Section R607 Glass Unit Masonry

Panels of glass unit masonry located in load-bearing and nonload-bearing exterior and interior walls shall be constructed in accordance with this section.

Hollow glass units shall be partially evacuated and have a minimum average glass face thickness of ³/₁₆ inch (5 mm). The surface of units in contact with mortar shall be treated with a polyvinyl butyral coating or latex-based paint. The use of reclaimed units is prohibited.

Hollow or solid glass block units shall be standard or thin units.

The specified thickness of standard units shall be not less than 3⁷/₈ inches (98 mm).

The specified thickness of thin units shall be not less than 3¹/₈ inches (79 mm) for hollow units and not less than 3 inches (76 mm) for solid units.

Isolated panels of glass unit masonry shall conform to the requirements of this section.

The maximum area of each individual standard-unit panel shall be 144 square feet (13.4 m²) where the design wind pressure is 20 pounds per square foot (958 Pa). The maximum area of such panels subjected to design wind pressures other than 20 pounds per square foot (958 Pa) shall be in accordance with Figure R607.4.1. The maximum panel dimension between structural supports shall be 25 feet (7620 mm) in width or 20 feet (6096 mm) in height.




FIGURE R607.4.1 GLASS UNIT MASONRY DESIGN WIND LOAD RESISTANCE

The maximum area of each individual thin-unit panel shall be 85 square feet (7.9 m²). The maximum dimension between structural supports shall be 15 feet (4572 mm) in width or 10 feet (3048 mm) in height. Thin units shall not be used in applications where the design wind pressure as stated in Table R301.2(1) exceeds 20 pounds per square foot (958 Pa).

The maximum area of each individual standard-unit panel shall be 250 square feet (23.2 m²). The maximum area of each thin-unit panel shall be 150 square feet (13.9 m²). The maximum dimension between structural supports shall be 25 feet (7620 mm) in width or 20 feet (6096 mm) in height.

The width of curved panels shall conform to the requirements of Sections R607.4.1, R607.4.2 and R607.4.3, except additional structural supports shall be provided at locations where a curved section joins a straight section, and at inflection points in multicurved walls.

Glass unit masonry panels shall conform to the support requirements of this section.

The maximum total deflection of structural members that support glass unit masonry shall not exceed ¹/₆₀₀.

Glass unit masonry panels shall be laterally supported along the top and sides of the panel. Lateral supports for glass unit masonry panels shall be designed to resist not less than 200 pounds per lineal feet (2918 N/m) of panel, or the actual applied loads, whichever is greater. Except for single unit panels, lateral support shall be provided by panel anchors along the top and sides spaced not greater than 16 inches (406 mm) on center or by channel-type restraints. Single unit panels shall be supported by channel-type restraints.

Exceptions:

1. Lateral support is not required at the top of panels that are one unit wide.

2. Lateral support is not required at the sides of panels that are one unit high.

Panel anchors shall be spaced not greater than 16 inches (406 mm) on center in both jambs and across the head. Panel anchors shall be embedded not less than 12 inches (305 mm) and shall be provided with two fasteners so as to resist the loads specified in Section R607.5.2.

Glass unit masonry panels shall be recessed not less than 1 inch (25 mm) within channels and chases. Channel-type restraints shall be oversized to accommodate expansion material in the opening, packing and sealant between the framing restraints, and the glass unit masonry perimeter units.

Before bedding of glass units, the sill area shall be covered with a water base asphaltic emulsion coating. The coating shall be not less than ¹/₈ inch (3 mm) thick.

Glass unit masonry panels shall be provided with expansion joints along the top and sides at all structural supports. Expansion joints shall be not less than ³/₈ inch (10 mm) in thickness and shall have sufficient thickness to accommodate displacements of the supporting structure. Expansion joints shall be entirely free of mortar and other debris and shall be filled with resilient material.

Glass unit masonry shall be laid with Type S or N mortar. Mortar shall not be retempered after initial set. Mortar unused within 1¹/₂ hours after initial mixing shall be discarded.

Glass unit masonry panels shall have horizontal joint reinforcement spaced not greater than 16 inches (406 mm) on center located in the mortar bed joint. Horizontal joint reinforcement shall extend the entire length of the panel but shall not extend across expansion joints. Longitudinal wires shall be lapped not less than 6 inches (152 mm) at splices. Joint reinforcement shall be placed in the bed joint immediately below and above openings in the panel. The reinforcement shall have not less than two parallel longitudinal wires of size W1.7 or greater, and have welded cross wires of size W1.7 or greater.

Glass units shall be placed so head and bed joints are filled solidly. Mortar shall not be furrowed. Head and bed joints of glass unit masonry shall be ¹/₄ inch (6.4 mm) thick, except that vertical joint thickness of radial panels shall be not less than ¹/₈ inch (3 mm) or greater than ⁵/₈ inch (16 mm). The bed joint thickness tolerance shall be minus ¹/₁₆ inch (1.6 mm) and plus ¹/₈ inch (3 mm). The head joint thickness tolerance shall be plus or minus ¹/₈ inch (3 mm).