CHAPTER 7. PREVENTIVE MAINTENANCE AND REMEDlAL CONTROL
This chapter will discuss inspection and in-place remedial treatment procedures for poles, piles, tim-
ber and other heavy wood members, as well as crossties. These maintenance activities can substan-
tially extend the service life of the treated wood products. Inspection protocols are addressed in
American Wood Preservers' Association Standards M2, Standard for Inspection of Treated Timber
Products. AWPA requirements for the care of preservative treated poles, piles, lumber and ties are
given in Standard M4, Standard for the Care of Preservative-Treated Wood Products.
7.1 POLES. Types of deterioration problems, inspection procedures and remedial treatments for
poles will be discussed in this section. Because of the complexity of pole inspection and main-
tenance, it is strongly recommended that installations contract with reputable commercial pole main-
tenance firms for the following services.
7.1.1 Problems To Be Found.
220.127.116.11 Decay. This section will address inspection and remedial treatments for
decay and insects in standing poles.
Internal Decay. internal decay occurs as a result of fungus infestations that
start in poles before treatment (while air drying on yards) and where wood destroying organisms are
able to penetrate the outer protective shell of preservative treated wood (Figure 5-1) surrounding
sterile, but unprotected wood. Deep checks which develop after treatment, mechanical damage
from improper handling, woodpecker holes or other actions which break the protective shell, pro-
vide avenues for entry of decay fungi. Due to the constant presence of moisture, internal decay is
most common at the ground line. Internal decay will also develop in pole tops cut or bored in the
field when supplementary treatment is neglected. Do not cut the butt ends off poles when they are
set in the ground. This exposes a central core of untreated wood at the bottom of the pole and
provides easy access to termites and decay fungi.
With southern pine poles, poor preservative penetration is an important contribution to internal
decay. Sapwood that has not been adequately penetrated with the proper amount of preservatives
readily decomposes. Well treated southern pine poles, that are predominately sapwood, are not
prone to suffer from serious internal decay (Figure 7-1). Douglas-fir poles are often air dried for
several years prior to treatment. Decay fungi become established in the poles during that time. If
the poles are not sterilized during preservative treatment, the fungi will continue to grow or rot the
center of the pole after it has been put in place. As with other species, checks and mechanical
damage in the shell of treated wood also expose the center of the pole to decay fungi.
External Surface Decay. External decay is most common at or below the
ground line (Figure 7-2). Each occurrence of external decay below the ground line reflects im-
proper application of the preservative or use of treating solutions with poor preservative properties.