Ch. 30 and 31 Review Questions
Explain how a low-E coating increases the R-value of glass.
A low-E coating increases the R-Value of glass by reflecting solar heat gain from the sun in the summer and reflecting radiant heat from the building in the winter.
If low-E glass is used in an IGU, on which surface is the low-E coating placed, and why? Explain.
A low-E coating is generally placed on the interior glass pane of an IGU. This location works well for cold climates because the low-E coating reflects the interior heat back.
Using a sketch, explain the anatomy of an IGU.
Glass Pane, Air Filling, Glass Pane, Primary Seal, Aluminum Tube Spacer with perforations at Top, Dissiccant (moisture absorbing substance) inside the Spacer, Primary Seal, Secondary Seal
Spandrel area of an all-glass curtain wall
Laminated Glass
Sketch in plan a hollow metal door frame and its junction with (a) a metal-stud wall and (b) a CMU wall.
Metal-Stud: - Lock-in Anchor CMU: - Masonry Anchor
Using sketches and notes, explain the process of manufacturing flat glass.
Mixing: Silica and Lime are granulated and mixed. Furnace: Raw materials are melted in a furnace. Float Bath: Molten glass is transferred to a float bath of molten tin where the thickness will be determined. The molten glass will float to the top because the molten tin is more dense. Cooling: Glass is then rapidly cooled to prevent crystallization. Annealing: Glass is first heated sufficiently to relieve any stresses created during the solidifying process. It is then cooled very slowly so that every glass particle cools at the same rate to ensure that no stresses are frozen in the glass. Cutting and shaping: Glass is then cut and shaped to the desired size and shape.
What does the acronym NFRC stand for? List the information provided in an NFRC label.
National Fenestration Rating Council U-Value: This measures how well a window or door resists heat flow. Lower U-factors indicate better energy efficiency. Solar heat gain coefficient (SHGC): This measures how much solar heat is transmitted through a window or door. Lower SHGC values indicate better energy efficiency. Visible transmittance (VT): This measures how much visible light passes through a window or door. Higher VT values indicate better natural light transmission. Air leakage: This measures how much air leaks through a window or door. Lower air leakage values indicate better energy efficiency. Product durability: This measures how well a window or door is likely to withstand the elements over time. - Window Style - Window Performance Grade - Window Size
Using sketches, explain the following terms: (a) punched windows, (b) strip windows, (c) window wall, and (d) curtain wall.
Punched window: - A window with an opaque wall around it. Strip windows: - An array of windows placed side by side to form a horizontal strip (or ribbon) window system. Window wall - A wall in which the windows extend from floor to floor. Curtain wall - Hangs as a curtain from the building's structure with a mounting bracket and bypasses the intermediate floors or roof.
Teller window of a drive-in bank
Security Glass
Sliding-glass entrance door
Tempered Glass
Which materials are commonly used for cladding wood windows? What is the purpose of cladding, and which parts of a window are clad? Explain how the cladding helps to secure a window to the opening.
- Aluminum, Vinyl, Fiberglass - Protect from the elements and to improve its durability. - Applied to the exterior of the window - Frame, Sashes, and Muntins - Provides a weather-tight seal and by prevents warping and shrinking. - Prevents from rotting or being damaged by insects. - Nailed or Screwed to secure to opening.
What is a low-E glass, and what are its benefits? (Low-Emissivity Glass)
- Bounces heat off glass - Energy Efficient - Adds 1.0 R-Value to the glass - Reduce the U-Value
Sketch in plan various types of wood door frames, and give the terminology used to describe various parts of a door frame.
- Double-Rabbet Wood Door - Single Rabbet Wood Door - Wood Door Frame w/ Applied Stop - Double-Rabbet Metal Door - Rabbet - Soffit Interior Rabbet: 1-9/16" Exterior Rabbet 1-15/16"
A window has been rated as HS-C3571×59. Explain each term of the rating.
- HS stands for horizontal sliding. This means that the window opens and closes by sliding horizontally. - C stands for commercial. This means that the window is designed for use in a commercial setting, such as an office building or retail store. - 35 psi stands for wind load. This is the amount of wind pressure that the window can withstand before it is damaged. - 71x59 is the window size in inches. The width is 71 inches and the height is 59 inches.
Using a sketch, explain why a tempered glass sheet is stronger than an annealed glass sheet.
- Quenching (suddenly cooling) causes the outer layers of the glass to harden quickly while the interior of the glass is still soft. - Because the inner material cools slower than the outer material, the thermal difference creates compressive stress on the glass surface. The interior compensates with tension.
Explain the purpose and anatomy of a nailing flange. Which types of windows are typically provided with nailing flanges?
- Runs continuously around the outside of a window frame - To make installation into rough opening quicker and easier - Provides a means of anchoring the window to the opening - Provides flashing for the window for waterproofing - Factory-glazed, residential windows
What is heat-soaked glass and where is it used?
- Tempered glass panes are subjected to cycles of heating and cooling to simulate long-term field conditions. - Less likely to break spontaneously - More durable than regular tempered glass. - Clearer appearance - Manufacturing Process is Expensive - Used where glass is subject to high levels of stress.
