Wood Handbook, Wood as an Engineering Material

Chapter 15 Wood Preservation

Table 15–5. Results of Forest Products Laboratory studies on 38- by 89-

by 457-mm (nominal 2- by 4- by 18-in.) Southern Pine sapwood stakes,

pressure-treated with commonly used wood preservatives, installed at

Harrison Experimental Forest, Mississippi

Preservative

Average retention

(kg m–3(lb ft–3))a

Average life or condition

at last inspection

Controls (untreated stakes) 1.8 to 3.6 years

Acid copper chromate 2.08 (0.13) 11.6 years

2.24 (0.14) 6.1 years

4.01 (0.25) 80% failed after 40 years

4.17 (0.26) 80% failed after 60 years

4.65 (0.29) 4.6 years

5.93 (0.37) 60% failed after 60 years

8.01 (0.50) 50% failed after 40 years

12.18 (0.76) 22% failed after 40 years

Ammoniacal copper arsenate 2.56 (0.16) 16.6 years

3.52 (0.22) 80% failed after 30 years

3.84 (0.24) 38.7 years

4.01 (0.25) 60% failed after 40 years

7.37 (0.45) 20% failed after 40 years

8.17 (0.51) 10% failed after 60 years

15.54 (0.97) No failures after 60 years

20.02 (1.25) No failures after 60 years

Chromated copper arsenate 2.40 (0.15) 28.7 years

Type I (Type A) 3.52 (0.22) 45% failed after 40 years

4.65 (0.29) 30% failed after 60 years

7.05 (0.44) 10% failed after 40 years

7.05 (0.44) 20% failed after 60 years

Type II (Type B) 3.68 (0.23) 30% failed after 40 years

4.17 (0.26) No failures after 46 years

5.93 (0.37) No failures after 46 years

8.33 (0.52) No failures after 46 years

12.66 (0.79) No failures after 46 years

16.66 (1.04) No failures after 46 years

Type III (Type C) 2.24 (0.14) No failures after 25 years

3.20 (0.20) No failures after 35 years

4.00 (0.25) 20% failed after 20 years

4.33 (0.27) 10% failed after 25 years

6.41 (0.40) No failures after 35 years

6.41 (0.40) No failures after 25 years

9.61 (0.60) No failures after 35 years

9.93 (0.62) No failures after 25 years

12.66 (0.79) No failures after 25 years

Oxine copper 0.22 (0.014) 26.9 years

(Copper-8-quinolinolate) 0.48 (0.03) 27.3 years

AWPA P9 heavy petroleum 0.95 (0.059) 31.3 years

1.99 (0.124) No failures after 45 years

Copper naphthenate

0.11% copper in No. 2 fuel oil 0.19 (0.012) 15.9 years

0.29% copper in No. 2 fuel oil 0.46 (0.029) 21.8 years

0.57% copper in No. 2 fuel oil 0.98 (0.061) 27.1 years

0.86% copper in No. 2 fuel oil 1.31 (0.082) 29.6 years

Creosote, coal-tar 52.87 (3.3) 24.9 years

65.68 (4.1) 14.2 years

67.28 (4.2) 17.8 years

73.69 (4.6) 21.3 years

124.96 (7.8) 70% failed after 54-1/2 years

128.24 (8.0) 90% failed after 60 years

132.97 (8.3) 50% failed after 46 years

160.20 (10.0) 90% failed after 55 years

189.04 (11.8) 50% failed after 60 years