In some cases, the expected range of movement can get overlooked and that can cause issues with the building structure down the road. One example of this is adjacent construction near the expansion joint. Movement of an expansion joint and joint covers can interfere with nearby construction like doorways, windows, and other elements that could collide and become damaged or non-functional if a joint moves as fully designed.
Exposure to elements
Equally important is exposure to elements when selecting the size and type of expansion joint systems. Depending on placement, each of these concerns should be addressed before the final size is determined and the appropriate product is selected.
Exterior expansion joint systems are exposed to all sorts of weather conditions:
- moisture from condensation, rain, snow, and ice melt;
- dry-out from ultraviolet (UV) exposure and hot temperatures; and
- erosion from wind, dirt, and flying debris.
Including the appropriate water barrier along with the rightly sized expansion joint system is a must. All the factors affecting a building’s envelope are pertinent to expansion joint systems as well.
Interior considerations
Interior expansion joints must also handle thermal fluctuations due to the use of heating in colder months and air-conditioning in hotter months. With regard to flooring expansion joints, how that surface will be used and maintained impact the type of material selected. For example, lots of foot traffic means constant cleaning of carpet or tiles involving the use of heavy commercial-sized cleaning equipment and maintenance water.
The functionality of the space also requires consideration. The need for appropriate hygienic barriers to prevent contamination in large commercial kitchens, food storage, and prep areas, food manufacturing and packaging, surgical and clean rooms, and laboratories is critical for health and safety reasons.
Fire rating considerations
Finally, both exterior and interior expansion joint systems often need to be fire-rated as both a smoke and fire barrier. This helps to contain fire or smoke damage to a restricted area within the building or from extending to an adjoining structure. Gaps for expansion joints are cut through building materials that are firewall-rated, so inherently, all installed expansion joint systems will also need to be of the same fire rating as the adjacent floors, walls, ceilings, and roofs. Smoke and fire barriers are placed either below (i.e. floors) or behind (as in walls, ceilings, and roofs) the expansion joint systems.
Untangling the codes
For architectural expansion joint systems, the International Building Code (IBC) is the most common standard. IBC references performance standards and test criteria from the Underwriters Laboratories (UL) 2079, Standard for Tests for Fire Resistance of Building Joint Systems, and ASTM E1966, Standard Test Method for Fire-resistive Joint Systems, as well as other sources such as the Americans with Disabilities Act (ADA) and the American National Standards Institute (ANSI) to ensure public safety. ASTM International provides a specific code for joint expansion system movements—it is ASTM E1399-97 (2017), Standard Test Method for Cyclic Movement and Measuring the Minimum and Maximum Joint Widths of Architectural Joint Systems.
Using correct specs
Sometimes, sizing and load capacity are overlooked in planning. Canned or generic references are provided by product manufacturers, which are then dropped into architectural specifications when products are selected. These specs are generic to provide a general idea of load capacity, but do not take into consideration how the expansion joint system will be impacted by foot traffic, cleaning equipment, very heavy loads, and so on. Additionally, many canned specs are old or outdated.
