Medical Construction & Design

JUL-AUG 2015

Medical Construction & Design (MCD) is the industry's leading source for news and information and reaches all disciplines involved in the healthcare construction and design process.

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electrical charge from the top of a structure into the ground. Air terminals, formerly known as lightning rods, are required at the ridge or highest spots on the roof of a structure. Most buildings will also require air terminals around the roof perimeter, at designated spacing throughout a roof and mounted on rooftop equipment. Mike Dillon, vice president of Bonded Lightning Protection, says, "Hospitals can have a lot of rooftop equipment, including HVAC units, exhaust fans, plumbing vents, security cameras, lighting fi xtures, antennae and even heliports. An air terminal will have to be installed on top of most of them and connected with conductors approved for lightning protection." His fi rm recently upgraded the lightning protection system at St. Mary's Medical Center in West Palm Beach, Florida. Some architects are hesitant to install lightning protection devices at visually sensitive areas such as entrance canopies and rooftop terraces. Dillon of ers reassurance that, "with planning, we may be able to use metal railings, parapet caps or other architectural elements in lieu of air terminals and disguise or hide the conductors." Conductors are either braided copper or aluminum cables that lead from the roof to ground level. They are typically installed in chases or other hidden locations within new construc- tion. If a building has a structural steel frame, columns can be used to provide an electrically continuous path to the ground. In renovations, conduc- tors can be mounted on the exterior face of building walls with minimal disruption to facility operations. The type of ground terminal used depends on the type of soil and level of protection required. In many instances, copper rods driven 10 or more feet into the earth provide suf cient grounding. Where greater protection is required or the soil has low electrical conductivity (such as sand or rock), a ground ring, The Computer Controlled Mobile Blending Unit for Self-Leveling SCA-0223-0515 ©2015 LATICRETE SuperCap, LLC. All trademarks shown are the intellectual properties of their respective owners. ® Snap to see more. Perfectly flat floors, delivered. MCDM AG.COM | J U LY/AUGUST 2015 | Medical Construction & Design 49 Rooftop equipment may require air terminals and connection to conductors to create a safe path for lightning surges to pass into the ground.

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