ASHRAE STANDARDS UPDATE

Titus has long been involved in ASHRAE, making contributions in the form of basic research and development as far back as the 1950’s. We still have a strong commitment to this organization and its activities. There are many Titus employees who serve on various ASHRAE committees in order to stay current on industry standards and trends as well as to have input on emerging technology. The purpose of this article is to keep you up to date with changes to several important ASHRAE standards.

Since its founding in 1894, ASHRAE has produced and maintained countless standards and guidelines related to the HVAC industry. In 2012, ASHRAE rebranded itself to expand its scope to become an international organization and to cover all aspects of the so-called ‘built environment’. Officially, these standards are updated every four years, but interim addendums are published and added as approved. Standards that cover emerging technology or critical topics such as the following are updated on a continual basis.

ASHRAE Standard 170-2017 ‘Ventilation of Health Care Facilities’

Standard 170 includes guidelines and minimum requirements to designers of health care facilities such as hospitals and clinics. The 2017 edition includes a number of important improvements to the 2013 standard:

• Adiabatic humidifiers will now be acceptable 
• Lowered requirements for exam rooms for less critical uses
• Clarification concerning the prohibition of controls to change pressure relationships between any spaces – not only airborne infection isolation and protective environment rooms
• Reduced requirements for electroconvulsive therapy procedure rooms
• Reduction in requirements for laboratories under certain circumstances
• Increased requirements for high hazard exhaust systems
• New space temperature requirements in sterile processing departments to match other industry groups
• New and clearer definition for primary diffuser arrays in operating rooms

In addition, the new edition has also been reformatted into three sections to cover hospital spaces, outpatient spaces, and nursing home spaces in order to better align the standard with Facility Guideline Institute publications that are similarly formatted.

ASHRAE Standard 55-2017 ‘Thermal Environmental Conditions for Human Occupancy’

Standard 55 sets the minimum conditions for acceptable indoor thermal environments including temperature, thermal radiation, humidity, air speed in the design, operation, and commissioning of occupied spaces. The 2017 edition includes several changes to the 2013 standard:

• Provides three compliance methods for comfort – graphical, analytical, and elevated air speed methods
• Provides a separate method for determining acceptable thermal conditions in occupant-controlled naturally-conditioned spaces
• Now uses clear and enforceable language with more easily understood requirements
• Provides clarification regarding approaches to elevated air speed calculations
• Reduces Appendix A to a single method for operative temperature calculations
• Adds a new requirement for calculating changes to thermal comfort due to solar radiation
• Includes documentation requirements and a sample form for compliance
• Standard 55 has therefore been substantially improved with the intent of clarifying its requirements and providing a clearer path to compliance.

Anyone interested in learning more is encouraged to obtain the latest editions of each of these standards.

For information on this topic, please contact Randy Zimmerman at rzimmerman@titus-hvac.com or Titus Communications at communications@titus-hvac.com.