Specification:Removing smoke stains from brick masonry

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=GENERAL=

SUMMARY
 This procedure includes guidance on removing smoke 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 Regional Historic Preservation Officer (RHPO).=0CPART 2---= PRODUCTS

MATERIALS
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Scouring powder containing bleach</li> -OR- Alkali detergent or commercial emulsifying agent. Trichloroethylene (highly refined solvent): <ol>

Other chemical or common names include Ethinyl trichloride.</li> Potential Hazards: TOXIC .</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> Filler material such as diatomaceous earth or powdered talc</li> Clean, potable water</li> </ol>

EQUIPMENT
<ol type="A"> Glass or ceramic container for mixing the solution=</li> Wooden utensil for stirring the ingredients</li> Wood or plastic spatula</li> Stiff bristle brush</li> Masking tape</li> </ol> =EXECUTION=

ERECTION, INSTALLATION, APPLICATION
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Scrub the affected area with a stiff bristle brush and scouring powder containing bleach.</li> -OR- Brush or spray apply an alkali detergent or commercial emulsifying agent. For small stubborn stains, apply a poultice of trichloroethylene and inert filler material. <ol> <li>Thoroughly rinse the area to be treated with mineral water.</li> <li>Mix the liquid solution to be used in a glass or ceramic bowl.</li> <li>Thoroughly moisten the stained surface with this liquid. Be sure to dampen well beyond the stain.</li> <li>Mix the remaining liquid with the white absorbent material to form a paste the consistency of oatmeal or cake icing. (Approximately one pound of paste is needed for every square foot of surface area to be treated).</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 masonry.</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 a desired level of cleanliness is achieved.</li>