Consulting-Specifying Engineer - June 2008 - (Page 46)

M Exhaust air NC Ducted return/ exhaust air EF X SD NO M E/A R/A NO M Fresh air AHU X E/A R/A Lined supply duct MS MS relay relay To FACP S/A S/A NC AHU Figure 4: This section view of corridor ceiling from Figure 2 shows the tight routing required for outdoor air ductwork and exhaust air ductwork for multiple tenant spaces. Source: Graef, Anhalt, Schloemer, & Assocs. Inc., used with permission from Opus North Corp. Inc. from the Burr Ridge Village Center Development, Burr Ridge, Ill. EM PWR SF EM PWR EM PWR EF EM PWR Figure 3: Two options in this schematic show how HVAC systems in retail development use the same outdoor and exhaust air envelope penetrations for smoke control systems. Source: Graef, Anhalt, Schloemer, & Assocs. Inc. for this type of envelope system, the center of glass values must be used to determine the thermal performance properties for estimating solar loads in the space. ASHRAE Standard 90.1 Chapter 5 discusses the proper way to handle building envelope features like vertical fenestration and acceptable alternative methods for calculating thermal performance values. These methods should be used to provide the most accurate picture of solar loads to leased spaces. Air distribution in spaces also must account for poor thermal performance of storefront systems to ensure that condensation does not occur on the glazing in spaces with high latent loads such as spas, hair salons, and daycares. In all respects, special attention should be paid to these exterior components as energy code requirements for HVAC systems are met. Fire and life safety The rating of walls and the adverse effect this has on building utilities and services often is an overlooked requirement of retail design. To remedy this, small retail malls may require fire separation around storage rooms that are 100 sq. ft or larger. Fire-rated assemblies also are encountered around atrium areas and require special attention from HVAC design. Both of these special types of occupancies are defined within the 2006 International Building Code (2006 IBC). It is important to verify that local codes comply with these requirements because fire and smoke protection requirements differ greatly at the municipal level and with the authority having jurisdiction. These assemblies can become a major cost issue if missed during design. Sprinkler systems or other approved fire-suppression devices would be needed on utilities that penetrate these fire-rated assemblies. Smoke control systems are required in atrium areas serving more than two floors in a mall building. The interlock of supply air devices and exhaust air devices with the lockout of heating and cooling functions often is used to accomplish the smoke control requirements of the pressurization method outlined in the 2006 IBC. This requirement can be a difficult challenge to meet air change requirements, air velocity requirements, and space considerations of equipment. In most cases, the air change volume requirement will be the driving force of supply and exhaust fan sizing to meet smoke control air volume requirements even if outdoor air economizers are provided with HVAC systems. These requirements for higher smoke control airflows result in larger ductwork sizes and can make plenum management practices more important when routing these distribution systems. 46 Consulting-Specifying Engineer • JUNE 2008

Table of Contents Feed for the Digital Edition of Consulting-Specifying Engineer - June 2008

Consulting-Specifying Engineer - June 2008 Contents Viewpoint Letters News M/E Roundtable No Gambling Allowed on Smoke Control in Las Vegas Be Prepared: Hospital Protections for Catastrophic Events Ready for Retail Commissioning Documents: Necessary Evil Codes & Standards Codes & Standards Case Study Equipment Lifecycles New Products Advertiser Index Green Space

Consulting-Specifying Engineer - June 2008

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