# Ventilation rate calculation - old or new ASHRAE?



## HerrKaLeun (Oct 18, 2010)

While doing the PPI sample exam I noticed that uses the old (pre-2004) ASHRAE 62.1 methods for calculating ventilation rates (see question 62).

that uses persons only. New ASHRAE requires a person and area based calculation. Obviously the results may differ.

What do you think one should use? I would assume whenever standards are needed, the most recent ones apply.


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## MechGuy (Oct 18, 2010)

HerrKaLeun said:


> While doing the PPI sample exam I noticed that uses the old (pre-2004) ASHRAE 62.1 methods for calculating ventilation rates (see question 62).that uses persons only. New ASHRAE requires a person and area based calculation. Obviously the results may differ.
> 
> What do you think one should use? I would assume whenever standards are needed, the most recent ones apply.



It will obviously depend on how much information you're given in the problem. If you're able to, do them both and see if the answers are similar. Most likely it will be the new method.


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## Bman (Oct 19, 2010)

Good question! The closet I came to an answer is on the page immediately following the Acknowledgements in the MERM, "Codes Used to Prepare This Book". Lindeburg states that he uses the most current codes for his publication, but since NCEES does not specifiy any exact dates or editions, that the exam must not be sensitive to the changes.... If you have to choose, I guess I would go with with the most recent.


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## HerrKaLeun (Oct 19, 2010)

Bman said:


> Good question! The closet I came to an answer is on the page immediately following the Acknowledgements in the MERM, "Codes Used to Prepare This Book". Lindeburg states that he uses the most current codes for his publication, but since NCEES does not specifiy any exact dates or editions, that the exam must not be sensitive to the changes.... If you have to choose, I guess I would go with with the most recent.


I assume all Lindeburg does is copying an old version and making some corrections to sell it as a new version. So he might be behind code-wise.

I believe area-based ventilation was introduced in 2004 ASHRAE version. I would hope NCEES has caught up on that assuming as an engineer I'm also expected to be reasonably up to date and one shouldn't use 6 year old methods, especially if the methods changed drastically.

I don't even know if I can get an old version of ASHRAE. Maybe I will google if there is a table of an old version for free....


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