MIL-HDBK-1110
hazard of hydroplaning on wet pavements, it is not necessary to
remove 100 percent of the rubber build-up on runways. From a
standpoint of surface preparation for marking pavements, however,
virtually complete removal is more important. While one
contractor was observed to be able to achieve 100 percent removal
with his equipment without apparent difficulty, others could not
do so using their equipment without considerable expense and
damage to the pavement. It may be necessary to settle for less
than 100 percent (e.g., 90 percent) removal to permit competitive
bidding until the technology for 100 percent removal becomes
widely available.
j) Procedure 10: Check of Application Equipment.
Paint spray guns and bead dispensers should be checked to
determine that they are properly metered and functioning.
Metering can be checked individually, directing paint or beads
into a container for collection. To check for proper application
and overlap of paint patterns (fans) from spray guns and beads
from dispensers, apply a small area of paint and beads onto
roofing paper or other disposable material taped to the pavement.
k) Procedure 11: Monitoring of Marking Operation.
The prevailing conditions should be recorded before starting to
apply markings. This includes temperature; dew point, if
solvent-based paints are used; rain or prospects of rain; wind;
type of equipment used; and any unusual conditions. Wind can
cause overspray of the paint onto the beads to significantly
reduce their retroreflectivity. General weather forecasts are
normally available from operations offices. A variety of
thermometers are available for measuring temperature, and
inexpensive sling psychrometers are usually used for measuring
humidity and dew point. Photography can be an excellent method
of recording conditions. Solvent-based paints should not be
applied unless the temperature is at least 5 degrees above the
dew point and above 40 degrees F and rising or if rain is
expected within an hour. In addition, water-based paints should
not be applied when the temperature is below 45 degrees F. Paint
should be applied when the wind is over 5 mph, unless it can be
shown that the marking can be applied properly with the existing
equipment. None should ever be applied when the wind is over 10
mph. The marking should be continuous (no underlap at all or
overlap of adjacent spray patterns greater than 1/4 inch) with a
constant color that matches the standard or submittal, and free
from wind-blown dust and dirt. The edges of the marking should
be relatively sharp and straight. The marking should be touched
with a finger to determine if complete drying has occurred within
the time specified for the paint. Dried paints should be probed
with a dull putty knife to determine that they are well bonded.
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