IEQp1 - calculator

There isn't a calculator that I know of to assess compliance with the natural ventilation criteria in Section 6.4 of the ASHRAE standard.

This prerequisite presents another important challenge for naturally ventilated buildings. ASHRAE 62.1-2010 effectively prohibits natural ventilation as a standalone strategy unless the openings to the outdoors that provide ventilation are permanently open or are controlled open during operating hours. There are a couple of other exceptions to this. Check out the exceptions in the ASHRAE standard or the online LEED reference guide.

Hi, Ben

I'm working on a project with natural ventilation only, but it has air conditioning systems (mainly simple split system).

Looking at the prerequisite template text:

"Provide documentation demonstrating the minimum outdoor air opening and space configurations meet or exceed the minimum values from the natural ventilation procedure outlined in ASHRAE 62.1-2010, Section 6.4."

I concluded that the effective requirements are the windows' opening sizes and the spaces' layouts, in order to comply with the maximum distances from the same openings. Because, otherwise, many projects will be unfeasible to comply with this prerequisite.

Hi Patrick, 

That's true that the natural ventilation procedure assesses the window sizes and space layouts. However, the section 6.4 begins by stating that "natural ventilation systems shall be designed in accordance with this section and shall include mechanical ventilation systems designed in accordance with Section 6.2 and/or Section 6.3." it then goes on to state the exceptions to the requirement to provide mechanical ventilation systems as follows. 

The mechanical ventilation systems are not required
when:

1. Natural ventilation openings that comply with the requirements of Section 6.4 are permanently
open or have controls that prevent the openings from being closed during periods of expected
occupancy, or

2. The zone is not served by heating or cooling equipment.