Data Center HVAC Design Considerations

Data Center #HVACData centers today not only require protection from the elements, but also need to be designed to save energy as it is estimated they consume about 1.5 percent of all total demand. According to the Natural Resources Defense Council, data centers are one of the largest and fastest growing consumers of electricity in the United States. In the U.S in 2013 three million computer rooms used enough electricity to match the annual output of 34 large coal-fired power plants. Annual consumption is projected to increase by roughly 47 billion kilowatt-hours by 2020. The NRDC recommends that best-practice efficiency behaviours across the data center industry need to be adopted as demand rises to unprecedented levels.

Energy Savings in Data Centers through HVAC Equipment

Traditionally when a building needs cooling, compressors engage and fans start to move air over cooling coils. This cooled air is used to condition the internal environment where the temperature is required to be lowered. This process is extremely effective but requires costly compressor and fan energy, adding avoidable cost considering external building temperature is lower than the temperature inside. When the outdoor enthalpy (a combination of temperature and humidity) is preferred over the indoor enthalpy, conditions are suitable for “free cooling”.  Depending on the geographic location of the facility, economizer cooling can represents a dramatic reduction in overall energy consumption.

Economizer Data CenterWhat is an Economizer and how can it reduce energy usage?

An economizer is like a window that automatically opens itself – with the added advantage of going through the rooftop AC’s filtration system. An airside economizer simply recognizes the preferred enthalpy of the outside air. When enthalpy conditions are suitable for “free cooling”, the economizer controls position outdoor air, return air, and relief dampers to facilitate free cooling through the first and sometimes second stages of cooling.

Economizers can contribute to a reduction in data center power consumption by utilizing the cooler external building temperatures to assist in cooling the facility and equipment when required. In maximizing energy savings and reducing HVAC cooling load, the cooling system’s product life can be extended.

A study on building control systems by Battelle Laboratories found that, on average, the normalized heating and cooling Energy Use Intensity (EUI) of buildings with economizers was 13 percent lower than those without economizers. When an airside economizer works properly, the savings are significant. Whether your company is looking to burnish its environmental credentials, to lower the cost of operating its data center, or both, a properly designed system integrating an airside economizer is a cornerstone of achieving both goals.

Economizers and Indoor Air Quality (IAQ)

A confined, un-aerated indoor space within a building allows gaseous fumes, odors, germs, and even fungi to grow in concentration to the point that the indoor air is qualitatively different from the ambient air. IAQ is important because the health and the comfort of people working indoors are an important factor in sustainable productivity. Poor IAQ in a working environment can cause discomfort or health problems sometimes resulting in a loss of productivity, increased errors, and even litigation. With the added benefit of reducing cost in power consumption, introducing outside air into a building via economizers can also contribute to improving indoor air quality. Following the relevant ASHRAE standards that apply to ventilation, air movement and exhausting of contaminants ensures that IAQ requirements will be met. To meet the requirements of ASHRAE 62 the outside air entering a building should be measured and controlled.

The most important part of an airside economizer are the damper blades that allow the control and supply of a fixed amount of outside air into the building. Parallel bladed economizers do a better job of mixing the outside and return air to provide optimal benefit to the system.  The sealing ability of the damper is essential to the system as a whole, when contending with extreme temperatures external to the building. AMCA certified dampers can ensure leakage rates meet the appropriate standards.

It has to be recognized that during different seasons and in different climates the benefits from economizers may vary.

Relevant Codes and Standards applicable to Data Center HVAC

Ruskin EconomizerFeaturing Ruskin’s exclusive one-piece galvanized airfoil blade and stainless steel jamb, the Economizers provide low-leakage performance as described in ASHRAE Standard 90.1.  Each unit also features Ruskin’s “SUREFLOW” sensing tubes and blade position indicator to help determine minimum airflow.  This also helps assist in mixed air temperature verses blade position field adjustments.

Data Center Protection

The Natural Resources Defense Council states that Data centers can be regarded as the back bone of a modern economy serving businesses and communications. Defending data means not only protecting it from Mother Nature but also giving back to her with sustainable designs. A question that must be considered during the design of a data center, is ‘How likely could the facility be compromised in extreme weather conditions such as tornadoes and hurricanes?’

When evaluating potential HVAC equipment it is advisable to use FEMA rated louvers and grilles. FEMA rated grilles and hurricane-resistant louvers have been tested against high windloads and large missile impacts. Outside air control dampers can seal up the center when necessary to reduce humidity and heat.

XP500 FEMA GRILLERuskin’s XP500S Extreme Weather Grille protects wall penetrations from flying debris caused by tornadoes, hurricanes, and severe storms.  This type of protection is critical in the design of Community Shelters (ICC-500) and Safe Rooms (FEMA 361). It offers designers a ventilation solution for their near-absolute life safety requirements. The heavy duty grille can be mounted internally, externally, or in conjunction with other louvers providing protection and certified performance. Rated for an industry leading 266 psf windload, the XP500S Grille meets or exceeds the building envelope protection requirements while complementing the construction of data centers.

Relevant Certification

  • FEMA P-361, Safe Rooms for Tornadoes and Hurricanes
  • ICC-500 – ICC/NSSA Standard for the Design and Construction of Storm Shelters

For more information about Ruskin’s complete product line, application and design support, and our state-of-the-art manufacturing capabilities, contact your local Ruskin representative nearest you or Contact Ruskin directly at (816) 761-7476.


Ventilation Rate Procedure for HVAC Systems in the Healing Environment

Ventilation Rate IAQ Procedure - Air MeasuringThe IBC/IMC, the AIA, and Chapter 7 of the ASHRAE Handbook—HVAC Applications all reference ANSI / ASHRAE Standard 62 for determining ventilation. ANSI / ASHRAE Standard 62 provides two methods for engineers to follow to determine the required minimum ventilation rate to achieve acceptable indoor air quality.

To obtain compliance for ventilation design, there are two procedures in the ASHRAE standard. The ventilation rate procedure states that acceptable IAQ is achieved by providing ventilation air of the specified quality and quantity to the space. The indoor air quality procedure identifies a method for achieving acceptable IAQ within the space by controlling known and specifiable contaminants.

Ventilation Rate Procedure

The ventilation rate procedure provides a more definitive, prescriptive procedure based on physiological needs and subjective evaluations. The indoor air quality procedure uses guidelines for the specification of acceptable concentrations of certain contaminants in indoor air —with no prescriptive formula for ventilation rates.

The Indoor Air Quality (IAQ) Procedure

The indoor air quality procedure typically does not result in lower outside air in healing environment applications since the various potential sources of contamination require ventilation rates to be equal to that of the ventilation rate procedure. Additionally, the indoor air quality procedure requires the designer to specifically identify how each of the known contaminants is to be dealt with. The problem facing system designers with this procedure is in determining the possible contaminants that may result from the eventual use/occupancy of the healing environment. For example, controlling formaldehydes, aldehydes, nitrogen dioxides, organics, etc., all need to be understood and accomplished with “engineering reason” when tackling this method. As a result, most designers opt for the more common ventilation rate procedure (VRP ) to determine outdoor airflow needs at the space and system levels. This method prescribes the outdoor air quality acceptable for ventilation, outdoor air treatment where necessary, ventilation rates, and the criteria for reductions of outside air where recirculation treatments occur.

ASHRAE also addressed maintenance of outside ventilation systems. ANSI /ASHRAE Standard 62-2001 identifies minimum ongoing operation and maintenance criteria. The requirements of this section apply to buildings and their ventilation systems and their components constructed or renovated. In section 8.4 of ASHRAE 62, it states:

At a minimum of once every three months or as specified in the Operations and Maintenance Manual, the outdoor air dampers and actuators shall be visually inspected or remotely monitored and determined to verify that they are functioning in accordance with the Operations and Maintenance Manual.

ANSI /ASHRAE Standard 62’s definition of a maintenance manual is as follows:

An operations and maintenance manual either written or electronic shall be developed and maintained on site or in a centrally accessible location for the working life of the applicable ventilation system equipment or components.

This manual shall be updated as necessary. The manual shall consist, at a minimum, of the operation and maintenance procedures, final design drawings, operation and maintenance schedules, and any changes made thereto and the maintenance requirements.

Measuring Air Quality

Ruskin Air Measuring Equipment

Ruskin has the most comprehensive line of air measuring and control solutions in the industry.  Products include differential pressure probes for high velocity applications, combination units that measure and maintain flow, and highly sophisticated, intelligent solutions that incorporate thermal dispersion technology with microprocessor based controls that communicate with any building automation system.


For more information about Ruskin’s complete product line, application and design support, and our state-of-the-art manufacturing capabilities, contact your local Ruskin representative nearest you or Contact Ruskin directly at (816) 761-7476.

Ventilation in Health Care Facilities #IAQ

Ventilation in Medical FacilitiesOutside air management is extremely critical in health care facilities. Today’s HVAC system designer has many choices when it comes to managing outside air. However, reviewing the requirements identified in the building codes permits the designer to focus on the control strategies that are compliant. With this knowledge, the HVAC designer can eliminate several alternatives and choose among the appropriate strategies.

ASHRAE, the American Institute of Architects (AIA), and the International Building Code (IBC) provide designers with the necessary IAQ standards and goals that will permit “acceptable indoor air quality,” but they are not intended to necessarily describe how to devise a ventilation system that applies these instructions to actual applications.

The Centers for Disease Control (CDC) recommends that ventilation systems be monitored to ensure proper ventilation, early detection of operational problems, optimized performance for particulate removal, and elimination of excess moisture. The CDC also advises that AIA and ASHRAE guidelines be used as minimum standards where state or local regulations are not in place for health care facilities.

IBC identifies requirements for ventilation that apply to all building types. Therefore, it is important that the system designer consult the ASHRAE Handbook—HVAC Applications, the AIA Guidelines for Design and Construction of Hospital and Health Care Facilities, as well as the IBC (or local building and mechanical codes). The Handbook further states that where higher outside air requirements are called for, they should be used.

Pressure Seal DampersIn addition to providing a controlled ventilation system that regulates and maintains a constant supply of design ventilation air, the HVAC designer must be cognizant of energy codes as well. A leakage criterion exists for dampers that are integral to the building envelope. More than half of the states have adopted the International Energy Conservation Code (IECC), referenced by the IBC. The IECC states that dampers integral to the building envelope “shall be equipped with motorized dampers with a maximum leakage of 3 cfm/ft² at 1.0 in. w.g. when tested in accordance with AMCA 500.” This requirement is only important for health care environments that are not occupied 24/7 (day care facilities, administration offices, doctor offices, etc.), as well as areas that utilize and require emergency lock-down systems.

Critical Air Paths

Ruskin PSD Pressure Seal Dampers are ideal for buildings with critical air paths including food facilities, federal buildings, pharmaceutical facilities, laboratories, hospitals, biotech labs, nuclear facilities, chemical process plants and military installations.

RSKN_Go_Green_LogoFor more information about Ruskin’s complete product line, application and design support, and our state-of-the-art manufacturing capabilities, contact your local Ruskin representative nearest you or Contact Ruskin directly at (816) 761-7476.

Acceptable Levels of Indoor Air Quality – IAQ

A key requirement for a “Healthy” building is having an acceptable level of indoor air quality for the people in that building.  The EPA ranks IAQ as one of its top five environmental concerns.

IAQ Outside air introduced into the buildingAccording to a USEPA study, the levels of contaminants in industrial facilities, commercial office buildings, schools, governmental facilities and other indoor environments can be many times higher than levels found outdoors.

Common problem sources are:

  • Manufacturing processes
  • Interior maintenance activities
  • Renovation projects
  • Office and cleaning chemicals
  • Off-gassing from furnishings and carpets (voc)

From the EPA’s web site http://www.epa.gov/region1/communities/indoorair.html :

“In the last several years, a growing body of scientific evidence has indicated that the air within homes and other buildings can be more seriously polluted than the outdoor air in even the largest and most industrialized cities. Other research indicates that people spend approximately 90 percent of their time indoors. Thus, for many people, the risks to health may be greater due to exposure to air pollution indoors than outdoors.”


For the building to be “Sustainable” the correct amount of outside air needs to be introduced into the building thereby maintaining a healthy environment.  Outside air displaces air in the building at a rate that has been determined is necessary to maintain an acceptable level of indoor air quality.  Obviously the cost to heat and cool the outside air that is introduced into the building over the life of the building can add to the energy cost, especially when too much outside air is introduced.  On the other hand when not enough outside air is introduced the possibility of sick building syndrome (SBS) or “building related illness” (BRI) is increased.


How do you know you are getting the correct ventilation to building occupants?

The answer is Ruskin’s Air Measuring Dampers and Louvers. Ruskin products accurately monitor and control ventilation air 100% of the time, ensuring proper ventilation while saving energy dollars.

RSKN_Go_Green_LogoFor more information about Ruskin’s complete product line, application and design support, and our state-of-the-art manufacturing capabilities, contact your local Ruskin representative nearest you or Contact Ruskin directly at (816) 761-7476.