Section 4161. Preservative Treatment.

4161.01 DESCRIPTION.
Preservative treatment of timber, lumber, piling, and posts shall meet requirements of applicable sections, within these specifications, which cover the individual materials. Unless otherwise specified, the treatment process and results of treatment shall meet requirements of this section.

4161.02 PRESERVATIVES.
Preservatives used for treatment shall meet requirements of Section 4160. Unless otherwise specified, treatment may be with creosote, pentachlorophenol, chromated copper arsenate (CCA), ammoniacal copper zinc arsenate (ACZA), or Copper Naphthenate.

4161.03 TREATMENT.
Except as provided herein, preservative treatment shall be in accordance with requirements and recommendations of AWPA Standard C1 and the applicable AWPA Commodity Specifications listed in the following tables for various materials and usages:

TABLE 1: MINIMUM PRESERVATIVE RETENTION REQUIREMENTS
(lb./cu.ft. of wood)
(kilograms per cubic meter of wood)
  Retention
Material and Usage Creosote(2) Pentachloro-phenol (2) Copper
Napthenate(2)		   ACZA(3) CCA(1, 3) AWPA
UC-Section-Special Req.
Lumber and Timber for Structures (192.2)
AWPA U1		 AWPA U1 AWPA U1   AWPA U1 AWPA U1 AWPA U1
Piles for Foundation:

     Douglas Fir

     Southern Pine

 

17
(272)
12
(192)

  

-

-

  

0.14
(2.2)
0.10
(1.6)

  

-

-

  

-

-

  

-

-

  

UC4C-E
Post, Guardrail, and Spacer Blocks:

     Sawed Four Sides		  

0.6
(9.6)

0.075
(1.2)		  

0.5
(8.0)

0.5
(8.0)
UC4A-B
Posts, Fence, Guide, and Sign:

     Round

     Sawed Four Sides



0.4
(6.4)
0.5
(8.0)

0.055
(0.88)
0.060
(0.96)
 		 0.4
(6.4)
0.4
 (6.4)		 0.4
(6.4)
0.4
 (6.4)



UC4A-B
UC4A-A-4.3
NOTE: (1) CCA shall not be used for the treatment of Douglas Fir.
              (2) Oil type preservatives
              (3) CCA, ACA, and ACZA are waterborne preservatives.
             (4) Retentions based on AWPA. Use Category and Commodity Specification for different applications.

TABLE 2: MINIMUM PRESERVATIVE PENETRATION REQUIREMENTS
inches (mm) of wood and/or % of sapwood penetration
  Penetration
Material and Usage Southern Pine Douglas Fir AWPA
Material Standard Section
Lumber and Timber for Structures
APWA U1 T1
APWA U1, T1		 APWA U1, T1
Piles for Foundation: 2.5 in. (63 mm) or 85% 0.75 in. (19 mm) and 85%
up to 1.6 in. (40 mm) and 85%		 T1-8.5
Post, Guardrail, and Spacer Blocks:

     Sawed Four Sides
2.5 in. (63 mm) or 85%
Under 5 in. (125 mm) thick:
0.4 in. (10 mm) and 90%
5 in. (125 mm) and thicker:
0.5 in. (13 mm) and 90%		 T1-8.1
Posts, Fence, Guide, and Sign:

     Round


     Sawed Four Sides

 2.0 in. (50 mm) or 85%


2.5 in. (63 mm) or 85%

3/8 in. (9 mm) and 100%
up to 1 in. (25 mm) or 85%

Under 5 in. (125 mm) thick:
0.4 in. (10 mm) and 90%
5 in. (125 mm) and thicker:
0.5 in. (13 mm) and 90%		  

T1-8.2


T1-8.1
Note: (1)Penetrations based on AWPA. Use Category and Commodity Specification for different applications.

Other aspects of the treatment process shall meet the following requirements:

A. Incising.
Coastal Douglas Fir lumber shall be incised.

B. Seasoning.
When sawed material is treated with waterborne preservatives (CCA), ACZA), the moisture content prior to treatment, as determined by resistance type moisture meter, shall not be more than 20% if kiln dried or not more than 23% if air dried. The moisture content shall be measured at a depth equivalent to the required penetration up to a maximum of 1.5 inches (38 mm). Unless otherwise specified, lumber 2 inches (50 mm) or less in nominal thickness that is treated with a waterborne preservative shall be dried after treatment to a moisture content of not more than 20% if kiln dried or not more than 23% if air dried.

C. Special Treatment for Guardrail and Sign Posts Treated With Oil Type Preservative.
Before being removed from the treatment cylinder, sign and guardrail posts shall be further subjected to live steam at a maximum pressure of 13 psi (90 kPa), and following that, to an additional period of vacuum to insure that the surface of the wood is free from accumulation of oil type preservative.

D. Method of Treatment.
The preservative used shall be the same for all the product furnished for each contract item or order. Unless otherwise specified, treatment with creosote oil, pentachlorophenol, or copper naphthenate solution shall be made by the empty cell process with initial air pressure. Treatment with waterborne preservative shall be made by the full cell process.

E. Results of Treatment
Unless otherwise specified, retention and penetration of preservatives shall be in conformance with the above tables. Preservative retentions shall be determined by assay method. Other treatment requirements shall be in accordance with AWPA Standards U1 and T1 and the applicable AWPA Specifications listed in the above tables.

F. Handling Treated Products.
Care and handling of preservative treated wood products shall be in accordance with AWPA Standard M4.

G. Product Marking.
The individual pieces of inspected, treated material shall bear a legible identification mark either hammer or heat branded, die stamped, or metal tagged. For material treated with waterborne preservatives, the identification mark may be ink stamped provided the information is clearly visible and legible. As a minimum, the identification mark shall indicate the treater, the species of wood, the preservative treatment type, and the retention level. Acceptable brands or marks shall be similar to the general guidelines for brands listed in AWPA M1 and M6. All treated wood material that requires a grade, with the exception of 45 inch (1145 mm) Terminal Posts1, shall contain a quality grade mark of an accredited grade monitoring and inspection agency approved under the American Lumber Standards Committee (ALSC).

1 In the event that Terminal Posts that are 45 inches (1145) in length to be used for Guardrails can not be stamped with a quality grade mark due to sizing of material, Terminal Posts shall then be stamped "MFG No. 1" to indicate that the Terminal Posts were cut from an original piece graded as a No. 1. Wane requirements will be waived.

Material less than 3 feet (1 m) in length does not require a grade mark; however, a certification statement from the mill/processor certifying the grade of the material shall be provided. See Documentation Section of Materials I.M. 462. Round wood posts, round wood piles, and round wood poles do not require a grade, since the grading rules apply only to sawn material.

In addition, each bundle of treated wood products shall have at least one plastic tag identifying the charge number for the bundle.

H. Inspection.
White and treatment inspections, certifications, and test reports for each shipment shall be furnished in accordance with Materials I.M. 462.