Open Ceiling Environments Need Special Care

It has become quite popular these days to design spaces without suspended ceilings, leaving ductwork and terminal units partially or fully exposed.

There are items that need to be understood with regard to diffusers and terminal unit selections when ceilings are to be omitted:

• Ceiling tiles tend to block high-frequency noises generated by ductwork and terminal units, and absorb those occurring within the occupied space. The sound spectrum in a space without a ceiling will tend to be somewhat harsh and much more reverberant.

• AHRI Standard 885 “Procedure for Estimating Occupied Space Sound Levels in the Application of Air Terminals and Air Outlets” uses a ceiling/space effect (Table D15) for estimating radiated sound levels for rooms with ceilings.

• AHRI standards are available for free download from their website at www.ahrinet.org.

• An alternate method of calculating a space effect (Table D16) must be used when the ceiling is omitted. The space effect calculation determines the attenuation in each octave band (Hz) based on the size of the room (ft³) and the distance from the listener to the sound source (ft).

• Space effect = (25) – 10 log (ft) – 5 log (ft³) – 3 log (Hz).

• It is interesting to note that this space effect applies the entire volume of the room to each device, regardless of the number of devices located within the space. 

Room example: 

We will start with a typical office that has 2400 ft³ of room volume, a 9 ft ceiling and a 3 ft ceiling plenum. According to Table D15, a typical lay-in ceiling would be expected to provide radiated sounds attenuations (dB) in octave bands 2-7 of 16, 18, 20, 26, 31 and 36 dB respectively. The ceiling/space attenuation from Table D15 applies to a room of any size, because research has shown that the ceiling type is far more important than the room size. If the room in question will not have a ceiling, we will need to calculate the space effect in order to determine the attenuation for the radiated sound path. The distance from the listener to the sound source will be approximately 6.5 ft and the room volume will increase to 3200 ft³ with the ceiling removed. 

Space effect = (25) – 10 log (6.5) – 5 log (3200) – 3 log (Hz)

Using the space effect equation, we can calculate the radiated sound attenuations (dB) in octave bands 2-7 as 7, 8, 9, 10, 11 and 11 dB respectively. 

Bigger space to make up for a lack of ceiling: 

Assume that our room has a 9 ft lay-in ceiling and a 3 ft ceiling plenum. According to Table D15, a typical lay-in ceiling would be expected to provide attenuations (dB) in octave bands 2-7 of 16, 18, 20, 26, 31 and 36 dB respectively. If we omit the ceiling in any size room, our space would need a minimum of 15000 ft² of floor space. Even with a room this large, we would expect to hear more high frequency noises unless we use sound absorption materials to soften the environment. 


Single-duct terminal unit over this room: 

Assume the unit is a DESV size 05 with a maximum design flowrate of 250 cfm that has an inlet pressure of 1.0 in wg. For our room with a ceiling, we would expect to have a radiated sound level of NC23. For the same room without a ceiling, we would expect to have a radiated sound level of NC36. In both scenarios, the NC level is being set by the 3rd octave band, centered on 250 Hz. This means it would be fine to put this unit over a conference room this size with a ceiling (not to exceed NC30) or over a shared office this size without a ceiling (ideally NC40). 


NC might not tell the whole story: 

Room criteria (RC) is another way of looking at room sound levels. Like NC, it provides a numerical sound level (known as a speech interference level or SIL), but it also looks for tonal imbalance in order to provide a letter indication of sound quality. For our room with a ceiling, we would expect RC12R. The R indicates a low frequency imbalance resulting in rumble. For our room without a ceiling, we would have the same rumble. However, the speech interference level is much higher. This is due to increased contribution in octave bands 4-6 (500-2000 Hz). These are known as the speech interference bands. Noise in these bands is both blocked and absorbed by typical lay-in ceilings. 

Luckily, spaces without ceilings tend to be more open and therefore the volume is often much larger than that of a typical office. The best way to keep sound levels low is to put the ductwork as high in the air as possible.

Single-duct terminals rarely cause sound issues, but extreme care must be taken when applying fan-powered terminals. Only the quietest fan-powered units should be used and it may still be necessary to add a partial ceiling – also known as an acoustic cloud – beneath these units. 

Please direct questions toward Titus Communications (communications@titus-hvac.com) and/or Titus' Chief Engineer Randy Zimmerman (rzimmerman@titus-hvac.com). 

Titus Revamps its Blower Coil & Air-Handler Product Line

Titus HVAC, the leader in air management, has upgraded and expanded its blower coil and air-handler product line. We have engineered a low-cost, efficient method of cooling and heating spaces in this market segment. Our new models include the TBL (vertical reduced footprint, bottom return blower coil), TBS (vertical reduced footprint, rear return blower coil), TBH (horizontal belt-drive blower coil), TBV (vertical belt-drive blower coil), and TBM (modular air-handler).

The blower coils’ breadth of options allows them to satisfy the indoor air-quality requirements of commercial applications. Achieving higher airflows than fan-coil units, the blower coils -- which generate 800 to 4,000 cfm -- have the capacity to service much larger facilities. Best suited for schools, healthcare facilities and office/retail buildings, units may be horizontally/vertically aligned and floor/ceiling mounted.

Horizontal blower coils -- which are installed in ceilings -- afford a wide range of application flexibility, while maintaining a simple, easy-to-install design. They are intended to provide comfort cooling and heating within small areas. The vertical belt-drive units -- ideal for closets, hallways and bathrooms -- can be laid on top of each other and are typically utilized in applications with a greater volume. Their belt-drive system provides more flexibility in terms of fan speed and cost advantage over a similarly sized direct-drive system. The revamped line gives engineers and architects the capability to better fit blower coils to their jobs.

TBM units are also configurable in horizontal, vertical, and footprint-savings arrangements. From basic air-handling to sophisticated isolation-room systems, they meet challenging specifications associated with indoor air-quality, controls and sound-sensitive projects. Modules are engineered to produce 600 to 10,000 cfm and may be stacked in a two-high configuration. They may be applied in many types of building structures such as schools, offices, hospitals, apartments/condominiums, assisted living facilities, and stores.

Our blower coils/TBM are shipped completely assembled, reducing field installation time and labor. They are thoroughly inspected and tested prior to shipment, eliminating potential problems at startup.

Additional Features and Benefits:

•  Heater/unit assembly listed for zero clearance; meets all N.E.C. requirements and is cETL listed in compliance with UL/ANSI Std. 1995
• Blow-thru electric heat with single-point power connection
• Hot water, chilled water, steam, and direct expansion coils; cold water/hot water changeover available for all models
•  Low-leak dampers with 2” filters
•  Mixing boxes with standard low-leak dampers, high-efficiency filter sections for 2” prefilter and 4” final filter, and blow-thru electric heat with single-point power connection
• Customized options including double-sloped IAQ galvanized drain pan, direct-drive plenum fans, high-efficiency filters, double-wall perforated lining, external face/bypass dampers, and inspection windows
• Foil faced fiberglass-insulated cabinets, main incoming-power disconnect (non-fused), fusing (main), magnetic contractors wired for disconnecting operations, and fan control package with heater interlock contacts (required for single-point power connection)

For more information on air management products from Titus, visit www.titus-hvac.com.

Please direct questions toward Titus Communications (communications@titus-hvac.com) and/or Titus' CB/DV/FC/AHU Product Manager Meghna Parikh (mparikh@titus-hvac.com). 

Chilled Beams in Healthcare Facilities

HVAC, lighting and additional systems found in healthcare facilities combine to utilize a vast amount of energy. In fact, hospitals consume more than 2.5 times the energy in comparison to average-sized commercial buildings. For this reason, the Department of Energy and ASHRAE have adopted legislation that calls for a 20% energy reduction in existing healthcare facilities and a 30% reduction in new construction.

The reheating of supply air in healthcare facilities has proven inefficient, due to high-ventilation requirements. This has become a primary target in the ongoing mission to decrease building energy use. Recently updated guidelines provide tremendous energy-savings opportunities. 

How Do We Save Energy In Healthcare Facilities? 

This can be accomplished by implementing active chilled beams in patient rooms and other areas in which the recirculation of room air is acceptable. ANSI/ASHRAE Standard 170-2013 Ventilation of Healthcare Facilities establishes revised regulations for ventilation rates and practices. This standard has also been adopted by the American Society of Healthcare Engineers (ASHE) as well as the AIA FGI Guidelines. 

Among the revisions are changes in the ventilation requirements for spaces wherein the recirculation of room air is allowable. They include patient nursing, diagnostic/treatment and labor/delivery/postpartum rooms. These areas previously required 6 air-changes-per-hour -- 2 of which were outside air -- of conditioned and filtered air be delivered to each space. 

The amended standard lowers the air-change requirement for these spaces to 4 air changes per hour. It also allows for the recirculation of room air to count as 2 of those total air changes, provided: 

1. Recirculation is limited to the room air itself and does not include any air from another space. 

2. Delivery of a minimum of 2 air changes of outside air -- filtered through a MERV 14 filter at the AHU -- is maintained. 

The standard also stipulates that no filtering of the recirculated room air is required, so long as it does not pass over a wetted surface. These updates clearly promote the use of fan-coil units and chilled beams to reduce reheating of the supply air. 

One of the advantages a beam system possesses over a VAV system is that it delivers a constant volume (2ACH^-1) of 100% outside air at 65°F, while the VAV system provides all of its sensible cooling by way of its 55°F primary air supply. This primary air provides 3.6 Btu/h-ft² of space sensible cooling; the beam's water-side cooling supplements this to match the room demand. The coil within the beam removes 16.4 Btu/h-ft² of sensible heat to supplement its primary cooling, whereas the VAV system must deliver 5.5 ACH^-1 to meet the 20 Btu/h-ft² design load of the space.

VAV systems and beam systems differ in how they handle periods of reduced demand. A VAV terminal can modulate its airflow delivery between its minimum airflow rate of 4ACH^-1 and maximum of 5.5 ACH^-1; on the other hand, the beam system throttles its chilled-water flow rate. The latter approach saves energy. If the space cooling demand drops below 72% of design, the VAV system must begin to reheat the supply air in order to balance the demand of the space. Additional reheat is required as space demands drop, increasing energy usage. 

That is not the case for a beam setup. The system's minimal primary air contribution -- 18% of the space sensible design -- allows it to respond to an 82% reduction in space demand, before reheat is required. This, combined with the fact the air-handling unit is always tasked to deliver less than half as much air as the VAV system, makes the beam system a hands-down winner! 

Please direct questions toward Titus Communications (communications@titus-hvac.com) and/or Titus' Senior Chief Engineer Ken Loudermilk (kloudermilk@titus-hvac.com). 

Terminal Units: Knowing when to 'Flip-out'

Let's examine a practical scenario that gives you more insight into terminal units:  

You have double-checked your terminal unit order to make sure every detail has been provided. The material, voltage, accessories and controls are selected. Knowing that everything has been evaluated and entered correctly, the order is submitted. Now, on to the next one!

Later, you receive a call about the order you so confidently completed. On the other end of the phone is the installing contractor, and he is flipping-out! This is actually more literal than figurative. 

The units are said to not fit into the allocated critical spaces, due to an improper handing specification. Controls were ordered for the right-hand side, but they have arrived on the left.

Maybe the piping for the hot-water reheat coils should be on the left, but the connections were shipped on the right. All of a sudden, a seemingly minor detail has become a massive emergency. What can be done?

Determining the Solution:

Do you have what is needed to extinguish the fire? Although not every unit can be rotated, it may be possible in your case. 

There are important aspects to understand when deciding if a unit is able to be flipped from its intended working position. We will examine this, unit by unit.

Cooling Only Units:

Single-duct terminals (ESVs) can be turned 90°, 180° and every other degree in between. They do not have any position-sensitive parts or equipment that prohibits their mounting orientation. Further consideration, however, is needed when you add controls to the unit. Pneumatic controls are position sensitive, meaning that PESVs must be adjusted before they are rotated.

Fan-powered boxes may only be rotated 180°. You must take into consideration that all of our units do not have top and bottom accessibility.

TFS & TFS-F units have top and bottom access panels, which allows for access to the motor – after rotation -- from the bottom of the unit. All other Titus fan-powered boxes are unable to be accessed from the top, unless the unit is flipped.  

Parallel units cannot be flipped, due to the gravity-operated backdraft damper that is installed on the outlet of the fan deck. This backdraft damper remains open if the unit is rotated, which hinders the unit’s performance. The position sensitivity of pneumatic controls is applicable to fan-powered units as well.

Units with Electric Reheat:

When it comes to units that utilize electric reheat -- single duct or fan-powered -- careful consideration must be taken. The airflow switch used in Titus’ electric heaters is position sensitive. You can rotate a unit with electric reheat, but you are limited to a full 180°. 

Any other mounting orientation has the potential to impede performance. The airflow switch is an important safety component for the heater. It is better to err on the side of caution and not get too creative.

If ever there is uncertainty, please contact Titus Terminal Unit Applications for more clarification.

Units with Hot-Water Reheat:

With use of hot-water reheat coils trending, knowing whether you can flip one has become a very vital piece of information. The performance of how-water reheat coils is integral to the overall functionality of the unit, so there is concern that flipping a coil will adversely alter performance.

Counterflow is the cause for this concern. Our 1-row and 2-row water coils are of a cross-flow construction, and we do not recommend rotating these coils. Titus does make left-hand and right-hand coils available for 3-row and 4-row. The thing to remember when flipping a water coil is the water always enters through the bottom and exits through the top.

A terminal unit that arrives on site with the wrong handing is not the end of the world. If you find yourself in this situation, remember it may be alright to flip-out!

Please direct questions toward Titus Communications (communications@titus-hvac.com) and/or Titus' Terminal Unit, UnderFloor Air Distribution Product Manager Derrick Smith (dsmith@titus-hvac.com).

TAO: Floor-Mounted Chilled Beam to be Featured at AHR Expo 2015

The Temperature Ambient Optimizer (TAO) by Titus is a hybrid unit that takes advantage of displacement, chilled beams, and radiation principles.

This revolutionary product is specifically designed for high-ventilation loads – greater than 200 BTUH per foot -- normally required in educational facilities, theaters and long hallways that have perimeter walls or windows.

What it Accomplishes:

The TAO can help find the path to a balanced and healthy system by providing the right proportion of heating or cooling to the perimeter wall to take care of the majority of the room load. Within desirable acoustic levels, it maintains the necessary displacement ventilation, humidity control, and temperature level of the room.

Supply air is discharged into the space -- at low air velocity -- as close to the floor as possible. This provides a very low and slow-moving pool of fresh air spreading over the entire floor.

Convection from people and other heat sources causes the fresh air to rise, which helps create very comfortable conditions in the occupied zone.

Comfort – temperature and air movement – is met by optimizing the air path wherein the two major loads are located. At the same time, the unit meets minimum ventilation requirements.

By redirecting a portion of the treated supply air toward the cold, outside wall/window, the heat load is neutralized and a thermal curtain is created. This reduces convection and radiation associated with the cold wall or window.

Description of Operation:

TAO units are provided with a constant volume flow of conditioned outside air that ranges between a 55°F and 66°F supply-air temperature from the air handler.

The most significant portion of the air is injected into the induction plenum and through the primary set of nozzles into the lower part of the unit and displaced into the room.

As the conditioned air leaves the nozzle, it will also induce the room air through the water coil to heat or cool the return air. Here, it is reconditioned, mixed with primary air, and delivered into the room at a discharge temperature of 64°F to 72°F.

The other portion of conditioned outside air is discharged through a secondary set of nozzles that are directed toward the outside wall/window. This neutralizes the perimeter load. 

The secondary set of nozzles induce room air through the secondary coil to increase the temperature of the supply air during heating mode.

The hot air rises along the perimeter walls and windows to neutralize the thermal load by creating a warm air curtain.

Benefits:

Since there are no blowers or motors operating within the TAO unit, the sound levels are further reduced and the overall energy consumption of the system can be improved.

According to the Building Owners and Managers Association, 60 percent of a building’s operating costs come from energy-related expenditures. To provide efficiency and help curb costs, the TAO takes advantage of all LEED certification requirements to obtain energy credits.

In addition, the stricter ASHRAE Standards of Thermal Comfort (Standard 55), Energy Savings and Perimeter Heating (Standard 90.1) can be easily achieved with this product in use.

Available in two unit sizes, the TAO is designed to fit under the window sill adjacently to the perimeter wall. Titus offers customizable cabinets in a variety of aesthetically pleasing woodgrain and natural stone finishes. 

Please direct questions toward Titus Communications (communications@titus-hvac.com) and/or Titus' Fan Coil, Chilled Beam, and Displacement Ventilation Product Manager Meghna Parikh (mparikh@titus-hvac.com). 

GRDs no longer have to be 'Plain White'

Titus woodgrain and natural stone finishes enhance architectural spaces by providing a seamless blend between our HVAC units and their surrounding areas.

Crafted through the process of sublimation, these finishes are easy to clean and do not require the same upkeep as traditional products. Titus currently offers more than 40 options in either a smooth gloss or textured finish, which will not deteriorate due to moisture, extreme temperatures and/or corrosion.

As the architectural industry searches for alternative materials to meet the growing demand for LEED and GREEN builds, Titus is proud to say we are the first commercial-HVAC company to bring this cutting-edge technology into the U.S. market.

Preparation and Coating:

The raw aluminum surface receives a traditional pretreatment of a chemical conversion, creating a thin layer of amorphous oxide with coating. Electrostatic guns then apply a 2.5 mils layer of nonhazardous powder paint. The polymerization is done with a 400°F temperature for 20 minutes. The base coat ensures adequate hardness of the final product, and protects the aluminum from light, weather, abrasion and humidity.

Decoration:

Next, a preprinted film transfer with organic photosensitive pigments and cellulose resin is completely wrapped around the product. The profile is positioned on the surface of a movable trolley, and air is removed through a vacuum-suction system. The result is a perfect thermoprint.

The trolley is then placed into a special oven, wherein the decoration is effected, turning the ink pigments from solid into gas and back to solid inside the paint layer. After cooling, the film is removed. Combined with other breakthrough technologies we apply to the endeavor, this process accounts for why our system is a global leader in color coating quality.

Current Offerings:

With it being ideal to coat fully assembled products, Titus woodgrain and natural stone finishes are only available for the CT product line, Omni, and Spectrum. We are in the process of adding ML diffusers and other architectural products into the mix. Our partnership with Hunter Douglas will be on display at the 2015 AHR Expo, as Titus’ booth will feature our products for the Gladius Ceiling (Omni) and 300C Plank System (ML).

Please direct questions toward Titus Communications (communications@titus-hvac.com) and/or Titus' GRD Application Product Manager Mark Costello (mcostello@titus-hvac.com).

How to plan and design for Hybrid ORs

Facility managers know that planning and designing hybrid operating rooms (ORs) with flexibility in mind is essential. With Titus being a leader in air management, we are able to provide not only the products necessary to create flexible hybrid ORs but the expertise, too. Our own Matt McLaurin, product manager, who specializes in healthcare, laboratory and cleanroom solutions, recently wrote an article on this important topic for Today’s Facility Manager. Read below for a snapshot of what Matt had to say.

Hybrid ORs: Plan and design a flexible future
Typically incorporating MRIs, CT scanners, or other cardiac catheterization lab (Cath Labs) tools, surgical suites that house these intraoperative imaging machines are commonly known as Hybrid Operating Rooms (ORs). Given that the 2014 edition of the FGI Guidelines for Design and Construction of Hospitals and Outpatient Facilities requires these imaging equipment tools to be permanently integrated into Hybrid ORs, it’s critical to design facilities with them in mind. To meet standards and codes, it is essential to anticipate and address challenges associated with Hybrid ORs by planning them for flexible futures.

Planning for design standards, challenges and flexibility
Facility managers know when designing a Hybrid OR that space planning is critical. A minimum of 650 sq. ft. of clear floor space is required for new construction ORs, and 600 sq. ft. for renovated ones, but depending on the modality of imaging equipment in place they can be up to 2,600 sq. ft. Along with a recommendation to install ORs in spaces with at least 750 sq. ft. and 10 foot ceilings, specifications that help accommodate for future upgrades, control and equipment rooms must be considered, as they are necessary for housing data and electrical equipment for imaging devices. Designing for multiple rooms to utilize a single device is another technique to reduce imaging equipment costs and space requirements. For this approach common control and equipment rooms must be accessible from each OR.
 
To read more of Matt’s article in Today’s Facility Manager, please click here.