All materials supplied by ADVANCED ACRYLIC DISPLAY & SUPPLY, INC., are of the highest quality available. However uniform, consistent measures to determine the degree of that quality are required. The goal of these specifications is to add clarity to those areas which are subjective, ambiguous, and/or not defined elsewhere.

GENERAL GUIDELINES:

• All glass viewing panels produced by ADVANCED ACRYLIC DISPLAY & SUPPLY, INC., are fabricated from laminated sheets of  either heat treated, or fully tempered, soda-lime float glass or low iron content soda-lime float glass. Laminated glass viewing panels consist of two or more plies of glass interleaved with clear polyvinyl butyl (PVB). The layers are bonded into a single unit by the application of heat and pressure.

• Due to the potential of spontaneous breakage inherent with heat treated and tempered glass, single ply panels should never be used for public exhibits. All glass viewing panels produced by ADVANCED ACRYLIC DISPLAY & SUPPLY, INC., shall be engineered so that in the event of a single ply failure, the remaining plies will withstand the load with a breakage probability less than 0.07%.

• All viewing panels shall be engineered and fabricated to withstand the designed water loads, thermal movement, and deflection criteria specified without failure of  the viewing panel to perform it’s designed function.

• All viewing panel edges will be relieved to prevent residual stress risers and possible damage during shipping and/or installation. 

• All glass viewing panels fabricated by ADVANCED ACRYLIC DISPLAY & SUPPLY, INC., shall meet, or exceed, all of the minimum physical values detailed in the FGMA Glazing Manual, Laminators Safety Glass Association Standard Manual, and the corresponding ANSI/ASTM specification(s). 

DESIGN CRITERIA:

• All glass viewing panels fabricated and installed by ADVANCED ACRYLIC DISPLAY & SUPPLY, INC., shall be engineered to ensure a minimum safety factor of 12, based on the following: 

                1. Modulus of Rupture in flexure for a 60 second load duration: mean 24,000 psi.

                2. Maximum allowable long term stress of  2,000 psi.

                3. Spontaneous breakage probability of less than 0.02%.

• Glass viewing panels shall have a maximum initial deflection based on the following:

                1. Maximum initial deflection of no more than 1/200 of  the panels short 
                    dimension, for panels supported on all four edges.

                2. Maximum initial deflection of no more than 1/300 of  the panels long dimension,
                    for panels supported on three edges only (top edge unsupported).

                3. Maximum initial deflection of no more than 1/400 of  the panels short dimension,
                    for panels supported at the top and bottom only.

OPTICAL SPECIFICATIONS:

• Glass viewing panels shall be virtually free of haze, bubbles, distortions, or inclusions, which significantly diminish the viewing quality of the window.  In inspecting glass panels, the central portion (a circular area equal to 66% of the total panels viewing area, centered on the panel) of the panel and the remaining outer portion of the panel have different dimensional acceptance criteria.

                 1. Haze may be some form of contamination trapped within the glass or PVB interlayer.
                    Either  condition, if visible from a distance of more than 48” from, and perpendicular
                    to the panels face is unacceptable and is cause for rejection of the panel.

                2. Distortions are surface irregularities in the form of bumps, dimples, ridges, or waviness.
                    A performance inspection utilizing a grid board and lights will be conducted to
                    determine viewing panel acceptability. The procedure for this inspection is detailed
                    in ADVANCED ACRYLIC DISPLAY & SUPPLY, INC., “Optical performance inspection”
                    procedures.

                3. Inclusions may be a piece of dirt, a stone, a grain of sand, a bubble or any foreign material
                    trapped within the panel itself.

                        a. Inclusions in the central portion of the panel are limited to one inclusion for each four
                            square feet of viewing area, with no more than one inclusion in any two adjacent one
                            square foot areas.

                                    (1) Inclusions whose diameter, or length, is less than .060” and do not exceed
                                        .125” in two dimensions are not considered.

                                    (2) Inclusions whose diameter, or length, is greater than .125” and that exceed
                                         .250” in two dimensions shall be counted.

                                    (3) Inclusions that penetrate the panel surface, or any whose diameter is
                                         greater than .250” and that exceed .500” in two dimensions are considered
                                         unacceptable and are cause for rejection of the viewing panel.

                        b. Inclusions in the outer portion of the panel are limited to one inclusion for each
                            square foot of viewing area, with no more than two inclusions in any two adjacent one
                            square foot areas.

                                    (1) Inclusions whose diameter, or length, is less than .250” and do not exceed
                                        .500” in two dimensions are not considered.

                                    (2) Inclusions whose diameter, or length, is greater than .250” and that exceed
                                        .500” in two dimensions shall be counted.

                                    (3) Inclusions that penetrate the panel surface, or any whose diameter is
                                        greater than .500” and that exceed 1.000” in two dimensions are considered
                                        unacceptable and are cause for rejection of the viewing panel.

                       c. The total number of counted inclusions allowable per panel is limited to the panel
                           viewing area in square inches divided by 500.
 

DIMENSIONAL REQUIREMENTS:

• Glass viewing panels shall meet these  dimensional  tolerances  when  measured at an ambient temperature of between 700 and 750 (f).

            1. Panel thickness as measure at any location on the panel shall be within +15%/-5% of the
                       calculated minimum thickness.

            2. Panel length and width/height shall be within +/-.250” of the specified nominal dimension.

            3. Panel flatness shall be within 1% of the length of the panel, as measured from
                corner-to-corner of the unrestrained panel, laying on a flat surface.

            4. Panel warp and twist when measured three corners relative to the fourth of the unrestrained
                panel, laying on a flat supporting surface shall be square and/or perpendicular to, within
                0.5% of the specified dimension.