SEISMIC BREAKAWAY HANGER
Seismic Breakaway Hanger FAQ's
What is a Seismic BreakAway Hanger?
The BreakAway Hanger is an engineered release mechanism for the Fireloop®/seismic expansion joint. It releases the seismic joint to move through its full rated motion during a seismic event.
How does it work?
The BreakAway Hanger is designed to support the Fireloop® seismic expansion joint during its service life and “break-apart” at a preset load. The ball plunger design precisely sets the load for release and can be reset after activation. The preset load is typically 1.4-1.5 times the static weight of the Fireloop® seismic expansion joint. You can watch a video demonstrating the BreakAway Hanger.
Is the BreakAway Hanger UL or FM listed?
Both UL and FM have stated there is currently no test protocol for this innovative new product. Currently the BreakAway Hanger falls under 2013 NFPA 13 section 1.7 “New Technology”. The BreakAway Hanger supports the seismic joint and only releases during an earthquake.
How is the BreakAway Hanger different from a hanger?
A hanger is designed to support the dead weight of the water filled pipe. The BreakAway Hanger is designed to support the Fireloop® seismic expansion joint and “release” during a seismic event, to allow the Fireloop® to move during an earthquake. After the event, the BreakAway Hanger can be reset and support the Fireloop® until the next seismic event.
Have Metraflex’s installation instructions changed, replacing the threaded rod support with the BreakAway Hanger?
Metraflex still recommends using the threaded rod as support where the installation has enough clearance for a minimum 12" rod, which is the required length for +/- 4" movement seismic joint. For Fireloop® seismic expansion joints with larger rated movements you are required to install a longer rod.
What if I don’t have enough clearance for the length of threaded rod required to allow full-rated movement?
Use the BreakAway Hanger. The BreakAway Hanger has a very short dimension to allow for very tight installations. During a seismic event it will activate to allow the full-rated movement.
Should I retrofit the BreakAway Hanger where installations use a threaded rod for support?
We recommend retrofitting a BreakAway Hanger only where the threaded rod is too short to allow full-rated movement of the seismic expansion joint.
How much seismic joint movement is needed in order to consider using a BreakAway Hanger?
Seismic joint installations should allow the joint to have its full-rated movement. The greater the rated movement, the longer the hangers and threaded rod need to be to get this amount of movement. The BreakAway Hanger should be used when there is insufficient room for support(s) to be long enough and give the seismic joint its full-rated movement. The BreakAway Hanger will allow an installation to achieve the full-rated movement even if hangers are too short. The BreakAway Hanger eliminates the need for a long threaded rod.
How do I prevent very long flexible legs from sagging?
Metraflex offers support saddles to keep the long, flexible legs of a seismic expansion joint from sagging, eliminating the need to design costly custom supports.
How do I know which BreakAway Hanger model I need?
BreakAway Hangers are sized based on Metraflex Fireloop® seismic expansion joint sizes/weights. Simply tell us your Fireloop® joint’s size and movement and we’ll provide the correct BreakAway Hanger. A sizing chart is also available, along with a video showing how the BreakAway Hanger works. BreakAway Hangers can be designed for Fireloop® seismic expansion joints with larger movements.
How do I prevent a very large Fireloop® seismic expansion joint from moving too much when the BreakAway Hanger is activated?
An optional cable tether is available which supports Fireloop® seismic expansion joint after the BreakAway Hanger has been activated. The cable tether allows full-rated movement while at the same time supporting the large seismic joint.