Canadian Consulting Engineer
ASHRAE proposes changes to 90.1 energy standard and 62.1 indoor air quality standardsBuildings Building Mechanical & Electrical (HVAC) Systems
ASHRAE is proposing multiple compliance options for verifying the performance of the building envelope under ANSI/ASHRAE/IES Standard 90.1-2013. Addendum 1 is one of 14 changes proposed to the "Energy Standard for Buildings Except Low-Rise...
ASHRAE is proposing multiple compliance options for verifying the performance of the building envelope under ANSI/ASHRAE/IES Standard 90.1-2013. Addendum 1 is one of 14 changes proposed to the “Energy Standard for Buildings Except Low-Rise Residential Buildings.”
The addendum provides multiple compliance methods for verification, including whole building air leakage testing and continuous air barrier inspections.
Chris Mathis, a member of the 90.1 committee, noted that the proposed changes will likely affect construction costs. However, he said that the savings in performance will more than justify the increased first cost. Additionally, Mathis says the costs will go down as builders become more familiar with the methods.
“Uncontrolled air leakage has long been an unquantified variable in load calculations for buildings large and small,” explained Mathis. “It has also been identified as the ‘weak link’ in many otherwise well insulated building enclosures. 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.”
ASHRAE is also proposing changes to Standard 62.1, Ventilation for Acceptable Indoor Air Quality in Buildings.” Specifically one of the addenda proposes an alternate compliance path for the ventilation rate procedure in Section 6 when it is applied to existing buildings.
The proposals recognize that the existing ventilation rate procedure in its indoor air quality standard may be difficult to apply in existing buildings.
Section 6 (including the ventilation rate procedure) was developed as a design standard and its scope states in part that “the provisions of this standard are not intended to be applied retroactively when the standard is used as a mandatory regulation or code.”
Roger Hedrick, chair of the Standard 62.1 committee, explains the rationale for the proposed changes: “For existing buildings, it may be difficult to apply the ventilation rate procedure (VRP), particularly for buildings with multiple-zone recirculating ventilation systems. This is because determination of some of the values needed to calculate ventilation rates may be difficult or impossible because required information is not available. An example is system ventilation efficiency (Ev), used in equation 18.104.22.168.”
Proposed addendum b provides an alternate path of compliance for situations where information required to determine the system performance is unavailable, or for smaller facilities with straightforward multiple zone applications.
Also open for public comment is proposed addendum c, which would revise the current definition of environmental tobacco smoke to include emissions from electronic smoking devices and from smoking of cannabis (now allowed by some jurisdictions). The existing requirements for separation of ETS-free spaces from ETS spaces remain unchanged.
Addendum q modifies Section 5.2, Exhaust Duct Location, to clarify air classes and to allow positively pressurized exhaust ducts inside the space of origin.
Public comments on the proposed changes to both standards are open until October 20, 2014.