Confirm ASTM F2170 in-situ RH probe placement depth and post-drilling waiting period before scheduling a concrete slab moisture test

Steps

1. Note that the ASTM F2170 full standard text is paywalled at store.astm.org (current designation like F2170-19a or later); do not assume a free copy exists
2. Cross-check probe depth guidance against at least two independent industry summaries (e.g., moisture-meter manufacturer technical pages, trade-press articles) rather than a single blog
3. Record the commonly cited rule: probes are set to ~40% of slab depth for slabs drying from one side (slab-on-grade) and ~20% of depth for slabs drying from two sides (suspended slab) — flag this as a secondary-source figure to verify against the purchased standard
4. Record the commonly cited equilibration wait time of 24 hours before taking a reading, noting industry sources describe this as a 2017 committee revision down from a prior 72-hour requirement
5. Advise the requester to confirm the exact current figures against the ASTM store abstract or a purchased copy before using them in a contract or spec dispute