VOCs in Basement

[gunnyv]

After reading the other thread on Low O2, I thought you might find this one interesting:

Companies responded to a basement fire in a ranch home built in the 1990s. They arrived to find a small fire in the vicinity of the furnace/hot water tank. After extinguishing the fire, they found that a rubber hose attached to the hot water tank for drainage had burned, and that it was near the pilot for the water tank. Once the house was ventilated with PPV, they returned to the basement with the LEL/O2/CO meter carried on the Truck co to investigate a strange odor. They found a low LEL level near the furnace, which they tracked to the floor drain. They then flushed the drain with a booster line for 15 minutes. They also noticed that the burnt portion of the garden hose was right about where it crossed the drain. The working theory is that a flammable gas escaping from the drain was ignited by the pilot light and burned the hose. After the flush, they still got LEL readings, so they told the occupant to stay somewhere else for the night and they would investigate further the next day.

Next day, as the only hazmat tech on duty, I was ordered to meet the Ops Chief at the house with our hazmat rig. Using a MultiRae 4 gas/PID, readings in the basement itself were less than 5ppm, even right outside the drain. I found a reading of 800ppm in the floor drain, and .1% LEL. No H2S or CO. I took samples and found no significant results on the Ahura or Hazmat ID. No sheen on the water. No significant findings on Spillfyter test strips or pH, etc. We do not have a gas spec or tedlar bags, and at the time we did not have Draeger tubes or CMS chips.

This is an interior drain that ran back to the sump pump. We found no elevated readings at the sump pump or any other other floor drains. No readings at the neighboring homes or outside. Homeowner denied pouring anything down the drain, and based on the surroundings, this wasn't a basement workshop. The only thing we could think of is that an old flammable liquid tank is in the ground nearby and seeping into his drain tile-but why no readings at the sump pump, which is where the drain tile would lead to first? The homeowner was advised to contact his insurance company and see if they would hire an environmental testing/remediation company.

It has been a year, and I just found out nothing has changed. The house is still vacant, the odor persists, and the insurance company can't find the problem. Any ideas?

[Trkco1]

Maybe something in or around the drain is decaying and giving off methane?

[SPFDRum]

Does the floor drain have the clean out plug in? If that is open, like above, any decaying matter could off gas from under the slab into the drain. With that plug out, the p trap will still hold water.

[gunnyv]

Does the floor drain have the clean out plug in? If that is open, like above, any decaying matter could off gas from under the slab into the drain. With that plug out, the p trap will still hold water.

Sounds possible. I don't remember seeing a trap at the drain, I thought it was just an elbow. Now I will have to see if we can go back to check.

If the insurance company couldn't find a plumber or drainage contractor to figure that out for almost a year, they suck.

We did diagnose something similar last year, a family had liquid seeping through the basement walls and up from the drains. We thought it was just water mixed with decayed organic material, later the County health dept discovered they had cut the pipe to the septic field 20 years before when they laid foundation for a sunroom.

[Trkco1]

Sounds possible. I don't remember seeing a trap at the drain, I thought it was just an elbow. Now I will have to see if we can go back to check.

I've seen some 90 degree elbows, that are used for drainage purposes, that come with a precut hole in them for residule water in the 90. I used one for my pool waste line.