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Historic Preservation - Technical Procedures

Spectitle:

Removing Blood Stains From Concrete

Procedure code:

0371007R

Source:

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

Division:

Concrete

Section:

Concrete Cleaning

Last Modified:

02/24/2012

Details:

Removing Blood Stains From Concrete



REMOVING BLOOD 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 blood stains
         from concrete using sodium peroxide and water.

    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).


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.   Sodium Peroxide:

         1.   Other chemical or common names include Sodium
              dioxide; Sodium binoxide*.

         2.   Potential Hazards:  TOXIC (DO NOT BREATHE THE
              DUST); CORROSIVE TO FLESH; FLAMMABLE (EXPLOSIVE IN
              WATER, ACID OR ORGANIC SOLVENTS).

         3.   Available from chemical supply house, drugstore or
              pharmaceutical supply distributor, hardware store,
              paint store, or water and sanitation supply
              distributor (often sold under a manufacturer's
              brand name; the chemical name may appear on the
              label).

         -OR-

         Sodium Orthophosphate:

         1.   Other chemical or common names include Tribasic
              sodium phosphate; Trisodium orthophosphate;
              Trisodium phosphate; TSP*; Phosphate of soda*.

         2.   Potential Hazards:  CORROSIVE TO FLESH.

         3.   Available from chemical supply distributor,
              supermarket, grocery, or hardware store.

         -OR-

         Sodium Thiosulfate - white sal or "hypo" of photographic
         fixing agent (NA2S2O3):

         1.   A hygroscopic crystalline salt used especially as a
              photographic fixing agent and a reducing or
              bleaching agent.

         2.   Other chemical or common names include Sodium
              hydrosulfite; Sodium Hyposulfite; Sodium
              subsulfite; Antichlor*; Hypo*; Hyposulfite of
              soda*.

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

         4.   Available from chemical supply house, dry cleaning
              supply distributor, drugstore or pharmaceutical
              supply distributor, photographic supply distributor
              (not camera shop), or water and sanitation supply
              distributor.

         -OR-

         Hydrogen Peroxide (H202):

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

         2.   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).

         3.   Potential Hazards:  TOXIC (when concentrated);
              CORROSIVE TO FLESH (gasoline, kerosene and mineral
              spirits are each a mixture of compounds from
              petroleum, all of which fall within a specified
              range of properties); FLAMMABLE (in high
              concentration).

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

    B.   Acetic Acid:  

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

         2.   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.)

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

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

    C.   Vinegar:

         1.   Potential Hazards:  CORROSIVE TO CONCRETE, STEEL,
              WOOD OR GLASS.

         2.   Available from grocery store or supermarket.

         3.   Vinegar itself, which contains about 4% acetic
              acid, may be suitable for some purposes requiring
              acetic acid.

    D.   Bandaging Materials

    E.   Clean, potable water

2.02 EQUIPMENT

    A.   Cloth mask

    B.   Stiff bristle brushes (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.   Saturate the surface with clear cold water.

    B.   Carefully sprinkle sodium peroxide powder over the
         surface in a thin layer.  

         CAUTION:  SODIUM PEROXIDE DUST IS HIGHLY TOXIC.  WEAR A
         CLOTH MASK OVER THE NOSE AND AVOID BREATHING THE SODIUM
         PEROXIDE DUST.  ALSO KEEP ALL AREAS OF THE SKIN PROTECTED
         FROM THE DUST.

         1.   Solids of sodium orthophosphate, sodium thiosulfate
              or a liquid 3% solution of hydrogen peroxide may be
              used instead of sodium peroxide.

              NOTE:  SODIUM THIOSULFATE SHOULD NOT BE USED IN
              CONFINED AREAS BECAUSE IT GENERATES ACRID FUMES OF
              SULFUR DIOXIDE.  

    C.   Sprinkle the surface with a fine mist of water or apply
         a water-saturated bandage and allow to sit for a few
         minutes.

    D.   Thoroughly rinse the surface with clean, clear water,
         scrubbing vigorously with a stiff bristle brush.

    E.   Neutralize any remaining alkali on the surface (not
         necessary if hydrogen peroxide is used):

         1.   Brush the surface with vinegar.

         2.   Rinse with clean, clear water and allow to dry.

         -OR-

         If alkali still remains,

         1.   Mix a solution of 1 part glacial acetic acid and 19
              parts water.

         2.   Brush the solution over the surface.

         3.   Thoroughly rinse the surface with clean, clear
              water and allow to dry.

                         END OF SECTION