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Historic Preservation - Technical Procedures

Spectitle:

Removing Manganese Stains From Brick Masonry

Procedure code:

0421111R

Source:

Developed For Hspg (Nps - Sero)

Division:

Masonry

Section:

Brick Unit Masonry

Last Modified:

02/24/2012

Details:

Removing Manganese Stains From Brick Masonry



REMOVING MANGANESE 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 brown stains
         from brick masonry resulting from deposits of manganese
         on the masonry surface.

    B.   Manganese is sometimes used in brick composition as a
         colorant.

    C.   Manganese staining is a form of efflorescence that
         develops when moisture in the wall draws salts and color
         from the brick composition to the surface of the masonry.
         As the water evaporates, color from the manganese is left
         behind.

    D.   Manganese stains are usually tan, brown, nearly black or
         gray in color, have an oily appearance and may streak
         down over the face of the brick.

    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 CLEAN MANGANESE COLORED BRICK WITH
    HYDROCHLORIC ACID WITHOUT NEUTRALIZING THE ACID DURING THE
    RINSING OPERATION.

    CAUTION:  DO NOT USE ANY ACIDIC SOLUTIONS ON TAN, BROWN, BLACK
    OR GRAY BRICK.  THERE ARE SPECIAL PROPRIETARY CLEANING
    COMPOUNDS AVAILABLE FOR CLEANING BRICK CONTAINING MANGANESE.
    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.   Chemicals for Heavy Manganese Staining:

         1.   Acetic Acid (80% or stronger):  

              a.   A colorless pungent liquid acid that is the
                   chief acid of vinegar and that is used
                   especially in synthesis (as of plastics).

              b.   Other chemical or common names include Vinegar
                   acid*.  (Vinegar itself, which contains about
                   4% acetic acid, may be suitable for some
                   purposes requiring acetic acid.)

              c.   Potential hazards:  CORROSIVE TO FLESH AND
                   CORROSIVE TO CONCRETE, STEEL, WOOD OR GLASS.

              d.   Available from chemical supply house (both
                   commercial and scientific), drugstore or
                   pharmaceutical supply distributor, grocery
                   store or supermarket, or hardware store.

         2.   Hydrogen Peroxide - 30-35% (H202):

              a.   An unstable compound used especially as an
                   oxidizing and bleaching agent, an antiseptic,
                   and a propellant.

              b.   Other chemical or common names include
                   Peroxide of hydrogen*; Solution of hydrogen
                   dioxide*; Superoxol*; (hydrogen peroxide is
                   commonly sold as a 3% solution; Superoxol is a
                   30% solution; Superoxol causes flesh burns; 3%
                   hydrogen peroxide does not).

              c.   Potential Hazards:  TOXIC (when concentrated);
                   CORROSIVE TO FLESH; FLAMMABLE (in high
                   concentration).

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

         -OR-

         Proprietary cleaner such as "Diedrich 940 Iron &
         Manganese Stain Remover" (Diedrich Chemicals), or
         approved equal.

    B.   For Light-colored Manganese Staining:

         1.   Oxalic Acid (COOH)2 or (H2C2O4):

              a.   A poisonous strong acid that occurs in various
                   plants as oxalates and is used especially as a
                   bleaching or cleaning agent and in making
                   dyes.

              b.   Other chemical or common names include
                   Ethanedioic acid.

              c.   Potential Hazards:  TOXIC; CORROSIVE TO
                   CONCRETE, STEEL, WOOD OR GLASS.

              d.   Available from chemical supply house, dry
                   cleaning supply distributor, drugstore or
                   pharmaceutical supply distributor, hardware
                   store, or photographic supply distributor (not
                   camera shop).  (Often sold under a
                   manufacturer's brand name; the chemical name
                   may appear on the label.)

    D.   Clean, potable water

    E.   Clean natural fiber rags

2.03 EQUIPMENT

    A.   Garden hose and nozzle

    B.   Stiff bristle brushes (no iron wire)

    C.   Wood scrapers


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 masonry 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 Heavy Manganese Staining:

         1.   Mix 1 part acetic acid, 1 part hydrogen peroxide
              and 6 parts water.

              CAUTION:  ALTHOUGH THIS SOLUTION IS VERY EFFECTIVE,
              IT IS A DANGEROUS SOLUTION TO MIX AND USE.  ACETIC
              ACID-HYDROGEN PEROXIDE MAY ALSO BE AVAILABLE IN A
              PREMIXED FORM KNOWN AS PERACETIC ACID.  THIS ACID,
              A TEXTILE CHEMICAL, IS ALSO DANGEROUS AND MAY BE
              DIFFICULT TO PURCHASE.

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

         3.   Brush or spray on mixture of acetic hydrogen
              peroxide (see Section 3.02 A. above for mixture).
              DO NOT SCRUB.  The stain should disappear quickly.

         4.   Thoroughly rinse the wall with clean, clear water.

         5.   Repeat the procedure if the stains recur after a
              few days.

    B.   For Light-colored or New Manganese Stains:

         1.   Mix 1 lb of oxalic acid crystals (0.45 kg) with 1
              gal (3.79 L) of water.

         2.   Follow procedures 3.02 B.-E. above.

3.03 ADJUSTING/CLEANING

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

                         END OF SECTION