Environmental Engineering Reference
In-Depth Information
offsite and onsite. Onsite removal has the potential for producing large
quantities of lead-containing dust that poses exposure risks to abatement
workers and to occupants of abated structures if it is not followed by proper
cleaning. Therefore, paint removal requires the application of very stringent
work practices and cleaning measures.
Paint removal is employed in structures of historical or aesthetic signif-
icance to preserve the building's unique character. Some components can be
removed and subsequently stripped offsite by furniture stripping compa-
nies. Such stripping services have become less available and more expensive
because of waste disposal requirements and costs. Nevertheless, offsite paint
stripping is the most desirable approach to removing paint from some build-
ing components.
Onsite paint stripping often requires engineering controls and work
practices that are similar to those of asbestos. Paint removal must be con-
ducted to minimize both the contamination of the abated building and
abatement worker lead exposures. Paint removal may be accomplished by
the use of wet scraping or wet planing, electric heat guns, hand tools with
local exhaust systems, chemical stripping, and vacuum and water blasting.
i. Wet scraping and planing. Wet scraping is used to remove loose
paint. A painted surface is repeatedly misted with water during scraping to
minimize lead dust production. Because wet scraping does not remove all
paint on a surface, it is used to prepare a surface for painting or as an initial
step in paint removal. Wet planing is similar to wet scraping. It is used to
remove LBP from friction and impact surfaces like the edges of a door or
window.
ii. Electric heat guns. Heat guns are used to thermally soften LBP,
which is then removed by scraping. Since they produce highly dangerous
(to workers) lead fumes which can cause significant building contamination,
heat guns that operate at temperatures >1000°F are not recommended. Low
temperature heat guns work well in removing LBP but have significant
disadvantages, e.g., the potential to cause burns and fires. Since heat guns
involve dry scraping, significant quantities of lead dust are produced.
iii. Local exhaust hand tools. Hand tools with local exhausts and
HEPA filters have been developed for use in LBP removal. These include
HEPA sanders, needle guns, saws, and drills. HEPA sanders and needle guns
are commonly used in LBP removal. In both devices, a HEPA vacuum system
is used to catch and filter lead dust as it is created. In needle guns, metal
rods are contained inside a shroud. When activated, the metal rods break
and loosen surface paint. They are best used on metal and masonry surfaces
since they have a tendency to damage wood.
iv. Chemical stripping. Chemical strippers (either volatile solvents or
caustic pastes) are used to soften paint so that it can be removed by scraping.
