We have 4 questions listed below regarding IEQ Prerequisite 1 - Minimum Indoor Air Quality Performance.
Question 1: Requirements, Case 1, Paragraph 3: We are seeking clarification or guidance concerning the last sentence stating “All other requirements must be met.”
We are renovating two floors of a 13 story building. We cannot verify the amount of ventilation air due to lack of air flow measuring stations or similar means to directly measure the quantity of outside vs. quantity of return air as the variable air volume controls modulate to meet the space loads. Case 1 allows an exception if we can, through engineering judgment, determine that the system provides at least 10 cfm per person.
However the last sentence of Case 1 paragraph 3 appears to then still require that we have to have controllability per ASHRAE 62.1-2007 paragraph 5.2.1 and paragraph 5.4. The question is then does Case 1 paragraph 3 actually provide an exception?
Question 2: Are there recommended methods and approved documentation approaches that are suitable to prove the systems meet 10 cfm per person for the entire building?
Question 3: Is an approach of measuring temperatures of return and outside air and resulting mixed air temperatures acceptable means to indirectly predict the ventilation air quantity? Can this be data and calculated amounts be obtained via a sampling of measurements at specific times of the year representing peak heating, cooling and mid season values?
Question 4: Can we extrapolate data from the renovation of our two floors to use as the basis for occupancy and ventilation rates for the rest of the facility? The TI work on our floors is the first renovation project; other floors are anticipated to be improved but no specific data or plans are available to make more specific estimates of the eventual renovation and resulting occupancy totals.
Brooke Bogart
PrincipalEcological Environments
4 thumbs up
February 11, 2014 - 5:11 pm
Laura - we encountered a very similar issue on our project. Wondering how you ended up addressing item #2. We are scratching our heads as this is a tremendous amount of work for our engineers far beyond the typical LEED CI scope. (and our building has more stories!) Thanks.
Dylan Connelly
Mechanical EngineerIntegral Group
LEEDuser Expert
472 thumbs up
February 17, 2014 - 1:39 pm
For #2 - you'd want to have a "test and balancing" contractor come out and measure your % of outside air for a couple different modes. Eg. Maximum ventilation, minimum ventilation, heating mode, cooling mode, etc.
Then you determine how much "house" air is provided to the project scope at a minimum and that will tell you your amount of outside air to your project scope. Determine the number of people and that is your outside air per person.
The complexity of the work and calculation depends on the building and system types.