Specification:Removing oil and tar stains from brick masonry

__NUMBEREDHEADINGS__

=GENERAL=

SUMMARY
 This procedure includes guidance on removing heavy oil and/or tar stains from brick masonry. See 01100-07-S for general project guidelines to be reviewed along with this procedure. These guidelines cover the following sections:  Safety Precautions Historic Structures Precautions Submittals Quality Assurance Delivery, Storage and Handling Project/Site Conditions</li> Sequencing and Scheduling</li> General Protection (Surface and Surrounding)</li> </ol> </li> </ol> These guidelines should be reviewed prior to performing this procedure and should be followed, when applicable, along with recommendations from the State Historic Preservation Officer (SHPO). =PRODUCTS=

MANUFACTURERS
<ol type="A"> Diedrich Technologies, Inc. www.diedrichtechnologies.com</li> ProSoCo, Inc. www.prosoco.com</li> </ol>

MATERIALS
<ol type="A"> For Tar: <ol> Dry ice or compressed CO2</li> </ol> </li> For Oil and Residual Tar Stains: <ol> Commercial cleaner such as "Diedrich ASPIR Solv" (Diedrich Technologies, Inc.), "Sure Klean Asphalt and Tar Remover" (ProSoCo, Inc.), or approved equal. -OR- For Poulticing: Mineral spirits : <ol> A petroleum distillate that is used especially as a paint or varnish thinner. </li> Other chemical or common names include Benzine* (not Benzene); Naphtha*; Petroleum spirits*; Solvent naphtha*.</li> Potential Hazards: TOXIC AND FLAMMABLE.</li> Safety Precautions: AVOID REPEATED OR PROLONGED SKIN CONTACT.</li>  ALWAYS wear rubber gloves when handling mineral spirits.</li> If any chemical is splashed onto the skin, wash immediately with soap and water.</li> </ol> </li> <li> Available from construction specialties distributor, hardware store, paint store, or printer's supply distributor.</li></ol></li>

-OR- Trichloroethylene (highly refined solvent):

<ol> <li>Other chemical or common names include Ethinyl trichloride. </li> <li> Potential Hazards: TOXIC. </li> <li> Available from automotive supply distributor, chemical supply house (both commercial and scientific), dry cleaning supply distributor, paint store, photographic supply distributor (not camera shop), or printer's supply distributor. </li> </ol> <li>White absorbent material (molding plaster, untreated white flour, white tissue, paper towels, powdered chalk, talc, fullers earth or laundry whiting).</li> <li>Plastic sheeting</li> </ol> </li> <li>Mineral water</li> <li>Clean dry towels for blotting the area after treatment</li> <li>White vinegar or commercial neutralizer such as "Sure Klean Masonry Restorer" (ProSoCo, Inc.), 101 Masonry Restorer/Cleaner (Diedrich Chemicals), or approved equal.</li> </ol> </li> <li>Clean potable water</li> </ol>

EQUIPMENT
<ol type="A"> <li>Rubber hammer</li> <li>Putty knife</li> <li>Glass or ceramic container for mixing the solution</li> <li>Wooden utensil for stirring the ingredients</li> <li>Wood or plastic spatula</li> <li>Stiff bristle brush (non-metallic)</li> <li>Masking tape</li> </ol> =EXECUTION=

ERECTION, INSTALLATION, APPLICATION
<ol type="A">

<li>For Tar: <ol> <li>Apply dry ice or compressed CO2 to the tar to make it brittle.</li> <li>Tap the tar lightly with a small rubber hammer.</li> <li>Using a putty knife, pry off loosened pieces of tar from the surface.</li> <li>Thoroughly rinse the surface with clean, clear water and allow to dry. </li> </ol> </li> <li>  For Oil and Residual Staining from Tar:</li> <ol> <li>Apply a commercial cleaner directly to the surface. <li>Apply cleaner using a stiff bristle brush following manufacturer's instructions.</li> <li>Allow the mixture to remain on the stain for period of time as recommended by manufacturer.</li> <li>Thoroughly rinse the surface with clean, clear water and allow to dry.</li> <li>Repeat the process as necessary to achieve the desired level of cleanliness. -OR- Apply a poultice containing a chemical solvent. </li> <li>Thoroughly rinse the area to be treated with mineral water.</li> <li>Mix naphtha (mineral spirits) or trichloroethylene with filler material to achieve a thick paste.</li> <li>Using a wooden or plastic spatula, apply the paste to the stained surface in layers no more than 1/4 inch thick. The poultice should extend well beyond the stain to prevent forcing the stain into previously clean stone.</li> <li>Check the coating for air pockets or voids.</li> <li>Cover the poultice with plastic sheeting and seal with masking tape.</li> <li>Let set for 48 hours (unless otherwise specified).</li> <li>After set period, dampen the poultice with mineral water.</li> <li>Remove the poultice with a wooden or plastic spatula to avoid scratching the surface.</li> <li>Thoroughly rinse the cleaned area with mineral water, blot with clean towels and allow the surface to dry.</li> <li>Repeat the process as necessary to remove any remaining residue until the desired level of cleanliness is achieved.</li> </ol> </li> <li>If acid or commercial cleaner is used, neutralize the surface using white vinegar or a proprietary chemical neutralizer. A neutral pH (7 pH) should be achieved. <li>Allow neutralizer to stand on wall about three minutes before rinsing. DO NOT LET IT DRY!</li> <li>Thoroughly rinse the surface with clean, clear water.</li> <li>Test the pH with litmus paper or phenolphthalein: <ol> <li> Dissolve a 2" piece of phenolphthalein in denatured alcohol.                 </li>              <li> Brush the solution onto the surface.  If it turns a shade from pink to magenta there is still chemical residue. </li>            </ol>          </li>          <li>Continue to neutralize the surface and test until there is no color change in the phenolphthalein solution or the litmus paper registers neutral.</li>        </ol>      </li>    </ol>  </ol>