About Cold-Formed Steel


Cold-formed steel offers a number of material characteristics and performance attributes that enable a building to withstand the demands on a building as a result of such major events as fire, earthquakes and high wind.  These characteristics include:

Lateral Load Resistance:  Regardless of material, an important consideration in structural design is the lateral load resistance of exterior walls, or how well the wall will resist high wind and seismic forces. Structures are designed to absorb energy produced by ground movement and wind by "flexing" or “deflecting” in varying degrees, depending upon the construction materials, design of the structure, quality of construction, level of engineering, and the applicable building code requirements.  Cold-formed steel is an optimal material for this purpose because it is ductile; making it more forgiving than other more brittle materials in earthquakes and high-wind conditions, and has inherent strength in uplift and gravity loading.

Consistent Performance: Steel behaves in a highly predictable manner when subjected to the structural loads and movements imposed by high wind and seismic events. This is because steel is an inherently stable, manufactured material with consistent chemical and mechanical properties: once a steel stud has been formed, it will remain straight with virtually no change to the thickness, width or other dimensions, as well as strength and stiffness. Likewise, fasteners used to join steel framing members retain their strength and reliability over time.

Strength-to-Weight Ratio: A key characteristic of resilient building materials is the strength-to-weight ratio. This relatively easy way to compare the merits of several different materials is determined by dividing the maximum imposed load by the weight of the material. Of all commonly used construction materials, steel has the highest strength-to-weight ratio. When cold-formed steel sheet is formed into a C-shape, like a stud, the bends act as stiffeners and increase the strength of the steel sheet dramatically, providing a strength-to-weight ratio that is up to seven times greater than that of dimensional lumber.

Connection Strength: Because the material and geometric properties of a steel-framing member are stable, the overall strength of the structure will depend upon the quality of connections between the studs. Steel framing typically uses screws that provide a mechanical locking connection where the load is carried in shear. This is in direct contrast to wood, where connection strength is often limited – not by the strength of the fastener, but by the resistance of the wood in bearing or withdrawal. This unique combination of material characteristics enable buildings framed with cold-formed steel to withstand some of the most devastating natural events, and even remain in service after a disaster.   

Seismic.  Earthquakes are one of the most destructive forces in nature.  In recorded history, single seismic events have altered the course of major rivers, erased significant areas of land from the map and devastated structures within a considerable distance of the earthquake’s epicenter. Buildings in high-seismic zones are designed to absorb energy produced by ground movement by "flexing" or “deflecting” in varying degrees, depending upon the construction materials, design of the structure, quality of construction, level of engineering, and the applicable building code requirements. Cold-formed steel is the ideal material for buildings design to withstand seismic forces for two key reason:  high ductility and light weight.  Steel is considered a ductile material because it has the ability to bend or stretch without breaking when a force is applied.  As the load is reduced, the energy is dissipated without permanent deformation or damage to the steel.  On the other hand, brittle materials like concrete or masonry units will fracture and fail at their ultimate loads.   The weight of a building will be heavily influenced by the structural system, and cold-formed steel is one of the lightest framing materials used in construction today.  Structural damage is typically caused by “inertia”, or the reluctance of upper stories to begin moving as the ground shifts, and then conversely, to stop moving once the structure has moved.  In a seismic event, the effect on a structure is similar to what players experience in the game “crack the whip.”  Lighter structures have less weight available to be subjected to the stresses of inertia.

Fire.  The building codes recognize cold-formed steel as “non-combustible” and therefore make it eligible for use in Type I buildings where the fire-resistance standards are the most stringent. This is because cold-formed steel does not burn and will not contribute to the spread or intensity of a fire.   Research has also set the melting point of steel at approximately 2700°F, which means that is will not melt in a building fire, where temperatures average 1000°F and almost never exceed 1800°F.   And while the yield strength of steel is reduced at elevated temperatures, modern building codes and fire protection methods take this into account.

High Wind.  A variety of windstorm types occur in different areas of the U.S., and can include hurricanes, tornadoes, straight-line winds, thunderstorms and downbursts.  The one thing they all have in common is the combination of uplift, and positive and negative pressures that the building must resist.  American Iron and Steel Institute (AISI) has established a set of ANSI-accredited design standards for cold-formed steel, with a prescriptive method for one and two family dwellings that addresses wind speeds up to 180 miles per hour.  Cold-formed steel framed system further benefit from the inherent ductility of steel in a high wind event, helping to minimize damage due to building movements.  In addition, screw fasteners used in cold-formed steel construction tend to provide better connections and more secure continuous load paths than typical nailing patterns.  

Flood.  When materials are underwater for any length of time, many are not salvageable after the waters recede.  This often makes the building uninhabitable.  Where it is not possible to elevate susceptible materials above the local flood elevation, the use of products that will not absorb and retain moisture are key to ensuring the survival of the building during and after the event.  In velocity zones where break-away construction is necessary to relieve pressure on a structure, cold-formed steel also is an effective option for wall designs.


Unparalleled Fire Safety

Every 20 seconds, a fire department responds to a fire somewhere in the United States, resulting in fire being the nation’s fifth leading unintentional cause of injury and death.  Consequently, the choice of construction materials that don’t burn or contribute to the spread and size of a fire should be very important considerations.

Unlike wood or other organic construction materials, steel is a non-combustible.  And because it can’t burn, steel doesn’t provide a means for a fire to start or fuel that will allow it to spread.  It maintains its non-combustibility throughout the entire lifecycle of building; during building construction, occupation or future renovation/repair.  The result is reduced fire risk to workers and occupants, less impact on municipal fire services, and lower property destruction and collateral damage to adjacent buildings if a fire should ever occur.

The building codes recognize cold-formed steel as “non-combustible” and therefore make it eligible for use in Type I buildings where the fire-resistance standards are the most stringent.   “Fire walls”  are code-mandated assemblies that help limit or slow the spread of flames in a building, and cold-formed steel frame assemblies have been proven to be fire proof in up to four hours when subjected to tests conforming to ASTM E119 (Standard Test Methods for Fire Tests of Building Construction).  Click here to search an online directory of fire-rated assemblies for both load-bearing and non-loadbearing conditions.

The performance of steel components and steel structures in fire has been researched more extensively than any other building material.  Decades of research into understanding the behavior of structural steel components when exposed to fire has given designers the confidence to engineer buildings that will provide optimum safety.

Cold-formed steel has also proven it can withstand the severity of fire exposure in tests that follow the rigorous protocols of NFPA 285 Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Non-Load-Bearing Wall Assemblies Containing Combustible Components.

Research has also set the melting point of steel at approximately 2700°F, which means that is will not melt in a building fire, where temperatures average 1000°F and almost never exceed 1800°F.   And while the yield strength of steel is reduced at elevated temperatures, modern building codes and fire protection methods take this into account. Further, fires in buildings don't reach temperatures high enough to melt steel.

Non-combustible cold-formed steel construction also makes sense from a cost saving standpoint, as insurers traditionally offer lower builders risk and general liability premiums compared to wood.  Click here for a white paper on cold-formed steel and insurance.

The Risks of Combustible Construction Materials

Code changes to permit increased building heights for combustible wood framing have had a predictable result: a rash of large, catastrophic fires in Canada and the US that have destroyed entire building complexes and caused significant damage to adjacent properties and infrastructure.  A record of recent multi-story wood frame building fires is available at this link.

The negative consequences from one of these major fires often extends far beyond damage to the structure itself, also putting neighboring buildings and occupants at risk and creating enormous potential adverse economic impact for local government, businesses and residents.  To understand and quantify these impacts, a study was conducted to detail the direct and indirect costs ranging from those associated with extinguishing the fire to productivity loss due to infrastructure damage and business disruption.  Using data from actual fire events in Los Angeles, and extrapolating them to quantify the potential economic from the continued construction of mid-rise buildings with combustible framing from 2014 to 2028, the study found that for this fifteen-year period, Los Angeles County may face:

  • Over $22.6 billion in potential exposure based on the average scenario; the range of exposure over the period is $6 billion to $39.1 billion (low and high scenarios).
  • Up to $378.9 million in forgone tax revenues based on the average scenario, the range being $347.9 million to $410 million over fifteen years.

These urban fires have challenged the resources and equipment of fire services, increased costs of construction insurance rates for builders, and prompted several concerned provinces and municipalities to implement regulatory strategies for site safety practices during the construction of combustible buildings that will ultimately increase construction costs and lengthen time to building occupancy. The mounting evidence of these building code changes calls into question whether the relentless pursuit of supposedly lower cost construction methods is more important than increased risk to safety of the public and protection of their property.


About Cold-Formed Steel Framing:  Simple, Safe and Strong

Cold-formed steel framing offers architects, builders and specifiers a range of features and benefits that all contribute to shorter construction times, lower material costs, safer structures, and faster revenue generation.  Steel is strong, safe, durable, versatile and cost-effective.  Steel has the exceptional environmental advantage of being highly recycled and infinitely recyclable.  Steel is tough and does not rot, spawl, split or absorb moisture and is resistant to pests unlike other building materials. And from an aesthetic or architectural viewpoint, steel structures can easily deliver creative design options and excellent value.

To learn more about cold-formed steel, click on the links, below:

How cold-formed steel framing is made

Learn more about the History of Cold-formed Steel

Steel framing success stories

Advantages of Cold-Formed Steel Framing

Cold-formed steel features superior chemical and physical qualities that give it a broad range of advantages over other framing materials. 

. Steel has the highest strength-- to-- weight ratio of any building material. Moreover, the strength of cold-formed steel also provides architects with greater flexibility, allowing designs that incorporate longer spans and other architectural features
How Cold-Formed Steel is Made
Cold-formed steel framing is made from strips of structural quality sheet steel that are fed through roll forming machines with a series of dies that progressively shape the steel into C-shaped sections, or formed into a variety of other shapes, including “U”, “Z”, and even hat-shaped sections, to meet the requirements of specific applications.  Cold-formed steel framing members can be formed from a wide range of material thickness that enables them to meet the requirements of nearly all structural and non-structural applications.

Cold-formed steel starts with the production of raw steel, which is made by combining iron ore or steel scrap with small amounts of carbon in a Basic Oxygen Furnace (BOF) or Electric Arc Furnace (EAF)

Molten steel is poured into slabs that are reduced into thinner strips of steel, called “hot band.”  Increasingly, steel mills are employing a new, very efficient process called direct reduction to make “hot band.”

In the steel finishing process, the hot band is reduced once again into “cold rolled steel.”  A protective coating of zinc is then added through the galvanization process.  The final product is called a “coil.”

To convert coils into cold-formed steel framing members, they are first slit into widths that match the intended dimensions of the final product.

The slit coils of cold-formed steel are formed into C-sections and other shapes usually by roll forming the steel through a series of dies. Penetrations for plumbing and electrical runs are also punched at pre-determined locations, helping reduce installation times.  No heat is required to form the shapes (unlike hot-rolled steel), and thus the name cold-formed steel. A variety of steel thickness is available to meet a wide range of structural and non-structural applications.

The cold-formed steel framing materials are then either used to build wall and floor panels, and roof trusses, or delivered to the job site in bundles.
Cold-formed steel is the preferred material for curtain walls and partitions in commercial construction due to its light weight, high strength, non-combustible nature and ease of installation, and for these same reasons is increasingly being use as the primary structural system for buildings up to 9 stories tall.
As a recognized green building material, steel framing projects can also earn credits or points for green building rating programs as well as other government incentives.

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