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Historic Preservation - Technical Procedures

Spectitle:

Removing Tobacco Stains From Concrete

Procedure code:

0371037R

Source:

Hstrc Concrete: Investigation & Rpr/Pre-Conf Training - 1989

Division:

Concrete

Section:

Concrete Cleaning

Last Modified:

02/24/2012

Details:

Removing Tobacco Stains From Concrete



REMOVING TOBACCO STAINS FROM CONCRETE


THE CLEANING OR REMOVAL OF STAINS FROM CONCRETE MAY INVOLVE THE
USE OF LIQUIDS, DETERGENTS OR SOLVENTS WHICH MAY RUN OFF ON
ADJACENT MATERIAL, DISCOLOR THE CONCRETE OR DRIVE THE STAINS DEEPER
INTO POROUS CONCRETE.  USE THE PRODUCTS AND TECHNIQUES DESCRIBED
HERE ONLY FOR THE COMBINATIONS OF DIRT/STAIN AND CONCRETE SPECIFIED.


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on removing tobacco
         stains from concrete using chemical poultices.

    B.   Safety Precautions:

         1.   DO NOT save unused portions of stain-removal
              materials.

         2.   DO NOT store any chemicals in unmarked containers.

         3.   EXCELLENT VENTILATION MUST BE PROVIDED WHEREVER ANY
              SOLVENT IS USED.  USE RESPIRATORS WITH SOLVENT
              FILTERS.

         4.   No use of organic solvents indoors should be
              allowed without substantial air movement.  Use only
              spark-proof fans near operations involving
              flammable liquids.

         5.   Provide adequate clothing and protective gear where
              the chemicals are indicated to be dangerous.

         6.   Have available antidote and accident treatment
              chemicals where noted.

    C.   See 01100-07-S for general project guidelines to be
         reviewed along with this procedure.  These guidelines
         cover the following sections:

         1.   Safety Precautions

         2.   Historic Structures Precautions

         3.   Submittals

         4.   Quality Assurance

         5.   Delivery, Storage and Handling

         6.   Project/Site Conditions

         7.   Sequencing and Scheduling

         8.   General Protection (Surface and Surrounding)

         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).

    D.   For additional information on poulticing, see 04455-02-R.


PART 2---PRODUCTS

2.01 MATERIALS

    NOTE:  Chemical products are sometimes sold under a common
    name.  This usually means that the substance is not as pure as
    the same chemical sold under its chemical name.  The grade of
    purity of common name substances, however, is usually adequate
    for stain removal work, and these products should be purchased
    when available, as they tend to be less expensive.  Common
    names are indicated below by an asterisk (*).

    A.   For Normal Staining:

         1.   Grit scrubbing powder

    B.   For Heavy Staining:

         1.   Sodium Hypochlorite (NaOCl):

              a.   An unstable salt produced usually in aqueous
                   solution and used as a bleaching and
                   disinfecting agent.

              b.   Other chemical or common names include
                   Bleaching solution*; Household bleach*;
                   Laundry bleach*; Solution of chlorinated
                   soda*.

              c.   Potential Hazards:  CORROSIVE TO FLESH.

              d.   Available from chemical supply house, grocery
                   store or supermarket, hardware store or
                   janitorial supply distributor.

              -OR-

              Javelle Water:  Made by user, see 03710-02-S for
              guidance on preparation.

              a.   Calcium Hypochlorite (CaCl2O2):

                   1)   A white powder used especially as a
                        bleaching agent and disinfectant.

                   2)   Other chemical or common names include
                        Chlorinated calcium oxide; Bleaching
                        powder*; Calcium oxymuriate*; Chloride of
                        lime*; Chlorinated lime*; Hypochlorite of
                        lime*; Oxymuriate of lime*.

                   3)   Potential Hazards:  CORROSIVE TO FLESH;
                        FLAMMABLE (WHEN IN CONTACT WITH ORGANIC
                        SOLVENTS).

                   4)   Available from chemical supply house, dry
                        cleaning supply distributor, drugstore or
                        pharmaceutical supply distributor,
                        janitorial supply distributor, swimming
                        pool supply distributor, or water and
                        sanitation supply distributor.

              b.   Sodium Carbonate (Na2CO3):

                   1)   A sodium salt of carbonic acid used
                        especially in making soaps and chemicals,
                        in water softening, in cleaning and
                        bleaching and in photography; A
                        hygroscopic crystalline anhydrous
                        strongly alkaline salt.

                   2)   Other chemical or common names include
                        Carbonate of soda*; Sal soda*; Soda*;
                        Soda ash*; Washing soda*.

                   3)   Available from chemical supply house,
                        grocery store or supermarket, hardware
                        store, paint store, or water and
                        sanitation supply distributor.

    C.   Filler material such as diatomaceous earth or powdered
         talc

    D.   Mineral water

    E.   Clean dry towels for blotting the area after treatment

    F.   Clean, potable water

    G.   Accessible source of water, soap and towels for washing
         and rinsing in case of emergencies associated with the
         use of chemicals

2.02 EQUIPMENT

    A.   Glass or ceramic container for mixing the solution

    B.   Wooden utensil for stirring the ingredients

    C.   Wood or plastic spatula

    D.   Stiff bristle brush (non-metallic)


PART 3---EXECUTION

3.01 PREPARATION

    A.   Protection:

         1.   Provide adequate wash solutions (i.e. water, soap
              and towels) before starting the job.

         2.   Whenever acid is used, the surface should be
              thoroughly rinsed with water as soon as its action
              has been adequate.  Otherwise it will continue
              etching the concrete even though the stain is gone.

3.02 ERECTION, INSTALLATION, APPLICATION

    NOTE:  DO NOT TRY MORE THAN ONE TREATMENT ON A GIVEN AREA
    UNLESS THE CHEMICALS USED FROM PRIOR TREATMENT HAVE BEEN
    WASHED AWAY.

    A.   For Normal Staining:

         1.   Stir grit scrubbing powder into how water until it
              has the consistency of mortar.

         2.   Thoroughly wet the concrete surface to be treated
              with clean, clear water.

         3.   Spread the mixture over the stained area to a
              thickness of 1/2 inch using a wood or plastic
              spatula and allow to dry.  Be sure to spread the
              poultice well beyond the stained area.  The liquid
              portion of the paste will migrate into the concrete
              where it will dissolve some of the staining
              material.  Then the liquid will gradually move back
              beyond the concrete surface and into the poultice,
              where it will evaporate, leaving the dissolved
              staining material in the poultice.

         4.   When the poultice has dried, brush or scrape it off
              with a wooden scraper.  

         5.   Using a stiff bristle brush, scrub the surface with
              scouring powder and clean water to remove any
              residual staining.

         6.   Thoroughly rinse the area with clean, clear water
              and allow to dry.

         7.   Repeat the process as necessary to achieve the
              desired level of cleanliness.

    B.   For Heavy Staining:

         1.   Mix 1 part hypochlorite (diluted with 4 to 6 parts
              water) with diatomaceous earth or powdered talc to
              form a thick paste.  

              a.   Select the amount of filler material to make a
                   poultice of the required size.  Add
                   hypochlorite solution to obtain the proper
                   paste-like consistency.

              b.   The undiluted hypochlorite solution can be
                   commercial household bleach (which is about 5%
                   sodium hypochlorite) or 5% potassium
                   hypochlorite solution or Javelle water.  For
                   guidance on making javelle water, see 03710-02-S.

         2.   Follow poulticing procedures in Section 3.02 A. 2-7
              above.

                         END OF SECTION