Talk:Air changes per hour

Ventilation rate per person

This calculation seems off: "Ventilation rates are often expressed as a volume rate per person-minute (CFM per person, L/s per person)." So the numerator in the equation should have volume (Air changes per hour), but the denominator should have persons. The problem is the "D" in the formula. It says it's Occupant density (occupants/ft). According to this, very high densities of people will lead to... very high CFM per person! Shouldn't the D be on the denominator? 192.252.228.172 (talk) 23:43, 25 May 2018 (UTC)

Units

"Of all the countries in the world, only three backwaters still use the archaic Imperial system of weights and measures:

   Liberia.
   Myanmar (a.k.a. “the country formerly known as Burma”)
   United States of America."

Time to change it to METRIC! — Preceding unsigned comment added by 220.233.189.143 (talk) 08:23, 26 January 2017 (UTC)

ACH for tight home may be 0.25 to 0.35 but the reference listed doesn't have this information

Listed reference, while a good reference, doesn't support these statics. According to the EPA, ASHRAE recommends a minimum of 0.35 air changes per hour. I haven't read the quoted ASHRAE document but the EPA is pretty authoritative source.

The ACH your referring to more involves EPA and ashrae ventilation requirements. And since recent changes doesn't allow for infiltration to provide ANY of this ventilation. This STANDARD (ashrae 62.2 I believei) s questionable at best, due to it only being efficient and effective in a limited number of climate zones. This article should however, somehow differentiate between nACH and ACH@ 50 pascals. Thermal-contractors (talk) 00:40, 6 February 2014 (UTC)Harry davis, thermal contractors, Blackshear,Ga

Mention ERV

Energy_recovery_ventilation (and related systems?) should be mentioned in this article. Fholson 12:55, 9 September 2011 (UTC)

A new section should be started called Mechanical Ventilation. It should include erv, hrv, and a few others. Thermal-contractors (talk) 00:43, 6 February 2014 (UTC)

Units Consistancy

For the ventilation rate equation, ventilation rate is given as ft^3 / person, but the equation listed above it ends up as ft^3/min-person = ((air changes / hr)*(person/ft^2)*ft)/(60 min/hr)=air changes - person / ft-min Wesharait (talk) 02:22, 20 November 2014 (UTC)

What is a 'ft^3'? — Preceding unsigned comment added by 220.233.189.143 (talk) 08:30, 26 January 2017 (UTC)

Cubic feet, more commonly written as ft³, but often as Wesharait has done if it's impossible/difficult/inconvenient to key superscripts. {The poster formerly known as 87.81.230.195 ] — Preceding unsigned comment added by 2.218.14.51 (talk) 00:50, 3 May 2018 (UTC)

Would it make sense to have the equation as M³/h instead of l/s?

1 L/s = 3.6 m^3/h
1 m^3/h = 0.2777777778 L/s (https://www.unitconverters.net/flow/liter-second-to-cubic-meter-hour.htm) eg

"Or

$\quad ACPH={\frac {Q}{Vol}}$

where:

• ACPH = number of air changes per hour; higher values correspond to better ventilation
• Q = Volumetric flow rate of air in cubic meters per hour (M³/h)
• Vol = Space volume L × W × H, in cubic meter

"

missing hospital ACH

I think it's 6 ACH for hospital rooms. Can someone who knows for sure edit the article? Thank you — Preceding unsigned comment added by 5.171.88.245 (talk) 21:16, 13 August 2020 (UTC)