Question regarding pressure relief damper control in a pressurized stairwell

[Sávio Almonfrey]

Dear Support Team,

I am modeling a pressurized stairwell in CONTAM and I am trying to implement a pressure relief damper using the control network elements.

The intended control logic is:

• When the pressure difference between the stairwell and the adjacent corridor reaches 60 Pa, the pressure relief damper should open to relieve excess pressure in the stairwell.
• This condition occurs when all stairwell fire doors are closed.
• When a fire door is opened, the stairwell pressure drops significantly. Under this condition, the relief damper should remain closed so that the fan airflow can be used to maintain stair pressurization.

To implement this logic, I tested several control elements, including:

• Lower Limit Switch
• Upper Limit Switch
• Upper Band Switch
• Upper Limit Control

However, I observed the following behavior:

1. With all doors closed, the damper opens correctly when the pressure differential reaches approximately 60 Pa.
2. When a fire door is opened and the stairwell pressure drops well below 60 Pa, the damper continues to discharge air to the exterior.
3. I expected the damper to close automatically once the pressure differential dropped below the control setpoint.

I am attaching two files:

• File 1: all doors closed, where the damper appears to work correctly.
• File 2: one door open, where the damper continues to discharge air to the exterior even though the pressure differential is below the control value.

My question is:

Is there a recommended way to implement this type of logic using the CONTAM control network?

Or is there a specific control element recommended to represent a pressure relief damper that:

• opens when ΔP ≥ 60 Pa;
• closes when ΔP < 60 Pa;
• automatically responds to pressure variations during the simulation?

I would appreciate any guidance or example model demonstrating how to implement this behavior correctly.

Best regards,

Sávio - Firefighter 

[Dols, William Stuart (Fed)]

Here’s a demo case.

It’s best to run a transient simulation to use controls.

This is simply meant to provide an example and should not be considered engineering judgement/advice on my part.

 

- Stuart

 

--
To unsubscribe from this group, send email to contam+un...@list.nist.gov
 
View this message at https://list.nist.gov/contam