Is the airpressure outside same as inside the room?

Question

I made an experiment that involves measuring the volume of the gas formed but I forgot to write down the temperature and the air pressure.The temperature in the room is nearly always the same but the airpressure I can only guess by the meteorology data for the day.So I'm wondering if the pressure outside for that time of day was 1026hPa then could it have been significantly different in the lab room which is not airthight sealed and is 2 storeys off the ground

Answer 1

Yes, except when:

1. The laboratory you are working in doesn't have any other source of forced air supply, such as air handling units (AHU). The pressure difference maybe as high as 100 Pa.

2. The altitude difference is very high now consider the equations:

Z = C ( Bo - B ) / ( Bo + B )
C = 16000 ( 1 + 2 ( To + T ) ) / 1000

Z = The difference in altitude in meters.
Bo and B = Barometric pressures in mm of mercury at two altitudes.
To and T = Centigrade temperatures at the two altitudes.

The Barometric Pressure at the higher altitude:

B = (Bo(C - Z))/(Z + C)

If B = 1026 hPa, To=T=28°C, and Z = 4 meters (approx height of 2 storey bldg.) then

B = (1026(1808 - 4))/(4 + 1808)

B = 1021.5 hPa

A difference of 4.5 hPa - significant?

Answer 2

No significant difference.

Some special rooms may have positive pressure to make sure nothing like unwanted particles gets in, or negative pressure to keep bad germs from getting out, but this is rare, and only a small difference anyway. A significant difference would make your ears pop when you go in or out. Even greater differences could kill you.

Answer 3

For all intents and purposes, 2 storey's up will not affect the air pressure .. it will be the same.