October 31 1974
INTERIM REVISION OF
Fed. Spec. TT-W-571i
October 28, 1968
INTERIM FEDERAL SPECIFICATION
WOOD PRESERVATION: TREATING PRACTICES
This Interim Federal Specification was developed by the U.S. Department of Agriculture, Forest Ser-
vice, Forest Products Laboratory, P.O. Box 5130, Madison, Wisconsin 53705, based upon currently
available technical information. It is recommended that Federal agencies use it in procurement and for-
ward recommendations for changes to the preparing activity at the address shown above.
The United States Department of Agriculture has authorized the use of this Interim Federal Specification
as a valid exception to Federal Specification TT-W-57li.
Scope. This specification covers the treatment of different forms and species of wood
with various preservatives. It covers treatments of wood items that will be exposed to either moderate
or severe hazard of attack by wood-destroying organisms so that an appreciable retention of preservative
as well as significant penetration into wood is necessary. Such results are attainable by pressure proces-
ses which are acceptable for all products listed in tables I, II, and III. Certain other processes are accept-
able for some items provided that they yield the retention and penetration requirements specified herein.
These processes include thermal treatments of some species of poles, and double-diffusion treatments of
posts, poles, and lumber. Reference is made to TT-W-572, Wood Preservative, Water Repellent, for the
treatment of items such as window sash that are used under mild exposure conditions whereby adequate
protection is afforded by short-dip treatments.
2. APPLICABLE DOCUMENTS
2.1 The following documents, of the issues in effect on date of invitation for bids or request for
proposal, form a part of this specification to the extent specified herein: