Treated wood
Table 1
MnDOT approved preservatives for the treatment of timber products1
| Product and usage | AWPA use category | AWPA commodity specification U1 |
|
|
|---|---|---|---|---|
| Special Reqs |
MnDOT approved (see Table 2 below) |
|||
| A Piles | ||||
| A1 – Round | UC4C2 | E | - | PCP, CuN, CA-C |
| B Posts: Fence, Guide & Sight | ||||
| B1 – Round | UC4A2 | B | - | MCA, CuN, ACQ-D, CA-C |
| B2 – Sawn Four Sides | UC4A2 | A | - | MCA, CuN, ACQ-D, CA-C |
| C Posts: Guardrail & Spacer Blocks, Noise | ||||
| C1 – Round | UC4B2 | B | - | MCA, ACQ-D, CA-C |
| C2 – Sawn Four Sides | UC4C2 | A | Sub Sec 4.33 | MCA, ACQ-D, CA-C |
| D Poles, Lighting | ||||
| D1 – Round | UC4B2 | D | - | MCA, CuN, CA-C |
| E Lumber and Timber | ||||
| E1 – Bridges, Prefab (nail laminated) Panels, other Structural Members, Culverts and other uses | UC4C2 | A | Sub Sec 4.33 | PCP |
| E2 – Noise Wall Facing – at or below ground level | UC4B2 | A | - | MCA, ACQ-D, CA-C |
| E3 – Building Construction or Repair – at or below ground level | UC4A2 | A | - | MCA, CuN, ACQ-D, CA-C |
| E4 – Decks, porches, handicap ramps, boardwalks, or pedestrian bridge decking | UC4A2 | A | - | PCP |
| F Lumber and Timber (not in contact with ground or water | ||||
| F1 – Handrails, Sidewalk Plank | UC3B | A | - | PTI, MCA, ACQ-D, CA-C |
| F2 – Noise Wall Facing – above ground level | UC3B | A | - | PTI, MCA, ACQ-D, CA-C |
| F3 – Building Construction or Repair | UC3B | A | - | PTI, CuN, MCA, CA-C |
| F4 – Bridges, Prefab (nail laminated) panels, structural members, and other uses | UC4C2 | A | Sub Sec 4.33 | PCP |
| G Glue-Laminated Structural Members (treated after gluing) | ||||
| G Glue-Laminated Structural Members (treated after gluing) | UC4B2 | F | - | PCP, CuN |
| H Plywood | ||||
| H1 – In contact with ground or water | UC4A2 | F | - | MCA, ACQ-D, CA-C |
| H2 – For use above ground | UC3B | F | - | PTI, CuN, MCA, ACQ-D, CA-C |
1 MnDOT approved preservatives does not include the actual wood treated product. MnDOT functional offices approve the final treated wood product for use on specific MnDOT projects.
2 Products listed must submit documentation as proof of passing results from test method AWPA E7, substitution of test method AWPA E20 is not acceptable.
3 Sub section 4.3: For AWPA Commodity Specification A, sawn products with a UC4C use category, review the table and text in the most recent version of the AWPA Book of Standards, to determine the appropriate wood type and treatment.
Table 2
Product definition and MnDOT use restriction of approved wood treatments
| Treatment | Definition | AWPA Specification Requirements1 | Standard AWPA Method for Determining Retention2 | Use Restrictions |
|---|---|---|---|---|
| PTI | Non-metal pesticide treated wood. |
AWPA P45 | A31 (Azoles), A43 (Imidacloprid) or A48 (PTI) | Cannot use within 100 feet of surface water3. Structural members must not be in contact with soil. |
| CuN | Copper naphthenate | AWPA P36 | A9 (Cu) or A21 (Cu), A41 (naphthenic acid) | Cannot use within 100 feet of surface water3. Cannot use within 100 feet of residential or recreational areas4. |
| PCP5 | Non-aqueous pentachlorophenol | AWPA P35 | A83 (Cl) or A9 (Cl) | Non-aqueous pentachlorophenol wood products will be phased out of use as appropriate approved products with better environmental performance become available. |
| MCA | Micronized Copper Azole | AWPA P61 | A21 (Cu) or A9 (Cu), A31 (Azoles) | Cannot use within 25 feet6 of surface water3. Fasteners must be in accordance with IBC 2304.10.5. |
| CA-C | Copper Azole Type C | AWPA P48 | A9 (Cu) or A21 (Cu), A31 (Azoles) | Cannot use within 25 feet6 of surface water3. Fasteners must be in accordance with IBC 2304.10.5. |
| ACQ-D | Alkaline Copper Quaternary- Type D | AWPA P29 | A9 (Cu) or A21 (Cu), A16 (Quat) or A18 (Quat) or A36 (Quat) or A37 (Quat) | Cannot use within 25 feet6 of surface water3. Fasteners must be in accordance with IBC 2304.10.5. |
1 Specification requirements and appropriate methods for determining retention shall be in accordance with the most recent AWPA standard.
2 Penetration and other treatment requirements shall be in accordance with AWPA Standard T1 and the AWPA Use Category Standards listed in MnDOT Specifications Table 3491-1.
3 For purposes of this document, surface water is considered to be a permanent water such as, but not limited to; rivers, streams, creeks, lakes, or ponds (not including artificially constructed sediment ponds).
4 Residences are characterized by the single-family or multiple-family dwellings. Recreational areas are characterized by unrestricted access to the public and include, but are not limited to; parks, playing fields, beaches, green spaces, open areas, wildlife management areas, and nature preserves. Setback distance from recreational area should be determined from vicinity where people likely congregate (example: picnic or playground areas).
5 Unless otherwise specified, the pentachlorophenol solution for wood treatment shall consist of not less than 5.0 percent of pentachlorophenol in heavy petroleum solvent (AWPA A9, Type A).
6 An MCA, CA-C or ACQ-D noise wall or boardwalk should, at no point along the structure, be closer than 25 feet to a surface water shoreline (lake, reservoir, impoundment, or stream).
Building structures with MCA, CA-C or ACQ-D treated wood such as pole barns, storage sheds, garages, or out-houses should be no closer than 6 feet to a surface water shoreline. (Minnesota Department of Natural Resources setback distances from surface water may apply.)
Guard rail barriers or similar low wood mass structure constructed with MCA, CA-C or ACQ-D treated wood posts should be no closer than 3 feet to a surface water shoreline.