Cleaning Unpolished White Granite

PART 1–GENERAL

1.01 SUMMARY

1. This procedure includes guidance on cleaning unpolished Sierra white and Milford pink granite. This treatment shall not be used on any polished granite.
2. 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).

3. Materials conservator should review specifications to ensure they are appropriate.

1.02 DEFINITIONS

1. Pressure Readings: Described herein, shall be measured at the nozzle of the spray apparatus, not at the masonry surfaces as follows:
   1. Low pressure wash shall measure between 100 psi and 400 psi.
   2. Medium pressure wash shall measure between 400 psi and 800 psi.
   3. High pressure wash shall measure between 800 psi and 1200 psi.
2. Construction Engineer: As referred to hereinafter, means that person or persons representing the Government or acting for the Government’s Contracting Officer.

1.03 QUALITY ASSURANCE

1. Cleaning operations shall be carried out by a firm with a minimum of five years specialized experience in the cleaning of historic architectural masonry.
2. The Contractor shall submit to the Architect written record of projects for which the Contractor has performed masonry cleaning of materials the same as those on this building.
3. The Contractor shall arrange with the Construction Engineer for a site visit of protective methods and cleaning materials and methods which he proposes to use to prove that chemical damage to glass, polished stone, or air conditioning units, finished surfaces, trees, shrubbery, and grass will not occur.
4. The Contractor shall test all drains which he plans to use to assure that those drains are functioning properly before beginning masonry cleaning operation in each area. The Contractor shall immediately notify the Construction Engineer of any drains which are stopped up or blocked to the Construction Engineer.
5. During cleaning operations, the Contractor shall prevent solids, such as masonry cleaning residue, from the drains and drain lines. Drains shall be covered with cheesecloth. The Contractor will be held responsible for clearing out drains and drain lines which become blocked or filled as a result of work performed under this contract.
6. Regulatory Requirements: Comply with municipal and Federal regulation governing the cleaning, chemical waste disposal, scaffolding and protection to adjacent properties.
7. Field Samples:
   1. The Contractor shall clean 25 square feet (approximate) sample panels on each type of masonry. Locations of sample panels to be cleaned will be selected by the Construction Engineer.
   2. Prior to cleaning sample panels, the Contractor shall submit to the Construction Engineer in his written description of cleaning methods, working pressures, materials and equipment proposed for use in cleaning each type of masonry. Actual samples of any chemical cleaners shall be submitted along with letters of certification from manufacturer that chemical concentrations do not exceed those specified above.
   3. Adjust the chemical concentrations, working pressures and methodologies during field panel cleaning, as directed by the Construction Engineer.
   4. Sample panels shall be cleaned by the Contractor using methods, materials, and working pressures previously submitted and approved. Sample panel cleaning shall be performed in the presence of the Construction Engineer. The working pressures during sample panel cleaning shall be varied up to the previously submitted and approved capacities to determine the best working pressure.
   5. The Contractor shall obtain the Construction Engineer’s written approval of cleaning methods, working pressures, materials, equipment used and sample panels before proceeding with building cleaning operations. For this written approval submit the Contractor shall allow a minimum of seven calendar days after completion of sample cleaning to permit the Construction Engineer to study the sample panels for negative reactions. Approved sample panels shall be marked and left untouched. Approved samples will be used as the standard for similar work throughout the project.

1.04 DELIVERY, STORAGE AND HANDLING

1. Packing and Shipping: Deliver materials to the site in the manufacturer’s original and unopened containers and packaging, bearing labels as to the type of material, brand name and manufacturer’s name. Delivered materials shall be identical to tested materials.
2. Storage and Protection: Store materials off the ground in a dry, clean location. Remove materials which are damaged or otherwise not suitable for use from the job

1.05 PROJECT/SITE CONDITIONS

1. Environmental Requirements: No cleaning shall be executed when air or masonry surface temperature is below 45 degrees F unless adequate approved means are provided for maintaining a 45 degree F temperature of the air and materials for a 48 hours subsequent to cleaning.

1.06 SEQUENCING AND SCHEDULING

1. Perform general cleaning of masonry before the repair and pointing of the masonry, unless mortar joints are in poor condition. Serious deterioration could foster excessive moisture infiltration into the masonry. Perform final wash down of the masonry no less than 30 days after pointing and repair and pointing is completed.
2. Perform cleaning and washing of the exterior masonry only during the periods of natural daylight.

PART 2–PRODUCTS

2.01 MANUFACTURERS

1. ProSoCo, Inc.

   www.prosoco.com

2. Diedrich Technologies, Inc.

   www.diedrichtechnologies.com

2.02 MATERIALS

1. White Granite Cleaner: Solution of 4% hydrofluoric acid with a trace of phosphoric acid (less than 0.1%), such as Sure Klean Restoration Cleaner (ProSoCo, Inc.), “Diedrich 101 Masonry Restorer Super Concentrate” - diluted 1:4 a 4% maximum acid solution (Diedrich Technologies, Inc.), or approved equal.
2. Warm Water: Potable, non-staining and free of oil, acids, alkalis, and organic matter, heated to approximately 180 degrees F.

2.03 EQUIPMENT

1. High Pressure Water Equipment: USE CAUTION. Provide equipment capable of providing water pressure, as measured at the pump, in the target range of 600 psi, at a temperature of 180 degrees F. The equipment shall deliver a constant water flow of 4-5 gallons per minute. Equipment shall have metal, accurate calibrated, operating gauges to monitor water pressure. See 04510-04-S and 04510-05-S for usage guidelines and dangers in using high-pressure cleaning equipment.
2. Spray tips: Fan type; stainless steel, dispersing a 25-50 degree fan spray and a cone shaped spray tip.
3. Brushes: Nylon or Fiber bristle brushes.
4. Protective clothing: Chemicals can cause severe burning of skin, eyes and lungs. Provide protective clothing appropriate to the materials and equipment in use.

PART 3–EXECUTION

3.01 EXAMINATION

1. Tests/Inspection: Inspect site conditions and drainage to determine that cleaning operations can be conducted without endangering or causing interferences with other materials or work at the site and to determine that drainage is adequate to safely carry away the waste material produced during the cleaning operations.

3.02 PREPARATION

1. Protection:
   1. All necessary precautions shall be taken to protect all parts of the building not being cleaned from damage during the cleaning process. The Contractor shall use masking tape where applicable to the edges of coverings during masonry cleaning operations, and remove such coverings when masonry cleaning operations are completed on that section of the building.
   2. All work shall proceed in an orderly fashion; working from top to bottom of each scaffold width and from one end of the elevation to the other.
   3. Take all necessary precautions and protective measures to protect surrounding materials on the site and surfaces of the building not being cleaned, from coming in contact with the cleaning materials and run-off.
   4. Fully protect all metals, painted surfaces, limestone and polished black granite from coming in contact with acid cleaner.
   5. Take necessary precautions to protect workmen and pedestrians from cleaning chemicals, overspray and run-off.
   6. Provide protection to prohibit chemicals or run-off from coming in contact with any painted, polished or metallic surfaces. Build dams to divert flowing water to drains in compliance with municipal codes. Contain or dilute used cleaning materials prior to disposal in accordance with code.

3.03 ERECTION, INSTALLATION, APPLICATION

1. Pre-wet the granite with a low pressure (100-400 psi) warm water wash.
2. Apply cleaner undiluted to maintain 4% maximum solution evenly by spraying at 125 psi or with soft fiber bristled brush. Let solution stand for 3-5 minutes.
3. Rinse granite with clean water at medium pressure (400-800 psi), removing all cleaner from stone.
4. Re-apply cleaner undiluted to maintain 4% maximum solution and let stand 3-5 minutes.
5. Rinse granite with clean water at medium pressure (400-800 psi) to remove all acid wash and soil from stone.
6. Stone shall be evenly clean without streaking or staining.
7. Apply cleaner at no more than 4% hydrofluoric acid and nor more than two times.