The job of an HVAC engineer includes the design of heating, ventilation and air conditioning systems according to the needs of each building. There are many HVAC industry organizations, and they have published standards to guarantee the correct design and installation of these important building systems. HVAC standards apply throughout the USA, and local building codes normally use them as reference – some standards have even been adopted internationally.
An HVAC installation must keep adequate indoor conditions for human occupancy, and these include ambient temperature, relative humidity and outdoor air supply. HVAC systems are characterized by their high energy consumption, exceeding all other building systems combined in residential and commercial applications. Energy efficiency measures are strongly recommended to reduce their operating cost.
The following are some of the main industry associations that publish technical standards for HVAC systems:
- ACCA – Air Conditioning Contractors of America
- ARI – Air Conditioning and Refrigeration Institute
- ASHRAE – American Society of Heating, Refrigerating and Air-Conditioning Engineers
- NFPA – National Fire Protection Association
- SMACNA – Sheet Metal & Air Conditioning Contractors National Association
How an HVAC Engineer Applies Standards in Project Design
Technical standards provide calculation procedures for many aspects of HVAC design, considered the best practices in the industry. For example, the ASHRAE Handbook is one of the most important standards for mechanical engineers, and it consists of four volumes: Fundamentals, Refrigeration, HVAC Applications, and HVAC Systems and Equipment
The ASHRAE Handbook is constantly being reviewed and updated by technical committees. An HVAC engineer who is an ASHRAE member gets the latest edition each year as one of the membership benefits. The Handbook is available in printed, CD-ROM and online versions.
ASHRAE also has Standard 90.1, which has been used nationally and internationally to improve the energy efficiency of buildings, and many local energy codes use it as reference. The Standard 90.2 is similar, but focusing on low-rise residential constructions.
ACCA has published a set of technical manuals with calculation procedures for many aspects of HVAC design, as well as equipment selection guidelines. There are both residential and commercial versions of the ACCA manuals, covering the following topics:
- System concept
- Load calculation
- System zoning
- Air distribution
- Equipment selection
- Duct size calculation
- Adjustment, testing and balance
SMACNA standards are very important in HVAC installations that use air ducts, since they provide the design requirements for both sheet metal and fiberglass ducts. By following the calculation procedures in SMACNA standards, HVAC engineers can ensure that air ducts are properly sized, while meeting airflow and static pressure requirements.
NFPA standards deal with fire protection, which is a very important aspect for heating equipment that burns natural gas, heating oil or any other fuel. One of the NFPA standards is the National Electrical Code (NEC) – it applies for all circuits that deliver power to HVAC installations, as well as their protection systems.
Industry standards may seem overwhelming at first, but they guarantee high performance and safety when designing building systems. A qualified HVAC engineer is familiarized with all applicable standards, and can use them effectively during the design process.