According to consultant and ASHRAE standards committee member Chris Mathis, uncontrolled air leakage has long been an unquantified variable in load calculations for buildings large and small.
“It has also been identified as the ‘weak link’ in many otherwise well insulated building enclosures,” he said. “These newly proposed envelope testing, inspection and verification procedures are intended to not only help deliver better performing building envelopes, but also should help reduce errors associated with envelope air leakage in equipment sizing calculations.”
Addendum l is one of 14 proposed addenda to ANSI/ASHRAE/IES Standard 90.1-2013, Energy Standard for Buildings Except Low-Rise Residential Buildings, currently open for public comment.
Other addenda open for public review until October 5, 2014 are:
•e relaxes the existing threshold for lighting control alterations while capturing a lot of energy efficiency by requiring more of the control requirements.
•f clarifies an exception to the automatic daylight responsive controls requirements for daylight areas under skylights
•j removes an exception to the variable air volume system ventilation optimization when energy recovery ventilation is installed.
•k requires envelope assemblies to comply with Appendix A when complying with the Energy Cost Budget Method in Appendix G.
•m updates the text in Section 10.4.1 on electric motors to provide information about the required efficiency of small electric motors shown in Tables 10.8-4 and 10.8-5. In addition, small electric motors were not included in the scope of the Energy Independence ad Security Act of 2007, but now have performance requirements and are being added to the standard.
•n updates the IEER values for air-cooled variable refrigerant flow air conditioners and heat pumps above 65,000 Btu/h. Depending on the cooling capacity and product classes, the new IEERs are between 15 and 20% better than the values they are replacing. The new IEERs become effective on Jan. 1, 2017.
•o clarifies wording regarding duct seal class to avoid misinterpretation that compliance with the text that is struck out could substitute for the seal class requirement.
•p updates Cooling Technology Institute Standard 201 in Table 6.8.1-7.
•q limits systems that can take advantage of the fan power pressure allowance for fully ducted return and/or exhaust air systems.
•r revises Section G3.1.1 Baseline HVAC System Type and Description to confirm the hierarchy for selecting baseline HVAC systems, clarify what floors to count and specify what building type to use when no one use is predominant.
•s adds Exception 2 to 18.104.22.168 to address single duct variable air volume reheat systems with direct digital control.
•u adds new requirements for transfer air in exhaust systems.
Also open for public comment is addendum bm, which makes the requirements from 90.1-2004 the baseline for modeling when using Appendix G. In addition, it allows Appendix G to be used as a compliance path.
To comment or learn more, visit www.ashrae.org.