Background:
Plaster has been widely used as the finish surface for interior walls for over 150 years.
Composed primarily of
calcium sulfate (hemihydrate), plaster may interfere with LeadCheck® color development
because some of the lead
may bind to the sulfate in the plaster instead of the LeadCheck® dye. It is possible,
however, with a minimum amount
of care, to accurately test for lead paint on plaster surfaces using LeadCheck® Swabs.
Method:
- Cut a notch into the paint down to the surface (See Instructions). Try not to
break or scratch the plaster surface.
- Clean the notch by brushing or blowing out any surface dust collected in the notched area.
- Activate a LeadCheck® Swab according to the standard instructions.
- Rub the swab tip into the notched area of the paint for about 30 seconds.
- Check the swab tip, paint surface and paint edge for a pink to red color development.
Interpretation:
- If no pink color develops, be sure to confirm the negative result by rubbing the
swab tip onto a dot on the
Test Confirmation Card supplied with the kit. If the confirmation card dot does not
immediately turn pink the
test is not valid - surface dust has likely prevented the LeadCheck® color development.
Repeat the test
using a new LeadCheck® Swab.
NOTE: If a yellow or orange color persists at the notched area or swab tip, this
indicates the presence of barium,
which was added to paints as an extender. The yellow/orange result is NOT a
positive color change for lead.
*LeadCheck® Swabs are a versatile and sensitive screening tool for the detection of lead on any surface. This applications note provides a suggested
method to allow testing for a specific application. Additional information and help are available by calling 800-262-5323 or 508-651-7881.
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