Distilled or deionized water typically has a microSiemen value of approximately 0.05, while most drinking water in North America ranges from 100-200µS. Data from the water management group at MetroVancouver, however, shows that water in the local reservoirs average around 25 µS! This poses a problem when water is heated using electrical energy, as this low electrical conductivity can come into play.

Take electrode heaters – they require a minimum of 70 µS in order to ensure that the water will be heated completely and efficiently. Not meeting that minimum cause’s excess energy to be used.

So while we enjoy the fresh taste of arguably the cleanest H2O on the planet, it’s clear that our water cannot produce a large enough current to heat itself properly, thereby affecting the temperature of the heated water or the quality of the steam that is produced.

Let’s put this into perspective using a real life example.  For the Jim Pattison Outpatient Care and Surgery Centre, in Surrey, BC, electrode steam generators were used to provide humidity of the supply air stream for the six operating theatres. Electrode units were chosen to ease the maintenance program for the healthcare centre. However, with the domestic water supply reading a microSiemen value of 10, steam was not being injected into the airstream, but rather hot water droplets. This caused the inside of the air handling units to become wet and didn’t provide the proper humidity to the air stream.

In order to raise the electrical conductivity of the water, we implemented a salt water injection system to provide the minimum 70 µS required. It worked like a charm!

So, when choosing water heaters or steam generators, be sure to understand the heating method used, as the water properties can greatly affect which method is chosen. This might be the only time you want to opt for unfiltered.

With buildings being responsible for over a third of green house gas emissions in Canada, a 17% cut in the emissions from the built environment, in a relatively short time frame, is an ambitious target. As a clear indication of the challenge we face, the Government revised their 2012 carbon emission targets downwards in June 2010, as there was little hope in achieving the original goal. 

As Engineers, we like a challenge and as mechanical and electrical engineers, we not only have the ambition, but also the knowledge and the tools to achieve a sustainable built environment. Right now, with today’s technology and knowledge level we can get to net-zero energy use buildings, even “living buildings”.  So, if we know how to do it, why isn’t every building designed to be as energy efficient as possible?

Well, human nature means people like to be incentivized to do things, and as individuals, we will each be driven by a different set of incentives. We may be passionate about our day jobs, but would we continue to go to work on those cold winter mornings if we weren’t paid? Some people wouldn’t, while some people would because remuneration is not their main or only incentive. 

The moral and social incentives of reducing green house gas emissions to avoid the adverse effects of climate change and improve air quality have not been sufficient to trigger the step change in approach and attitude required. While policies are developed at a national level, the federal structure in Canada does not obligate provinces to implement and legislate these policies consistently across the nation, making it difficult to incentivize the provinces and municipalities to contribute towards meeting national emission targets. The lack of reference to an energy code, whether it be ASHRAE 90.1 or MNECB, in some Province’s building codes is a clear outcome of this, and a significant barrier to the reduction of building GHG emissions.

With a revised version of the Model National Energy Code for Buildings soon to be released, swift adoption by all provinces will provide the coordinated political will that is necessary. The new MNECB will promote the use of “absolute energy” (energy intensity) use benchmarks in kWh/m²yr, instead of the existing methodology of percentage energy cost reductions from a reference building, removing some of the current complexity and confusion. 

The lack of an economic incentive is probably the biggest hurdle to overcome. The low cost of energy in Canada currently offers building owners and operators no incentive to incorporate energy efficient design into their buildings. However, with rising energy costs, and oil prices edging towards $150 a barrel, the winds of change may soon blow in favor of energy reduction.

But, do we have the luxury of waiting for market forces to do our bidding to meet the GHG emission targets? Or should we drive the desired behavior now via manufactured incentives?  To date, incentives have been successfully implemented in parts of Canada and many European countries.

The long payback period of many low-carbon and renewable technologies has been a barrier to their inclusion on many projects. Feed in Tariffs (FIT), where renewable energy generators are paid a premium for the energy they produce for a guaranteed term, help to produce a decent return for the investor, typically lowering the payback period to 10-15 years. FIT’s have been successfully applied in Ontario, where it is helping to replace coal-fired generation, and many European countries, particularly in Germany, where the renewable energy sector now employs 340,000 people and has a turnover of €8.7 billion.

Another potential form of incentive is the development of energy budgets for buildings and the introduction of ‘fines’ through higher energy prices for buildings that exceed this budget. This may appear controversial to some, but we should not avoid debating this degree of step change because it seems too difficult and complex to achieve.
M&E engineers must take a leading role in this debate and the promotion of energy performance as an incentive and key driver of design rather than an add-on, since this will provide the best opportunity for future projects to meet financial targets as well as energy targets.

It’s an exciting time to be working as an M&E engineer in the construction industry and I believe we are up to the challenges that lay ahead, but a little help from incentives wouldn’t be a bad thing.

In my books it’s fraud and greenwashing at its best.  While I like the fact that a lot of folks are getting on the ‘green’ bandwagon and trying to require better building performance in terms of sustainability; however, unless the project is, in fact, vetted by a third party review and granted LEED Certification, it’s meaningless to use the term LEED Equivalent. I have to wonder how the USGBC and CaGBC will begin to clamp down on their brand and the un-paid use of all their intellectual property in the form of LEED checklists and documentation materials. I’m pretty sure that Starbucks® would be all over me with lawyers if I opened a coffee shop and called it “Geoff’s Starbucks Equivalent Coffee”. 

There are also many building developers who like to promote their new buildings as being LEED Equivalent. I wonder if it’s okay to promote a building as being “Code Equivalent”?  How would the occupant feel if he knew his condo was built to Code Equivalent?  Well, gee, we didn’t comply exactly to the code required piping, but it is equivalent to what the code required…it’s metal, long and has a hole at both ends, etc. – that kind of argument wouldn’t get too far at the building inspector’s desk, that’s for sure!

I think the USGBC and the CaGBC are in a tough spot. The purpose of the LEED program from the beginning was “market transformation”, and in the last few years, the LEED uptake has been growing exponentially. So it probably pleases the green building councils that everyone is recognizing the brand and using it to try to seek improvements in the built environment, but at what cost to them?  Will this further dilute the LEED brand and the effectiveness of measuring and comparing if buildings are becoming greener and more sustainable?  If the green building councils come down hard on the folks that are calling their buildings LEED Equivalent, will this lead to a backlash against LEED and slow the market transformation?  I know all the institutional, municipal, and provincial folks are well meaning when they call for new buildings to have some kind of green building approach brought to bear, but again, I ask – what, exactly is LEED Equivalent if nobody is going to vet or enforce the LEED credits being sought?

It’s like taking an exam at university, but knowing it’s not going to be marked. Do I still pass the course?  Do I still get to call myself a mechanical engineer?

The trouble we have as consultants to the industry is that we are service providers, and if the client wants that service, we’ll be too happy to provide it. After all, we need fees to feed our machine, right? As a design professional, I have to question the ethics of using someone else’s intellectual, trademarked property to satisfy a client, knowing that the LEED Equivalent route is being taken, and the CaGBC isn’t going to get anything in return, even though we’ve used their materials. Isn’t that like using pirated software?

I think we as industry professionals need to take a stand and tell clients who want LEED Equivalent, that we won’t provide that service, we won’t fill in the LEED scorecard, nor will we perform any act that requires the use of the LEED materials. Oh, we’ll still have to do energy modelling, since most building designs around here couldn’t comply with the prescriptive requirements of ASHRAE 90.1 Energy Performance standards anyway.  What we should be selling is full-on LEED registration and certification.  If it ain’t LEED certified, it ain’t nuthin’.

I also think that the developers, municipalities and anyone else who is writing the terms LEED Equivalent into their project requirements needs to think long and hard about how any enforcement of the “equivalent” part of the process will be addressed. Are we on the honour system here?  Human beings are not the best examples of sticking to the honour system if enforcement is weak or not performed at all. Especially when this industry is based on seeking fixed fees for building projects. You can bet that if it is known that certain things are never going to be checked at the end of the day, it’s pretty easy to rationalize the scope of work towards trying to keep the business afloat.

At the end of the day, it’s about integrity. If we want to be accepted and treated as professionals, then we have to maintain a level of integrity, and that requires that we treat the use of other people’s copy-written intellectual property for what it is.

Let me assume my curmudgeonly “old guy” role here for a little bit. I started out on the drafting table with a slick Vemco V-Track drafting machine – a selection of mechanical pencil leads, and a deluxe electric eraser for rendering drawings on vellum paper. Then I graduated to plastic leads on mylar film, and in the late 1970’s the new Pin-Bar System was introduced, with the sales pitch to make our business faster and easier! The key point here was that in order for us mechanical designers to start and finish our working drawings, the architectural and structural design HAD to progress     to a point where the design and drawing changes were going to be minimal, and where we could quickly add our material to the overall package. No one liked the erasure marks and blemishes on the drawings where changes had to be made to the backgrounds to suit architectural wall changes! It was unprofessional and messy.

The “Early” Advantages of the Pin-Bar System

The Pin-Bar System used from the late 1970s through the early ‘80s helped render cleaner looking drawings because the architectural backgrounds and structural elements were on separate “slicks”, as we called them.

This system allowed the separate discipline drawings to be layered over each other in an indexed manner for coordination checks and fine-tuning before they got printed for tender, as well as reduced re-drawing at the Consultant level, resulting in faster and easier drawing production.

As mentioned earlier, architectural and structural disciplines HAD to be completed up to a point where further design and layout changes were minimized before the mechanical and electrical disciplines drew their final detailed tender drawings on top of the architectural and structural slicks. There was still an integrated design path where all of the disciplines fed the architect and structural consultant their required clearances, and coordination requirements prior to committing to the final drawings, using tracing paper and hand-drawn sketches.

Entering the AutoCad® Age

I went to an early computer aided drafting course back in 1982 when the CAD programs required a mainframe computer, a digitizing tablet as big as a desk, and detailed computer programming language skills to manipulate the program. The early CAD programs were mainly developed by large aerospace and automobile corporations.  They were mainly intended for machine design where repetitive details and common machine design components needed to be designed, for converting into computer aided manufacturing (CAM) processes for computer driven milling machines and lathes to spit out hundreds of the same part. I came back convinced that this technology would be very slow to invade the architectural and building design industry, since every building was a unique, one-off product i.e. Model #1, Serial #1.

It was still a heck of a lot quicker at that time to get out a pencil and straightedge and whip up a decent plan, versus using a CAD program originally developed for machine design and trying to adapt it to drawing building systems and plans.

The mid to late 1980s…

CAD programs and the computer industry were advancing by leaps and bounds by the mid-1980s. In the very early 1980s we had the first “personal desktop computers” coming into the office – remember the Radio Shack TRS-80s, IBM PC’s, Apples, Atari’s, Osbournes, etc. and the associated 8” floppy disks of data and programs!  By 1988 the first few large architectural firms in Vancouver were starting to use this great new CAD stuff to design buildings, and we sub-consultants had to scramble to keep up if we wanted to work with these folks. Basically adapt or die!

I started to see the issues I worried about back in 1982 come to a head – many architects used different CAD software which required translation to enable the AutoCad® software to read it (Arris, MacDraw, Holguin, etc.). Even those architects that DID use AutoCad® software used different line types, layer types, and drawing formats which still required a great deal of conversion effort before we consultants could use the base plans delivered by the architects. There was a huge slow-down in the design process as the building design industry embraced and climbed the steep learning curve of using all this new technology and software. The drafting exercise now turned into learning a detailed computer language, and complicated micro-coordination of all of the baggage that comes along with making a lot of colored lines on a computer screen print out as a readable drawing! The drafters’ brains became full of computer and techno language, and the knowledge of what it was that we were actually trying to draw became secondary to the whole exercise.

In the 1990s…

By the early 1990s, the building design industry seemed to settle down to AutoCad® as the default CAD software. The problem was that all those early versions of AutoCad® were trying to be “all things to all people”, and the software wasn’t specifically adapted to what we were used to drawing in the buildings industry. Through the 1990s we all learned to standardize the line types, layers, and drawing file exchange formats to the point where we were actually getting productive.

However, the formerly fairly rigid building design process turned into anarchy - clients and architects could make design changes right up the last minute before tender, and expect the rest of the design team to instantly pick these up in the new CAD file that was e-mailed, and then send the drawing files out for printing. Window areas got changed at the last minute, floor plans were changed at the last minute, various fundamental drawing elements got changed at the last minute – causing much gnashing of teeth for the sub-consultants who had to re-calculate room airflows, cooling and heating loads, lighting layouts, and major drawing elements in a panic to get the tender documents out. Getting enough time to check and coordinate the building systems drawings became non-existent. Add to that the fast-tracked construction management process, where building systems were tendered well before the architectural plans were complete – and we get to where we are today.

Revit®, BIM, and Beyond

I actually have high hopes that the 3-D building design modeling software that is now taking our industry by storm allows us to return to a more disciplined building design process because the architectural model and structural model must be designed and rendered to a more finished stage before we building services folks start plugging in our services elements to the model. I fantasize that this will be almost like going back to the Pin-Bar System, and force the client and architects to advance the building design a lot earlier in the building delivery process.

Implementing Revit® and 3-D building modeling into the building design process will take another decade before it becomes mainstream – to the point of actually adding to better building design and a more productive building design process.

We’re in for an interesting ride, I think.  Like any tool, used properly, it can certainly enhance the building design and delivery process, but on the other hand, as we’ve learned from the 2-D CAD era, garbage in = garbage out….

“It would have been better to install the VFDs in the corridor,” says the maintenance contractor. “Reading the display upside down is okay, but I’m going to have to lie on my back to change a fuse.”  The ceiling is 20 feet above, and there is a decorative drywall ceiling below half of the AC unit – so we all agree,  yes, it would certainly be tough to lie on your back up there.

The mechanical contractor and I exchange a glance and recall when the VFDs were installed, all we thought of at the time was making up schedule delays, commissioning life safety systems, and figuring out why the toilets didn’t work on the 3rd floor, and not about changing fuses on VFDs. What the Operations Guy didn’t know was that the hallway had been redesigned three times before he had a contract to look after the building’s HVAC system, which required relocation of mechanical and electrical systems as well.

The fact is: the engineer, contractor, and Operations Guy are all looking out for the owner’s best interests; however, we’re all coming from totally different perspectives. Between controlling costs, satisfying the fire department, and meeting deadlines, there are considerations that fall between the cracks and get left up to the owner’s Operations and Maintenance (O&M) team to deal with.

Rather than having the Operations Guy feel frustrated about taking over a new building that already has “quirks”, can more of these things be dealt with up front?  What incentive is there for the owner and the design team to spend more time on operational requirements?

Back in the eyewear shop, we hypothesize about the VFDs. If the Operations Guy charges out at $190/hr and spends an extra 30 minutes a year servicing a dozen other VFDs like this, over a 40+ year lifetime of the building, that’s a lot of time and money on an item that is usually overlooked and can easily be avoided. Could a half-day of the Operations Guy’s time at the front-end of the project have saved all that?  Probably, and then some, if he also looked at plumbing, lighting, door sizes, and elevator access etc. In most instances, making the point to incorporate O&M input at the design stage will pay for itself before the building is a year old.

Photo: Variable Frequency Drives mounted below a Heat Recovery Ventilator in an eyewear retail suite.

Extending an elevator or stairwell one more level to the roof may eliminate the need to close streets and hire a crane truck to service rooftop equipment. Interlocking sump pumps to the security system may prevent an undetected flood in the electrical substation. And locating VFDs in a back corridor would avoid after-hours service inside a tenant’s space. None of these are code requirements, and all of them carry at least some extra capital cost – but closing the street for a crane truck will soon make these seem trivial.

The bottom line is that different buildings have different needs that are not always predictable. No matter how experienced the engineers and architects are, something can always be done better, in hindsight. Involving O&M staff at the beginning takes time, and may even seem patronizing at first, but in the end it is extremely beneficial.

Final thoughts at the eyewear store: That VFD on the ceiling will stay where it is because the landlord is receiving rent, the tenant is making money, and the building is bright and comfortable. It’s a good reminder of that one more thing to look out for next time – unfortunately it was too late this time.  The Operations Guy thanks us for hearing him out, and leaves us with, “we need your engineering expertise, but sometimes you need a little of my grey hair too.”

“Don’t worry we’ll use bio-fuels or hydrogen to replace oil”
“Don’t worry, we’ll find more oil anyway”
“Don’t worry somebody will develop cheap fusion power”

I’ve become much less a believer in techno-solutions, and I am putting a lot more faith in sticking to the basic fundamentals of better passive building design equals low energy, high comfort buildings.

Taking the low-tech approach

A common inquiry in most building construction discussions is: “how can I save money by using high efficiency equipment?”

The assumption is that the only way to improve the energy efficiency of a building is to replace heating or air conditioning system equipment with new “high efficiency equipment”. This mentality is also used for new construction.

How often have you heard: “I’m building a new house and I want to know the best/most efficient system to heat and cool it?”

What is completely ignored in this thought process is that the heating and cooling systems are sized to make up for heat lost or gained through the building envelope.  Therefore, the first place to design energy efficiency into a building is at the roof, walls and windows. A high efficiency heating plant in a low efficiency building is like trying to improve the mileage of your SUV by dropping in a Toyota engine, but you still end up using almost the same amount of gas and lose the speed and performance of the SUV.

I don’t understand why people think that there is so little they can do about the building envelope, and that the only way to design an “energy efficient building” is to use high efficiency mechanical systems and equipment. Maybe it’s because the whole building industry has been so fractionalized into a large number of building system specialists, and those individual specialists are blind to the rest of the building design issues that they don’t have any perceived control over. 

As an HVAC systems designer, I learned early that the first thing you do is the building heating and cooling load calculations. What I saw after years of designing HVAC systems and selecting appropriately sized high efficient boilers and chillers (sometimes I’m a little slow on the uptake too) was that the whole HVAC system sizing, capital costs and operating costs were in direct relation to the quality of (or lack of) the building envelope design and construction.  Hey! I said, maybe if the building envelope design was altered to use more insulation, better windows and some kind of exterior shading to keep the direct sunshine from creating excessive internal cooling loads, I could save a ton of money on the HVAC systems, as well as being able to have a very energy efficient system operation.  A very low-tech approach!

A business without incentives

There are many climate zones in North America where a well designed envelope and window system can allow a very low energy, small HVAC plant to keep the indoors comfortable, with lots of natural daylight (but minimal solar heat gain loads). The common argument is that the “payback” for the expensive envelope and window construction just isn’t justified. I think that’s because the building industry, like all industries, are programmed for “economic growth”, increased sales, move more product, etc. So the last thing a building HVAC designer wants to do is to reduce his scope, lower his sales potential, and cut down on potential fees and profits. The other problem is what kind of HVAC system is being used for the cost-benefit study effort as the baseline comparison? There are radically different capital and operating costs between a forced air heating system and a hydronic heating system, and the economic study has to be base-lined to get as close to apples and apples comparisons. That’s a lot of detailed work for most designers and HVAC contractors, and with the net effort being made to reduce the HVAC systems and costs (and potential fees based on a percentage of the system costs), where’s the incentive?

Knowledge is power – do your research!

The average public, due to their lack of understanding and knowledge of how buildings are designed and built, can only use “cost” as the common discriminator when comparing options and alternatives. The understanding of different levels of performance, quality, and operation are only compared on a straight bottom line capital cost comparison. It is not uncommon for most people to think that there is no difference in comfort or operation between a forced air heating system and electric baseboards, except that the installed cost of the electric baseboards is a lot cheaper than the forced air heating system. All that is understood is that both types of systems will heat the space, right?

One of the best techno-solutions I’ve found in the last five years is the internet and web search engines. Imagine - the biggest library of information at your fingertips accessible   anytime, anywhere! I think that there is no excuse for someone who is investing a huge portion of their finances in their own home or new building project to not research and learn as much as they can prior to blindly leaving their fate in the hands of designers and builders. There is more to building a house than choosing the colour of the granite countertops and light fixtures. If you think that the building codes and city inspectors will make sure the builders are doing it right, you are sadly mistaken. 

This is a quote from Canadians for Properly Built Homes: 
“Many Canadians are living in a home that does not meet the minimum health and safety standards of the building codes as these codes are often not being enforced by municipal inspectors during construction.” 

I live in the Vancouver area, one of the world centres for leaky condos, and having seen how these things are built, it’s not surprising at all to me how these building disasters happen. The only thing I wonder about is how many more problems are we not reading about are swept under the rug or ignored. Has the home buying public become so numbed by the lack of quality in buildings that “mediocre” is the acceptable level of quality?

REFERENCES/FURTHER READING:

1. Canadians for Properly Built Homes  and the associated weblinks.
2. R-2000 Homes- Value for Money? 
3. The Canadian Consumer Information Gateway
4. National Association of Home Builders (NAHB) Research Centre Toolbase

One of the big questions is Why?  Well, what are all these claimed building energy efficiency improvements being compared against?  Part of the problem lies with the ASHRAE 90.1 Standards for Building Energy Efficiency and their energy modelling rules that compare a mythical Reference Baseline Building energy use and energy cost, to the Proposed Design Building parameters, which is also what the LEED program requires for claiming the Energy Efficiency Credits.

Basically the ASHRAE 90.1 rules laid out in the Appendix G section that covers how the energy modelling comparison is to be made, requires the Reference Building to be exactly the same geometry and physical characteristics as the Proposed Design Building, but use the standard prescriptive minimum values that ASHRAE requires to meet the minimum prescriptive energy use requirements.  Then ASHRAE assigns default systems to the Reference Building to simulate the “business as usual” building HVAC and Lighting systems, while the design team assigns its proposed building systems and operational parameters to their Proposed Design Building Model.

Hey, wait a minute!!  This means that if the Proposed Design Model has already incorporated best solar orientation, external sun shading, and an articulated façade to reduce the building heating, cooling, and lighting loads based on passive design approaches, the Reference Building must also include the same basic configurations.  So let’s get this straight – if we do the proper integrated design team approach to incorporate as much passive design approaches as possible before we even think about what kind of energy efficiency systems we want to apply, we don’t get much, if any credit for that !!  So what IS the baseline “business as usual” building energy efficiency we are trying to compare our Proposed Design to?  Well, there isn’t one!

That’s part of the whole problem - there is no real baseline building energy efficiency reference, other than an accumulated average of all contemporary buildings of the same type and occupancy.  One way to describe how this works is the following analogy:

You can take a Humvee that gets 15 miles per gallon in stock form, then tune it up and improve its performance so it gets 20 miles per gallon – that’s a 30% energy efficiency improvement – so assign 4 LEED Energy Credits for that accomplishment.  OK, let’s start with a Toyota Yaris that gets 35 MPG in stock form, and tune it up and improve its performance so it now gets 45.5 MPG, a 30% improvement in energy efficiency.  Guess what – 4 LEED EA credits for that, too.

There is no credit for starting off with an energy efficient building design in the first place.  Both vehicles have four wheels, air conditioning, and a great stereo, and will get you from point A to point B in the same amount of time.  And, in fact, the ASHRAE 90.1 and LEED Energy modelling method allows you to pick the Humvee as the Reference Case, which makes it a lot easier to demonstrate better energy savings for the proposed Design Building!  No wonder LEED buildings don’t seem to save very much energy compared to the accumulated average of all the contemporary buildings that are built “to Code”.  You end up comparing a bad building design (Reference Baseline) with a little bit better “bad building” to achieve “energy reductions”, and some LEED Credits. 

This graph illustrates how the ASHRAE 90.1 energy modelling rules work with respect to the Reference Model to Design Model comparison, and the results.  The GA/EA is the “Glass Area to Envelope Area” ratio, and the bars show how the baseline energy use of the Reference Case changes with the building geometry.  This illustrates the effect of the various cumulative passive building strategies on the annual energy use for this example office building in Vancouver, BC, modeled in compliance to the ASHRAE 90.1 Appendix G Performance Path requirements.  The Humvee’s are at the left and the Toyota Yaris’s are on the right.

Another issue to consider when a building project here in British Columbia is going to be taken through any sustainable building programs like LEED, and BC Hydro’s High Performance Building Program, is that separate energy models are going to be required for each of the following:

•  BC Building Code ASHRAE 90.1-2004 Requirements for Minimum Code Compliance
•  LEED Canada ASHRAE 90.1-2007 Requirements for LEED Energy Credits
•  BC Hydro Powersmart Program – “modified” ASHRAE 90.1-2004 Requirements as well as specific BC Hydro system type requirements.

So, at the end of those energy modelling exercises, when we say this project will save X% energy use against… What?  Which standard?  What Baseline? Compared to what other buildings?  The energy modelling results that are generated by this method DO NOT show the energy that the Proposed Design Building will actually use, and should never be used to predict the actual building energy consumption due to the energy modelling rules being imposed on this process.

One other little nugget of information that any Architects reading this should be aware of – the current BC Building Code which references the ASHRAE Standard 90.1-2004 has a prescriptive requirement of a maximum of 40% glazing to opaque wall ratio, and requires vestibules at exterior main doors for all buildings over 4 stories in height.  What this means is that if the Proposed Building design has more glazing than that, then an Energy Model is REQUIRED to prove Code Compliance by the performance path to show that the building meet the Minimum Code requirements of ASHRAE 90.1-2004.  That WILL incur additional time and effort for the design team to accomplish.