ANY HELP I WILL APPERICIATE
ITS ALL ABOUT THE AIR CHANGE PER HOUR , I MET SOME GUYS FROM A BIG COMPANY AND THEY ARE THE CLIENT AND THEY ARE COMPLAINING FROM NOT HAVING ENOUGH AIR CHANGE IN THEIR RENTED SPACE
THE SYSTEM UNDER CONSIDERATION WHICH INSTALLED IN THE BUILDING IS AIR WATER SYSTEM
AIR HANDLING UNITS 100% FRESH AIR
FAN COIL UNITS
IN THEIR SPACE WE HAVE FRESH AIR DUCTS RUNNING IN THE FALSE CEILING FOR SUPPLYING FRESH AIR , MY MEASUREMENTS FOR THE FRESH AIR IN THE CEILING WAS AROUND 290 m3/h (235.43 cfm) THEIR OFFICE SURFACE AREA IS AROUND 130 m2 (1400 ft2) THE NUMBER OF PEOPLE WORKING THERE IS 8-11 PERSONS NOW ACCORDING TO SOME NORMS IN THE TERRITORY I AM WORKING THEY ASKED FOR 10 ACH FOR THEIR SPACE
THIS REQUEST IN MY VISION IS SO SILLY AND NOT LOGIC
I KNOW THAT THERE IS ACH AND SPACE ACH ACCORDING TO ASHRAE.
I DONT BELIEVE THAT I NEED TO SUPPLY FRESH AIR TO THE SPACE 10 TIMES MORE MEANING 2900 M3/H (1707 CFM !!!!) THEY HAVE 5 FCUs IN THE CEILING EACH OF ABOUT 300 cfm.
NOW WHERE CAN I FIND SOME CALCULATION FOR ACH IN SYSTEM AND SITUATION LIKE MINE (PRIMARY AIR FROM AHU AND FAN COIL UNITS IN THE CEILING) I SUBMITTED A REPORT FOR CALCULATING FRESH AIR ACCORDING TO ASHRAE 62 BUT THEY REFUSED IT!!!!!
HOW CAN I SHOW THAT THEY ARE WRONG I DO BELIEVE THAT ACH IS APPLIED ONLY FOR VENTILATION BUT IF WE HAVE AIR CONDITIONING UNITS LIKE VAV AND FCU THE ASPECT IS CHANGED.
GOOD NEWS! Your caps lock button works fine.
Air Changes per Hour = Cubic Feet Of Room divided by (Cubic Feet per Minute X 60 minutes per hour)
Example: 10 feet long by 10 feet wide by 8 FT high room = 800 cubic foot room
Air supply to room is 100 cfm (x 60 minutes/hour) = 6000 cubic feet per hour.
6000cfh divided by 800 cubic feet = 7.5 air changes per hour.
thanks for help but I know how to make such calculation my question was is it normal to ask for such big amount of fresh air for such 8-11 person doing desk works??
Originally Posted by koolkahuna
or there is another way of calculations?