Roof Drains

[Jason Reid]

A client has raised a concern about sewer gas from a combination storm/sewer backing up to the roof drains. The issue is that the roof drain is near an air intake for the main air handler. There has been a suggestion to wet trap the drains. Is this simply p-trapping?

[BobParticipant]

: A client has raised a concern about sewer gas from a combination storm/sewer backing up to the roof drains. The issue is that the roof : drain is near an air intake for the main air handler. There has been a suggestion to wet trap the drains. Is this simply p-trapping?You have sewer and stormwater (roofdrains) running into the same pipe ??. This is incorrect the swewer and stormwater are supposed to be completly different systems, with NO stormwater going into the sewer. This causes the treatment plants to have a heart attack during rain and they are not able to handle the load. Do not wet trap the vent. the vent is used to remove gases from the sewer and to let air pressure out when water runs done the sewer. traping it is the same as the trap in a sink or wc, it will not let the air out. if your customer is concernd about sewer gas into air intake, move the vent around away from it. you need about 6m from the vent to air intakeDISCLAIMERAll advice is given with-out seeing the job, and hence all advice MUST be taken as advice with limited knowledge on the exact situation. NO responsibility can or will be taken. And yes, I am a licensed plumber with my own business in Brisbane Australia

[BobParticipant]

: : A client has raised a concern about sewer gas from a combination storm/sewer backing up to the roof drains. The issue is that the roof : : drain is near an air intake for the main air handler. There has been a suggestion to wet trap the drains. Is this simply p-trapping?: You have sewer and stormwater (roofdrains) running into the same pipe ??. This is incorrect the swewer and stormwater are supposed to be completly different systems, with NO stormwater going into the sewer. This causes the treatment plants to have a heart attack during rain and they are not able to handle the load. : Do not wet trap the vent. the vent is used to remove gases from the sewer and to let air pressure out when water runs done the sewer. traping it is the same as the trap in a sink or wc, it will not let the air out. if your customer is concernd about sewer gas into air intake, move the vent around away from it. you need about 6m from the vent to air intake: : DISCLAIMER: All advice is given with-out seeing the job, and hence all advice MUST be taken as advice with limited knowledge on the exact situation. NO responsibility can or will be taken. And yes, I am a licensed plumber with my own business in Brisbane AustraliaSorry, perhaps I was not clear. The city is still running a combined storm and sanitary at the street. They are in the process of splitting them apart, however there are still some lines from the sanitary connected to the storm. These lines are only broken off when a major renovation is happening. So, while I am running storm separate from the sewer, there may still be gases in the storm line. I would not vent the trap, because of the obvious reasons. However, if I were to trap the roofdrain, it most certainly will clog from all the roof debris in the base of the trap.

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