Quantcast Pressure Preservative Treatments - mo312_10029

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In controlling decay in horizontal members not exposed in enclosed spaces,
fumigants such as vapam and chloropicrin are effective.
1.5.1 Introduction. Due to the limited availability of durable woods
such as green heart, cypress, redwood or cedar, the Navy must use relatively
non-durable wood that is treated with preservatives to-protect from attack
by decay fungi and insects, Preservatives applied to wood by nonpressure
processes usually provide only superficial protection.  For maximum
protection, all wood components at CDAA sites world-wide should be
initially preservative treated by pressure processes.
1.5.2 Incising. Background.  Preservative penetration in hard-to-treat
woods such as Douglas-fir, Western-fir, Western-hemlock, redwood and
pines that contain a large amount of heartwood, is significantly increased
by incising wood before treatment. The incisions made in sawn materials
arc commonly 1/4 to 1/2 inch long and deep and about 1/8 inch wide. For
such woods, incising should be specified, non-incised material should not
be accepted as an alternate in bids. Only Southern, Red or Ponderosa pines
arc exempt from this requirement.  Whenever possible, specifications
should state that components should be cut to lengths needed in construc-
tion and bored to accept fasteners prior to preservative treatment. Requirements. All wood products, larger than 2 inches,
from species other than Southern, Red or Ponderosa Pine, must be incised
prior to treatment, provided the incisions will not make the material unfit
for the use intended.
1.5.3 High-Band Poles.  CDAA surveys have identified significant
premature failures in high-band poles at several sites throughout the world.
The predominance of failures can be attributed to factors which enhance
decay fungi activity such as metal support sleeves, pole butt chamfering
techniques, and the generally hostile environment in which these products
arc subjected. These problem areas are discussed in detail in sections
(1.3.1) and (1.3.2) respectively.


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