2 evaluation of cleaners for government issued headstones
-
Upload
mary-striegel -
Category
Education
-
view
1.635 -
download
5
Transcript of 2 evaluation of cleaners for government issued headstones
Evaluation of Cleaners for Government Issued Headstones
Mary F. Striegel and Jason ChurchNational Park Service
National Center for Preservation Technology and Training
Draft: Do Not Use, Cite, or Quote
NCA Maintains 3 million+ gravesites.
• Today’s marker is tomorrow’s historic headstone.
Draft: Do Not Use, Cite, or Quote
NCA preserves historic headstones which are 50 years or older.
Draft: Do Not Use, Cite, or Quote
NCPTT is a leader in advancing preservation technology.
Draft: Do Not Use, Cite, or Quote
NCPTT was contracted by NCA to evaluate cleaners for marble headstones based on soiling and biogrowth.
Draft: Do Not Use, Cite, or Quote
Recommendations must meet NCA National Shrine Standards.
• Headstones, markers, niche covers are clean, free of debris and objectionable accumulations.
• Headstones, markers, niche covers are not damaged by cemetery operations.
Draft: Do Not Use, Cite, or Quote
Definitions
Draft: Do Not Use, Cite, or Quote
The StudyPhase I (2004-2005)
• Define Goals
• Choose Cleaning Criteria
• Evaluate commercially available cleaners based on:
– Appearance
– Biological Re-growth
– Physical and Chemical Changes
– Ease of Use
Draft: Do Not Use, Cite, or Quote
Selection of Cleaners:
Table 1. Chosen Cleaners are ordered from Acidic to Basic.
Cleaner H2Orange2 Grout Safe Kodak Photo-Flo D-2 Marble Cleaner Daybreak
pH 3.81 7 9.5 10.5 12.1
pH Acidic Basic Alcohol Chelate Solvent Surfactant Bactericide
D-2 9.5 X X
Daybreak 12.1 X
H2Orange2 Grout
Safe 3.81 X
Kodak Photo-Flo 7 X X X
Marble Cleaner 10.5 X X X X
Draft: Do Not Use, Cite, or Quote
Bath National Cemetery
• Bath, NY
San Francisco National Cemetery
• San Francisco, CA
Santa Fe National Cemetery
• Santa Fe, NMAlexandria National Cemetery
• Pineville, LA
Jefferson Barracks
National Cemetery
• St. Louis, MO
Field Test Sites
Draft: Do Not Use, Cite, or Quote
Implement Field Studies5 cleaners + water
1,440 test patches
240 stones
5 National Cemeteries
Draft: Do Not Use, Cite, or Quote
Micro-organisms• Bacteria: can
slowly cause stone loss
• Fungi: Can change visual appearance
• Algaes: provides the most visual changes
Fungi sample found on marker in San Francisco.
Draft: Do Not Use, Cite, or Quote
Phase II (2005-2007)
• Monitor regrowthin the field for 18 months
• Evaluate cleaning effects on test stone in the lab
• Elimination: H2Orange Cleaner and Kodak PhotoFlo
Draft: Do Not Use, Cite, or Quote
Elimination: Bath National Cemetery
Draft: Do Not Use, Cite, or Quote
Phase III (2008-2011)
• Long-term monitoring at two sites
• Pineville and Jefferson Barracks cleaned study headstones
• Alternate laboratory study was devised at Harvard University
Draft: Do Not Use, Cite, or Quote
Results
Draft: Do Not Use, Cite, or Quote
Significant Findings from the Study
• Field studies showed:
– Kodak Photo-Flo was the first cleaner to fail in the field (greatest biological regrowth)
– H2Orange Safe Cleaner failed after six months at Jefferson Barracks National Cemetery (killed bacteria but left green fungi)
Draft: Do Not Use, Cite, or Quote
Significant Findings from the Study
• Lab studies showed:– Daybreak cleaner left
significant salt deposits on stone
– D2 Biological solution left small amounts of salts on stone (pH buffer additive?)
– D2 Biological Solution was reformulated, no salts found on repeat testing with new formula
Daybreak
Draft: Do Not Use, Cite, or Quote
Significant Findings from the Study
• Further biological studies showed:
– WEG Marble and Granite Cleaner failed after 188 days in laboratory accelerated studies.
– D2 Biological Solution performed as well as Daybreak without harmful salt residues.
Draft: Do Not Use, Cite, or Quote
ClimaticDifferences
Semi Arid Steppe: Santa Fe
Humid Subtropical: Alexandria
Mediterranean: San Francisco
Humid Continental: Bath Jefferson Barracks
Draft: Do Not Use, Cite, or Quote
Location Differences• Sunny areas:
Biocidal effects last much longer.
• Shady areas:
Fungal growth is more likely to return.
Draft: Do Not Use, Cite, or Quote
Issues to Consider
Draft: Do Not Use, Cite, or Quote
Headstone Soiling
• Dirt
• Air Pollution
• Biological Organisms
• Bird Droppings
• Plant or Tree Sap
Draft: Do Not Use, Cite, or Quote
Other Threats to Headstones
• Salt Damage
• Freeze Thaw Cycles
• Improper Cleaning
Draft: Do Not Use, Cite, or Quote
Preservation Practices
• Use the gentlest least invasive method
• Consider long-term effects
• Minimize cleaning impacts
• Don’t remove original surface
Draft: Do Not Use, Cite, or Quote
Cleaning known to damage stone
• Bleach and Bleach like products
• Strong acids or bases
• Power tools
• Pressure washing
Draft: Do Not Use, Cite, or Quote
Cleaner Factors to Consider
• Manufacturer’s Recommendations
• Dilution ratio
• Dwell time
• Biocidal Cleaners
• Lightening with time
• Temporary non-permanent color changes during cleaning
Draft: Do Not Use, Cite, or Quote
Recommended Actions
Draft: Do Not Use, Cite, or Quote
Cleaning Recommendations
• Use D2 Biological Solution or similar biocidalcleaner, following manufacturer’s directions. Do not dilute.
• Apply to WET stone surface using a sprayer.
• Gently agitate with a soft bristle brush.
• RINSE thoroughly with water.
Draft: Do Not Use, Cite, or Quote
Cleaning Frequency Factors
• Research offers observations, but frequency of cleaning will depend on location and climate of individual cemeteries.
• Different locations will need different cleaning schedules.
Draft: Do Not Use, Cite, or Quote
Spot Cleaning
• Minimize the frequency of cleaning the entire cemetery by scheduling spot cleaning on those headstones located in shady areas that exhibit more biological growth and soiling.
Draft: Do Not Use, Cite, or Quote
Summary
• Of the five cleaners tested, D2 Biological solution was most effective and left no harmful residues.
• Daybreak is a bleach solution.– Continued use of Daybreak will result in long term
damage to headstones.
• Use of high pressure power washers can erode the headstone surface and deteriorate headstone.
• Use of chemical cleaners can be successfully accomplished by a three-person team.
Draft: Do Not Use, Cite, or Quote