Relative Humidity, Temperature, and Moisture Content This is Part 2 of a two-part series on cellulose insulation and moisture. Cellulose insulation is a hydrophilic material, meaning that absorbs moisture readily. Under certain conditions condensation dampens cellulose insulation causing permanent damage due to shrinking, slumping, and very slow drying. Moisture adsorption into a hydrophilic material, expressed as[…]Read more
Old and new water barriers Once upon a time, builders stapled 15-pound asphalt felt to wall and roof structural sheathing as a water-resistive barrier (WRB). The 2012 International Residential Code (IRC) still specifies: “one layer of No. 15 felt… or other approved water-resistive barrier.” Most builders used perforated felt to allow water vapor to escape[…]Read more
This is a two-part blog about hygric buffering, cellulose wall insulation, and moisture problems in high-performance buildings. Why not to install cellulose insulation in deep wall cavities Cellulose shrinks, slumps, and dries very slowly after wetting. Deep wall cavities are have more risk because the outdoor side of the wall is colder than shallower cavities. Voids left by[…]Read more
Introducing 29 New RESNET CEU Courses Attention raters, rater trainers, and RESNET training organizations: Saturn Resource Management now offers 29 new short courses that qualify for RESNET CEUs. These short e-learning courses mix media such as slides, slide narrations, videos, illustrated text, exercises, and quizzes. Our e-learning lessons contain between 15 and 25 slides. We[…]Read more
We’ve been dealing with the ASHRAE ventilation standard for a while. 62-89 goes way back. We used that one for a long time, and it worked well enough. After we taught our students how to use 62-89, they could understand it and implement it. Then came 62.2. We first wrote about 62.2-2010 in this blog back in[…]Read more
Focus on the Envelope Home owners and builders seldom give the building envelope the priority it deserves. The insulation, air barrier, windows, and doors are the most important features of a new home. These envelope features determine a home’s energy efficiency and comfort. They’re also permanent and may never change. Homes with better thermal resistance and airtightness need smaller HVAC systems.[…]Read more
KM’s History Knowledge management has a long history, including apprenticeship programs, discussion forums, corporate libraries, professional training, mentoring programs, and now data bases designed to manage knowledge. Computers and software have enhanced our ability to manage knowledge. The financial services industry was the earliest adopter of computer-based KM. Academics adopted KM as a research topic and course topic around the[…]Read more
What is a credit? Saturn uses a formula to calculate how many average hours of student effort that a lesson or course requires. Of course, effort hours differ among different students, but our calculation is a good average. The easiest way to understand the convoluted world of educational credit is to explore some definitions.
What the EPA Says EPA’s new final rule on Carbon Pollution Emission Guidelines for Existing Stationary Sources: Electric Utility Generating Units “Energy is transmitted, not electrons. Energy transmission is accomplished through the propagation of an electromagnetic wave. The electrons merely oscillate in place, but the energy – the electromagnetic wave – moves at the speed of[…]Read more
The Experimental Findings Building Science Corporation (BSC) published a recent report that spawned a Journal of Light Construction (JLC) article called “Moisture in Fat Walls”. Two of the three walls studied are double walls with R-values in excess of R-40. The setting for the buildings studied is Massachusetts.