Thread: My first sediment trap

It's only taken 6 years, but I finally didn't need to call out the lack of a sediment trap (at least on the heater).

First one I've seen in my service area!

It's only a little trap now, but I'm sure it will grow into a full-fledged trap someday!

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We call them 'drip legs' here. A sediment trap here is a Sediment and Erosion Control (SEC) structure, typically a pond or some such. I was wondering (from the title) why a Home Inspector was looking at one of those

Hmmm....the code calls them sediment traps. I've heard many people use the word drip leg, but I don't know what it refers to.

The photo I posted is definitely a sediment trap, but there must be another use for the term where you live.

I think it refers to trapping condensate versus solids (sediment) since some water (in vapor state) is present in the pressurized gas.

There are sediment traps (and that one is constructed wrong) and there are drips.

Each has its own specific purpose, and those purposes are completely different, so one valve cannot serve two purposes.

Worth repeating: "(and that one is constructed wrong)"

Bruce,

Image attached is a graphic of a "properly constructed" sediment trap.

Local terminology gets drip legs and sediment traps all "corn-fused". JP is right ... they each have their place and proper use and terminology.

"Sediment Trap" is the proper verbiage as related to W/H's, furnaces, etc..

Take a look at your JPG and the routing of the black iron. The gas flow has to "change direction" so the debris can fall out into the trap as it turns. Not sure my preceding sentence is correct, but that is my understanding.

Drips and Sediment Traps


Drips (also called drip legs and drip tees) and sediment traps are components in a fuel gas system that help remove impurities from fuel gas. They look similar and are installed in the same place, but they serve different functions. A drip helps remove moisture from fuel gas, whereas a sediment trap helps remove particulate impurities from fuel gas.

(Photo: Drip tee)

Both drips and sediment traps begin with a tee fitting into which a short-capped pipe (about 3 inches long and called a nipple) is inserted and turned toward the ground. The difference between these components is where the gas connector enters the tee fitting. With a drip, the gas connector enters the tee fitting at a 90-degree angle to the nipple and in line with the gas line entering the appliance. With a sediment trap, the gas connector enters the tee fitting in line with the nipple and at a 90-degree angle to the gas line entering the appliance. The theory is that particulate impurities will more easily fall into the nipple if the gas flow is in line with the nipple and must change direction to enter the appliance.





(Photo: Sediment trap)

IRC G2419.2 requires drips only if the gas supplier advises that wet gas exists. This condition is rare in modern gas systems. IRC G2419.4 requires independent sediment traps unless one is incorporated as part of the appliance. Exceptions are gaslights, ranges, clothes dryers and outdoor grills.

Originally Posted by Bruce Ramsey

Drips and Sediment Traps
[/URL]Drips (also called drip legs and drip tees) and sediment traps are components in a fuel gas system that help remove impurities from fuel gas. They look similar and are installed in the same place, but they serve different functions.

Only partially correct.

Sediment traps are installed as close to the appliance as possible, and at least down stream of the equipment shut off valve.

Drips, on the other hand, are installed and any location where condensate could collect, which means at low points in the piping system. The older codes actually stated that drips were installed at the lowest points in the piping because, with slope steel piping, there was typically one low point. With CSST and its wavy up and down routing, there will be collection points in many locations, and the piping should still be sloped so the condensate can collect at that low point, but the code recognizes that there will likely be multiple low points.

The photo shows the drip at the wrong location as the drip is located at the high end of the sloped piping and it should be at the low end of the piping (sloping down to the left in the photo).

If drips are necessary, then several conditions are required:
- G2419.1 (408.1) Slopes. Piping for other than dry gas conditions shall be sloped not less than 0.25 inch in 15 feet (6.4 mm in 4572 mm) to prevent traps.
- G2419.2 (408.2) Drips. Where wet gas exists, a drip shall be provided at any point in the line of pipe where condensate could collect. A drip shall also be provided at the outlet of the meter and shall be installed so as to constitute a trap wherein an accumulation of condensate will shut off the flow of gas before the condensate will run back into the meter.
- G2419.3 (408.3) Location of drips. Drips shall be provided with ready access to permit cleaning or emptying. A drip shall not be located where the condensate is subject to freezing.

There is that "ready access" wording again.