Exploring the 3 Methods for Fire-Rated Expansion Joints

Ensuring Fire Safety & Structural Integrity 

Expansion joints play a crucial role in most commercial buildings, as they are essential for accommodating the expected movements caused by various factors such as thermal changes, wind sway, and seismic events. These joints act as a buffer, allowing the building to expand and contract without causing structural damage. However, when these joints are located in fire-rated floors or walls, it is imperative to use a product or system that is rated to the same level of fire resistance. Building codes mandate that these joint assemblies be tested by accredited agencies like UL or Intertek Warnock-Hersey, following the standards outlined in ASTM E-1966 or UL 2079.

There are three primary methods commonly employed to achieve the required fire rating for expansion joints:

1. Pre-compressed seals with an integrated intumescent coating represent the latest advancement in providing fire ratings for joints. These innovative systems are specifically designed for joints measuring 6 inches or less. They offer the remarkable capability of accommodating up to 50% movement in both compression and extension. Whether used in horizontal or vertical applications, these seals can be exposed or concealed behind a metal cover plate. Apart from their fire-resistant properties, they also provide a watertight seal, adding an extra layer of protection. Additionally, their silicone face can be customized and colored to match the desired aesthetic of the project, enhancing the overall visual appeal.

2. Fire barrier systems utilizing draped or compressed ceramic fiber blankets are another effective approach to achieving fire ratings for expansion joints. These systems are capable of handling joints with larger dimensions, extending up to 32 inches. They possess excellent range of motion capabilities, ensuring flexibility in accommodating building movements. Similar to the previous method, these systems can be installed in both horizontal and vertical applications, although they typically require a metal cover plate to achieve the desired fire rating. The ceramic fiber blankets employed in these systems provide effective insulation and fire resistance, enhancing the overall safety of the structure.

3. The third method involves the use of rated mineral wool products that are compressed into the joint and covered with a sealant. This particular approach is commonly employed for smaller joints, typically measuring 4 inches or less, which have a limited range of motion. You will often find these fire-rated joints used in floor assemblies, where their compact size is advantageous. When properly compressed into the joint, the rated mineral wool serves as an effective barrier against fire, and the sealant applied on top provides an additional layer of protection.

By employing these fire-rated expansion joint systems, commercial buildings can ensure both structural integrity and fire safety. These systems not only accommodate the building's movements but also meet the stringent requirements for fire resistance. The testing procedures conducted by accredited agencies guarantee that the expansion joint assemblies conform to the necessary standards and regulations, instilling confidence in their performance during potential fire incidents.

In most commercial buildings expansion joints are a fact of life.  These joints are necessary to accommodate expected building movements due to thermal changes, wind sway and differential movement typically caused by seismic events.  When these joints occur in a fire-rated floor or wall, a product or system that has been rated to that same level must be used.  This means if the joint occurs in a 2-hour rated floor assembly the expansion joint system used to fill the joint must also be rated for 2 hours.  Per current building codes, these joint assemblies must be tested at an accredited testing agency such as UL or Intertek Warnock-Hersey and be tested in accordance with ASTM E-1966 or UL 2079 test standards.

Nystrom understands the complexities of building expansion joints and seals. Please visit our website for more information or to see how Nystrom can help on your next project.