The Consumer Products Safety Commission (CPSC) and the Department of Housing and Urban Development (HUD) have issued an interim guidance document on the best approach to identifying problem (a.k.a. Chinese) drywall. The document states that the guidance is based primarily on the presence of metal corrosion in homes.
Prerequisite (must meet both criteria) to warrant further consideration:
Visual inspection must show:
- Blackening of copper electrical wiring and/or air conditioning evaporator coils, and
- Drywall must have been installed between 2001 and 2008
Additional corroborating evidence (must have at least 2 of the following conditions for drywall installed between 2005-2008 and at least 4 conditions for drywall installed between 2001-2004):
- Corrosive conditions in home, as evident by the formation of copper sulfide on copper metal test strips placed in the home for 14-30 days, or the confirmation of sulfur in the blackening of grounding wires or condensation coils.
- Confirmed markings of Chinese origin for drywall in the home.
- Strontium levels in drywall samples greater than 1200 ppm.
- Elemental sulfur levels in drywall samples exceeding 100 ppm.
- Elevated levels of hydrogen sulfide, carbonyl sulfide and/or carbon disulfide emitted from drywall samples tested using ASTM Standard Method D5504-08.
- Corrosion of copper metal to form copper sulfide when copper is placed in test chambers with drywall samples collected from the home.
A copy of the document can be found HERE