Average Retentions per AWPA Required Assay Zones and Penetration Depths for Species and Products | ||||||||||||||||||
AWPA Minimum Preservative Assays and Penetrations | Calculations of Treatable Fractions | |||||||||||||||||
CCA-Treated Product Information | Assay Zone | Penetration | Representative Size (in) | Untreated size (in) | Treatable fraction | |||||||||||||
Commodity | Product | Species | Use Category | ≤2" thick | >2" thick | <5" thick | ≥5" thick | Thick/Dia | Width | Thick/Dia | Width | |||||||
Sawn | Sawn Product | SP | all | 0.0 | 0.6 | 0.0 | 1.0 | 2.5 | or | 85% | 2.5 | or | 85% | 1.5 | 5.5 | 0.3 | 4.3 | 84% |
Spruce, SPF West | all | 0.0 | 0.6 | 0.0 | 0.6 | 0.4 | and | 90% | 0.5 | and | 90% | 1.5 | 5.5 | 0.3 | 4.3 | 84% | ||
Decking | HF, DF, LP | 3B | 0.0 | 0.2 | 0.2 | and | 90% | 1.25 | 5.5 | 0.85 | 5.1 | 37% | ||||||
Posts | Round building | SP | ≤10" dia | >10" dia | ||||||||||||||
4B | 0.5 | 2.0 | 0.5 | and | 90% | 2.5 | and | 90% | 10 | dia | 5 | dia | 75% | |||||
DF | 4B | 0.25 | 1.0 | |||||||||||||||
Other & Modified farm | SP | 4B | 0.0 | 1.0 | 2.0 | or | 85% | 6 | 6 | 4 | 4 | 56% | ||||||
LP | 4B | 0.0 | 1.0 | 1.25 | or | 85% | 6 | 6 | 4 | 4 | 56% | |||||||
Crossties | Crossties | DF | 4A, B, C | 0.0 | 0.5 | 0 | 0.5 | 90% | 7 | 9 | 6 | 8 | 24% | |||||
Poles | Poles | SP | 4A, B, C | 0.5 | 2.0 | 3.5 | or | 90% | 12 | dia | 5 | dia | 83% | |||||
Piles | Foundation | SP | 4C | 0.0 | 2.0 | 2.5 | or | 85% | 12 | dia | 7 | dia | 66% | |||||
Land & Fresh water | SP | 4C | 0.0 | 3.0 | 3.0 | or | 90% | 12 | dia | 6 | dia | 75% | ||||||
Zone 1 | Zone 2 | |||||||||||||||||
Marine | Sawn | SP | 5A, B & C | 0.0 | 0.5 | 0.5 | 2.0 | 3.5 | or | 90% | 6 | 8 | 3.5 | 5.5 | 60% | |||
Round | SP | 5A, B & C | 0.0 | 0.5 | 0.5 | 2.0 | 3.5 | or | 90% | 12 | dia | 8 | dia | 56% |