in many cases.
I did a study of plumbing design of some cases. Infact I asked one of trainees with me to help me carry out the design from scratch for an elevated station and when we compared it to actual provisions done on some stations in country, results were shocking.
As a strategy, in line with IGBC requirements, we modelled the design from rainwater collection to rainwater harvesting. And a summary of the same is given below for all of you to check and consider in designs.
1. Inadequate provision of stormwater drainage on stations.
2. Violation of National Building Code - part 2, clause 4.5.11. There is detailed requirements given here for storm water drainage.
3. Violation of code of practice for fixing rainwater gutters and downpipe for roof drainage IS: 2527.
My advise to Architects is to atleast once read through these above references. Trust me you will realise that things can be made better if you knew about these.
For example as per code every 90 degree bend makes efficiency of a rainwater pipe lesser by 25%, which means that if you provide 2 bends in a RWP you are going to need double the number of downtake pipes.
Hope you find this advise useful and utilise the knowledge for better coordination and checks with plumbing design.
☔☔☔