Temperature increase far from the fire source

[AleksanderKamienski]

I have a problem with one fire scenario, which I presented in the cfast.txt file.

In the initial 50 seconds of simulation when most doors are closed, strangely long corridors (also those that are far from the fire source - on the other side of the building - for example c37, c65, c92) have a temperature increase of about 50 degrees Celsius. I wonder what causes this because the fire is really far away and realistically there should not be such a sudden increase. I wonder if the setting HALL = .TRUE could have had any effect on this. Below is a photo to illustrate the problem. The corridors on the right are the aforementioned c37, c65, c92 far from the source of fire in the building which is shown on the left side of the photo.

cfast.txt

[preneke]

I see what you pointing at and it does seem strange. I will remind you that CFAST is a zone fire model and in cases with rooms that have a floor aspect ratios that are far from 1 the assumptions of a zone fire might be pushed to an possibly past its limits. HALL is an attempt to fix that for the early fire but maybe it just isn't working well here. Have you tried it without HALL. However, once I get a chance to look at this more closely my first thing to check will be the connections. SmokeView is impressive but complicated is complicated so it is hard for me to tell from the picture but I don't understand the connections. I can guess the left side but where is hot gas coming from on the right side. Also how is gas getting to the other floors. A lot of mechanical ventilation could play havoc with everything and the HALL feature was not designed to work with mechanical ventilation. I will close out this stream of consciousness with my realization that I don't know how SmokeView shows a HALL with the gravity wave in the early fire. While waiting for me check your connections and trying running it without HALL and see what happens.

[preneke]

Aleksander,
Did you send the correct file. This file is incomplete. Targets don't have materials. One vent numbered 302 named d140 is trying to connect a room on the ground, s2,1 to a room, c99, that is 10 m above the ground.

[preneke]

I meant the name of the room is s21 not s2, missed placed comma.

[AleksanderKamienski]

Right, the target didn't have material, I already added it in the files below. As for the d140 connection, it's a door connecting the four-story staircase s21 with the corridor c99 - this is how we model it. If this is the wrong way, please let me know. From what I've checked, &VENT connections connect the appropriate compartments. I ran the simulation after adding materials to targets and there's still the same problem.

Then I removed HALL = .TRUE everywhere and ran the simulation again. It didn't help because there are still these temperature increases in the corridors on the other side of the building.

Below I present two modified contents of the cfast.in file

cfast_in_materials_added_to_targets.txt

cfast_in_materials_added_to_targets_hall_deleted.txt

If I make any mistake in the cfast.in file that I am not aware of, please let me know

[preneke]

I have run the case. I can't seem to get SmokeView to load the data from the run but when I look at the spread sheets the corridors are cooling off. The temp color bar goes from the coldest temp to the hottest temp in the simulation and since the outside is so much colder then interior rooms with leaks will cool off. What you are showing doesn't look what I am seeing exactly but in the case I have the corridors and other rooms I am sure are cooling off. Check to see if that is what you are seeing.

[AleksanderKamienski]

I think it's different for me because the corridors don't cool down. For example, when it comes to the temperature of the upper layer and the height of the upper layer in corridor c37, it looks like this:

the situation is similar in other corridors, for example c92

[preneke]

Can you put the <filename>_compartments.csv file generated by CFAST? If they are different then either we are running different versions of CFAST or you have a different input file. I have run this with the latest version 7.7.5. Is that the version you are running? If not get the latest version and try it again. From: AleksanderKamienski ***@***.***> Sent: Friday, June 6, 2025 5:08 AM To: firemodels/cfast ***@***.***> Cc: Reneke, Paul A. (Fed) ***@***.***>; Assign ***@***.***> Subject: Re: [firemodels/cfast] Temperature increase far from the fire source (Issue #2187) [https://avatars.githubusercontent.com/u/33099769?s=20&v=4]AleksanderKamienski left a comment (firemodels/cfast#2187)<#2187 (comment)> I think it's different for me because the corridors don't cool down. For example, when it comes to the temperature of the upper layer and the height of the upper layer in corridor c37, it looks like this: cfast_temperatures.png (view on web)<https://github.com/user-attachments/assets/e5fbaaae-57ea-4d2d-b94e-dd673878bf17> the situation is similar in other corridors, for example c92 - Reply to this email directly, view it on GitHub<#2187 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ADDV4MFOOWTEHKCCQUDNIL33CFK6BAVCNFSM6AAAAAB6R2DVJ2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDSNBYGU4TENRZGA>. You are receiving this because you were assigned.Message ID: ***@***.******@***.***>>

[AleksanderKamienski]

I downloaded the latest version of cfast in version 7.7.5 from github and compiled it on gnu_linux_64. It's interesting that the results are different than before, there is no longer a problem with higher temperature in corridors, everything looks realistic.

With the HALL = .TRUE option everything also works properly.

It's strange because I also used version 7.7.5 earlier (which was visible in the cfast.out file), although I had it compiled for some time so the files were probably not the most up-to-date. The results were completely different.

Sorry for taking up your time and I will remember to make sure that I have the latest cfast files downloaded in the event of similar problems in the future.

[preneke]

Not a problem. I am glad to help. From: AleksanderKamienski ***@***.***> Sent: Friday, June 6, 2025 9:48 AM To: firemodels/cfast ***@***.***> Cc: Reneke, Paul A. (Fed) ***@***.***>; Assign ***@***.***> Subject: Re: [firemodels/cfast] Temperature increase far from the fire source (Issue #2187) [https://avatars.githubusercontent.com/u/33099769?s=20&v=4]AleksanderKamienski left a comment (firemodels/cfast#2187)<#2187 (comment)> I downloaded the latest version of cfast in version 7.7.5 from github and compiled it on gnu_linux_64. It's interesting that the results are different than before, there is no longer a problem with higher temperature in corridors, everything looks realistic. With the HALL = .TRUE option everything also works properly. It's strange because I also used version 7.7.5 earlier (which was visible in the cfast.out file), although I had it compiled for some time so the files were probably not the most up-to-date. The results were completely different. Sorry for taking up your time and I will remember to make sure that I have the latest cfast files downloaded in the event of similar problems in the future. - Reply to this email directly, view it on GitHub<#2187 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ADDV4MERZ2FQWDY37CE7WAT3CGLYVAVCNFSM6AAAAAB6R2DVJ2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDSNBZGMZDQNZWHA>. You are receiving this because you were assigned.Message ID: ***@***.******@***.***>>