exhaust Calculation
exhaust Calculation
(OP)
is this the correct computation for exhaust
example:
floor area A
bldg height B
product vol C
Ventilation
Air Change D
Exhaust fan A x B x C x D / 60
= CFM Exhaust fan
example:
floor area A
bldg height B
product vol C
Ventilation
Air Change D
Exhaust fan A x B x C x D / 60
= CFM Exhaust fan





RE: exhaust Calculation
RE: exhaust Calculation
RE: exhaust Calculation
to mintjulep how about the air change is there any standard for all location?
if no how to compute the air change of the area?
RE: exhaust Calculation
C doesn't belong in the formula.
RE: exhaust Calculation
you mean the product volume?
RE: exhaust Calculation
whatever reference or code you have will tell you how to apply the values.
Most normal warehouses regualted by code just use area. Soemtimes volume etc. If you have specific components, you need to reference those guides. The code often doesn't address such specific cases. Also refer to OSHA or guidelines of that specific industry. If you store flux-capacitors, the National Flux Capacitor Association (google for NFCA) may have guidelines that you may apply while meeting or exceeding code.
RE: exhaust Calculation
my clients want a 2 exhaust fan and 1 fresh air the area is 104.96ft width 167.28ft length and 29.52ft heigth.
that is the formula that im using.and the air change is 3min per hour. the output is 5370 cfm and the supply air is 9586.is this is correct?can you help please.thanks is advance
RE: exhaust Calculation
- where is [C] in your calculation
- How did you calculate supply rate, 9586cfm
RE: exhaust Calculation
the calculation of the supply is CFM multiply by 105% it is possible that for that area is only two exhaust?
RE: exhaust Calculation
RE: exhaust Calculation
RE: exhaust Calculation
is this the correct computation for exhaust
example:
floor area A
bldg height B
product vol C
Ventilation
Air Change D
Exhaust fan A x B x C x D / 60
= CFM Exhaust fan
=supply CFM * 105%
RE: exhaust Calculation
RE: exhaust Calculation
im still learning for calculating the exhaust.please
RE: exhaust Calculation
- supply calculation is cfmx105%, cfm of what, do you mean exhaust cfm, if this is the case then how come 5370x105/100 = 9586 ??????????
RE: exhaust Calculation
floor areas is 7,276 sqf (A)
bldg ht is 29.52 f (B)
= 214,787.52
Production vol * 50% (C)
= 107,393.76
Air Change * 3% (D)
= 322,181.28
/ 60
= 5,369.70 CFM
is this is correct?
Im Still learning how to compute!
RE: exhaust Calculation
- why did you choose C as 50%.
- how did you calculate supply cfm
RE: exhaust Calculation
Since you are not clear in your design intent, For a simple ware house, a.06 cuft/min per sqft(ASHRAE std) of the ware house is use here so you needed a fan or fans with a 436.56 CFM approx; 450 CFM,you may needed two @ 250 CFM each. but this is not enough to conclude that it meets your requirements. if you consider occupancy, then 5 person per 1000 sqft,means you have to to consider 15 people, are they smoker? like other friends here, if you consider the PEL, you may use the air change method too.
Next, How do you convey the air to the fan,with duct or without,if ducted,calculate the static pressure necessary to overcome the air resistance in the ductworks.
Hope that helps
RE: exhaust Calculation
its only a loading bay of DHL
RE: exhaust Calculation
- why did you choose C as 50%
- how did you calculate supply cfm
RE: exhaust Calculation
RE: exhaust Calculation
In fairness to you and all the guys here, They tried to help but with your limited knowledge in the dynamics of ventilation, We can only help you so much.
All the best.