ashrae_logo ASHRAE 62-1989
What is ASHRAE Standard 62-1989?
ASHRAE (American Society of Heating And Refrigeration Engineers) Standard 62-89
is a industry based standard, developed as a consensus based guideline for
engineers, designers, contractors and manufacturers involved in the HVAC industry.
Entitled "Ventilation For Acceptable Indoor Air Quality" it has become a world wide
reference document for building designers, code makers and other regulatory bodies in the design and operation of ventilation systems in buildings. The goal is to ensure good air quality for building occupants. As an official document of ASHRAE, its members, primarily professional engineers (PE's), are obligated to follow these guidelines in all their designs. Deviation from these standards opens the design engineer to significant liability if indoor air quality problems result.The majority of building regulations and codes in the country derive their required
ventilation rates from ASHRAE standard 62-1989. It has a enormous impact on our day to day lives. This little known society has a critical influence on the quality of indoor air we breath every day. For example, the recommended outside air ventilation rate of 15 cfm per person (cubic feet per minute) has become a world wide baseline for building ventilation.What is an "Interpretation" To The Standard?
From time to time, situations, or conditions arise where it is difficult to determine if a particular design technique or control approach meets the standard. This can be a result of changes in technology or the occurrence of a particular situation not considered by a standard when it was first written. To handle such situations, ASHRAE has developed a process that allows interested individuals to submit questions that can clarify uncertainties and ambiguities that relate to the standard. This is called an interpretation. Anybody can submit an interpretation to a standard. Interpretations are written documents that generally describe the factors in the standard that affect or cause uncertainty to a particular application or practice. A interpretation describes how the author believes the particular situation that is of concern should be handled. A committee established by ASHRAE of a diverse group of its members then reviews the interpretation and decides whether the interpretation is correct or not. If accepted by the committee, the interpretation becomes part of the standard.What is CO2 Demand Controlled Ventilation?
People exhale CO2 at a very constant and predictable rate. In addition outside CO2 levels tend to be very low and constant (typically around 400 ppm). An indoor measurement of CO2 is a dynamic measurement of the number of people in a space (generating CO2) and the amount of low concentration fresh outside air being brought in to dilute or purify the inside air. As a result a indoor CO2 measurement can be a good indicator of the amount of fresh air being delivered to a space. A high CO2 level, say over 1200 ppm would indicate a space was poorly ventilated. Typical symptoms of poorly ventilated spaces vary by individual but can range from general irritability and sleepiness to strong physical reactions causing stress and illness.