How can i calculate room cfm and if i have area , how can i calculate tonnage for A/C for UAE climate?

for AUE climate data you may use HAP4.8 data as following:

Tdp = F , Twb = F , Summer daily range.5 F

For load calculation you may use HAP or Elite or you can find many excel sheet to calculate load simply 

you may use the rule of thumb :

offices, commercial: : sq. ft / ton 

Banks court houses: : sq. ft / ton 

police station post office : : sq. ft / ton 

Restaurant: : sq. ft / ton 

Kitchen: : sq. ft / ton 

Hospitals: : sq. ft / ton 

Residential: : sq. ft / ton

 Apartment: : sq. ft / ton 

School: : sq. ft / ton 

library & museum: : sq. ft / ton 

malls: : sq. ft / ton

Two Methods for Calculating Head Load:

Using E Excel Sheet Calculation.

HAP(Hourly Analysis Program  4.9)