Room Pressure Control
Room Pressure Control
(OP)
Guys,
I have been told by a controls engineer that active pressure control is not the right solution for small rooms.according to his experience,small rooms experience large swings in pressure when active pressure control is used.More stable pressure control can be achieved for small rooms by using volumetric offset,according to him.Could any one please confirm if this is correct and if yes why?





RE: Room Pressure Control
(offset) between supply and exhaust airflow rates.
This constant volumetric difference will result
in positive or negative pressures in spaces in
spite of changing duct pressures.
Volumetric offset is sometimes combined with pressure
override which prevents the terminal devices from
going out of control during long periods of room
imbalance (keeping doors open).
Pressure offset is used to maintain space pressures
relative to a corridor (or reference space) with
changing duct pressures.
With Volumetric offset the volume of individual
terminal supply units can be summed and flow rates
can be adjusted to maintain desired constant
space velocities.
The controller accepts a series of input analog signals
and performs the required calculations and outputs a
series of analog signals to maintain environment control
of the local space. The calculations are prepared using a
proprietary logic based program with appropriate
PID control loops. This results in a stable and rapid
control signal to all terminal devices.
Volumetric offset usually has field adjustable
set points and the number of inputs and outputs
are selectable to the application.
RE: Room Pressure Control
More importantly, establishing pressure control could kill needed air exchange rates and could vary the required cfm over the life of the space (e.g., by someone banging up the door or by a gasket peeling off). If pressure control were a building-wide practice, how do you size your AHUs/exhaust fans?
One vote here for the control guy. Good luck, CB
RE: Room Pressure Control
RE: Room Pressure Control
RE: Room Pressure Control
RE: Room Pressure Control
Could that have been set up with a disreard
protocol at the workstation ?
RE: Room Pressure Control
RE: Room Pressure Control
I suppose disregard protocols at workststations
can be a bad idea, I was field checking a
roof that had noisy dust collectors on it
and accidently ended up being trapped in
a steel shed because the door was slammed shut
by a wind gust which broke the door latch.
I pulled a disconnect on a large fan which sent an
alarm signal to a central control station
and a mechanic showed up 5 minutes later and it
took 2 men 15 minutes to get me out of there.
If they had that fan on disregard at the time,
I would not be writting this, no one knew
where I was at the time and it would have
taken maybe 10 or 20 days before anyone
would have needed to go into that shed.