Applying VRF? Don’t Overlook Standard 15

Variable refrigerant flow (VRF) systems have become increasingly popular as an HVAC equipment option providing high energy efficiency at reasonable initial costs with the added benefit of simultaneous heating and cooling. However, when considering VRF in potential applications, ASHRAE Standard 15 – Safety Standard for Refrigeration Systems, must be considered to prevent danger to occupants should a refrigerant leak occur. The application of Standard 15 is based on an Occupancy Classification and a System Classification. The Refrigeration Concentration Limit (RCL) set by Standard 15 for a building is based on the smallest space in the building served by an individual evaporator unit.

Options to comply with Standard 15 and still be able to install VRF HVAC are to:

  1. Remove the smallest space(s) that are not compliant with Standard 15 and condition those spaces with a different unit.
  2. Use a common ducted evaporator to condition the two smallest spaces together.
  3. Use an above ceiling evaporator unit ducted to one or more of the smaller spaces.

Ambiguities in Standard 15 also contribute to uncertainty in how it should be applied to VRF systems. Standard 15 states that if two or more rooms are joined by permanent openings, the combined volume can be used to determine RCL. However, the standard does not specify if an undercut door or transfer opening qualifies as a permanent opening, and does not specify minimum opening sizes. Designers should consider the implications of this type of application of Standard 15 for VRF systems.


HUD Policy Update on Performance Contracting

HUD releases Notice 2011-36 to update its policy on performance contracting.  Notice PIH 2011-36 replaces PIH 2009-16.

Learn more at Hud.

Energy Star Requirement Change

The U.S. Environmental Protection Agency (EPA) is updating Energy Star requirements for home dishwashers and furnaces. The new requirements are a part of Energy Star’s overall commitment to protect people’s health and the environment by encouraging energy efficiency.

Effective January 20, 2012, both standard-sized and compact residential dishwashers meeting the new Energy Star requirements will be between 10 and 30 percent more energy efficient than conventional models, and about 8 percent more efficient than dishwashers that met the previous Energy Star requirement. If every dishwasher in the U.S. met the new requirements, consumer energy and water bill savings would grow to approximately $235 million per year, reducing annual greenhouse gas emissions equivalent to those from more than 180,000 vehicles.

Learn more on the EPA website.