 Let's see what's on thinking man's mind. What are the different ratings available for interior fire doors. Thank you thinking man. Another excellent question. I thought that fire doors were rated three fourths of what the wall was rated. This is the biggest misunderstanding when it comes to the rating of fire doors. This is true, but only for 45 and 90 minute doors. Let's take a look at the others. I will be basing my answer using references from NFPA 80 2013, which will answer the question of what the fire door is classified as and IBC 2015, which will show us where in a building they're used. Other additions are similar. Always consult your state and local codes as well. A fire door assembly has two main goals. First to stop the spread of fire within into or out of a building and second to limit the transfer of smoke. Not all areas in a building need the same protection. That's why there's so many ratings from a doors perspective. It depends on what part of the means of egress the fire door assembly is protecting. IBC table 716.5 shows the fire protection rating for doors and firewalls as three hours. Firewalls are used to divide a structure into two separate buildings. The division must be vertical and go all the way through the roof. The image from NFPA 80 shows us that a three hour door is classified as a label. For the most part, fire barriers will either be rated for one or two hours. Fire barriers protecting enclosed exit stairs and horizontal exits will be one hour rated when connecting a building three stories or less and two hour rated when connecting a building four stories and higher. Fire door assemblies will be classified as be labeled either 90 minute for two hour walls or 60 minute for one hour walls. Then there's this little almost gotcha called other fire barriers and a little further down the table. Other fire partitions. This would include places like mechanical rooms, large storage rooms, laundry rooms and other similar spaces. There'll be a one hour fire barrier or fire partition with a three quarter hour also known as a 45 minute rated fire door and that's classified as see label. Fire partitions are wall assemblies that enclose an exit access corridor. They also separate elevator lobbies. Smoke barriers are used to create smoke compartments in large buildings and you see them in hospitals a lot more than anywhere else. The doors are required to be one third hour also known as 20 minute doors. While their primary function is to slow the passage of smoke. Make no mistake about it. They are fire doors to this is the minimum level of fire protection rating and I can hear Ronnie Dangerfields voice in my head saying these doors have no class. There is no letter designation that goes along with a 20 minute door. Smoke doors that have an S label have no fire rating at all, but that doesn't mean that they're not important. I just don't have time today to get into them. And I'm sure that thinking man will have that question for future episodes. For more information and continuing education opportunities. Please visit also Abloy Academy by clicking on the link in the comments below. Please click like and subscribe to this channel and follow me on Twitter at art consultant or connect with me on LinkedIn for updates. You can email code questions to me at Catherine dot flower at also Abloy dot com and who knows maybe they'll be featured in a future episode. Thanks for joining me in the code corner today. My name is Katie flower and my goal is to help you achieve safe purity in the built environment.