Thermal Displacement Diffusers

Options for Surface Mounting Ceiling Diffusers

One of the more frequently asked questions we receive in application engineering is in regards to surface mounting Titus diffusers. When a ceiling grid is not present, surface mounting is specified and the installation questions arise. Linear diffusers are available with concealed mounting, square and rectangular diffusers with square or round inlets are not.

The most important thing to know about surface mounting is that it normally requires additional framing to which the units will be secured. We often receive calls for mounting instructions after the sheet rock has been installed which is too late to provide framing without removing the installed surface. 

Framing requirements will vary from one job to the next, but there are some general guidelines and terminology we use.

Obviously installing screws in the face of a diffuser will work as it does for grilles but the duct return flanges behind diffuser edges are generally not available to provide a secure mounting base for screws. Also, many surface mount frames do not have a flat surface nor is there a screw hole fastening option available. Furthermore, screw fastening certainly does not enhance the aesthetics of the installed diffuser. 

The TRM mounting frame makes installation of grilles, diffusers and other ceiling components in plaster and sheetrock ceilings as simple as inserting them in a standard T-bar type ceiling

All sheetrock is mounted to ceiling joists. Joists are usually parallel to each other and spaced at two to three feet apart depending on local building codes, and in most cases, the framing for the diffuser can be mounted to the top of, and perpendicular to the joists. Screws are then used to mount the back pan to the framing. Framing members should be centered on the diffuser location to allow sufficient clearance for the diffuser inlet and associated duct. Additional care must be taken so as to avoid any protrusions or features that will occupy the space necessary for the framing on the rear side of the diffuser. Framing should also be at a depth that will allow the diffuser to firmly seat against the sheet rock. Most diffuser back pan heights are less than the depth of the joist. The sheet rock or ceiling surface is installed into an opening provided for the diffuser.

The diffuser core should be removed prior to installation to allow for screws to be installed in the top of the back pan transition; this is the flat portion on the rear of the back pan. Screws are then used to secure the back pan to the framing. It is helpful to use washers to prevent the screw heads from being driven through the back pan if the framing is not flush to the rear of the pan. In most cases the screws can be placed in a manner to not be visible from the occupied space after the diffuser core or face is re-installed.

The illustration above shows how the TMS diffuser would be mounted in sheetrock  

As an alternative to the framing process, and one that we suggest if the ceiling surface has been installed without prior framing for the diffuser mounting, is to use our rapid mount frame. The TRM frame can be installed in the space between the joists following the installation of the ceiling. 

The TRM replicates a standard ceiling grid module and a lay-in (type 3) frame diffuser. The diffuser can then be laid in the TRM frame. The TRM frame does add a border to the finished appearance of the diffuser, but also can be utilized as an access port to the space above the ceiling by simply pushing the diffuser up and out of the opening. 

While the TRM does represent additional diffuser cost, the reduced labor requirement and flexibility of the installation sequence offers a distinct advantage.

The TRM is available in steel and aluminum and is ordered as a separate line item. Remember, when using the TRM frame, the (type 3) diffuser frame must be used instead of the (type 1) diffuser frame.

For information on this topic, please contact Mark Costello at mcostello@titus-hvac.com or Titus Communications at communications@titus-hvac.com.

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.

The Case for Lynergy - SCR Heaters vs. Lynergy

An SCR controlled heater is a time proportioned heater that modulates to supply the exact amount of heat required to satisfy the zone requirements. Titus offers (2) types of SCR style electric reheat options and this article will help clarify the differences between the two. Our two SCR heater codes are the CXX and LXX codes. The CXX code is an SCR heating code that offers lower kW’s available per voltage than the LXX as well as other voltage requirements like 580V & 600V. The LXX code (Lynergy) is the Titus branded SCR heater which has more capabilities than the CXX code but no special voltages available.

CXX: 

• Utilizes an air flow sensor instead of a standard mechanical air flow switch
• 0-10v DC or AC/DC pulse
• Special voltages and lower kw options are available
• No quick ship options available

LXX (Lynergy):

• More cost effective
• Faster lead time
• Utilizes a mechanical air flow switch instead of an air flow sensor
• 0-10VDC
• 2-10VDC
• 3 point floating
• Incremental
• On/off
• 2 stage
• 3 stage
• Binary

If you are looking for very low kW or voltages higher than 480V then the CXX code will work best. For faster lead times, competitive pricing, and more control functionality then the LXX Lynergy code will be the best choice. 

• To learn more about the SCR heater platforms and Lynergy functionality you can go to the following: 
• Titus website at www.titus-hvac.com 
• Titus SCR Heat Application Guide:
•  https://www.titus-hvac.com/file/5753/AG-Lynergy-02.pdf
• Listen to the Titus Timeout Podcast for Lynergy:
• https://www.titus-hvac.com/flv/Podcast_Lynergy%20Inputs.mp4

For information on this topic, please contact Phil Baxter at pbaxter@titus-hvac.com or Titus Communications at communications@titus-hvac.com.

How Innovation in Testing and Training is Driving the HVAC Industry Forward

The virtual tour of this state-of-the-art laboratory and interactive learning experience is a must-see.

Technical innovations, such as virtual and augmented reality along with predictive analytics, continue to advance the engineering, architectural and construction industries while simultaneously helping companies improve their quality, safety, efficiency and costs.

At Titus, we have a history of innovation and a goal to continue to advance the science of air distribution. By embracing new technologies and incorporating them into our existing sales, marketing and training, it makes us more capable to interact with these industries and the next generation of industry professionals.

In addition to our product innovations, we invest in a state-of-the-art lab and classroom that we call the Comfort Zone. Spread over 39,500 square feet, our laboratory provides an extensive array of testing and mock-up services that allow guests to truly immerse themselves in all aspects of HVAC design. And you won’t find a traditional training room here; instead we offer an interactive learning experience.

Get behind-the-scenes highlights and take a virtual tour

The facility includes underfloor testing, throw rooms, a critical environment lab, innovation towers, a reverb room, a chilled beam testing chamber and in-situ rooms. I’ll walk you through a few special features and then share a link to a virtual tour of the entire facility.

Underfloor testing

The Underfloor Air Distribution (UFAD) room is a multi-purpose space designed to demonstrate underfloor products, cold wall situations, and serve as an auxiliary throw room for ceiling diffusers. The UFAD room can showcase air patterns created by various models of ceiling diffusers and be used as a mock-up facility to show unique solutions for tricky air distribution problems. During smoke test demonstrations, thermal imaging dramatically shows the difference in the temperature. Underfloor diffusers are floor mounted to simulate actual site installation and test air is precisely delivered to the diffusers at a flow rate of up to 5,000 cfm. Any site requirements for equipment and furnishings can be mocked up to resemble real-world installations for an accurate determination of airflow patterns and temperature mapping. The effect of sills and soffits on air diffusion against an external wall can also be studied.

Throw room

This 80'L x 28'W x 9'H room tests products with increased accuracy, including slot diffusers with long throw, large size displacement ventilation units and chilled beam products. A modular hydronic system enables the testing of chilled beam and water sourced products while units are operating at cooling and/or heating mode. A 20' x 40' radiant heater is installed under the floor for better load control of the room during various performance testing, including isothermal throw tests and isovel air pattern mapping in accordance with ASHRAE Standard 70.

Critical environment lab

In this specialized room, we model laminar flows in a cleanroom or laboratory setting with a cleansing air wash or an isolating air curtain. Physical site conditions are mocked up in the room to determine the effect of equipment placement on airflow patterns, and smoke can be easily introduced into the air stream by remote control. Test air is precisely delivered to a diffuser by a computer-controlled delivery system at a flow of up to 5,000 cfm. Isothermal heated or chilled air can be supplied to any diffuser inside the critical environment room for a 30 degree F temperature differential.

Innovation towers

Within three towers, visitors can interact virtually with Titus products on a tabletop display and experience them firsthand. Product displays include the Spectrum Diffuser, Underfloor, VAV, Energy Solution products, Chilled Beams, Radiant Ceiling Panels and Terminal Units.

Reverb room

Our reverberation room allows pure tone sound testing qualification per AHRI-220-2007. It is acoustically isolated from outside noise and vibration with room-inside-a-room construction and an isolation base. Advanced sound measurement equipment offers precise and highly repeatable testing. With a custom-made modular hydronic system, products with water cooling/heating coils can be tested for sound performance while units are operating in cooling or heating mode.

Chilled beam testing chamber

Our chilled beam testing chamber is one of two test chambers located in the United States. It is used to conduct capacity testing in accordance with ASHRAE Standard 200, as well as research and development testing for our chilled beam product line. It features room-within-a-room construction with a conditioned buffer space that prevents heat transfer into or out of the inner test chamber. Precise instrumentation measures the operation conditions and delivered capacity of the unit under test. During testing, the room temperature is maintained within 1 degree F through the use of load dummies. The energy used to maintain space temperature is measured as a validation of the measured capacity. The chamber also features automated control and data acquisition software which enables incredibly precise test results at an increased pace of testing.

In-situ rooms

Two different sized in-situ rooms are built with a 3' plenum space allocated above the ceiling for terminal unit installations. With commercial carpeting, drywall, mineral board ceiling tiles, light fixtures and t-bar grid ceiling construction, these rooms mimic typical office spaces and are built per Cerami and Hines in-situ room specifications. Advanced sound meters make high-precision noise measurements and are frequently used for radiant and total sound mock-up tests requested by building owners and engineers.

See it for yourself

Ready to start your virtual tour? Let me know which part looks most intriguing to you.

For an innovative solution to meet your unique needs, visit titus-hvac.com.

Looking to the future,

Jenny Abney Sivie, LEED AP BD+C - Director of Advanced Business Development, Titus HVAC

This article as written can be found on LinkedIn's website https://www.linkedin.com/. For information on this topic, please contact Jenny Sivie at jsivie@titus-hvac.com or Titus Communications at communications@titus-hvac.com.

6 Tips on Designing for Sound with Terminal Units

How to implement effective acoustic design with terminal units

As anyone wearing headphones at the office to keep coworkers from bothering them can tell you, noise is an issue in public spaces. While the primary focus of HVAC systems is temperature and humidity control, experienced designers know that controlling sound is vital to a comfortable and productive environment.

Total peace and quiet may sound relaxing, but actually isn’t ideal. Acoustic privacy is a state where someone at their desk can hear nearby conversations, but not enough to be distracted by them. Good acoustical design is not about trying to eliminate sound, but rather manage it appropriately. Too quiet and you destroy acoustic privacy. Too loud and you interfere with speech or even cause hearing damage. You also don’t want any annoying rumbles, hisses, identifiable machinery sounds, or undue modulation of the system cycling off and on over time. 

Good design practice requires mechanical system designers to establish the acceptable noise for an occupied space and then determine the selection criteria for all system components. AHRI Standard 885, Procedure for Estimating Occupied Space Sound Levels in the Application of Air Terminal and Air Outlets, provides a consistent method and the most current application factors. This article won’t cover the calculations involved, but rather focuses on underlying factors and actionable recommendations. 

The key approach to noise control breaks each issue into three overall components: the source that creates the noise, the paths that transmit the noise, and the receiver who hears the noise. Air terminals are often a primary source of sound in a mechanical system. The path for sound emanating from an air terminal is either through the plenum, down the duct into the conditioned space where it reaches the occupant, or some combination of both. 

In any application, both radiated and discharge sound needs to be considered. Radiated sound escapes through the terminal casing and/or induction port and travels through the plenum and ceiling to enter the occupied space. Discharge sound travels out the terminal through the ductwork and air outlet. Radiated sound is the primary issue when using fan-powered terminals, while discharge sound is common with non-fan terminals. Unlined ductwork can result in higher discharge sound levels for all terminal types.

Once the radiated and discharge sound paths are determined, the resulting room sound level can be evaluated. Several factors outside the mechanical system play a part, including the dimensions of the room, carpet and furniture, just to name a few. An accurate analysis is a complex process, and as a reminder, AHRI Standard 885 provides a consistent method for accomplishing it. 
Engineers can minimize the sound contribution of air terminals to an occupied space with the following good design practices: 

• Whenever possible, terminals should be located away from occupied areas and placed over areas less sensitive to noise such as corridors or storage areas.
• Use lined ductwork or attenuators downstream of air terminals to help attenuate higher frequency discharge sound. Used in moderation, flexible duct is also an excellent attenuation element. However, remember to keep flexible duct bends as gentle as possible.
• Sharp edges and transitions in the duct design should be minimized to reduce turbulent airflow and the resulting sound contribution.
• Rather than using mechanical devices to restrict airflow, use fan speed controllers to reduce fan rpm. This form of motor control also often has the added benefit of being more energy efficient, especially when applied to ECMs.
• Separate the air terminal and return air grille as far as possible, in order to allow duct attenuation to reduce discharge sound levels.
• Design systems to operate at low supply air static pressure. Not only will this reduce the generated sound level, it also provides more energy efficient operation and allows the central fan to be downsized.

While it is crucial for designers to understand acoustical ratings in order to write good specifications, the careful selection and proper installation of every element of the entire system are required to ensure an optimal environment. Using the best products for the job will save you time, money and headaches in the long run. 

For additional guidance and innovative solutions to meet your unique needs, find your local Titus representative at titus-hvac.com.

Always here to help, Randy

Randy Zimmerman is a Chief Engineer at Titus and is an ASHRAE DL and LEED Green Associate with more than 30 years of experience in HVAC product development and applications. He serves on numerous ASHRAE technical committees and also represents Titus in various AHRI product section committees. 

This article as written can be found on LinkedIn's website https://www.linkedin.com/. For information on this topic, please contact Randy Zimmerman at rzimmerman@titus-hvac.com or Titus Communications at communications@titus-hvac.com.

Helios Installation and Operation Video