Replacing Damaged Pigmented Structural Glass Panels

PART 1-GENERAL

1.01 SUMMARY

1. This procedure includes guidance on selectively replacing all cracked and broken structural glass panels with new to match original adjacent structural glass panels. It also includes information on regrouting open or deteriorated joints.
2. See also 08810-01-R, 08810-01-S and 08810-03-R for additional guidance on the preservation of pigmented structural glass.
3. Safety Precautions:
   1. Comply with municipal and Federal regulations governing the cleaning, chemical waste disposal, scaffolding protection to adjacent properties and workers.
   2. Refer to Federal Government Specification Section 01546, Health and Safety, and comply with all the section requirements.
4. 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).

1.02 DEFINITIONS

1. Work Description: Prior to commencing the work, the Contractor shall submit to the Contracting Officer’s representative a written description of the entire methods and procedures proposed for all the work to be carried out to the structural glass and including, but not limited to, preparation, cutting out, protection, regrouting, replacement and, bedding application modes and ratios and content of materials.
   1. No frozen materials are to be used. Protect finish against premature drying out caused by sunlight and drafts.
2. Work Description: Prior to commencing the cleaning operations, the Contractor shall submit to the Contracting Officer’s representative a written description of the entire methods and procedures proposed for cleaning the structural glass including, but not limited to, methods of grinding, sanding and polishing, drying times and methods, method of sealing and proposed protection and handling procedures.

1.03 SYSTEM DESCRIPTION

1. Performance Requirements:
   1. The general objective for structural glass repair and replacement is to match the pigment and all aspects of the structural glass with the original in all respects.
   2. The general objective of structural glass cleaning is to remove dirt, grime and coatings from the surface without damaging the underlying material and to give all the structural glass a clean uniform appearance without blotches.

1.04 SUBMITTALS

1. Product Data: Submit manufacturer’s product and technical literature and instructions including all recommendations for their application and use to the Contracting Officer’s representative for all cleaning and patching materials. Include test reports and certifications, substantiating that products comply with requirements.

1.05 QUALITY ASSURANCE

1. Qualifications: The work of this section shall be performed by a firm possessing a minimum of three (3) years of specialized experience in the restoration and cleaning of historic architectural structural glass, similar to work required in this project. The Contractor shall submit to the Contracting Officer’s representative references of previous work, justifying the firm’s experience. The Contracting Officer’s representative reserves the right to approve or disapprove the use of the Contractor contingent upon the firm’s experience.
   1. NOTE: The quality of the work is highly dependent on the competence of the Contractor because matching is a specialized skill.
   2. In the event that the Contractor wishes to modify any methods specified in this section, he shall submit his proposal in writing for consideration and review. The Contracting Officer’s representative will have the right to ask for control samples before final approval. Any such modifications or changes shall be at no additional cost to the Government.
2. Regulatory Requirements: Comply with municipal and Federal regulations governing all work included in this section and including, but not limited to, cleaning, waste disposal and protection to adjacent properties.
3. Field Samples: Sample panels for cleaning and replacement of structural glass shall be prepared for review and shall establish a standard for all structural glass work. The locations and types of control samples are to be indicated on a plan, with a photograph of each control sample to be submitted to the Contracting Officer’s representative. No work shall commence until a written review of the control samples has been obtained from the Contracting Officer’s representative.
   1. The Contractor shall clean sample structural glass panels of each color of structural glass, for review by the Contracting Officer’s representative. Locations of sample panels to be selected by the Contracting Officer’s representative.
   2. The Contractor shall prepare an 8 linear foot sample showing the regrouting of joints between the structural glass panels. Samples are to be prepared for each structural glass color. The location of sample panels are to be selected by the Contracting Officer’s representative. All samples are to be reviewed and approved by the Contracting Officer’s representative.
   3. The Contractor shall prepare a sample panel of replacement structural glass. The sample panel should be made to match the original structural glass in all respects.
   4. All the control samples are to be located on floor plans and clearly numbered in the field. The approved samples are to be identified on separate plans and are subject to review and approval in writing by the Contracting Officer’s representative.
   5. All procedures and methods for sample preparations are to be submitted by the Contractor to the Contracting Officer’s representative for review and written approval.
   6. Retain and protect the approved samples throughout the contract. The approved samples shall be the sole responsibility of the Contractor.
   7. Any work considered by the Contracting Officer’s representative to be of a lower grade than the reviewed samples, in any respect, will be the sole responsibility of the Contractor to replace.

1.06 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 site.

1.07 PROJECT/SITE CONDITIONS

1. Environmental Requirements: Improper use of chemicals may constitute a health hazard. Refer to manufacturer’s Material Safety Data Sheets for hazard data, special protection, for use and precautions to be taken in handling and storage. Comply with manufacturer’s recommendations for proper use of chemicals.
2. Existing Conditions:
   1. The Contractor is responsible to take all necessary precautions and measure to protect all surrounding materials from damage that may be incurred during the structural glass restoration work described in this outline specification. Any damage caused by the Contractor to other materials is unacceptable and shall be repaired or replaced by the Contractor to the satisfaction of the Contracting Officer’s representative, at no cost to the Government.
   2. The Contractor is responsible for providing all protection necessary to adjacent materials.
   3. The Contractor shall provide for all site attendance and for all inspections of structural glass work and materials, as required by the Contracting Officer’s representative.

PART 2-PRODUCTS

2.01 MANUFACTURERS

1. Pilkington, www.pilkington.com
2. PPG Industries (formerly Pittsburgh Plate Glass), www.ppg.com
3. General Electric, www.ge.com
4. Vitrolite Specialist, www.vitrolitespecialist.com

2.02 MATERIALS

1. Water: Potable, non-staining and free of oils, acids, alkalis and organic matter.
2. Pigments: Pure mineral earth pigments resistant to alkalis and non-fading. Suitable colors are to be selected to match existing in all respects, to the standard of the approved samples.
3. Cleaning Agents - Structural Glass: Application for removal of soil and grease build-up. Use a mild solution of water mixed with potable ammonia.
4. Cleaning Agent - Surface Masonry: Application for removal of soot and soil build-up. Use a light detergent or a mild chemical wash.

5. Solvents such as methyl ethyl ketone, methyl isobutyl ketone or acetone.

   Methyl Ethyl Ketone:

   1. Other chemical or common names include 2-butanone; MEK*.
   2. Potential Hazards: TOXIC AND FLAMMABLE.
   3. Available from chemical supply house, hardware store or paint store.

   Methyl Isobutyl Ketone:

   1. Other chemical or common names include Asymmetric ethyl methyl acetone; 3-methyl-2-pentanone; Secondary butylmethyl ketone; MIBK*.
   2. Potential Hazards: TOXIC AND FLAMMABLE.
   3. Available from chemical supply house, hardware store or paint store.

   Acetone (C3H6O):

   1. A volatile fragrant flammable liquid ketone used chiefly as a solvent and in organic synthesis.
   2. Other chemical or common names include Dimethyl ketone; Propanone
   3. Potential Hazards: VOLATILE AND FLAMMABLE SOLVENT
   4. Available from chemical supply house or hardware store.
6. Asphalt-Based Mastic Adhesive: Application for attachment of glass panels to masonry substrate.
7. 1/16” Adhesive Cork Tape: Applied to the horizontal edges of the glass panels to provide separation for the glass panels.
8. Joint Cement or Caulking Compound: Application for filling narrow 1/16” to 1/32” joints between structural glass.
   1. Use a joint compound with an integrated watertight surface, capable of being used in the narrow joints described above.
9. Replacement Glass Panels. Alternative products may be used with RHPO approval. Contact manufacturers and/or supplies for current product inventory; examples of product names include “Vitrolux”, “Spandrelite”, “Sheet Plastic”, or approved equal.
   1. Alternative products should be a good color and finish match to the existing original structural glass to the satisfaction of the Contracting Officer’s representative.
10. Clean, soft cloths

2.03 EQUIPMENT

1. Crock neck polyethylene laboratory squeeze bottle or large syringe without needle.
2. Piano wire
3. Joint tools
4. Soft bristle brushes

PART 3-EXECUTION

3.01 PREPARATION

1. Protection: Prior to commencing the cleaning operations, the Contractor shall submit to the Contracting Officer’s representative for review a written description of proposed materials and methods of protection for preventing damage to adjacent materials and the building during the cleaning of the structural glass.
2. Surface Preparation: All bonds, joints, patterns, etc., are to be maintained to the original layout. Jointing strips are only to be used in previous locations unless otherwise noted.
   1. Removal: Where existing glass panels are damaged and broken, they should be carefully removed. Soften the mastic by injecting solvent behind the panel using a squeeze bottle or syringe. Separate the panel from the wall using a taut piano wire to cut through the softened mastic. Remove all existing asphalt-based mastic adhesive from the substrate.
   2. Existing Substrate: Clean the existing substrate thoroughly with a light detergent or mild chemical wash to remove all built-up soiling. Allow substrate to dry out fully prior to installation of structural glass panels.
   3. Rake out all loose joint cement. Wash all joints with a soft bristle brush and water. Allow all joints to dry fully prior to regrouting.
   4. Repair minor hairline cracks. See 08810-01-R for guidance.

3.02 ERECTION, INSTALLATION, APPLICATION

1. Clean substrate with a light detergent or mild chemical wash. Allow to dry.
2. Clean old structural glass to be reinstalled. Remove soil and grease build-up and all old asphalt-based mastic.
3. Install new structural glass panel: Apply daubs of asphalt-based mastic adhesive to the glass and then attach directly to the substrate, leaving a cavity of 3/8” between the glass and substrate. The temperature should not be less than 40 degrees F. The daubs of asphalt mastic should be 2” to 3” in diameter and cover 50% of the glass panel area. Asphalt-based mastic is recommended to cover a 3” perimeter width of the glass panel and around all holes and openings.
   1. Use a 3” square 3” leg 18 gauge stainless steel angle spaced 1’-0” (maximum) on center in the vertical dimension and 2 angles per structural glass panel in the horizontal direction.
   2. To be installed to provide support for the structural glass panel.
   3. Push the glass panel onto the substrate truing it for level and plumb and maintaining the necessary cavity.
   4. Glass seams: All glass seams and abutments to be protected or separated. Apply 1/16” thick adhesive cork tape along the horizontal edges of the structural glass panels and recessed 1/8” from the front face of the panel.
4. Grout the joints:
   1. Rake out all loose joint cement.
   2. Blend the caulking compound to match the color of the original caulking by adding pigments.
   3. Fill the joints neatly and avoid spreading the caulking compound over the adjacent structural glass panels in order to minimize necessary clean up.
   4. When the material has hardened, remove excess caulking compound by the manufacturer’s specified solvent. This should be applied sparingly to a clean rag and the glass wiped clean and dry.