Designed to provide the same cable management facilities as our standard riser bases, but in zones of high seismicity, the SRB Series seismic certified riser bases have been rigorously tested to satisfy the 1997 UBC and 2001 CBC Seismic Zone 4 and the 2000 IBC, 2003 IBC, 2002 ASCE Standard 7 and 2003 NFPA 5000 Seismic Use Group III lateral force requirements for protecting 1,000 lbs. (1 bay), 1,500 lbs. (2 bays) or 2,250 lbs. (3 bays) of essential equipment in upper floor installations when used with optional MRK-Z4 or VRK-Z4 seismic floor anchor brackets (see pg. 32) with an Ip value of 1.5. With standard 24″ height (custom heights available upon request), these riser bases are constructed of substantial 11-gauge steel. Accepts standard angles (pg. 28) to support surrounding raised floor tiles. Available for select enclosures, these riser bases require the use of seismic brackets.