Engineered Systems - December 2008 - (Page 20)

BuildingAutomation BY PAUL EHRLICH, P.E., AND IRA GOLDSCHMIDT, P.E. Ethernet/IP Infrastructure Keep to yourself, or try to play well with others? All of the world’s communications systems appears to have converged on the use of the Internet Protocol (IP) with Ethernet connections being the preferred method for local connection. BAS systems have standardized on this type of connection, and many owners are looking to a future where even the VAV box and light switch will be on the network. If so, then why has this issue become one of the most vexing BAS design challenges? Simply put, should a BAS use its own dedicated Ethernet/IP system, or should it use that which is provided for the building’s business-enterprise communications and managed by the IT department? For us, there are many obvious reasons why the use of the enterprise network is the right solution. • Dedicated BAS Ethernet/IP communications is a duplication and an added construction cost. • It often requires additional specification design by the BAS designer (for the dedicated Ethernet/IP system) — another added cost. • Without careful coordination, the BAS Ethernet/IP equipment may not meet the facilities’ IT standards (even though it is a separate system, this still can be a concern to IT folks). • Enterprise networks are typically higher quality, offer higher reliability, and are actively managed with staff ferreting out potential attacks and problems. • Determining how and where the Ethernet/IP LAN connects to Internet (for remote communications) can sometimes lead to confusion. That being said, we are not the IT folks that sometimes are skeptical or even resistant to being saddled with the added communications switches, cabling, and support for adding BAS connections to the enterprise network. We are also not the ones that are justifiably concerned with the risks of connecting building systems to the enterprise network including potential traffic, threats, and other issues that could potentially wreak havoc with the IT infrastructure. Unfortunately, as BAS designers, we are not always best equipped to argue these issues with IT experts, and frankly they are not always the most open and receptive folks to work with. Clearly, the BAS designer is faced with the choice between fighting for what is believed to be the best engineering approach vs. taking the path of least resistance by avoiding the potential IT battle. You could say that this is an example of the consulting engineer’s dilemma when confronting many building design issues. Also, it is not to say that placing the BAS system on the enterprise network is not without its challenges, which range from other IT coordination issues to schedule impact to network security. We’ll cover that side of the issue in a future column. ES BAS USE OF We are not the ones justifiably are not the ones justifiably conce e co cerned with the risks of e ss connecti connecting building systems to ting ilding ldi stems to t the enterprise network including the enterprise network, including potenti potential traffic, threats, and other ial affi ffic, th hreats, and oth her iss issues that could potentially wreak sues tha hat uld potentially wrea l tentiall reak havoc with IT infrastructure. havoc with IT infrastructure Unfortunately, as BAS designers, y, g , we are not always best equipped to argue these issues with IT experts, and frankly they are not always the most open and receptive folks to work with. Paul and Ira first worked together on a series of ASHRAE projects including BACnet committee and “Guideline 13 – Specifying DDC Controls.” The formation of Building Intelligence Group provided them the ability to work together professionally providing assistance to owners with the planning, design and development of Intelligent Building Systems. Building Intelligence Group provides services for clients worldwide including leading Universities, Corporations, and Developers. More information can be found at www.buildingintelligencegroup.com. We also invite you to contact us directly at paul@buildingintelligencegroup.com or ira@buildingintelligencegroup.com. 20 En g i neer ed Sy stem s December 2008 http://www.buildingintelligencegroup.com http://www.buildingintelligencegroup.com

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Engineered Systems - December 2008 Contents Editor's Note HVAC Challenge Back2Basics Case In Point Commissioning Building Automation HVACR Designer Tips Applications Checklist Lakefront Library: Radiant Systems Meet Natural Ventilation Before (And After) The Flood Basics For Refrigerant Chillers Wire-To-Shaft Efficiency For HVAC Pumps Products Glossary Classifieds Advertiser Index Tomorrow’s Environment

Engineered Systems - December 2008

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