---
title: Five Considerations for Life Safety Dampers
description: Learn five important considerations for choosing life safety dampers. Make sure your UL dampers are ready to respond to fire events.
---

[MCDLG Newsstand - HVAC Industry Info](https://newsstand.mcdlg-hvac.com)

# [Five Considerations for Life Safety Dampers](https://newsstand.mcdlg-hvac.com/five-considerations-for-life-safety-dampers)

 Written by [Jess Jordan](https://newsstand.mcdlg-hvac.com/author/jess-jordan) | Oct 21, 2026, 3:00:01 PM

You have likely seen fire and smoke dampers mentioned in your project’s requirements. These are life safety dampers, and they are part of your building’s passive fire protection. Life safety dampers react to fire and smoke hazards by closing off ventilation openings and ductwork during an emergency.

You will need them at key points in your building. Here are five things to consider when selecting life safety dampers for your building.

Fire Resistance Rating

Every fire damper and combination fire-smoke damper will have a fire-resistance rating. Some dampers may have a high temperature rating, upwards of 800 degrees Fahrenheit, but that does not mean they work as fire dampers. For fire safety, the damper needs a fire-resistance rating.

The fire resistance rating is the time, in hours, that the damper remains intact during a fire. This rating is determined through UL-approved testing. Check out our article on fire dampers for the full story on fire resistance testing. To summarize, testers mount a sample damper into the opening of a test oven.

The damper must remain fully closed and intact for 1.5 hours or 3 hours while subjected to flames from the test oven. The duration of the test depends on the desired rating.

You will place fire dampers in designated “fire areas”, where the walls, ceiling, and floor will all have fire resistance ratings. To be specific, the fire damper will go inside the opening (penetration) of a fire barrier or partition. You will want a fire damper with a rating that closely matches the barrier’s rating. It won’t be an exact match.

If your fire barrier has a rating less than three hours, then choose a fire damper rated for 1.5 hours. For three or more hours, use a 3-hour-rated fire damper. This general rule also applies to combination fire-smoke dampers, since they also have fire-resistance ratings.

 

## Fire Response Device

Life safety dampers need the means to react to an emergency. For fire, dampers have a fusible link or a sensotherm disc. These fire-response devices hold the damper in the full-open position.

They use heat-sensitive materials, which cause the device to break at a specific temperature. Once broken, the damper’s blades will rotate to the full-closed position. Here is a quick Condenser read on these devices.

Fusible links are common for curtain-blade fire dampers, though multi-blade fire dampers can also use fusible links. The fusible link is a cheap and effective response device, because it has a relatively low melting point. Manufacturers offer fusible links rated at 165 °F, but you can choose to use links rated at 212 °F. Sensotherms have the same heat ratings for their low-range discs, while the high-range discs have ratings at 250 or 350°F.

When installing a fire damper near a heating element, like a heating chamber or a hot-air register, consider using links and low-range sensotherms rated as 212°F. This higher rating ensures that the device will not trigger when exposed to regular heating. For other applications, use the standard 165°F.

 

## Static and Dynamic Closure

Static and dynamic closure refer to the damper's ability to close against an airstream. A dynamic fire damper has specialized springs that drive the closing action, while a static fire damper relies on gravity for closure.

Consider whether your HVAC system will shut down during an emergency. Static fire dampers are cheaper, but they cannot close against airflow. If a fire starts and the system fans are still running, the static fire damper will remain open even when the fire response device activates. For these situations, use a dynamic fire damper.

Combination fire-smoke dampers are always dynamic. They need to close at the first sign of fire or smoke.

 

## Elevated Temperature Rating

The elevated temperature rating differs from the fire resistance rating. Where fire resistance rating is the duration of fire resistance, the temperature rating is the heat of smoke-filled air. Smoke dampers must close and maintain a tight seal at this temperature.

Testers derive the temperature rating from the smoke damper’s temperature degradation testing. They bake a sample damper for thirty minutes at 250°F or 350°F; manufacturers choose the desired rating when submitting the damper for testing. At the end of the thirty-minute bake period, the smoke damper must open and close three times against airflow. On the third closure, testers will also measure the amount of air leaking through the damper.

Smoke dampers and combination fire-smoke dampers will have a temperature rating of 250°F or 350°F. According to the 2021 International Building Code, [the minimum temperature rating](https://codes.iccsafe.org/content/IBC2021V2.0/chapter-7-fire-and-smoke-protection-features#IBC2021V2.0_Ch07_Sec717.3.2.2) for a smoke damper is 250°F, while any life safety damper operating inside a smoke control system [must have a temperature rating of 350°F](https://codes.iccsafe.org/content/IBC2021V2.0/chapter-7-fire-and-smoke-protection-features#IBC2021V2.0_Ch07_Sec717.3.3.1).

Combination fire-smoke dampers follow the same rules. They must be prepared to react to either hazard.

 

## Leakage Class

Leakage class is a classification of a smoke damper’s expected leakage when fully closed.

Smoke dampers aren’t fully airtight. They slow the spread of smoke through ductwork. Testers will measure the amount of air passing through a closed sample damper after heating it. The amount of leakage will fall under one of three potential classes:

- Class 1: 8 cfm/sq.ft. at 4.5 in. w.g. or 11 cfm/sq.ft. at 8.5 in. w.g.
- Class 2: 20 cfm/sq.ft. at 4.5 in. w.g. or 28 cfm/sq.ft. at 8.5 in. w.g.

There is a third class under UL 555S, but the IBC requires leakage class one or two.

Manufacturers, [like Air Balance](https://www.airbalance.com/ProductTypes/Details/Smoke-Dampers), will offer all their smoke damper models with leakage class 1 or 2. This way, you don’t have to limit your selection by leakage class.

Consider using smoke dampers with leakage class 1, especially when designing a smoke control system. Tight closure is always better.

 

## Your Options

Manufacturers will provide many options for meeting your life safety requirements. It’s important to build safe structures with passive fire protection. Remember to meet these requirements with the right life safety dampers.

 

[View full post](https://newsstand.mcdlg-hvac.com/five-considerations-for-life-safety-dampers)

```json
{
  "@context" : "http://schema.org",
  "@type" : "BlogPosting",
  "author" : {
    "@type" : "Person",
    "name" : "Jess Jordan"
  },
  "dateModified" : "2026-10-21T15:00:01.792Z",
  "datePublished" : "2026-10-21T15:00:01Z",
  "headline" : "Five Considerations for Life Safety Dampers",
  "image" : {
    "@type" : "ImageObject",
    "height" : 642,
    "url" : "https://3289606.fs1.hubspotusercontent-na1.net/hubfs/3289606/Images/Blogs/Five%20Considerations%20for%20Life%20Safety%20Dampers/MCDLG%20Blog%202026%20-%20Five%20Considerations%20for%20Life%20Safety%20Dampers%20-%20Cover.webp",
    "width" : 1201
  },
  "mainEntityOfPage" : "https://newsstand.mcdlg-hvac.com/five-considerations-for-life-safety-dampers",
  "publisher" : {
    "@type" : "Organization",
    "logo" : {
      "@type" : "ImageObject",
      "height" : 60,
      "url" : "/hs/hsstatic/content_shared_assets/static-1.4092/img/default-amp-logo.png",
      "width" : 60
    },
    "name" : "MCDLG Newsstand"
  }
}
```