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GLAZING DETAILS AND INSTALLATION
Small, Intermediate and Large Light Glazing
  1. Determine thickness* and rabbet dimensions from Tables 14(A, B, C, or D) or Table 15. When unusual loading, temperature or humidity conditions exist, special engineering analysis may be required.
  2. Determine from Table 16 the recommended thermal expansion clearances for Plexiglas® sheet in the sash for both horizontal and vertical dimensions. The total height and width of the Plexiglas® acrylic light should be cut shorter than the overall sash opening dimensions by the amount shown in Table 16. The cut Plexiglas® acrylic edges must be smooth and free of chips and hairline cracks.
  3. For smaller lights (up to 24" x 24"), select installation method from Figures 3 to 5. Use nonhardening elastic glazing compound. Apply back putty to the rabbet and bed the Plexiglas® acrylic light in the sash, so that it is centered both vertically and horizontally. Fasten Plexiglas® acrylic light with glazing points or clips, apply face putty and trim the sealant to slope away from the sheet for proper watershed. Metals or wood beads can also be used as in Figure 5, with the elastic glazing compound serving as a weather sealant in the sash.
    For larger lights, select sealing details and sealant type. See Figure 6 for intermediate lights up to 72", and Figure 7 for large lights. Specify installation method from Figures 3 through 7.

* These thickness recommendations are based on meeting wind load requirements for the maximum light size specified. Where high impact resistance is a prime requirement of the Plexiglas® glazing, the Plexiglas® sheet thickness may need to be increased. Breakage resistance data listed earlier can serve as guides for selecting the proper thickness of Plexiglas® to withstand high impact.

Tables 14A, 14B, 14C and 14D:
Allowable Framing Sizes for Plexiglas® Acrylic Sheets

Table 14A -- Sheet Thickness of 0.177" (4.5mm)

Plexiglas® G or MC


Rabbet
Dimentions*
(inches)

Depth

Width

7/16

1/2

5/8

3/4

7/16

7/16

7/16

7/16

Maximum
Sash
Opening
(inches)

20psf

24 x 40

24 x 46

24 x 63

24 x 85

30 x 39

30 x 45

36 x 58

36 x 77

36 x 38

36 x 43

48 x 53

48 x 71

37 x 37

42 x 42

51 x 51

60 x 65

30psf

24 x 39

24 x 44

24 x 59

36 x 71

30 x 37

30 x 43

36 x 53

48 x 63

36 x 36

36 x 41

48 x 48

58 x 58

-

40 x 40

-

-

40psf

24 x 37

24 x 43

24 x 56

36 x 65

30 x 36

30 x 41

36 x 49

48 x 57

35 x 35

36 x 39

46 x 46

54 x 64

-

39 x 39

-

-
* Width noted does not include interior vision strips.

 

Table 14B -- Sheet Thickness of 0.236" (6.0mm)

Plexiglas® G or MC


Rabbet
Dimentions*
(inches)

Depth

Width

7/16

1/2

5/8

3/4

1

1/2

1/2

1/2

1/2

5/8

Maximum
Sash
Opening
(inches)

20psf

24 x 41

24 x 47

24 x 67

60 x 72

-

30 x 40

30 x 46

36 x 62

69 x 69

-

36 x 40

36 x 45

48 x 58

-

-

39 x 39

44 x 44

55 x 55

-

-

30psf

24 x 40

24 x 46

24 x 63

48 x 71

60 x 96

30 x 39

30 x 45

36 x 58

60 x 65

72 x 90

36 x 38

36 x 43

48 x 53

63 x 63

84 x 84

38 x 38

42 x 42

51 x 51

-

-

40psf

24 x 39

24 x 45

24 x 61

36 x 72

48 x 96

30 x 38

30 x 43

36 x 54

48 x 66

60 x 90

36 x 37

36 x 42

48 x 48

60 x 60

72 x 82

37 x 37

41 x 41

-

-

78 x 78
* Width noted does not include interior vision strips.

 

Table 14C -- Sheet Thickness of 0.354" (9.0mm)

Plexiglas® G or MC


Rabbet
Dimentions*
(inches)

Depth

Width

1/2

3/4

1

1-1/8

1-1/4

5/8

3/4

3/4

3/4

7/8

Maximum
Sash
Opening
(inches)

20psf

24 x 39

48 x 85

-

-

72 x 120

30 x 48

60 x 81

-

-

-

42 x 47

72 x 79

-

-

-

46 x 46

77 x 77

-

-

-

30psf

24 x 48

48 x 79

-

-

72 x 120

30 x 46

60 x 75

-

-

-

42 x 45

70 x 70

-

-

-

45 x 45

-

-

-

-

40psf

24 x 27

48 x 75

72 x 76

-

72 x 120

30 x 46

60 x 70

-

-

-

42 x 43

67 x 67

-

-

-

43 x 43

-

-

-

-
* Width noted does not include interior vision strips.

 

Table 14D -- Sheet Thickness of 0.472" (12.0mm)

Plexiglas® G or MC


Rabbet
Dimentions*
(inches)

Depth

Width

1/2

3/4

1

1-1/8

5/8

7/8

7/8

1

Maximum
Sash
Opening
(inches)

20psf

24 x 49

48 x 90

72 x 120

72 x 120

30 x 48

60 x 86

-

-

42 x 47

72 x 83

-

-

46 x 46

-

-

-

30psf

24 x 48

48 x 85

72 x 116

72 x 120

30 x 46

60 x 81

-

-

42 x 45

72 x 78

-

-

45 x 45

77 x 77

-

-

40psf

24 x 47

48 x 81

72 x 108

72 x 120

30 x 46

60 x 72

-

-

42 x 43

72 x 72

-

-

43 x 43

-

-

-
* Width noted does not include interior vision strips.

 

Table 15 (up to 24" x 24")

Plexiglas® G & Plexiglas® MC Sheets

Thickness (in)

Minimum Rabbet Depths (in)

20 psf

30 psf

40 psf

.098

9/32

5/16

11/32

.118

9/32

9/32

5/16

.177

1/4

9/32

9/32

.236

1/4

1/4

9/32

 

Table 16: Expansion Clearance for Plexiglas® G & MC Glazing (in)

Length (in)

Clear

Tinted*

To 36

1/16

1/16

To 60

1/8

3/16

To 96

3/16

5/16

To 120

1/4

3/8
*Less than 60% light transmission.