Rolling Steel Fire Door Components 101


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By now, we know how important rolling steel fire door assemblies are to a facility’s overall passive fire protection system. In the event of a fire, these devices act as the first line of defense to prevent flames, smoke, and toxins from spreading throughout a building. We know that fire doors serve a number of functions, but primarily they are a part of the building’s fire protection plan to act as a barrier against the spread of fire and smoke.These openings are such a critical piece of the fire safety plan and are, in essence, meant to strengthen the effectiveness of the active fire systems, such as fire alarms and sprinklers. Compartmentalizing a building with fire-rated separations like fire walls and fire partitions is critical to ensure the fire and smoke doesn’t spread. The inspection of fire and smoke doors, including rolling steel fire doors, in required per NFPA’s Life Safety Code® and NFPA 80, among other codes to ensure they are in proper working order and functioning as intended.

A fire rated steel rolling door is one that has the ability to self-close in the case of a fire. The intention of a rolling steel door is to prevent a fire from spreading from one room to another. The rating on the door will have to match or supersede the rating of the wall upon installation, or else the door is deemed useless to the building’s fire protection system.

The fire door drop test ascertains whether your fire doors meet the required fire safety compliance. As your doors are used daily, they tend to become coated in grease, dust and other debris which could cause a problem with the way they function. Annual fire door inspections are intended to make sure that your door’s components are free from debris, all parts are undamaged and in working order, and more importantly, that the fusible links are in working order.

We’ve put together this infographic to share information on the main components of a rolling steel fire door. We’ll talk you through what to look for on the rolling doors in your facility.

Major Rolling Steel Fire Door Components:


A housing that mounts horizontally, serving as an enclosure for the counterbalance assembly and door header. The hood is made of fire-rated sheet metal and keeps the brackets rigid and intact.

Counterbalance Shaft

A system of springs or weights to provide the amount of force needed to raise the door and maintain it in the open position.


End supporting plates bolted to the wall or to extensions of the guide wall angles that serve to support the barrel and form end closures for the hood.

Fusible Links

The fusible link is the most common fire door release device. The link is compromised of two pieces of metal held together by a low-melting solder. They are used to connect two pieces of sash chain or cable on a fire door. Upon melting, the fusible link causes the release arm or dropout arm to become activated, initiating the closing of the door.

Release Mechanism

Releases the door in the even to of a fire. The release mechanism is often tied to a fire alarm system or smoke detector system.


Each of the individual section of the curtain is called a slat. These are connected in a way that they can make the door “roll up” when it is in an open position.

Sash Chain

The sash chain is used in conjunction with S hooks and Fusible Links to hold the release system in place. Once a fusible link melts, the sash chain goes slack and releases a predetermined amount of spring tension allowing the fire door to automatically close. The sash chain must travel smoothly through any pulley system upon activation of the fusible link or release. The chain must be free of any kinks that would prevent it from closing completely.


This is the “door” itself—the steel curtain is what covers the majority of the space when the door is closed and it is tucked away when the door is open.


A turn buckle is a tightening part that you can use to tighten up the cable/sash chain

Fire Rated Label

While not necessarily a true operational component of fire door, the fire rated label contain valuable information  regarding the construction of the door, including the name of the manufacturer, the testing laboratory, and the fire-protection rating.


Seals are installed around all edges of the door to insure that temperatures stay as consistent as possible when the door is in the closed position.


Fire door guides retain the edges of the curtain while opening. Typically they are constructed of steel angles that are galvanized, non-galvanized, painted or stainless steel. Usually the top of guides are flared, providing a smooth transition for the curtain to enter into the guides.


The barrel is a cylindrical, steel tubing or pipe, whose main function is to house the counterbalance springs and other related hardware. The barrel must be large enough to house all of the springs required to correctly balance the door.

End Locks

Molded nylon, steel stamping or malleable iron castings which are riveted to curtain slat ends at every other slat to prevent slats from shifting laterally or from sliding out.


The gears are the mechanical a part of the motor system that rotates to facilitate opening and closing of the rolling fire door. Gears can fail to turn due to lubrication or rust and should be checked carefully during routine inspection. 


Some rolling fire doors are motorized and as such have a mechanical system that allows you to open and close the door with just the press of a button.

Want more information about rolling steel fire doors, their inspections, and the codes that mandate them? Sign up for our online training course coming soon that will give you ALL of the information you need to be able to perform these mandatory safety inspection in-house.