Palram SUNLIT - Manual (Page 16)

14
14
Preparation for Glazing
Determination of Rabbet Depth and Thermal Expansion Allowance
These parameters depend on the SUNLITE sheet dimension, and relate to the four sides of the sheet (four-sides clamping system), or
to the two edges parallel to the rib channels (two-sides clamping system).
1. Allowance for expansion - SUNLITE roughly expands 3mm for every meter (1/8 in. per 3 1/3 ft.) of length (or width) for a service
temperature range of about 50°C (90°F), the practical working range in most cases. For a sheet of 1m (or 40 in.) wide, 1.5m (60 in.) long,
a net allowance of 3 mm (width) and 5mm (length) should suffice in theory. We recommend doubling this allowance for practical
reasons. Allowance should be divided between both sides of the sheet. When the ends of panels are protected by a recessed ‘U’
channel, allow suitable internal space for thermal expansion.
2. Edge Engagement: (the overlap of the glazing over its frame).
3. Rabbet Depth: (expansion allowance + edge engagement). Palram recommends a rabbet depth of at least 20 mm
(0.8 in.) for widths up to 1.0 m (40 in.) and a depth of 25-30 mm (1.0 - 1.2 in.) for wider spans.
Wooden frame
Silicone sealant
Fastening screw
Top aluminum
glazing profile
Bottom aluminum
glazing profile
Supporting
steel beam
Rubber sealing
profile/gasket
SUNLITE sheets
Sealing gasket
Fixing screws
Legend
a = Expansion allowance
b = Edge Engagement depth
c = Rabbet depth: a+b
a
a
b
b
Wooden clamping
profile
Rubber sealing
strip
SUNLITE sheets
Figure 16c
Schematic Sketch of Rabbet depth and Expansion Allowance (”Wet” and “Dry” methods)
a. Sheet width
b. Sheet length
c. Sash (frame) width
d. Sash length
e. Edge Engagement depth (overlap)
f. Thermal expansion allowance
g. Rabbet Depth e + f
Figure 16b
“Dry” Glazing
Figure 16b
“Wet” Glazing