Fire Ratings! Concrete! and Unicorns??

[@khaldounrahal3306]

Thanks Tyler. Simple and informative.

[@adamr1637]

Great explanation. Thanks for sharing.

[@TylerLey]

Thanks!

[@mihaiilie8808]

New subscriber and its a good channel.
Make a video about Ytong .Its crazy that such avangard and widespread material its not available in North America.
To get an idea about how resistant to heat the autoclaved celular concrete is,i tell you that ive build my kiln in wich i fire ceramic from Ytong blocks and then lined the interior with one inch zirconia ceramic blanket rated to 1400 C.
Ive also fired fired ( made)4 kilos of brick with just one kilo of wood biomass,but thats another story.
USA is missing 2 most important things in constructions,Ytong ( autoclaved cellular concrete not necesarely ytong brand) and the ppr pipes wich are superior to all the pex-al and all the otther similar pipes.

[@kushalghosh1559]

Awesome video Dr Ley.Sir,is there a rating available for composite structural systems?Can you refer some reading material regarding forensic evaluation of fire damaged steel structures?

[@TylerLey]

Kushal,
I don't know of any publications on fire damage for steel. You should get ASTM E119. It has a lot of great information. There are a lot of publications on how the stress vs strain relationship changes with different types of metals. You can often times model a fire or estimate a fire in a building and then use that information to determine the temperature of the steel members. Once you have this information then you can estimate the changes in strength and stiffness and then estimate the capacity. I hope this helps.

[@kushalghosh1559]

Thank you sir for your valuable advice.I will try to get ASTM E119 .I came across a few papers like files.engineering.com/download.aspx?folder=e3ecce14-4a0e-4ca0-a089-8a99e0e01e67&file=Integrity_of_Structural_Steel_After_Exposure_to_Fire.pdf, web.wpi.edu/Pubs/ETD/Available/etd-050406-105306/unrestricted/rnacewicz.pdf.

[@HergerTheJoyous]

How dare you question time honored processes! Furthering ones knowledge is the work of the devil! Lol. Just kidding your doing good work!

[@TylerLey]

Thank you!

[@TylerLey]

Thanks Wroger,
It looks like you have studied fire a lot. I really appreciate your thorough response with additional links. I totally agree with you that fires are very complicated and are not easy to understand or design for.
I agree with you that the standard provides us something that everyone can design for and compare but I don't think it represents an average fire in an average situation. The test was originally developed to provide designs for office buildings. These buildings were dominated by paper in the past and paper is a great fuel. Our office buildings have changed a lot and I think we should keep that in mind when we look at the fire ratings. Many engineers hear the fire ratings and think that in all fires that the component will survive for X hours. This isn't true. I think the fire ratings could be used to compare different structural systems but even then there are a lot of different scenarios and challenges in a fire.
This could be fixed if they changed the results from the fire test from 1h, 2h, 3h to something like A1, A2, A3 with descriptions for what each one means. They could also give more information about the results by changing the letter in front to give more insight into what happened in the test. For example, a B2 could mean that it survived 2 hours but there were significant deformations. This gives a lot more information than just 2h.

[@TylerLey]

I think these are all good ideas!
I think we both agree that the current method could be improved.

[@TylerLey]

@Wroger Wroger I think this is a good framework. To test this you would have to use finite element modeling. This would be a lot of effort but I agree that it would be a good thing to do for a design. It would be good to take into account how building use changes over time. I am not sure the best way to do this.
It would be nice if we could make this simpler. For example, you could have three levels of rating systems for the use of the room. High, medium, and low fire loading. You could then pick a combination of systems or methods to design for that. This means if you have X square meters of adjacent high fire loading then that forces you to use a certain fire suppression system or maybe if they are separated by a certain distance then you could use a lower fire suppression system. You could figure this out with a bunch of computer model runs and then just use a series of simple tables for design purposes.

[@TylerLey]

WOW! You know a lot about fires.
I agree with what you are saying. I was talking about a way to come up with a general use policy based on the use and size of the space to determine the required fire protection system or structural design. If you looked at enough cases then you could come up with a general recommendation for different cases and then you could codify it. This is a common procedure for engineering design. Since doing fire testing would be costly, many people would suggesting using modeling to investigate the performance. You could even do this analysis probabilistically. You also might be able to do this based on case studies of past performing structures in a fire. The best may be a combination of both of these.