Transactions - American Society of Heating, Refrigerating and Air-Conditioning Engineers . he equation with approximate accuracy in tempera-tures to obtain the difference in density between equal volumesof the inside and outside air, as follows; for a room fifty feet \ /.0864 X-1()0\ /.0864 V -J(iO \ / .0864 X H)\ »?• Pi = \ T60 +0- ) \ ^ieo+To )= ? ^ I 1^ foot If this same room with the same conditions as before had oneopening at the top instead of the bottom as in Fig. 4, and if 504 CAN WE LOCATE THE NEUTRAL ZONE IX HEATED BUILDINGS f the atmospheric pressure equalized with
Transactions - American Society of Heating, Refrigerating and Air-Conditioning Engineers . he equation with approximate accuracy in tempera-tures to obtain the difference in density between equal volumesof the inside and outside air, as follows; for a room fifty feet \ /.0864 X-1()0\ /.0864 V -J(iO \ / .0864 X H)\ »?• Pi = \ T60 +0- ) \ ^ieo+To )= ? ^ I 1^ foot If this same room with the same conditions as before had oneopening at the top instead of the bottom as in Fig. 4, and if 504 CAN WE LOCATE THE NEUTRAL ZONE IX HEATED BUILDINGS f the atmospheric pressure equalized with the room pressure, atthis point, the difference in weight of the two columns of airwould be the same as in the case with the opening at the bottom,but the external air being heavier would press on the under sideof the room with greater force because the outside air is of greaterdensity than that within. If an opening were made in the bottom,the room would appear to be under a vacuum for the heavierair would at once flow through the opening into the room. densiiy d femperature tT. We have designated the pressure exerted against the insidewalls as Pi, and in a similar manner we will designate thepressure against the outer surface of the walls as Pe, then theequation to obtain the difference in weight or pressure by thedensity is: Pe = h (d — dj), or to obtain it from the temperature it will be: .0864 X 460\ /.0864X460 Pe = h /.0864 X 460 \ / .0864 X 460\V 460 + t ) V 460 + ti / 460 +1 7 V 460 + The conditions illustrated in these two extreme examples showclearly the fact that different pressures above or below the out-side pressures must exist in a room or building when the con-tents are heated to a temperature above that of the external air. In a similar manner if a room or building is cooled in thesummer months the reverse of these conditions will obtain. Additional openings into rooms will produce different condi-tions, also a change in the location of the openings
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