Mineral Area College is a two year public comprehensive community college located in the beautiful Ozark Mountains of eastern Missouri, in a rapidly growing region 40. Ap Biology Seventh Edition Campbell Reece Notes From Underground here.

A subset of green builders have always been grumpy about foam. Such builders look at rigid foam panels and spray foam as suspect products: they are made from petroleum, laced with mysterious chemicals, and impermeable to vapor flow.

Gala Freed From Desire 2011 Free Download here. Not all green builders agree with this analysis, however. Here’s the opposing view: most new homes include many products derived from petroleum, including drain pipes, bathtubs, window frames, and the plastic sheathing on Romex wiring — so why focus only on insulation?

Moreover (the argument goes), there’s nothing wrong with using petroleum-derived insulation; in fact, converting oil into insulation makes more sense than burning the stuff to drive our cars. Regardless of whether you are a “foam is evil” builder or a “foam is a useful product” builder, you probably agree that it’s handy to have a range of available products to solve construction quandaries.

That’s why it’s good news for builders that mineral wool insulation can be installed on the exterior side of wall sheathing, just like polyiso Polyisocyanurate foam is usually sold with aluminum foil facings. With an R-value of 6 to 6.5 per inch, it is the best insulator and most expensive of the three types of rigid foam. Foil-faced polyisocyanurate is almost impermeable to water vapor; a 1-in.-thick foil-faced board has a permeance of 0.05 perm. While polyisocyanurate was formerly manufactured using HCFCs as blowing agents, U.S.

Manufacturers have now switched to pentane. Pentane does not damage the earth’s ozone layer, although it may contribute to smog.. Almost everyone agrees: it’s a good idea to keep wall sheathing warm The thermal performance of a wall is greatly improved when wall sheathing is protected by an exterior layer of insulation. Exterior wall insulation keeps wood warm, keeps wood dry, reduces the condensation potential, reduces thermal bridging Heat flow that occurs across more conductive components in an otherwise well-insulated material, resulting in disproportionately significant heat loss. For example, steel studs in an insulated wall dramatically reduce the overall energy performance of the wall, because of thermal bridging through the steel., and probably increases the durability of the wall.

RELATED ARTICLES by John Straube However, some builders worry about the use of rigid foam to keep stud bays warm — not only because “foam is evil,” but because foam does not allow the wall assembly to dry to the exterior. (Although this concern is unwarranted, it exists.) Such builders have often wondered whether rigid mineral wool panels (for example, insulation panels made by or ) could be sandwiched between wall sheathing and vertical furring strips — in other words, whether mineral wool could be substituted for XPS Extruded polystyrene. Highly insulating, water-resistant rigid foam insulation that is widely used above and below grade, such as on exterior walls and underneath concrete floor slabs. In North America, XPS is made with ozone-depleting HCFC-142b. XPS has higher density and R-value and lower vapor permeability than EPS rigid insulation., EPS, or polyiso to insulate the exterior of a wall.