House trap config with Combined Sewer?

[DIYorBust]

This question seems to be stumping everyone on the job. This house was built before the code and had a combined sewer. The code in NYC, based on IPC, requires separate sanitary and storm sewers even though both will empty into a combined sewer at the street(because the city does not have seperate sewers in this area).

The plumber interepreted that to mean that there should be a seperate house trap on the storm sewer into which all the outdoor patio drains empty. If this is the case, do the patio storm drains need a trap? Also, does the storm sewer house trap need to be vented(I assume yes) and what vent would it connect to? Presumably if it is vented to the stack, sewer gas could emerge from any untrapped patio drains.

Thanks!

DIY

 

[Reach4]

The code in NYC, based on IPC,

I am pretty sure you are incorrect on the assumption that the plumbing code in NYC is based on IPC.

 

[Sponsor]

 

[DIYorBust]

I am pretty sure you are incorrect on the assumption that the plumbing code in NYC is based on IPC.

They actually are, but heavily modified. Primarily, various provisions of IPC were made more restrictive and conservative, but most of it is pretty similar to IPC.

"The 2014 New York City Construction Codes, effective December 31, 2014, are patterned after the family of model construction codes published by the International Code Council (ICC). While the ICC Codes, with their interpretive commentary and history of amendments, will in the future be a rich new source for interpreting the City’s building laws, New York City has extensively modified the ICC text. As modified, the provisions incorporate the collective wisdom of more than 350 years of building regulation in the City."

"Many jurisdictions have adopted the I-Codes, but with fewer modifications than New York City. New York City is recognized as a unique and premiere urban environment, with no other American city matching the diversity of New York’s built environment. From the canyons of Manhattan to the brownstones and houses of Brooklyn, Queens, the Bronx, and Staten Island, New York City poses a unique challenge for any building code. Because of this, the committees extensively reviewed and modified the I-Codes in many technical areas."

Source: https://www1.nyc.gov/assets/buildings/building_code/update_1_combined_instructions.pdf