What’s the Definition of an ‘R-20 Wall’?

first_img Start Free Trial Already a member? Log in This article is only available to GBA Prime Members Builders often talk about the R-value of their walls. But if a builder claims to have an R-20 wall, what does that mean?Building codes commonly include a table listing the minimum prescriptive R-values for walls and ceilings in different climate zones. For example, Table R402.1.1 in the 2012 International Energy Conservation Code (IECC) informs builders that the minimum prescriptive R-value for walls in Climate Zones 3, 4, and 5 is “20 or 13+5.”This type of table raises many questions. For example, if a builder chooses to comply with the R-20 option, how is R-20 calculated? The code provides some guidance on the issue, but not much. According to a footnote at the bottom of the table, the “first value is cavity insulation, second is continuous insulation or insulated siding, so ‘13+5’ means R-13 cavity insulation plus R-5 continuous insulation or insulated siding.”The code language governing the prescriptive R-value requirements has changed in recent years. If you want to know the specific language that is enforced in your jurisdiction, you’ll have to consult your local code book. For example, the prescriptive requirements in the 2009 International Residential Code (IRC) note (in section N1102.1.1), “Computed R-values shall not include an R-value for other building materials or air films.”A footnote to Table N1102.1 in the 2009 IRC — equivalent in most respects to the prescriptive table (Table R402.1.1) in the 2012 IECC — notes, “R-19 batts compressed in to nominal 2×6 framing cavity such that the R-value is reduced by R-1 or more shall be marked with the compressed batt R-value in addition to the full thickness R-value.” This footnote is confusing. Who should do the marking? Does this instruction mean that the builder has to mark the insulation in every stud bay? How do you mark an unfaced batt — with spray paint? Or is…… center_img Sign up for a free trial and get instant access to this article as well as GBA’s complete library of premium articles and construction details.last_img read more

University of Michigan launches its own self-driving shuttle service

first_imgDavid Curry Tags:#Autonomous car#bus#Internet of Things#IoT#Mcity#Michigan#Navya Arma#shuttle#University of Michigan The University of Michigan is trialling its own self-driving shuttle service, taking students on a two-mile trip from the North Campus Research Complex to the Lurie Engineering Center.The Navya Arma shuttle will take 15 passengers at a time, and students ride for free. To start, the university is running two shuttles on the route, on regular business hours.See Also: Detroit passes Silicon Valley as center for self-driving researchMichigan has become a hotbed for self-driving development, thanks to the university’s heavy investment and the state’s legalization of self-driving cars without the need for a driver inside.Mcity, the university’s 32-acre simulated city project, will be in charge of the shuttle service.“The Arma at Mcity supports the university’s interrelated missions of research and education,” said S. Jack Hu, U-M vice president for research. “It also underscores the importance of international collaboration as we work with companies from around the world to help society realize the substantial benefits in safety and sustainability promised by automated vehicles.”The team in charge want to see how pedestrians and drivers react to the autonomous shuttle and will have cameras dotted all around the exterior of the vehicle. It will also be monitoring the amount of people that use the shuttle service, to see if it as popular as other transport services for students.The university is not the only actor in the self-driving scene in Michigan, General Motors, Ford, Honda, and Uber have all started tests in the state. A 311-acre test site being built on an old Ford WW2 bomber factory, is set to become the largest private environment for automakers to test self-driving systems. 5 Ways IoT can Help to Reduce Automatic Vehicle… IT Trends of the Future That Are Worth Paying A…center_img For Self-Driving Systems, Infrastructure and In… Related Posts Break the Mold with Real-World Logistics AI and…last_img read more