Monday, August 22, 2011

Visiting Reps in Montana

I spent the week travelling across Montana calling on our reps and doing presentations to a number of engineers. On Friday, I did an all day seminar on the Basics of Air Distribution for the NEBB organization. A number of engineers attended along with the NEBB air balancers. The presentation was well received.

Afterword, several balancers remarked that they wish the engineers who specify the work that they do had the benefit of the discussions I presented. They were pretty basic. It appears that many engineers, especially the younger ones, haven’t had any training in the basics of diffuser placement and proper selection. At least, in the eyes of the balancers who have to make their projects work.

I guess we need to get back to basics with the younger crowd, who in the complexity of computer aided design may lack general common sense and a few simple rules that can be obtained through proper education as well as experience.

Authored by: Dan Int-Hout, Chief Engineer Krueger

Friday, August 12, 2011

ASHRAE Standards

I have been asked a number of times about why Addenda A to the 62.1 2010 Standard isn’t available from ASHRAE. This addenda gives Displacement Ventilation credit to UFAD diffusers if the throw to 50 fpm is less than 4 ft, on the assumption that the ventilation will remain in the occupied space, and is based on ASHRAE sponsored research using both physical measurements and CFD calculations. The DV credit allows a reduction in ventilation (outdoor) air of 20% (divide the minimum rate by 1.2).

ASHRAE Standards that are on “continuous maintenance”, which include Standards 90.1, 55, 62.1 and several others, are modified by addenda through the ASHRAE public review process. Once an addenda is approved, it becomes a part of the Standard. This has caused a number of complaints that it was hard to stay up with what constituted the “current” standard. As a result, ASHRAE has decided to ‘bundle’ addenda into a single release, at the mid point between reprints of the standard. This is typically 18 months. So while Addenda A to 62.1 was approved (there were no comments) before the 2010 Standard was released, it will not be printed and available for probably another 6 months. The change is noted below:

























Authored by: Dan Int-Hout, Chief Engineer Krueger

Monday, August 1, 2011

LEED 2012 Review

LEED 2012 is now out for a second public review. The section that most affects us in the HVAC/Air Distribution business is the IEQ credits. The following is excerpted from the USGBC announcement:

Indoor Environmental Quality
The Indoor Environmental Quality credit category has undergone significant structural reordering for second public comment, but retained familiar requirements in the new credits. This reorganization streamlines the credit category and more effectively addresses overlapping goals of the former credits.

Achieving the Indoor Environmental Quality credits now has more direct benefit to occupants by comprehensively addressing environmental quality impacts. The weightings tool helped to highlight that many of the Indoor Environmental Quality credits were competing with themselves for points when addressing the human health impact category. The reorganization more clearly shows that the category has 4 macro themes, ventilation, lighting, acoustics, and general occupant experience, all of which have holistic credits addressing how buildings can enhance health, safety, productivity, the ability to learn, and also continue to bring biophillic “outdoor” design elements to built spaces.

These changes include:
--- Thermal Comfort credit follows the Assessment credit so that all ventilation-related credits are in order. Interior Lighting is now in order with Daylight.

--- Acoustics. The credit has been significantly re-written with more exact requirements and more referenced standards for all of the sections.

I think the really important thing in the 2012 proposal is that by stating that “HVAC noise shall not exceed…”, and providing a couple of calculation paths, especially directly referencing AHRI 885, will go a long way for making the Engineering community sign on to this requirement. The specification of construction details instead of a ’guestimate’ of reverb time is also a major step. All the engineers I call on (I see about 1000/year) were concerned about the open resulting sound requirement, as there are a lot of sound sources they can’t control.

I encourage all of you reading this that are involved in the LEED process to review the 2102 draft, and would encourage your positive comments towards the acoustic requirements.

http://www.usgbc.org/DisplayPage.aspx?CMSPageID=2360

Authored by: Dan Int-Hout, Chief Engineer Krueger