A thin layer of intumescent coating in the vents' honeycomb cells reacts on exposure to flame or heat at 300°F (149°C). It expands rapidly, filling the cells with a carbonaceous foam that prevents flames from propagating through the honeycomb. The coating is based on fire retardant chemistry that meets the requirements of the ASTM E-84 Test Procedure, and is classified by UL as providing Class A flame spread protection and low smoke density. HEICF 1594 coating helps enclosures meet the requirements for Network Equipment Building Systems (NEBS) compliance, and Bellcore GR-63-CORE Physical Protection Standards for Fire Resistance (Spread).
StreamShield EMI vents provide more than 50 dB shielding effectiveness from 1 GHz to 10 GHz. Open area of the honeycomb is 95% uncoated and 85% with the intumescent coating. The standard vents are constructed of one or two layers of 0.125 in. (3.175 mm) cell and 0.50 in. (12.7 mm) thick aluminum honeycomb crimped in a stamped aluminum frame. Other sizes are available. The framed vents are available for round and rectangular openings. They can be provided with integral conductive mounting gaskets, compression stops, studs for push-in attachment and other options.