ICC Adopts ASHRAE 62.1

Approval of ASHRAE’s Standard 62.1 ventilation rate calculation procedure for the International Mechanical Code (IMC) in May marks a milestone for the high-profile mandatory-language standard after years of development aimed at code adoption.

The International Code Council approved an ASHRAE proposal to incorporate the prescriptive ventilation rate procedure from ANSI/ASHRAE Standard 62.1-2004, Ventilation for Acceptable Indoor Air Quality, in the IMC. The code establishes minimum regulations adopted and implemented by federal, state and local government agencies for mechanical systems in new buildings.

“With adoption of the new ventilation rates into building codes, we can expect to see reduced air intake flow in many previously over-ventilated buildings,” said Dennis Stanke, chair of the 62.1 committee. “With adoption of the new calculation procedures, we can expect to see improved indoor air quality in many previously under-ventilated multiple-zone systems. Ventilation systems with lower outdoor rates compared to the current code reduce both first costs and energy costs, while system designs that account properly for air distribution within buildings result in better indoor air quality than designs based on over-simplified air distribution assumptions.”

The current ventilation criteria in the IMC are based on ASHRAE Standard 62-1989. Based on 20 years of IAQ research and experience with ventilation system design, ASHRAE introduced an improved version of the standard in 2004 to include the new rates and calculation procedures. This code change makes both the IMC and the 2006 Uniform Mechanical Code consistent with the ASHRAE standard.

“The new ventilation rate procedure requires designers to account for pollutant sources from both the building and its occupants, and to account for the efficiency of different ventilation systems when delivering outdoor air to the breathing zone,” Stanke said.

The new requirements will be included in the 2007 IMC Supplement.

In other ASHRAE news, the organization also announced the publication of a new refrigeration safety standard. Expanded requirements for safety relief protection are contained in ASHRAE’s new 2007 refrigeration systems safety standard. ANSI/ASHRAE Standard 15-2007, Safety Standard for Refrigeration Systems, establishes procedures for operating equipment and systems to assure the safety of building occupants and system technicians.

A significant change over the 2004 standard is expanded requirements for safety relief protection piped internally to systems.

“In the interest of keeping refrigerants contained within a refrigeration system, a growing number of designers sought to implement pressure relief protection that discharged overpressure refrigerants to a lower pressure portion of the system,” said Douglas Reindl, committee chair. “This change is intended to guard safety in these applications by expanding requirements for the engineering of internal relief devices.”

Another change is the update of Appendix F, which outlines the principles of relief device selection for positive displacement compressors. The list of refrigerants with corresponding properties included in the appendix has been significantly expanded.

“This will help users enhance the safety of refrigeration systems by utilizing improved methods for pressure relief protection,” said Reindl. Standard 15 was first published in 1919 for regulation of refrigerating machines and refrigerants.

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