Understanding Variable Refrigerant Flows

Common in Europe and Asia, VRF systems have recently become more popular in North America.  Its  ability to respond to fluctuation in space load conditions, means it can reduce energy costs significantly.

There are two basic systems--water-cooled and air-cooled.  A simple VRF system consists of an outdoor condensing unit and multiple indoor evaporators. The condenser and evaporators are connected by a complex set of oil and refrigerant pipes and governed by individual thermostat controls.

Installation 

While VRFs can help save on energy costs,  it is not suitable for all facilities.  Before installing an HVAC system, you should have a professional engineer determine if a VRF system is appropriate for your building.

If the engineer recommends the use of a VRF, the next decision is to determining whether you will need a water-cooled system or an air-cooled system. As the requirements for these two systems can vary and may impact architectural elements.

Air Cooled VRF

For air-cooled systems, an exterior space is required for the installation of a condenser. The space selected for the installation must be away from windows, accessible to maintenance and support weight of the units.  These units, can be unsightly and may need to be hidden from view with an architectural enclosure.

Water Cooled VRF 

For water cooled system is used, a small closet is often required to house the required water source units that compromise units.

In addition, for both air cooled and water cooled systems, a feasible path to route the refrigerant pipes is required.

Another challenge for specifying VRF systems is the provision of a separate outside air supply to each indoor unit to comply with ASHARE Standard 62.1 and building codes.  This requires larger facilities to have a separate outside air fan and control system, and in humid climates providing outside air to each indoor unit helps ensure good indoor air quality.

Negatives of VRF systems

Due to the limitation on the indoor coil maximum and minimum dry and wet bulb temperatures, the units are unsuitable for 100% air applications, particularly in hot and humid climates.   Another concern, is that the cooling capacity available to an indoor section is reduced when there are lower outdoor temperatures, which limits the use of the system in a cold climate to serve rooms that require year-round cooling, such as a server room.

That being said, VRF systems offer benefits beyond energy savings. Its ability to heat and cool separate space at the same time in the same building,  vary compressor speed to meet load condition, and its quieter operations are also other reasons why a VRF system should be considered.

Do We Need More Engineers?

The Engineer Debate:
Quantity vs. Quality

According to the Bureau of Labor Statistics, the number of science and engineering jobs in the U.S. is expected to grow more than 1 million between 2010 to 2020. What's more, it is expected that the nation will need 1.3 million of these professionals to replace workers who are exiting the field.

Despite these statistics, engineering ranks number 6 on the hardest jobs to fill in the U.S. As many firms struggle to find competent employees to hire.  The question is why, when there seems to be so many engineers looking for employment and so many eager firms looking to hire?

It is this question the PE Magazine attempts to dissect in their October issue.  So who is right? Does the U.S. need more engineers or fewer engineers? And does the problem stem from the lack of preparation of our graduates or does responsibility rest on the unrealistic expectations of firms who are hiring?  

Perhaps both are to blame.  Here is a breakdown of some of the noticeable deficiencies of graduates with engineering degrees along with the firms seeking to hire:  

The Graduates 

• The large majority of graduates lack  field experience, which means firms must invest a substantial amount of time training recent graduates. 
• There is no universal software used by every firm. Often graduates aren't familiar with the software utilized by the firm they are applying to because often what they use in their classes is not always the same. 
• Lastly, graduates lack initiative on the job, which if a sought after quality by most firms. 

The Employers 

• One of the major problems with employers is that they desire something unavailable in the market place. As experienced engineers with the technical skills they require often have secure positions and/or expect substantial wages for their expertise. 
• Likewise, employers have unrealistic expectations for their new hires.  
• Lastly, many employers don't want to pay what it may take to secure talent. 

What's the Solution?  

There isn't a perfect solution, but clearly the academic and professional world must work together to overcome these difficulties.

Engineering curriculum should require students to partake in an internship for a semester, which is common for degrees like education.  Likewise, engineering firms must recognize that perfection does not exist. Instead, new hires must be viewed as the investment that they are.  It may take years for the new hire to reach its full productivity comparable to the employee's salary. 

Tell us what you think?
Should companies be concerned about the potential lack of engineers or is it simply a result of inefficient preparation of graduates or unrealistic expectation?

The Benefits of Displacement Ventilation

One of the most common forms of air distribution for HVAC system is overhead mixing, which is why you will often see air distribution devices--diffusers--blowing tempered air on commercial facilities such as offices, schools and hospitals. 

Diffusers use high pressure to throw the tempered air into a room, mix with the room air and subsequently heat or cool the space.

• Less energy because the space is condition only when occupied

• Less energy from reduced fan power by blowing that air at a slower pace

• Increased comfort of occupants because less air movement 

• Decreased contaminant risks, because there is no mixing of air.  

This technology has its flaws, as the mixed air can be subjected to airborne contamination and consequently lead to poor indoor air quality. Another concern with mixing ventilation is the location of the diffuers. It is common for diffusers to be placed 8-12 ft above the floor. This means that energy is wasted heating and cooling unoccupied space.  

For these reasons, an increasing number of energy and HVAC engineers are turning to alternative designs  in order to temper the space in more effective, efficient and clean ways. 

A popular alternative to this traditional mixing ventilation is a method referred to as displacement ventilation.  Displacement ventilation  is an air distribution technology that introduces cool air to a space at a low velocity through larger diffusers usually located near floor level.  

By utilizing buoyancy forces in a room, generated by heat sources such as people, lighting, computers, electrical equipment, exc., this system is able to remove contaminants and heat from the occupied space.  The conditioned air is then able to migrate naturally to the heat sources of occupants throughout the room. This is due to the fact that heat drives air movement, and since our bodies naturally give off a thermal plume of consistent heat, the conditioned air finds its way to us and cools us off. 

As air conditioned air enters the space, it displaces the room air through natural buoyancy and exhausts through a high point in the room.  Because the the air is not mixed contaminant particles can be removed. 

Displacement Air Ventilation is Recommended

Displacement ventilation is a recommended ventilation system for a variety of facilities because of the above mentioned benefits.  The ASHARE has passed Addendum G to standard 170-2008 "Ventilation of Healthcare Facilities" and recognizes the use of displacement ventilation in healthcare facilities, likewise The Collaborative for High Performance Schools recommends displacement ventilation as the preferred distribution method in education facilities.

Sources: 

Erway, Joel. Engineering.com " Rethinking Air Distribution with HVAC Systems" 15 October 2013. 

Engineering Guide-Displacement Ventilation Guide" 

HVAC Commissioning--Why You Need it

HVAC commissioning can enhance the lifespan
 of your mechanical equipment. 

What is HVAC Commissioning?  

HVAC commissioning is a thorough and comprehensive testing of a mechanical system's performance.  Many owner's are less than eager to spend more money, when they are already spending money to the contractor or engineer to fix the problem.   What most owner's don't realize is that commissioning can extend the life of equipment, while reducing operating costs and increasing the comfort of occupancy.

While the equipment should be properly installed in theory, there is not always sufficient evidence that the system is operating as optimally as it was design.  Varying operating conditions can certainly affect the equipment's ability to function properly.  It is usefully after the installation that the user discovers problems, and many times will attempt to fix the problem with patch and it makes it impossible to go back to the original intent of system.

Commissioning Process

Typically the commissioning contractor is the original contractor who installed the work, while the commissioning agent is the engineer who designed the project or was involved with the design process. The agent will stimulate a variety of operation conditions and work with the contractor to determine if the system is responding properly.

If discrepancies are noted, they will be diagnosed and resolved during the commissioning process.  Once, this is completed, the equipment is turned back over to the owner in perfect condition and in mechanical systems should be commissioned.

Any project with an automatic control of mechanical systems should be commissioned including:

• air conditioning unit 
• heating or cooling plant upgrades 
• project involving replacement or installation of automatic valves or dampers
• any installation or replacement fans, heating and ventilating units and duct heaters 

Looking for a competent engineering firm to commission your mechanical system?  RGD Consulting Engineers has 35 years of experience and can make sure your facility is operating effectively and efficiently.  

Autodesk to Acquire Structural Fabrication & Detailing Technology from Graitec

Autodesk, Inc. has signed an agreement with Graitec shareholders in order to acquire certain technologies, including Graitec's Advanced Steel and Advanced Concrete product lines and employees.  This addition to Autodesk will further enhance their product offers for structural engineering along with their portfolio of technology for Building Information Modeling (BIM) for structural fabrication and detailing.

According to Amar Hanspal, Autodesk senior vice president of Information Modeling and Platform Products, Autodesk is committed to offering its users the most comprehensive engineering tools.  The acquisition of Graitec technology "will provide our customers with a more seamless structural engineering workflow from design to fabrication and to construction, with enhanced offerings for structural steel and concrete detailing." 

Graitec, a company based out of France,  provides CAD and engineering software for structural engineering, civil engineering and building construction globally. Its products support BIM-based steel and reinforced concrete workflows.  The company will continue to produce  BIM software and services to complement Autodesk, so that the industry can continue to pursue maximum efficiency and performance. 

The acquisition is likely to occur at the close of the 4th quarter of the fiscal year 2014. 

This article was derived from the press release titled "Autodesk Signs Agreement to Acquire Structural Fabrication and Detailing Technology from Graitec, published on October 2, 2013 in Market Watch. 

Solar Powered Systems Give Hope for Developing Countries

Solar Powered Sterilization System developed
by researchers at Rice University. 

For developing countries, the basic amenities are a rarity often taken for granted by those who are privileged enough to use them on a daily basis.

However, technological advancements, such as solar power systems, are giving hope that one day developing countries may have access to electricity, sewage treatment and other services.

Researchers from The Rice University Laboratory for Nanophotonics in Houston, have developed a solar-powered sterilization system that uses nanometerials to create steam from water.  This system has the ability to convert as much as 80% of sunlight's energy to heat that is capable of killing germs. Researchers are optimistic that this system could help countries that lack sanitation.

In a report published by the Proceedings of the National Academy of Sciences, when the system is used in conjunction with a specially designed autoclave, it is capable of sterilizing medical instruments and sanitizing human waste.  The setup can reportedly handle the waste of a family of 4 with two treatments a week.

According to Naomi Halas, one of the team leaders, a professor and fellow nanophotonics researcher at Rice, the ability of the solar system to efficiency convert sunlight into steam, opens the door for sterilization systems that are independent of electricity.

The efficiency of the system originates from the use of light-harvested nanoparticles. These particles heat up so quickly that they instantaneously vaporize the water and create steam, all before the water even boils.

This system is more than 24% energy efficient. This is even more remarkable when compared to the photovoltaic solar panels, which have an energy efficiency of around 15%.

The heat and pressure created by the steam also sufficiently kills microbes as well as spores and viruses.

This article was derived from the headline "Focused Attention," which appeared in the October 2013 edition of Mechanical Engineering. 

Benefits of Spiral Round Ductwork

Spiral Round Ductwork is more Efficient than
Conventional Rectangular Ducting. 

For facilities managers, optimized facility performance is an important part of their job.  That's why many facilities are moving toward spiral round ductwork as opposed to conventional rectangular ducting. Static regained spiral round ducting can do more with less when compared to conventional rectangular ductwork: 

• Costs about 1/4 less 
• Weighs 25% less 
• Easier to install 
• Less bulky than conventional rectangular ducting in variable (VAV) or constant volume systems (SPIDA). 

Spiral round ducting can enhance the HVAC systems performance, as systems that include static regain designed spiral round ductwork use less energy, deliver air to every VAV box and create a more comfortable indoor environment for occupants and visitors. 

Take for example the leakage rate of rectangular ductwork compared to spiral round ductwork. Leakage for rectangular ductwork occurs at a much higher rate than spiral ductwork, which has a leakage rate of less than 1% (SPIDA). 

By reducing leakage, there is a significant impact on the HVAC energy efficiency and occupant comfort. The right amount of conditioned air can be directed to the intended locations within a facility, which results in better indoor air quality and a more comfortable environment for occupants. 

Another benefit of spiral round ductwork, according to the American Society of Heating, Refrigeration and Air Conditioning (ASHRAE), is the allowance of spiral round ductworks for higher uses of air velocity than compared to rectangular ductwork. Higher velocity, static regain designs are state-of-the-art for current lower installed costs VAV systems.  

Direct Digital Control (DDC) strategies can enhance the efficiency of a round ductwork system. DD/VAV controls allow for fan pressure optimization because you can identify which VAV box in the system requires the maximum static pressure and then control the fan to provide just that amount of static pressure and no more. 

This article was derived from the headline "The HVAC Factor: Spiral Round Ductwork", which appeared on September 17, 2013 in the Today's Facility Manager. 

NFPA: 13: To Reinstall or Not a Removed Sprinkler

According to the NFPA 13, Installation of Sprinkler Systems, once a sprinkler is removed it cannot be reinstalled.  This rule was added to the 2013 edition of the NFPA because of concerns that the sprinkler could be damaged during the removal process.  

The addition of this stipulation is not surprising as removing a sprinkler can cause damage to occur to the threading, water seal or operating element. While there may be no visible signs of damage, the sprinkler's performance may still be negatively affected. 

A simple requirement and yet this new stipulation has stirred debates. The controversy stems from the wording, which simply states "When a sprinkler is removed" without any specifications for its removal.   

This ambiguity is the reason for that two interpretations have emerged.  Both of which are directly related to whether or not there is the presence of a drop riser nipple, or other fitting between the sprinkler and the branch-line outlet. 

According to one side, provided the sprinkler is detached from the sprinkler system without the sprinkler being touched, the potential for mechanical damage is completely eliminated.  The sprinkler and the fitting can therefore be reinstalled. 

The other side of the debate argues that regardless whether or not the sprinkler has been physically touched, it can still be damaged as it waits to be reinstalled. For example, the sprinkler or the container in which it is stored could be dropped or kicked and compromise its functionality.  

These two sides faced off at the development of the 2013 edition of the NFPA 13 and it is likely more attention will be given to this issue at the development meetings for the 2016 edition.  

This article is derived from Matt Klaus's "Since U Been Gone," originally published in the NFPA Journal September/October 2013 edition. 

BIM-The Way of the Future?

Technological advancements have revolutionized how many industries operate. Take for example, the telecommunications industry.  In recent years, the art of letter writing has quickly been replaced by email and texting. In fact, communication has never been easier. 

For the construction industry, change has occurred more gradually, but now, Building Information Modeling, or BIM, may be finally changing that.  

   

What is BIM? 

BIM is a three dimensional digital representation of a building and its characteristics.  As one of the most promising developments in architecture, engineering and construction, BIM allows for the creation of a virtual model through a digitally constructed building.

This computer generated model contains precise geometry and data, which can be used to make decisions and improve the design process.

Benefits of BIM

BIM technology has numerous benefits for design professionals and facility owners and managers. 

• Tighter Coordination: BIM enables all members of the design team, including the customer, contractor and specialists to work more collaboratively. This improves the project's development through every stage of the design process.  No longer will the interaction of firms and disciplines be confined to the exchange of construction documents.  BIM enables tighter integration of the design teams, which results in a more cohesive and effective design.
• Less Costly Revisions: The integration of the schedule and cost information improves the sequencing during construction. You can get a complete picture during the design.
• Life Cycle Data: BIM is further enhanced after the construction of the facility. BIM is first and foremost about the information and data.  It acts as a computerized maintenance management system. Equipment specifications and schedules are easily accessible and critical functions can be integrated into the system.

Additionally, in a study conducted by the Stanford University, Centre for Integrated Facilities Engineering of 32 major projects using BIM (2007), it was determined that BIM will enable:

• Up to 40% elimination of unbudgeted change 
• Cost estimation accuracy within 3% 
• Up to 80% reduction in time taken to generate a cost estimate. 
• A savings of up to 10% of the contract value through clash detections. 
• Up to 7% reduction in a project time. 

McGraw-Hill Construction reported that the use of BIM technology increased from 17% in 2007, 49% in 2009, to 71% in 2013. Despite it's rapid growth, the widespread implementation of BIM technology still faces significant challenges. Still, the potential of BIM technology makes it an indispensable tool and skill for the design professional. Those who opt not to adopt BIM, may find themselves falling behind. 

Resources: 
http://www.smartplanet.com/blog/take/the-future-of-construction-meet-bim-or-else/441

http://www.burnsmcd.com/Resource_/Article/5721/PdfFile/aticle-SeeingtheFutureBIM.pdf

http://www.construction.com/about-us/press/bim-adoption-expands-from-17-percent-in-2007-to-over-70-percent-in-2012.asp

http://www.wspgroup.com/en/wsp-group-bim/10-truth-bim/

Removing the Cloak of Invisibility from the Engineer Profession

The engineering profession is one of anonymity, with most
people being unable to define what exactly an engineer does. 

Engineers are responsible for designing some of the world's most fundamental systems. While they may not have made your clothes, the machine that did was most certainly designed by an engineer. Likewise, your home couldn't have been built without the collaboration of an engineer.

The fact is engineers have their hands in just about everything. Still, if you were to ask someone to define the engineer profession, his or her response would be more than lacking. 

So why is the engineer profession such a mystery? 

Alan Werner, P.E. explains that the nature of the engineer's job is partly to blame for the invisibility of the engineer profession.  Think about it.  The engineer's primary objective is to solve problems before they even exist. For the public, this can be difficult to understand. If the problem isn't visible, then the engineer who solved the problem in the first place is by default invisible. 

This issue is perpetuated by the engineering profession as a whole, which seems to prefer being unknown. They are satisfied with simply accomplishing the goal and moving on without the public recognition of a job well done. This likely contributes to the "invisible engineer."

How do we overcome the invisible engineer phenomenon? 

First and foremost, the engineering community must bring awareness to the process that goes in to creating a useful & successful design.  As a society, we so often emphasis the final product rather than the steps it took to get there. This is reinforced in our education system and often in the professional world.

The engineer and the industry must re-emphasize the effort and innovative problem solving that goes into the design process.  But how?  Here are some ways we can bring awareness to the engineering profession:

1. Community Involvement

One of the easiest ways to bring awareness to the engineering profession is by simply getting involved in the community.  Building relationships with others can help debunk stereotypes, while emphasizing the importance of engineering.

2. Education Programs

Encourage education programs that emphasize the design process. This will help students become active problem solvers, while helping them to appreciate the process instead of simply the final product. 

3. Media Exposure 

One of the most effective methods of gaining exposure for the engineering profession is through the media. Particularly the digital media, as the internet can make an message viral. 

More ideas? Leave a comment to let us know! Remember the engineering community plays an integral role in our developing and growing world, by bringing awareness to the engineer profession we can continue to make gains as a society. 

This article was derived from Alan Werner, P.E. N.S.P.E., "Why are Engineers Invisible" originally published in the Magazine for Professional Engineers in August/September 2013.

Generators: What you Need to Know

Nothing is more frustrating than a power outage.

From unpredictable weather to man-made natural disasters your business's operations are in jeopardy of being disrupted. Even more disheartening is the statistic that when businesses are forced to close because of a disaster, at least one in four never opens again.

By having a generator for your facility, you can ensure that your operations can continue to run smoothly no matter the disaster happening around you.

Choosing a Generator 
There are a variety of generators available and knowing the advantages and disadvantages of both can better help you make an informed decision.   One of the first choices you must make is whether or not to invest in a portable or standby generator.

Portable vs. Standby

Portable generators must be
manually hooked to appliances. 

Portable Generators

During a power outage, you must hook up your portable generator and plug it into the appliances you want to power or a subpanel. While portable generator are less money, they have limitations. Your portable generator can only be hooked up to a certain number of appliances at a time.

Standby generators  are wired into
 the building's electrical system.

Standby Generators

Unlike portable generators, standby generators are wired into your building's electrical system through a power switch.  Your standby generator will automatically start during a power outage.  A standby generator isolates your "emergency" electrical wiring and provides power to the selected equipment from the normal power source which then transfers the emergency load to the generator.  When power is restored the switch will also connect "emergency" circuits back to the utility lines and turn off the generator. In addition to the convenience of automatic switching, permanent generators offer higher power levels compared to portable units and longer run times.  

Sizing your Generator 

To choose the appropriate sized generator you must determine what your electrical needs are. Consider all the items you would like to power during an outage. Find the wattage and the year it was made. Add up the wattage of all your appliances and other items you want to power and double it. This can give an estimate of the amount of 

Choosing the Right Fuel

Most generators run on gasoline, but there are also other fuel alternatives that  s depending on your needs.

Natural Gas

Advantages:  Cleaner compared to oil and coal, inexpensive and readily available.

Disadvantages: Extremely explosive and a fire hazard, emits carbon dioxide and it is a limited or non-renewable resources.

Propane

Advantages: Long shelf life, doesn't evaporate overtime, clean burning, quieter engine noise level, and more emission compliant. 

Disadvantages: Pressurized cylinder of flammable gas, fuel system is more complicated, tanks are not as aesthetically pleasing, fuel system plumbing results in higher installation cost, somewhat expensive fuel.

Diesel

Advantages: Higher ratio of costs to energy density, assures steady power,reduces maintenance because there are no spark plugs or wires, long life span and least flammable fuel source.

Disadvantages: Expensive, tends to be nosier, large and bulky and considered a pollutant.

Be Careful What you Say...Your Walls Could be Listening!

Princeton researchers develop a way to
 embed ultra-thin radios  to plastic sheets. 

Eavesdropping just took on new heights with the creation of walls that can listen and even speak. 

Researchers at Princeton University have developed a way to embed ultra-thin radios to plastic sheets, which can be placed on a variety of structures.  These listening walls have the potential to be the foundation for invisible communication systems inside buildings or to function as sophisticated structural monitors for bridges and roads. 

Originally the intent of this technology was for the application of smart building energy management. Through the use of distributed radio arrays that are patterned on wallpaper, temperature sensors and occupancy sensors are able to communicate with a central management system. 

These thin plastic sheets have the potential for several applications. The sheets can be painted without diminishing their function and can be applied to irregular surfaces such as bridge decks or supporting columns because of their flexibility. 

Patterning Circuits on Plastic 

One of the major difficulties with this technology was patterning circuits on the plastic sheets, as the high temperatures needed to create circuitry will melt the plastic. New methods for patterning circuits on plastics have helped researchers surpass this problem. However, these new methods compromise the performance of electronic components such as transistors, which are vital in the operation of complex devices such as radio transmitters. 

Transistors, the building block of modern electronics, are devices that control or switch the flow of electrons in circuits. The silicon crystal that forms the base of transistors allows for electrons to move quickly.  

Because plastic is susceptible to melting at high temperatures, researchers turned to amorphous silicon transistors in place of crystalline silicone, as amorphous silicon does not require high temperatures like the crystal form.  However, amorphous silicon lacks the highly ordered inner structure of the crystal form. This inhibits the electrons ability to move efficiently, as it is like changing from a smooth superhighway to a gravel road. 

Researchers were poised with the challenge of speeding up the movement of electrons through the transistor (faster movement means higher frequency), despite the lower-performing amorphous silicon transistors. 

The Super-Regenerative Circuit 

To overcome this problem, the Princeton researchers found inspiration from the father of FM Radio, Edwin Armstrong. In 1922, Armstrong developed the super-regenerative circuit, which uses other components to increase the radio's frequency and bypass the poor performance of the amorphous silicon transistors. 

In 1922, Edwin Armstrong
developed the super-regenerative circuit.

By bouncing electrons between a capacitor and an inductor, the super-regenerative circuit, is able to store and discharge energy.  The energy change caused by the bouncing electrons depends on the super regenerated circuit's capacitor and inductor--not the transistor.  This allows the radio to operate at a high frequency despite the poor quality of the transistors. 

The key was to prevent the electrons from being lost as they bounced back and forth between the capacitor and the inductor, as lost electrons would than be compensated through the faulty transistors. This meant high quality capacitors and inductors.  

This was good news to researchers as large inductors are easier to build. And due to the fact that the radios were designed to fit on walls, there was plenty of space. In the end, despite the poor quality transistors, the circuit worked perfectly with the new system.  

The Future of Structural Monitoring Systems? 

Researchers are developing ways to use this technology to create flexible structural health monitoring systems for bridges, buildings, pipelines and other structures.  

Plastic sheets embedded with radios
could better detect structural problems. 

Currently, engineers are able to use single-point sensors or fiber optic strips to detect structural problems. Unfortunately these devices are limited and can only collect data from relatively small spaces. This makes detection of early problems difficult, as most problems occur on larger spaces. 

Plastic sheet technology could make monitoring these structures more efficient.  The linked sensors could potentially detect imminent structural problems over larger areas. 

While the research of this project still remains in early development the results are encouraging. A prototype is in the works, but it will take many years of research and development before this technology is utilized in such a manner. 

This article was originally published, "The Walls have Ears: Princeton researchers develop walls that can listen, and talk" from Phys.org on August 21, 2013.  

Sick? Your Air Conditioning Could be the Cause

Is your air conditioning making you and your family sick? 

For many, air conditioning is the embodiment of comfort living, particularly in the summer months when the heat index can be unbearable.  But could your air conditioning be causing more harm than good? 

According to the Director of the Common Cold Centre at Cardiff University in Wales, Professor Rob Eccles, exposing the body to extreme temperatures could actually make you sick. 

 Here's Why: 

As warm blooded animals, the human body's optimal temperature is around 98 degrees Fahrenheit. In extreme cold environments the body will fight to maintain this body temperature.

Cold temperatures cause blood vessels
 to  constrict and diminish number 
of white blood cells.

One of the body's defense mechanisms against the cold is the thermal regulator in the brain. As soon as it receives a message from the temperature sensors in the skin, the blood vessels are alerted to constrict. This immediately causes a person's skin to become ashen or mottle, which is quickly followed by shivering in order to generate heat to raise the body temperature. 

As a result, the blood vessels in the nose and throat, both of which are favorite locations for bacteria and viruses to hide, will constrict therefore limiting blood flow. 

As the blood flow diminishes, the white blood cells that typically fight bacteria and viruses do too. This allows these dormant risks to develop in to colds. Low blood flow to the throat means that there isn't enough white blood cells to ward off infection. 

Sweating exacerbates the problem because it keeps the body colder. This makes it more of a challenge for the body to maintain its optimal temperature. 

Going from hot to cold environments could put
you at risk for a cold. 

Professor Eccles emphasizes that a cold will only develop if the bacteria or virus is already present in the body.  

This phenomenon occurs when going from a hot environment to a cold atmosphere not the other way around. Though, Professor Eccles recommends limiting the number of times you go from a cold environment to the hot outside as when your body acclimates to the heat and steps back inside the chilling cycle will begin again. 

This article was derived from the headline "Does Going from Hot to Cold Cause Colds?" which appeared on August 20, 2013, in the U.S. edition of The Wall Street Journal. 

Benefits of Green Building

The green building phenomenon is sweeping across the world, but many doubt the benefits of this movement.

Instead, they believe it is simply a political agenda or a means for more costly construction projects.

The reality is, a green building project can have environmental, economic and social benefits as described below: 

Environmental Benefits 

• Emission Reductions--Green building techniques such as solar powering and daylighting can increase energy efficiency and reduce harmful emissions.
• Water Conservation-Implementing water recycle programs for urinal flow and irrigation can significantly lower water consumption and increase savings.
• Temperature Moderation-Conscientious building designs and site selection can reduce the urban heat island effect caused the heat retention properties of tall buildings and urban materials.

Economic Benefits

• Energy & Water Saving- Green design and technology can drastically reduce operation costs. This can offset any additional project costs, while offering long-term savings. 
• Increased Property Advantages-Low operating costs that come with green facilities can lead to lower vacancy rates and higher property values.
• Increase Employee Productivity & Health-There is a positive correlation between indoor environmental conditions and improved employee health and productivity. 
• Sales Improvements-Studies show stores with more natural light have more sales. 

Social Benefit 

• Improved Health-Poor indoor environment quality can contribute to respiratory problems, allergies, and nausea headaches. Implementing green building features can provide for a healthier and more comfortable living and working environment.  
•  Improved schools-About 40% of the schools in the United States are subject to poor environmental conditions that can affect the health and learning of students.  Studies show that schools utilizing green building techniques often experience a reduction in student absentees and see an improvement in test scores. 
• Healthier Lifestyles & Recreation- Sustainable designs preserve natural environments and provide for more recreation and exercise opportunities. They also promote alternatives to driving such as bicycling and public transport. 

What’s so special about Clubhouses?

Ballen Isle Country Club
West Palm Beach, Florida

The Complexities of Designing HVAC Systems for Clubhouses  

Clubhouses are unique among buildings. They house restaurants, community centers, banquet halls, entertainment complexes, retail spaces, fitness and spa centers and even offices all wrapped up into one facility! 

Dripping Diffusers

The clubhouses' unique nature is one of the major reasons why faulty HVAC systems are common; especially in humid climates such as Florida.

Perhaps, one of the most frequent issues that engineers uncover during a due diligence survey is a facility operating under a severely negative air pressure condition.

Common Symptoms of Negative Air Pressurization  

•  A lack of fresh or clean air, instead a musty smell or other bad odors lingering in the air
• Condensation on the Diffusers
• Visible Mold or Mildew Growth along with Moisture on the Walls 
• Sticky or Damp Furnishings
• Varying Temperatures Throughout the Facility 
• Stagnant, Stale or Heavy Air that causes Humidity or Condensation 
• A Rush of Air or Draft when Opening an Exterior Door 

According to Bob Davenport, RGD Consulting Engineers' Principal Engineer, who has over 35 years of experience designing HVAC systems, "Operating a clubhouse with severely negative pressure can result in serious indoor air quality problems over time." 

Solutions

 If not caught before the start of microbial growth, negatively pressurized facility can be a costly issue to rectify. This is why having the proper HVAC equipment and a good maintenance program is important to preventing issues such as negative air pressure from occurring. 

Ensuring that the clubhouse building is equipped with 100% outside air pre-conditioner, runs continuously and supplies a constant and equal volume of dehumidified outside air to the building is key to maintaining the air pressure. 

There are a variety of methods for achieving this goal, and the most effective HVAC design system can be determined by a professional engineer after completing a thorough survey of the facility's systems. However, even the best designed HVAC systems can fail when they are not maintained. 

Just as important as working closely with an engineer for the design of your facility's HVAC system, is the creation of an aggressive maintenance program.   With these two factors planned well, your facility's HVAC system will stay balanced and healthy for years to come. 

This article is adapted from "Is Your Clubhouse Stuffy" written by Robert Davenport, PE, LEED AP + BC. 

Self-Healing Concrete...the Future of Structures?

Bonita Bay Country Club Construction 2013
Bonita Springs, FL 

Self-healing concrete? It's closer to being possible than you think.

Concrete is a remarkable material. It can be molded into a number of forms, it sets like stone and it is extremely strong when combined with a metal such as steel.  It's no wonder it is the basic structural foundation for buildings, roadways and bridges.

Despite all these notable qualities, concrete has a major weakness--water.  Water poses a serious threat to the stability of a concrete structure, as all it takes is one small crack for water to get inside to turn a concrete structure into a pile of rubber.

Corrosion of the rebar in concrete. 

In colder climates, water can freeze and expand, compromising stability.  Water can also bring carbon
dioxides, sulfates and sulfate reducing bacteria that can cause even more damage to a structure. Perhaps the worst consequence of water in concrete is if it reaches the metal rebar. Overtime, the metal will rust, expand and slowly destroy the structure.

The key to preventing water from entering concrete is preventing the cracks from occurring. This is easier said than done. As even the most carefully prepared concrete is susceptible to cracking, especially when in a moisture prone area.

Researchers at the University of Bath in collaboration with Cardiff University and the University of Cambridge may have discovered another way to prevent concrete from cracking--a concrete mix with bacteria within microcapsules. The hope is that when water enters a crack, the bacteria will germinate and produce limestone, which will then plug the crack before water can do damage to the rebar.  The bacteria would actually use the oxygen present to repair the structure.

While this study is still in its early stages, researchers are optimistic that self-healing concrete will be able to increase the life of concrete structures vastly and would remove the need for repairs, reducing the lifetime cost of a structure by up to 50 percent. It would also reduce man-made carbon dioxide revisions.

Currently, researchers are assessing how the varying strand of bacteria survive in concrete over a period of time.

Thermostat Wars: HVAC vs. Home Security Industries

The HVAC industry is battling with homeowners, home security and home automation companies to determine who has the authority to install thermostats as a part of "smart home systems." 

The issues has taken on new heights with several HVAC industry organizations pushing for legislation to prevent home security and other non HVAC companies from replacing thermostats with products that communicate with security and home control systems. 

HVAC companies claim that HVAC systems use exclusive protocols and special communicating thermostats to control equipment that don't follow standard thermostat configurations, protocols or wiring. 

According to Dominick Guarino, the CEO of the National Comfort Institute, this approach to this issue has little substantiation, as many home security and home automation companies have their employees complete extensive education to be able to install this technology. However,  the issue that should be at the forefront of this battle, is who is responsible if the technology is incorrectly installed.  

Guarino recommends that instead of fighting this issue on a government level,  HVAC companies should fight this battle in the marketplace through education.  Let your customers know that having a third party install an intelligent thermostat could have negative consequences.

To learn more about this issue, visit the original article here.

Due Diligence: Why you Need it Before Buying

Buying a building can be a daunting task, but don't let a bad decision haunt you for years to come. Being a pro-active buyer and having a professional engineering firm perform due diligence to your facility prior to

your purchase can significantly decrease problems later down the road.

What is Due Diligence? 

Due Diligence is the process of systematically investigating and verifying the condition of a facility in order to audit the potential investment. If you are considering purchasing a commercial property,  due diligence can confirm that your intended use of the facility is possible.

A professional engineering team can help you evaluate whether or not there are any major issues with the building.  After the analysis of your facility, the firm will produce a report of their findings that will include:

1. Analysis of the structural, mechanical, electrical, plumbing and fire protection systems' conditions and adequacy. 
2. Estimated life span of existing equipment and structural support. 
3. Recommendations for immediate repairs and replacements.
4. Upgrades for improving existing systems' efficiency and reducing costs.
5. Building Code Violations that needed to be addressed.

Are you looking to Buy?

 Let RGD Consulting Engineers help you get the most of your investment.  While many engineering firms specialize in particular areas, RGD is a multidisciplinary engineering firm and able to evaluate all your structural, mechanical, electrical, plumbing and fire protection systems.  Contact us to see how we can help you on your next project.

Understanding Green Certification Programs

As the Green Building movement expands, so do the resources available to design professionals and business owners.  Knowing your your project's objectives and goals can help you determine what

certification program is best for you.

Here are a few organizations that offer Green Building Certification program:

1. The Global Building Initiative (GBI)  

The Green Building Initiative is a web based green building program. This LEED alternative is, aims to reduce a facility's overall environmental impact, while improving sustainability.

The program is geared toward new construction and big renovation projects, but offers guidance and a cost effective green building rating system.

The GBI can help reduce operational costs, qualify for tax incentives, meet federal mandates or increase the marketability of your buildings.

2.  GBC Florida Green Commercial Building Certification Program.     

This nonprofit corporation is committed to spread the green building initiative in the state of Florida.  They provide a variety of resources and sponsor a variety of education programs for design professionals, consumers and government entities.

3. USGBC's  LEED Program 

LEED or Leadership in Energy & Environmental Design, offers flexible and comprehensive certification programs that address the entire building's lifecycle. 

With LEED, building owners and operators have a practical means for measuring and implementing green building design, construction, operations and maintenance solutions. 

LEED uses third-party verification to determine that a facility or community was built with environmental and sustainability in mind. 

LEED Green Building Certification to Include Cradle to Cradle

Despite the controversy surrounding the federal governments preference to LEED building certifications, the latest LEED Version 4 rating system was overwhelmingly approved (85 percent) last week by the U.S. Green Building Council with the inclusion of the Cradle to Cradle Certified Program. 

Developed 25 years ago by American Architect William McDonough and German chemist Michael Braungart, Cradle to Cradle aims to enforce the environmental qualities of materials used in green buildings. 

“We salute the USGBC’s courageous leadership in making material health a priority in the face of immense challenge from industry,” says William McDonough. “The stand they have taken will help continue their meaningful input as an agent of market transformation.”

Cradle to Cradle will officially be adopted into the LEED certification criteria in November 2013.  

What does that mean for your LEED Project? 

With the addition of Cradle to Cradle to the LEED Version 4 rating system, you can get credits for materials & resources if you disclose and optimize where your building materials are sourced and purchased. 

Facilities that utilize at least 20 Cradle to Cradle Certified products or use "at least 25% by cost of the total value of permanently installing building products" can earn points toward certification. 

For more information visit USGBC or view the original press release. 

• Cradle to Cradle® is a registered trademark of MBDC.
• Cradle to Cradle Certified^CM is a certification mark licensed by the Cradle to Cradle Products Innovation Institute
• U.S Green Building Council is a certification mark licensed to the U.S. Green Building Council.