Laundry drain help needed

I have very limited knowledge of what are acceptable drain / trap / vent configurations so please forgive me if this sounds rather simple.

My existing laundry has a 2†drain pipe cast I think coming straight up out of the floor. A 1½ galvanized nipple then 2 galvanized T fittings stacked on top of each other. Bottom T goes left to a trap and laundry sink. The top T goes right to a trap and washer stand pipe. The pile continues straight up into the vent.

I’m going to be ripping the whole works apart and I’m wondering if this configuration is ok to keep. Should I be adding a vent for each fixture instead of the T’s going left and right and sharing the pipe as a vent.

Does that make sense? I wish I could post a picture of it.

I’m just not sure if the inspector is going to kick my butt around.

I think you are okay with the vent, but...current code requires the washing machine standpipe to be 2", so keep it 2" for that, and reduce to the smaller pipe for the sink.

If nothing else, the sink drain should be the top tee.
If both are vented seperatly like the picture above, it will pass any inspection there is.
Keep the 2" for the waste fittings and washer, you can go 1.5" on the vents and the trap arm for the sink.

drain

The separate vent for the washer is not always required.

Hi,

What is the advantage of having the 2 vent lines?

Is that flex tubing and compression fittings on the supply valves?

Thanks!

art

The advantage of two vents?

Some inspectors require a vent for each trap.
If the washer didn't have a vent in the picture, it would have been that the sink was "wet vented" over the washer.

Not all inspectors let you do that.
It's not that one vent wouldn't work, it's done with one vent in many places.
It's whatever "your" inspector lets you do.
In Washington State, it looks like the picture.

In the picture, the water uses a combination of copper and PEX lines.
The connections between the two are standard pex fittings.
With Wirsbo, the collar is put over the end of the tube, and then expaned with a tool.
Then the expanded tube with collar is slipped over the fitting.
The only way to remove the tubing after a few seconds, is to cut it off.

The washer box has hammer arrestors built right into the shutoffs.
Many codes require hammer arrestors at the washer.

Thanks. I was just curious since the 2 vent lines are so close to each other.

Terry,
I'm not a plumber, but I thought I understood the directions of branches for vents made with sanitary tees. The washer vent in your picture seems to contradict my understanding. The sanitary tee after the washer trap seems to be in a direction to admit water to the drain from above rather than air going up.

What am I missing?

I can't imagine that it will really affect the flow of air in the vent.

Don't you always want to assume water will be travel down any pipe (vent or otherwise) when orientating (that a word) fittings? Wouldn't want rain water, condensate, etc. to get trapped in there.

Jason