MNM Exam 2 Exam Questions and Answers 100% Pass

MNM Exam 2 Exam Questions and Answers 100% Pass What are the primary functions of enclosures? - Answer- keep water out Prevent Air Leakage Control Light Control the Radiation of Heat Control the Conduction of Heat Control Sound What are the secondary functions of enclosures? - Answer- Resist Wind Forces Control Water Vapor Accommodate Movement Thermal Expansion/Contraction Moisture Expansion/Contraction Structural Movements Resist Fire - sometimes a primary function, depending on context Address Installation Requirements for the Exterior Wall Allow for Maintenance Weather Gracefully Where should glass be used at? - Answer- -Glass should be used where it can supply daylighting and provide views, but also limited to prevent overheating, glare, or excessive heat loss through the envelope. -Windows that can be opened and closed by the occupants can help reduce energy costs, in some cases What areas of the envelope should be air-tight? - Answer- The entire envelope should be detailed for air-tightness. Fresh air to be provided by building ventilation system, not by air leakage through ext. wall How can you maximize heat in the winter? - Answer- south-facing walls to let in heat and sunlight What 3 conditions must be satisfied for water to penetrate a wall? - Answer- -There must be water present at the outer face of the wall. -There must be an opening through which the water can move. -There must be a force to move the water through the opening. -If any one of these conditions is not satisfied, the wall will not leak How can you prevent water leakage? - Answer- -Keep water away from the wall, if possible via overhangs or projections. -Try to seal every opening. This "barrier wall" typically proves unreliable. -Eliminate or neutralize the forces that move water through a wall. -Provide strategies for internal drainage or secondary defense, via cavities within the wall assembly that allow for drainage (pressure equalized design and rainscreen design What are the 5 forces that move water through a wall? - Answer- gravity momentum surface tension capillary action air currents/pressure differentials How does water get into the building through gravity? - Answer- Is a factor in pulling water through a wall only if the wall includes an inclined plane that slopes into—rather than out of—the building -Sometimes a loose gasket or errant bead of sealant can create this condition even if components are designed correctly How does water get into the building through momentum? - Answer- -Momentum of falling raindrops can drive water through a wall only if there is a suitably oriented slot or hole that goes completely through the wall. -Neutralized by applying a cover to each joint in the wall or by designing each joint as a simple labyrinth How does water get into the building through surface tension? - Answer- -Causes water to adhere to the underside of a cladding component. -Allows water to be drawn into the building. -Provision of a drip on any underside surface to which water might adhere will eliminate the problem. How does water get into the building through capillary action? - Answer- -This is the surface tension effect that pulls water through any opening that can be bridged by a water drop. -Primary force that draws transports water through the pores of a masonry wall. -Can be eliminated by making each of the openings larger than a drop of water can bridge. -Can also/alternatively provide a concealed capillary break somewhere inside the opening What is pressure-equalized wall design? - Answer- Allows wind pressure differences between inside and outside of exterior wall to neutralize themselves How does pressure-equalized wall design work? - Answer- -Create an airtight plane, called the air barrier, behind the outer face of the wall. -Air barrier is protected from direct exposure to the outdoors by an unsealed, labyrinth- jointed layer known as the rainscreen. -Between the rainscreen and air barrier is a space known as the pressure equalization chamber (PEC What are pressure-equalized chambers? - Answer- -Pressure-equalized chambers must be divided into compartments small enough that the volumes of air cannot rush through the joints in higher-pressure areas of the face and flow across the air chamber to lower- pressure areas, carrying water with them. -PECs are normally no taller than one story or wider than one or two column bays. May be much smaller in some applications Rainscreen principal vs. Rainscreen cladding - Answer- -The term rainscreen principal originated with the concept of pressure-equalized wall design, and at one time it was used exclusively in reference to pressure-equalized cladding systems. -More recently, the term rainscreen cladding has come to be applied more broadly to any cladding system with a system of internal drainage, regardless of the extent of compartmentalization of the drainage space and the degree of pressure equalization that can be achieved. What are sealant joints? - Answer- seams that are closed with rubberlike compounds What is the purpose of sealant? - Answer- Role of sealant is to fill the joints between wall components, preventing the flow of air and/or water while still allowing reasonable dimensional tolerances for assembly and reasonable amounts of subsequent movement between the components What is the typical width of sealant joints? - Answer- Sealant joint widths are usually 3/8 to ¾ inch, but can be as small as ¼ inch and sometimes range up to 1 inch or more What is gunnable sealant? - Answer- -Viscous, sticky liquids that are injected i