Expansion joint is an opening within a structure, at predetermined locations, designed to absorb structural movements can be defined as follows:
A. Thermal - caused by temperature changes within the structure. Thermal movement is horizontal.
B. Seismic - caused by earthquake activity beneath the structure. Seismic movement may be horizontal, vertical, or shear; or a combination of all three.
C. Wind load induced by high winds forcing the structure to sway. Wind load induced movement is normally horizontal or shear.
Movement rating is an attempt to categorize the anticipated range of horizontal change in a joint opening. For example, a 4” (100mm) nominal joint which is expected to have a range of horizontal movement of plus 2” (50mm) or minus 2” (50mm), would be denoted as +/- 50%. Joints designed for thermal movement will typically have a movement rating in the +/- 10% to +/- 25% range.
Joints designed for seismic movement will typically have a rating of +/- 50%. Wind load movement is also rated as seismic.
Nominal joint width is the design width of an opening at median temperature. In some cases, the joint opening is different at the time of installation of an architectural joint system. This may simple be due to thermal conditions.
Expansion joint system is simply a transition across an expansion joint opening. In other words it is a cover, a bridge or an insert. It may be simple cover plate, engineered system, insert or may be compression seal. Many systems, however, are engineered to fulfill a variety of additional functions. Some of these functions include:
A. Fit a predetermined opening size.
B. Absorb building movement, thermal or seismic.
C. Be compatible with various surface finishes.
D. Support a given load. (floor condition only)
As with most architectural products, It should be selected on the basis of Form and Function. First, determine, the function or condition. For example, will the system be installed on the floor, wall, ceiling, or roof? If it is a floor system, what loading will it be subjected to? Is it to be an interior or an exterior system? Secondly, determine the form, or appearance of the desired product. Should the system match a hard tile floor? Should it be concealed?, or is an exposed cover plate acceptable? A simple joint selection chart is available and should assist in guiding you through the joint selection process. Prospec Specialties architectural joint systems provide the most comprehensive and advanced range of systems available in the market.
ASTM-E1399-97 Standard Test Method for Cyclic Movement and Measuring Joint Width of Architectural Joint Systems. For information on the scope of this Standards, please contact Prospec Specialties.
Yes. for any floor system it is important to know the load joint cover will be subjected to. Any load greater than system design may cause the system to fail. Failure may result in danger to pedestrians and damage to vehicles and property. The joint edges may break down and the abutting finishes may be destroyed, creating the need for an expensive and sometimes difficult repair process. Load ratings in Tons are included in the charts to assist you in your selection process. A description of our load engineering is also provided.
A. Fir barrier are applied: in all floor and wall joints that occur in fire rated locations. A fire barrier is installed under joint cover.
B. to prevent fire and smoke from penetrating an expansion joint opening for an specified rating period e.g. 1, 2, 3 hours.
C. in some cases, to prevent temperature on the cold side of an expansion joint opening from rising above a predetermined rate for the specified rating period, e.g. 2 hours. The “cold side” of an expansion joint opening refers to the area within a structure adjacent to, or opposite the area where a fire or smoke source is located.
D. there are two main types of fire barriers used in expansion joint opening. They are:
a. Mineral woll +Fire rated sealant
b. Ceramic blanket
UL-2079-is the most common Standard referred to for Joint Systems.
Hose Stream Test, ASTM E-1966, ASTM E 1399, ASTM E-119
The size of expansion joints in a building is usually determined by the s t r u c t u r a l e n g i n e e r. Historically joints above 4” are used in seismic areas. Building in non seismic areas required 1” to 4” joints. But today many buildings in non-seismic areas are also using larger joints.
What size joint is engineer calling for?
Is he expecting 4” wide joint or 4” of movements?
Start with floor cover because it has the greatest on the building occupants. Wherever rolling equipment and people move you should specify a flush cover. For loads above 500 lbs. specify heavy-duty covers.
Prospec Floor Covers have matching or coordinating wall and ceiling covers.
Does your building need to provide for thermal or seismic movement, wind sway or lateral shear? Prospec has joint cover that can meet all your requirements including 100% movements in all directions.
Is it important that the expansion in your building be hidden?
Prospec offers covers that are completely unobtrusive. aren’t a concern we have covers for those applications as well.
It is critical to maintain the integrity of fire-rated compartments. When an expansion joint penetrates a fire-rated wall, a fire barrier equal to the wall’s rating is required. The barrier must also run floor to floor (not stop at the ceiling).
Expansion joint covers in exterior walls can be a flash point for rain to enter if not properly designed. Prospec offers factory formed transitions for all exterior wall and roof covers to assure impermeability.