Drip leg required?

[Welmoed Sisson]

Did an inspection of a 2001 standard tract home with two split systems: one in the attic, one in the basement. Both are natural gas. The one in the basement had a drip leg, but this one in the attic did not. Are drip legs required on attic systems?

[Rick Cantrell]

A drip leg is unlikely to be needed for the location shown, however it does need and required to have a sediment trap.

[Welmoed Sisson]

What's the difference between a drip leg and a sediment trap?

[Rick Cantrell]

What's the difference between a drip leg and a sediment trap?

Drip legs and sediment traps look the same, and are very often confused.

Sediment traps are required before an appliance.
Sediment traps collect dirt, rust, and other debris in the gas line before it gets to the control valve of an appliance.

Drips legs are used to collect water droplets.
They are located in low areas of a gas line.
Drip legs are only needed if the gas is wet.
Most gas is dry, therefore drip legs are not often required.

[Raymond Wand]

See

http://www.inspectionnews.net/home_inspection/fireplaces-chimneys-solid-fuel-burning-appliances-home-inspection-commercial-inspection/5392-drip-legs.html

[Bill Wieczorek]

See

http://www.inspectionnews.net/home_inspection/fireplaces-chimneys-solid-fuel-burning-appliances-home-inspection-commercial-inspection/5392-drip-legs.html

I asked a heating guy that was servicing my furnace the same thing. His answewr was if one is on the second level they don't consider the drip leg necessary because any moisture on the higher floor will drain down to the lowest level. As long as there is one below is all he felt is required.

[Stuart Brooks]

I had an inspection a new Condo community a few years back. I went outside to the water heater closet off the balcony and noticed there wasn't a sediment trap installed on the gas water heater. The installation manual was right there on the water heater document pouch. I open it up and looked up the supply piping section. It clearly stated that "a sediment trap SHALL be installed as closed as possible to the control valve". I took a picture and included it in the report.

I write it up a a repair if it's not there. I DO NOT reference a code.

[John Kogel]

You could just call it a "Dirt leg" and cover both bases. ;)

[Jerry Peck]

You could just call it a "Dirt leg" and cover both bases. ;)

Close, but no cigar. :)

While the sediment trap 'could' be called a "Dirt leg" because it does collect debris, the the drip leg collects water which condenses within the piping ... yeah, yeah, I know, that water is 'dirty water' ... not to be confused with The Standells Dirty Water - YouTube (http://www.youtube.com/watch?v=p8h2gVcDQ9E)

[blue mary]

Drip legs are required to be installed in a manner that meets or exceeds fuel piping codes and manufacture requirements for appliances and devices. The drip leg serves as an area within the fuel piping system to protect your appliances and regulators from damage.

[Jerry Peck]

(underlining is mine)

Drip legs are required to be installed in a manner that meets or exceeds fuel piping codes and manufacture requirements for appliances and devices.

"that meets or exceeds"

According to the IRC, drips (commonly known as drip legs) are "not required" ... unless the gas is considered a "wet gas".

From the IRC:

- Section G2402 (202)
- - General Definitions
- - - DRIP. The container placed at a low point in a system of piping to collect condensate and from which the condensate is removable.

(underlining is mine)
- G2419.1 (408.1) Slopes.Piping for other than dry gas conditions shall be sloped not less than 1/4 inch in 15 feet (6.4 mm in 4572 mm) to prevent traps.


(underlining is mine; i.e., "for other than dry gas" ... "wet gas" piping shall be sloped and have drips)
- 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.

(Note that sediment traps are not the same as a drip.)
- G2419.4 (408.4)Sediment trap.
Where a sediment trap is not incorporated as part of the appliance, a sediment trap shall be installed downstream of the appliance shutoff valve as close to the inlet of the appliance as practical. The sediment trap shall be either a tee fitting having a capped nipple of any length installed vertically in the bottommost opening of the tee as illustrated in Figure G2419.4 or other device approved as an effective sediment trap. Illuminating appliances, ranges, clothes dryers, decorative vented appliances for installation in vented fireplaces, gas fireplaces and outdoor grills need not be so equipped.