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Historic Preservation - Technical Procedures

Spectitle:

Removing Vanadium Stains From Brick Masonry

Procedure code:

0421112R

Source:

Developed For Hspg (Nps - Sero)

Division:

Masonry

Section:

Brick Unit Masonry

Last Modified:

02/24/2012

Details:

Removing Vanadium Stains From Brick Masonry



REMOVING VANADIUM STAINS FROM BRICK MASONRY


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


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on removing yellow or
         green stains from brick masonry resulting from deposits
         of vanadium salts on the masonry surface.

    B.   Vanadium staining is a form of efflorescence that
         originates in the raw material used to manufacture
         certain brick units.  It develops when moisture in the
         wall draws salts and color from the brick composition to
         the surface of the masonry.  As the water evaporates,
         vanadium staining is left behind.

    C.   Vanadium stains are yellow, green, brownish-green or
         brown and are frequently mistaken for organic growth.
         They typically occur on red, buff or white brick.  They
         often result from impurities within the masonry or from
         metal anchoring or support systems which contain vanadium
         alloys.  Vanadium stains also develop as a result of
         washing with hydrochloric acid.

    D.   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.

    E.   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).


PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   Diedrich Chemicals
         7373 S. 6th Street
         Oak, Creek, WI  53154
         800/323-3565

2.02 MATERIALS

    CAUTION:  DO NOT USE ANY ACIDIC SOLUTIONS ON LIGHT-COLORED
    BRICK.  THERE ARE SPECIAL PROPRIETARY CLEANING COMPOUNDS
    AVAILABLE FOR CLEANING LIGHT-COLORED BRICK.  THEY SHOULD BE
    TESTED FOR EFFECTIVENESS PRIOR TO USE.  THE ADVICE OF THE
    BRICK MANUFACTURER SHOULD BE REQUESTED AND FOLLOWED.

    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.   Potassium Hydroxide (KOH):

         1.   A white deliquescent solid that dissolves in water
              with much heat to form a strongly alkaline and
              caustic liquid and is used chiefly in making soap
              and as a reagent.

         2.   Other chemical or common names include Caustic
              potash*; Caustic potassa*; Hydrate of potassa*.

         3.   Potential Hazards:  TOXIC AND CORROSIVE TO FLESH.

         4.   Available from chemical supply house, drugstore or
              pharmaceutical supply distributor, hardware store,
              or garden and lawn supply center.

    -OR-

         Sodium Hydroxide (NaOH):

         1.   A white brittle solid that is a strong caustic base
              used especially in making soap, rayon, and paper.

         2.   Other chemical or common names include Caustic
              soda*; Hydrate of soda*; Hydrated oxide of sodium*;
              Lye*; Mineral alkali*; Soda lye*; Sodic hydrate*;
              Sodium hydrate*.

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

         4.   Available from chemical supply house, drugstore or
              pharmaceutical supply distributor, hardware store,
              or paint store.

    -OR-

         Proprietary Cleaner:

         1.   For normal-colored brick, try "Diedrich 202V Vana-Stop"
               (Diedrich Chemicals), or approved equal.

         2.   For light-colored brick, try "Diedrich 222 Non-acid
              Masonry Cleaner" (Diedrich Chemicals), or approved
              equal.

    B.   Clean, potable water

    C.   Clean natural fiber rags

2.03 EQUIPMENT

    A.   Garden hose and nozzle

    B.   Stiff bristle brushes (non-metallic)

    C.   Wood scrapers


PART 3---EXECUTION

3.01 PREPARATION

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

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.   Mix 1/2 lb (0.23 kg) potassium or sodium hydroxide with
         1 qt. (0.95 L) water -OR- 2 lbs (0.91 kg) potassium or
         sodium hydroxide with 1 gal (3.79 L) water

    B.   Thoroughly wet the masonry surface with clean, clear
         water.

    C.   Brush or spray apply the potassium or sodium hydroxide
         solution (see 3.02 A. above) to the masonry surface.

    D.   Allow to remain on the surface for 2 or 3 days.

    E.   Thoroughly rinse the surface with clean, clear water to
         remove any white salt accumulations resulting from the
         hydroxide, and allow to dry.

    -OR-

    F.   Use a proprietary cleaner to remove the staining.  Follow
         manufacturer's instructions for application and
         precautions.

         NOTE:  PROPRIETARY CLEANERS MUST BE TESTED PRIOR TO USE
         FOR STAIN REMOVAL.

3.03 ADJUSTING/CLEANING

    A.   Upon completion of the masonry cleaning work, clean
         window glass and spattered adjacent surfaces.

                         END OF SECTION