Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

Fire-Stop Ratings

F-rated, T-rated and L-rated fire-stop systems.

Openings for electrical and HVAC installations in smoke and fire-rated constructions must be sealed to resist the passage of heat, fire and smoke.

Fire stop systems are typically categorized according through-penetration of

  • flames
  • temperature
  • smoke

Ratings according ASTM E814,"Fire Tests of Through Penetration Fire Stops" are

F-rating, Flame Ratings

The F-rating is expressed in hours and the number indicates the specific length of time that a barrier can withstand fire before being consumed or before permitting the passage of flame through the opening.

A F-rated opening shall also withstand a hose stream test.

T-rating, Thermal Ratings

The T-rating is expressed in hours and the number indicates the length of time that the temperature on the non-fire side of the penetration does not exceed 325 oF (163 oC) above the ambient temperature. This ensures that the temperature on the side of the wall away from the flame does not reach the flash point of any materials on that side of the wall.

L-rating, Smoke Ratings

The L-rating is the amount of air (or cold smoke) that can leak through a penetration and the number indicates the amount of air in cubic feet per minute.

L-ratings are tested with a differential pressure of 0.30 inches water column (75 Pa) at 75 oF and at 400 oF.

Related Topics

Related Documents


Search is the most efficient way to navigate the Engineering ToolBox.

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with older versions of the amazing SketchUp Make and the newer "up to date" SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp Make/Pro from the Extension Warehouse !

Translate this Page

Translate this page to Your Own Language .

About the Engineering ToolBox!

Privacy Policy

We don't collect information from our users. More about

We use a third-party to provide monetization technologies for our site. You can review their privacy and cookie policy here.

You can change your privacy settings by clicking the following button: .


This page can be cited as

  • The Engineering ToolBox (2005). Fire-Stop Ratings. [online] Available at: [Accessed Day Month Year].

Modify the access date according your visit.

3D Engineering ToolBox - draw and model technical applications! 2D Engineering ToolBox - create and share online diagram drawing templates! Engineering ToolBox Apps - mobile online and offline engineering applications!

Unit Converter