Meaning
Standard test protocols published by consensus bodies establish uniform field procedures for measuring relative humidity within internal concrete structures. The standard designated as astm f2170 specifies the insertion of calibrated relative humidity sensors into drilled sleeves set to prescribed depths within a slab. Field technicians record equilibrium humidity values to evaluate whether a concrete deck has dried sufficiently to receive moisture-sensitive floor coverings.
The procedure applies specifically to solid concrete slabs and does not govern lightweight screeds or surface moisture meters.
Probe Deployment
Hole preparation requires precise depth control and vacuum cleaning to remove pulverized concrete debris. Deploying an astm f2170 probe involves drilling to forty percent of a slab depth when drying from one side or twenty percent when drying from two sides. A plastic sleeve seals the hole walls against transient ambient humidity.
Readings taken before achieving thermal and vapor equilibrium yield false values.
Equilibrium Threshold
Equilibrium time within the isolated hole allows internal pore vapor to equalize with the sensor chamber. The astm f2170 protocol mandates a minimum waiting period of seventy-two hours between sleeve insertion and final reading. Sensor calibration must occur within twelve months prior to use.
Premature readings distort risk assessments for adhesive bond failure.
Failure Penalty
Surface coverings installed over damp concrete experience adhesive hydrolysis and blistering. Premature sign-off based on hasty testing under astm f2170 leads to floor system delamination and expensive remediation. Repair costs often exceed ten times the initial cost of proper moisture testing.
