It only takes a pinch of salt to a gallon of soil to throw your sample into a high chloride situation. Do not mix soils.
Three soil samples (300g) in zip lock bags fit nicely in a small $7 USPOST Priority Mail Flat Rate box which can arrive next day if mailed early. GSO is also almost as inexpensive as USPost if delivering from West Coast States.
Recommendations for Collecting Representative Soil Samples
The goal is to have a soil sample from the depth and location that the infrastructure will be installed. We recommend testing 1/4 gallon (eg. Soda Can size~ 300g or sandwich bag) soil sample per acre be tested with a minimum of 3 samples for small lots. Zip lock bags are great for collection. For residential developments, we recommend testing every 5th lot for corrosion series to avoid future construction defect surprises. If one lot pops up much more corrosive than all others, we would recommend collecting more samples from the lots surrounding the problem lot to determine if the peak is isolated to it.
If this is for evaluating corrosion towards piles, concrete, and underground utilities, then we need samples from depths of 1 foot (most important for piles and concrete), 3 foot (for underground utilities and grounding wires), and 10 ft (for piles, very expansive soils, sewage, vaults, and storm drains), and ground water table information. If using helical anchors, we want to collect soil samples from the depth of the bottom of the anchor. The goal is to have a soil sample from the depth and location that the infrastructure will be installed. With all of this information, we can be aware of the soil corrosivity at various strata for all materials thus providing the most accurate engineering information possible. For pipelines such as water mains, we recommend collecting soil samples from pipe depth at every 1,000 ft of pipe alignment or wenner 4 pin tests of 2, 5, 10, X …, (X+5) to depth of pipe spacings. A doctor doesn’t test a spot on your arm to test if the mole on your leg is dangerous. You sample where it matters. Please feel free to call us if you would like more guidance.
Collecting water samples
Samples should be collected in sterile bottles. In a pinch, buy a distilled water bottle, empty the bottle and use for water collection. The sample should be shipped in a cooler and tested as soon as possible.
At Project X Corrosion Engineering, we specialize in testing soil and water corrosivity, providing corrosion control recommendations, investigating causes of corrosion, building inspection, cathodic protection design, corrosion control, and failure analysis. We help clients determine why they have a corrosion problem in the first place and what they can do to avoid corrosion problems in the future. We do not sell products or perform construction. We provide unbiased recommendations requiring the least amount of maintenance and cost. Customer service and reasonable turn around times are our priority.
Doing your corrosion homework can save you expensive headaches in the future. Digging up a water main pipe leak in grass plus repair typically costs $15,000. You can imagine what it costs to fix slabs, corroding rebar in slabs, difficult access infrastructure.
Do not hesitate to call us for any questions.