Expansion Joint Covers
What are the standard gasket colors and are custom colors available?
There are four standard gasket colors that include black, white, gray and greige. Custom colors are also available although minimum quantities and extra charges may apply.
What are the most important criteria when selecting a joint cover/system?
There are several, but the following have the greatest impact on the selection process and are ranked accordingly.
1. Structural joint opening - This is nearly always established by the structural engineer and determines the type of cover needed, i.e., thermal or seismic movement. Note: The term "seismic" is only a factor of joint width, not function. Some of our 3 and 4 inch covers are not labeled seismic yet can be used if the joint opening is only 3 or 4 inches, even in "seismic" design schemes.
2. Anticipated movement - Again, determined by the structural engineer and normally specified as plus or minus 'x' when 'x' may be a dimension, i.e., 1 inch, or a percentage of joint opening, i.e., 50%.
3. Type of building - The anticipated use of the building will help determine the type of cover system chosen. For example, a hospital will require covers that are easy to keep clean and also have a flush top surface since wheeled equipment is an aspect of normal building occupation. This would lead to the selection of a gasketed cover system. We recommend that the selection process start with the choice of floor cover as this is affected the most by such building usage. Wall covers are then simply matched to the floor cover selected.
CAUTION: rolling loads can have a significant impact on the function of a cover system. If heavy-wheeled equipment is expected, such as in airports, covers labeled "heavy duty" should be selected.
4. Aesthetic considerations - Once the above criteria are established, the final piece of the puzzle is appearance. Historically seismic joint covers have been known to ruin even the most carefully designed interior finishes scheme. Fortunately, C/S has developed a complete range of covers with reveals that help conceal most of the cover plate regardless of the joints.
How do I maintain the integrity of a fire rated element such as a floor or firewall?
Every cover system in the C/S portfolio has a fire barrier assembly designed to work with it. These fire barriers are tested at UL to ensure full code compliance. Assemblies are available in standard 2-hour ratings but also 1,3 and even 4-hour ratings in some cases. Due to the high cost of UL tests, not all structural configurations have been tested. Some discretion may be needed to determine if a standard configuration applies in the case of a non-standard application. If in doubt, call the supplier and ask for additional testing to support your design. UL will normally accept small scale testing as an extension of an existing full-scale test and give it a rating.
Are all testing agencies equal?
Definitely not! Even though other agencies test to the same ASTM standards they don’t all have follow up and labeling services. Underwriter’s Laboratories has a factory labeling and quality inspection that guarantees that the product installed in your building is exactly the same as the product tested successfully in the lab. It is important to specify UL tested and labeled to ensure peace of mind for your client.
What's the significance of ASTM-E 1399?
ASTM-E 1399 is a relatively new code that stipulates that all expansion and seismic joint cover systems be tested through 500 movement cycles and remain functional. Since these covers are intended to move in this way, specifying ASTM-E 1399 is simply a quality assurance for your client. In the case of fire barrier testing, UL 2079 stipulates that the assembly must be cycled 500 times prior to testing. A critical quality assurance factor ensuring peace of mind for your client.
Is it important for me to work out all the transitions between adjacent cover systems?
It is very important that these transition details are worked out thoroughly since bad transitions can ruin even the best joint cover schemes. However, any competent joint manufacturer should be willing to assist you with these details during the design phase of the project.
CAUTION: Transitions in exterior covers, particularly between roof and wall covers, are critical to the water tightness of the exterior envelope.
What is the most common cause of failure of joint cover systems?
The most common cause is improper selection of the type of cover. In particular, heavy-rolling loads can destroy even the best floor covers if they aren’t designed to take high loading.
CAUTION: There is another element that’s critical to the successful function of the floor covers, and that’s the use of shims during installation. It is common practice to oversize block-outs in the concrete and then use shims to level the floor cover. This is OK provided the contractor pours a leveling grout between shims to ensure a continuous base for the floor cover. Most often the covers are bolted down through the shims and the block-out filled with grout/lean concrete. In this case, it’s unlikely that the grout will find its way consistently beneath the frames resulting in poorly bedded floor covers. The use of rolling equipment will cause rocking or bouncing of the frame and eventually lead to failure of the grout pocket and cracking of the floor finish. It is imperative that you specify that, if shims are to be used in the installation process, the contractor ensures that there is a continuous support bed beneath the side frames of the floor cover. We would go further and suggest these frames be inspected prior to filling the block-out with grout.
- What are the standard gasket colors and are custom colors available?