Matching Results to ASHRAE Smoke Control Ex 19.7 | Tenability in CONTAM

[Anders Bjork]

Hello, 

Has anyone been able to match the tenability results for ASHRAE Smoke Handbook Example 19.7? I am having trouble getting the transient contaminant concentrations described in the given solution. 

More generally, I'd welcome other (simpler?) examples as I become familiar with running transient contaminant studies in the program. Any help appreciated, please!

Please see attached files for more information.

Thank you,

Anders Bjork,

Technical Writer, Thunderhead Engineering

[Anders Bjork]

To clarify, I think I need help specifically with the combination of stack effect and leakage of contaminants.

Anders

[Dols, William Stuart (Fed)]

Anders,

I have not attempted to develop the example case to which you referred.

 

Have you reviewed the Introduction to CONTAM Tutorial videos that are provide by NIST?

Stack flow and transient contaminant simulations are covered in Parts 5 and 6.

 

- Stuart

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[Anders Bjork]

Stuart,

Thank you for your reply. I have peeked at that tutorial video, which does cover those topics. 

• To meet my needs, I am trying to simulate only 20 minutes of the day, with 5 second time steps. Is there a way in CONTAM to display the contaminant concentrations for a zone over just 20 minutes? Right now, the CONTAM plots show only the full 24 hour period. This makes it hard to look at the first 20:00 of data.
• More generally, do you have any advice on running transient simulations that are less than one day?

Thank you,

Anders

[Dols, William Stuart (Fed)]

Anders,

It seems the PRJ file you shared in your initial message is configured to do just what you ask.

 

 

 

- Stuart

 

From: Anders Bjork <bj...@thunderheadeng.com>
Sent: Tuesday, March 11, 2025 2:11 PM
To: Dols, William Stuart (Fed) <willia...@nist.gov>
Cc: CONTAM <con...@list.nist.gov>
Subject: Re: [contam] Re: Matching Results to ASHRAE Smoke Control Ex 19.7 | Tenability in CONTAM

 

Stuart,

Thank you for your reply. I have peeked at that tutorial video, which does cover those topics. 

• To meet my needs, I am trying to simulate only 20 minutes of the day, with 5 second time steps. Is there a way in CONTAM to display the contaminant concentrations for a zone over just 20 minutes? Right now, the CONTAM plots show only the full 24 hour period. This makes it hard to look at the first 20:00 of data.

Thank you,

Anders

[William Dols]

Anders,

My apologies.
I was running ContamW version 3.4.0.4 and not the latest release.
It appears that in fixing one bug, we created another.
Please install 3.4.0.5 and work with that when plotting these shorter simulations.
I will log this issue for correction.

- Stuart

[Anders Bjork]

Hello Stuart,

By the way, do you have any guidance on how much less accurate the "two-opening two-way flow" model is than the "single opening two-way flow" model? This was also a part of the previous files for the ASHRAE 19-7 example.

The CONTAM User Guide 3.4 says in Doorways Large Openings, "The [2-opening] model becomes less accurate as the neutral plane shifts from the center of the opening. "

I think this is due to the 2/9 * H deviation from the center of the opening, but I ran some quick comparisons in .prj files and they all (with 3m height levels) did not seem affected by the opening moving up or down.

Have you looked into this? Or perhaps, do you know where I could learn more about the math and the uncertainties involved?

Thank you,

Anders

[Dols, William Stuart (Fed)]

Theory of the Large Opening models is presented in the Theoretical Background section of the CONTAM User Guide.
References are provided in that section.
I’ve attached a PDF of an in-progress modification to that section.

I’ve also attached a some examples that show comparisons between various methods of modeling two-way flows.
You can see in the “Test_TwoWay-wind_10ms.prj” that differences occur between the One-opening and Two-opening models.
This is due to the neutral level being within, but not “near the middle” of the opening.
The two-opening model assumes two openings that are always located the same distance from the center of the opening.

 

- Stuart

 

From: Anders Bjork <bj...@thunderheadeng.com>
Sent: Monday, May 5, 2025 6:08 PM
To: CONTAM <con...@list.nist.gov>
Cc: Dols, William Stuart (Fed) <willia...@nist.gov>; CONTAM <con...@list.nist.gov>; bj...@thunderheadeng.com <bj...@thunderheadeng.com>
Subject: Re: [contam] Re: Matching Results to ASHRAE Smoke Control Ex 19.7 | Tenability in CONTAM

 

Hello Stuart,

 

By the way, do you have any guidance on how much less accurate the "two-opening two-way flow" model is than the "single opening two-way flow" model? This was also a part of the previous files for the ASHRAE 19-7 example.

 

The CONTAM User Guide 3.4 says in Doorways Large Openings, "The [2-opening] model becomes less accurate as the neutral plane shifts from the center of the opening. "

 

I think this is due to the 2/9 * H deviation from the center of the opening, but I ran some quick comparisons in .prj files and they all (with 3m height levels) did not seem affected by the opening moving up or down.

 

Have you looked into this? Or perhaps, do you know where I could learn more about the math and the uncertainties involved?

 

Thank you,

Anders

 

 

On Tuesday, March 11, 2025 at 4:28:27 PM UTC-5 William Dols wrote:

Anders,

My apologies.
I was running ContamW version 3.4.0.4 and not the latest release.
It appears that in fixing one bug, we created another.
Please install 3.4.0.5 and work with that when plotting these shorter simulations.
I will log this issue for correction.

- Stuart

 

On Tuesday, March 11, 2025 at 2:32:21 PM UTC-4 William Dols wrote:

Anders,

It seems the PRJ file you shared in your initial message is configured to do just what you ask.

 

 

 

- Stuart

 

From: Anders Bjork <bj...@thunderheadeng.com>
Sent: Tuesday, March 11, 2025 2:11 PM
To: Dols, William Stuart (Fed) <willia...@nist.gov>
Cc: CONTAM <con...@list.nist.gov>
Subject: Re: [contam] Re: Matching Results to ASHRAE Smoke Control Ex 19.7 | Tenability in CONTAM

 

Stuart,

Thank you for your reply. I have peeked at that tutorial video, which does cover those topics. 

• To meet my needs, I am trying to simulate only 20 minutes of the day, with 5 second time steps. Is there a way in CONTAM to display the contaminant concentrations for a zone over just 20 minutes? Right now, the CONTAM plots show only the full 24 hour period. This makes it hard to look at the first 20:00 of data.

[Anders Bjork]

Stuart,

Thank you so much for your help with this. I found the attached examples very helpful.

I now understand that the 2-Opening 2-way flow models are based on the neutral plane centered within the opening, and I can see how the flow solution differs when the neutral plane shifts away from the center, but is still within the height of the opening (as in the 10m/s wind example).

It is my understanding that the relative height of the (2-way) opening, due to the assumed uniform temperature of each zone, is inconsequential. Is this true for all cases?

Also, I really like the drafted in-progress modifications, especially Fig. 20.

Anders