Roof drain piping

[cieg22]

I'm working on a warehouse that's had a ton issues with leakage, and the client adamantly wants the roof drainage, which currently is picked up by roof-drains and interior piping, redirected to downspouts outside the building. The downspout will tie into the storm sewer (like the existing system it's replacing). The building is about 60' tall, and we are in a cold climate. Can anyone direct me to a code/standard/guidance that would provide direction about exterior downspouts on tall buildings, specifically dealing with things like maximum allowable drops, ventilation requirements, and considerations of bends and such in freezing temps? While I found some general stuff about downspouts in the International Plumbing Code, I didn't see these issues addressed. TIA.

 

[1503-44]

You might want to contact the nearest city's building department.

 

[LittleInch]

Try this and following a few of the links

https://www.eng-tips.com/viewthread.cfm?qid=451231

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[PEDARRIN2]

Exterior downspouts are typically handled by the architect and the roof change (roof drain to gutters) would be their scope. 2015 IPC 1106.3 has some information about sizing the vertical leaders. 2012 IPC 1106 has a bit more information. Not anything specific about heights, maximum or otherwise. No need for ventilation for storm and do not think you would have bends.

 

[HTURKAK]

Not sure i got the full picture . I guess the roof inlet gullies connected to lateral headers and the headers directed to exterior wall so the the down spouts outside the bldg. Is this true?

Will you provide more details ; size of the bldg, roof type (flat roof or roof with ridges and valleys ), the building is heated or not, design temperatures ( max and min ), propose piping material ???

 

[cieg22]

Thank you all for the input. To answer the question above - this would not at all be a typical (or ideal) situation. There's no budget to change the roof, I'd have to pipe down from the drain and then out through the wall to a downspout. After thinking about this some more today, I'm going to try persuade the client again to keep the piping inside. Thank you all for your help.