Cool Roofs are a Compelling Choice in the North


Cool Roofs are a Compelling Choice in the North

Dark Roof’s Summer Cooling Penalty is a Deciding Factor

Cool roofs reflect the sun’s energy and reduce air conditioning loads in the summer, so do dark roofs absorb energy in the winter and reduce heating costs? In northern regions where heating costs are significant, can dark roofs be energy efficient? Some building professionals specify dark absorptive membranes for northern cities like Chicago and Minneapolis believing that they are lowering their clients heating costs and lowering year round energy costs.

An analogy, only slightly tongue in cheek, would be to ask if Chicagoans walking along Michigan Avenue in the winter wear dark clothes to stay warmer? Or do dark colored cars outsell light colors in the Windy City?

So, do dark roofs help improve building energy efficiency in northern cities? Let’s take a look at the arguments.

Heating Degree Days versus Cooling Degree Days

There is no doubt that heating degree days in northern areas are far greater than cooling degree days. For example:

Cooling Days

This means that the number of days the temperature was below 65°F multiplied by how many degrees the temperature was lower, was 9,317. This far outnumbers the cooling degree days and some have argued that therefore dark roofs are appropriate for northern cities such as Minneapolis. However, it’s important to examine the cost of cooling versus the cost of heating.

Energy Costs

Data from the U.S. Energy Information Administration for commercial customers in Minnesota in 2015 allows us to compare the cost of heating versus cooling. Assuming gas as the energy source for heating:

BTUs

Added to this, cooling is less efficient than heating. This means that one can’t simply compare the number of heating versus cooling degree days to make a judgment.

Verdict

Degree day comparisons don’t enable a choice of roof reflectivity to be made. Put simply, neither EPDM nor TPO / PVC can be specified on the basis of the number of heating degree days versus those of cooling degree days.

Cooling versus Heating Costs

Heating – Gas Costs

Natural gas is becoming ever more plentiful in the US and costs are fairly stable meaning that heating costs can generally be budgeted for with confidence. Added to that, utilities usually charge commercial customers a flat amount per cubic foot used. Frequently, volume discounts apply and larger customers pay less per BTU of heat than smaller ones.

Cooling – Electricity Costs

Today’s electric bills, especially for commercial and industrial customers, are fairly complex. However, the basic components are as follows:

  • Base Use Rate – the charge per kilowatt hour (kWhr) of energy use.
    • This is common for residential but rare for commercial customers.
    • Can vary depending on the time of year, eg. summer versus winter.
  • Time of Use Rate – the charge per kWhr of energy use that varies depending on the time of day or year.
    • This is increasingly applied to commercial customers.
    • The rate is highest during times of peak demand, such as between 1 and 6 pm. It is lowest during periods of low demand such as 3 to 6 am.
    • If the rate varies by time of year, then summer rates might be highest, when air conditioning use is at its highest.
  • Demand Charge – the cost per kilowatt (kW) of power demand.
    • The charge applies to the highest demand that a customer had for power at any time during a month.
    • To help understand the concept, think of how fast an electric meter is spinning when a lot of equipment is turned on and the air conditioning is running at maximum load. This might be the situation for a short period of time, so energy use could be low, but the power demand could be very high for that short period.
    • It is typically based on the highest power draw seen in 15 minute increments during a month.

All of these components make building electric charges difficult to predict and budget for. Plus, unlike for gas, higher usage levels can dramatically increase the cost of that energy.

Most building professionals clearly understand the impact of the base electric rate or tariff and time of use rates. It is easy to appreciate that lowering air conditioning demand will reduce electric bills. However, those tariffs frequently represent 50% or less of a total electric bill with the demand charge being 50% or larger. By understanding the impact of air conditioning on demand charges, it can be seen that cool roofs have a large role to play impacting building energy efficiency.

Demand Charges

A simple way to think of demand charges versus energy use is to look at an electric meter:

How to read your meter

In a traditional residential meter shown on the left, the upper dials keep track of the cumulative energy use. The lower wheel shows the demand by how fast it is spinning. A more modern or small commercial meter shown on the right displays the same data in a digital fashion.

As an air conditioner does its work during a month, the energy use is added up, leading to an eventual charge based on kilowatt hours. But, on the hottest day of that month, during an afternoon period when the sun was at its highest and creating a higher thermal load through the roof and walls the air conditioner will be operating at a high load. Therefore its “demand” for power will spike and that spike will result in a charge per kW. Even if that spike is for just 15 minutes, that demand charge could be >50% of the monthly bill. Let’s look at a small office building to better understand this:

The customer has a 2 ton air conditioner that draws 7.2kW at maximum load. Each month it runs at an average 50% load for 10 hours a day with an electric charge of $0.090/kWh. That results in a monthly charge of 10 hours x 30 days x 7.2kW x 50% x $0.090/kWhr = $97.20

But, on a sunny day during that same month, the air conditioner might run at maximum load for 15 minutes, triggering a demand charge of $15.00 / kW. The resulting demand charge would be 7.2 kW x $15.00 / kW = $108.00

In this example the demand charge is larger than the use charge. Since dark roofs increase the need for air conditioning, they not only drive up monthly electricity consumption costs, they can significantly increase demand charges, as well.  A cool roof, on the other hand, reflects heat away and helps reduce both monthly consumption and demand charges.

Verdict

Not only is electricity more expensive than gas, but the rate structures are complex. Seemingly small increases in electricity use can result in large additional costs due to the compounding effects of time of use rates and demand charges.

Cool roofs lower a building’s energy use, thereby lowering operating costs. However, overall electric use is often only 50% of the electric charge and the maximum power draw and its demand charge can represent the other half. Cool roofs lower the internal temperature rise on hot sunny days and therefore lower the load on air conditioning equipment.

Location Doesn’t Matter!

As the following data indicates, it doesn’t matter where a building is located; if it uses air conditioning then converting to a cool roof will result in savings.

Let’s compare buildings in the northern, southern, eastern, and western U.S. The basic assumptions are:

Size: 100,000 sq.ft.
Electric use cost: $0.090 / kWhr.
Electric demand cost: $15.00 / kW
Gas cost: $0.80 / therm

To make the calculations conservative, we assumed a high insulation level of R-30, a heater efficiency of 80%, and an air conditioner coefficient of performance of 3.2. Using the Cool Roof Calculator tool, we estimated the impact of converting from a dark roof to a reflective membrane in the following locations:

Region City Savings
Southern USA Houston, TX $5,200 / yr
Northern USA Minneapolis, MN $2,600 / yr
Western USA San Francisco, CA $2,400 / yr
Eastern USA Raleigh, NC $4,100 / yr

Verdict

In warm and hot regions, cool roofs provide for larger energy savings, however, even in more moderate and even northern climates cool roofs improve a building’s energy efficiency. Modeling shows this to hold true so long as a building uses gas to heat and has air conditioning.

Will a Cool Roof Always Result in Actual Cost Savings?

There are a few reasons why some may not receive lower electric bills after converting to cool roofs. For example, overall electric costs may rise year over year or the utility rate structure could change. Also, changes in the building’s use, equipment, or operating patterns could increase overall lower consumption. Suffice to say, modeling shows that cool roofs reduce the impact of solar energy on a building and several case studies have demonstrated reduced utility bills. But, each building is unique and should be evaluated on its own terms.

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Published at Tue, 08 Aug 2017 20:41:01 +0000


RCMA Is Accepting Abstracts for International Roof Coatings Conference


RCMA Is Accepting Abstracts for International Roof Coatings Conference

The Roof Coatings Manufacturers Association (RCMA) is now accepting abstracts for its fourth biennial International Roof Coatings Conference (IRCC) program. The deadline for submission of abstracts is Oct. 31, 2017. 
 
The 2018 IRCC will take place July 23-26, 2018, at the Fairmont Chicago Millennium Park, in Chicago. The conference will feature a host of networking opportunities, educational sessions, and other programming geared toward professionals involved in the roof coatings industry.  
 
“Our last conference was a success, with an over 40 percent growth in attendance,” says Jared Rothstein, RCMA Industry Affairs Manager. “We expect that the 2018 IRCC will provide more opportunity for our industry to join together, discuss issues, consider emerging trends, and enjoy each other’s company.”
 
Possible conference presentation topics include global market developments, green building trends, application practices, energy cost savings evaluations, roof coating formulation advancements, roof systems analysis, and in-situ field research. Roofing industry professionals, building envelope technology experts, material scientists, and those in the design community are encouraged to submit their abstracts for consideration.
 
Those interested in presenting at the 2018 IRCC should visit the IRCC website for more information and to complete the abstract submission form.  A list of conference partnership, sponsorship, and exhibition opportunities is also available on the IRCC website. 

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Published at Fri, 04 Aug 2017 21:00:01 +0000


RoofersCoffeeShop.com Welcomes DaVinci Roofscapes


RoofersCoffeeShop.com Welcomes DaVinci Roofscapes

DaVinci Roofscapes uses state-of-the-art polymer chemistry to manufacture beautiful, durable composite roofing tiles.

RoofersCoffeeShop.com, the place where the industry meets for technology, information and everyday business, is pleased to welcome DaVinci Roofscapes as its first composite roofing manufacturer partner.  DaVinci Roofscapes is a leading manufacturer of award-winning composite roofing products that are manufactured to overcome the natural weaknesses of stone slate and wood shake.

The company offers its traditional DaVinci Slate® and DaVinci Shake® along with single-width Bellaforté Slate® and Bellaforté Shake® products. With 49 standard colors available, DaVinci’s revolutionary composite roofing tiles offer homeowners and contractors the authentic colors and natural textures of quarried slate, hand-split cedar or machine-sawn shakes. In addition, homeowners and contractors can choose from a selection of DaVinci EcoBlend® cool roof colors that meet the stringent requirements of Title 24 for California residents.

All DaVinci products are backed by a Lifetime Limited Warranty which assures that the product will stand the test of time, providing beauty and durability for decades.

RoofersCoffeeShop.com is proud to welcome DaVinci Roofscapes.

About DaVinci Roofscapes
The experienced team members at DaVinci Roofscapes develop and manufacture industry-leading composite slate and shake roofing systems with an authentic look and superior performance. DaVinci leads the industry in the greatest selection of colors, tile thickness and tile width variety. The company’s reliable products have a lifetime limited warranty and are 100 percent recyclable. All DaVinci high-performing roofing products are proudly made in America where the company is a member of the National Association of Home Builders, the National Association of Roofing Contractors, the Cool Roof Rating Council and the U.S. Green Building Council. For information call 1-800-328-4624 or visit www.davinciroofscapes.com.

About RoofersCoffeeShop.com
RoofersCoffeeShop.com is committed to being a roofing professional advocate by supplying consistent information, education and communication avenues for all roofing professionals, and especially contractors, while promoting the positive growth, education and success of the roofing industry overall. Visitors to the site continue to find excellent opportunities for sharing information while participating in important ongoing conversations concerning new technologies, safety and the overall roofing trade. From the rooftop to the board room, RoofersCoffeeShop.com is “Where the Industry Meets!” For more information, visit www.rooferscoffeeshop.com.

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Published at Thu, 03 Aug 2017 15:14:41 +0000


PPG Brochure Highlights 50 Years of Duranar Coatings for Metal Building Components


PPG Brochure Highlights 50 Years of Duranar Coatings for Metal Building Components

PPG has published “The Gold Standard in Architectural Metal Coatings: Celebrating 50 Years of DURANAR Coatings,” a 16-page brochure commemorating the 1967 introduction of polyvinylidene fluoride (PVDF) coatings for metal building components.
 
According to Brian Knapp, PPG director, coil and building products, the booklet illustrates the historical significance of Duranar coatings.
 
“Our PVDF coating was a product that enabled architects to design metal components and facades with color,” he explains. “Until we introduced Duranar coatings, anodized aluminum was virtually the only metallic option to provide long-term performance on monumental buildings. It wasn’t until Duranar coatings were specified for several major projects that architects and building owners felt comfortable considering color finishes as a design option for metal.”
 
Over the past half-century, Duranar coatings have been specified by architects to protect and enhance some of the world’s most recognized architectural landmarks. Buildings profiled in the brochure include the Empire State Building in New York, Shanghai Tower in China, The Louvre Pyramid in Paris, and Centre Videotron in Quebec City.
 
Other prominent landmarks finished with Duranar coatings include One World Trade Center in New York; Shanghai World Financial Center in China; Petronas Towers in Kuala Lumpur, Malaysia; and the Rock and Roll Hall of Fame in Cleveland.
 
The brochure is organized by building type—skyscrapers, landmarks, convention centers, transportation facilities, libraries and sports venues. Each building profile includes photographs, location, approximate opening date, the selected Duranar coatings color and the architect’s name.
 
In addition to publishing the brochure, PPG will highlight Duranar coatings in trade-show displays throughout the year and offer special customer promotions and giveaways. A dedicated web portal, duranar50.com, features images and descriptions of other landmark buildings finished with Duranar coatings, as well as articles, white papers and additional educational materials.
 
To learn more about the 50th anniversary of Duranar coatings or to download a copy of the 50th anniversary brochure, visit here or call (800) 258-6398.
 

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Published at Wed, 02 Aug 2017 18:00:37 +0000


Miami-Dade County and ARMA Team Up to Update High-Wind Codes


Miami-Dade County and ARMA Team Up to Update High-Wind Codes

ARMA awarded the Miami-Dade Regulatory and Economic Resources Department the 2017 ARMA Public Partnership Award.

ARMA awarded the Miami-Dade Regulatory and Economic Resources Department the 2017 ARMA Public Partnership Award. Aaron R. Phillips, Corporate Director of Technical Services at TAMKO Building Products and chair of the ARMA Codes Steering Group, presented the award to Michael Goolsby and Miami-Dade team members who worked on the project. Pictured at the ceremony are (from left) Eduardo Fernandez, Gaspar Rodriguez, Michael Goolsby, Aaron Phillips, Alex Tigera and Jorge Acebo.

In the aftermath of 1992’s Hurricane Andrew, the entire building code for South Florida was rebuilt from the ground up. When it was launched in 1994, the South Florida Building Code was a groundbreaking document that set new roofing application standards and testing protocols for every component and system in the building envelope. More than two decades later, it was clear the building code for Miami-Dade County’s high-velocity hurricane zone (HVHZ) needed to be updated. Beginning in 2014, Miami-Dade County officials worked with the Asphalt Roofing Manufacturers Association (ARMA) and others in the roofing industry to ensure the current code language was clear and up to date.

Two-and-a-half years later, their work is complete. The 2017 Florida Building Code is scheduled for implementation on Jan. 1, 2018, and it will include every one of the proposals and public comments jointly submitted by ARMA and Miami-Dade. As a result of this successful collaboration, ARMA presented the Miami-Dade Regulatory and Economic Resources Department with the inaugural ARMA Public Partnership Award in 2017 for their work together in updating the building codes for the HVHZ.

Members of the joint task force on the project shared their thoughts on the experience with Roofing, including Mike Fischer, ARMA’s Vice President of Codes & Regulatory Compliance; Michael Goolsby, Miami-Dade Board and Code Administration Division Director; Jorge Acebo, Roofing Product Control Examiner; Alex Tigera, Roofing Product Control Examiner; and Gaspar Rodriguez, Code Compliance and Training Officer, Roofing.

They all believe this collaboration between industry and government could serve as a successful model for other industry trade associations and other code bodies to follow. “This kind of cooperation between a public regulator and a private trade association is rare enough,” says Fischer. “The overwhelmingly positive results are unprecedented.”

The Problems

Miami-Dade staff and ARMA representatives both saw shortcomings in the roofing requirements for HVHZ. There were outdated references that needed to be removed, including test standards that were out of date. This often resulted in questions that slowed down the product approval review process. Members of the roofing industry also wanted to explore coordinating the Miami-Dade HVHZ protocols with other national testing requirements to further streamline testing procedures.

Fischer summed up ARMA’s goals this way: “ARMA is a responsible advocate for the asphalt roofing industry. We take that role seriously. We are an advocate. Our job is to represent the collective interests of the producers, but we try to be responsible about it. And it’s that drive to be responsible which led us to this partnership with the Miami-Dade staff.”

At the first meeting between ARMA and Miami-Dade, Fischer tried to break the ice. “The first thing we said when we came into that meeting was, ‘Hi, we’re from industry and we’re here to help,’” Fischer recalls. “I will tell you that when we started that meeting in the morning, the Miami-Dade staff was probably skeptical of what we were there for. By the end of the day, we had laid out a project plan of how we were going to work together, and that set the tone for the rest of the project.”

Fischer knew it would take the two entities working together to get things done. “In the Florida process, we knew we had to work with Miami-Dade, as they are a key stakeholder. We brought in other roof covering manufacturers for some of the discussions, and we also talked to the FRSA, the Florida Roofing and Sheet Metal Association—the contractors—so they were at the table for quite a bit of this as well.”
ARMA set up a special task group to focus on the Miami-Dade protocols. The task force went through documents one by one with members of Miami-Dade group, identifying problems and sections that were out of date. They hashed out compromises when they didn’t agree.

Protecting the Public

Goolsby worked on the project on behalf of Miami-Dade along with members of his team including Acebo, Tigera and Rodriguez. “We cover a lot of territory,” notes Goolsby. “We maintain the building code and write the building code, but we also oversee all of the contractor licensing in Miami-Dade County. We have about 15,000 local licensed contractors. Of course, we handle product approvals, and we also service all of the boards here. We have a board of rules and appeals. We also oversee 35 building departments throughout Miami-Dade County. We try to make sure the code is uniformly enforced in all of those jurisdictions. So, we cover a lot of bases.”

The top priority is protecting the public. “In a general sense, we provide for the health, safety and welfare of the public,” Goolsby says, “But it’s these issues of life safety that are the most critical.”
Evacuating South Florida is difficult, so the residential portions of the code were written under the assumption that many people might have to ride out a storm in their homes. “We wanted their home to be just as strong as any commercial structure,” says Goolsby.

Acebo notes that ensuring the code is properly followed is as crucial as the code itself. He believes the inspectors’ role includes reassuring homeowners that systems are being installed correctly. “It’s important to us to fulfill our role to provide independent corroboration that the work is being done and installed properly,” he says. “The great thing about this particular effort is that it was truly collaborative. It was great to work with them and establish the language that was common with other jurisdictions or other certification agencies.”

Promising Results

Members of the joint task force agree that the changes make the code easier to understand. They also should streamline product approvals process.

“These updates definitely help the manufacturers get through the product approval process, specifically for Miami-Dade HVHZ requirements,” Fischer states. “It also helps the roofing contractor because we made sure the documents have the installation language updated, so it gives better direction to the installers of the products. And that trickles up to the general contractors in new construction, as it speeds up their processes and takes out some burdens.”

“At the end of the day, as a responsible advocate, one of ARMA’s main motivators was to make sure their industry’s products get installed the way they are intended to be installed,” Fischer continues. “That benefits the end user—the building owner and building occupant.”

Acebo agrees that the approvals process helps everyone—homeowners, contractors, manufacturers and inspectors. “If questions come out of the field from homeowners, manufacturers or contractors as to whether something is being applied or used properly, we can serve as that independent third party that doesn’t really have a stake in it other than to serve as an arbitrator who can clearly indicate whether something is right or not according to what has been provided and tested.”

The collaboration was so successful that the task force is already looking at other changes in the future. The Miami-Dade code is used as a model for other code bodies, and the joint task force could serve in that role as well, according to Fischer. “This is a model of collaboration between a governmental agency and private industry groups that will serve us well,” he says. “We are going to continue to do this with other groups, and frankly we’re going to continue doing it with Miami-Dade because this process isn’t ever done. Things will always be changing and we always have to keep up to date.”

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Published at Mon, 31 Jul 2017 19:00:16 +0000


SBS System Delivers Roof Design for the Brewery District


SBS System Delivers Roof Design for the Brewery District

Brewery District Building 3, New Westminster, B.C., Canada

Owner Wesgroup Properties wanted an aesthetically pleasing pattern for their roof design as well as the option to expand and add additional stories.

Owner Wesgroup Properties wanted an aesthetically pleasing pattern for their roof design as well as the option to expand and add additional stories.

The Brewery District is a dynamic, progressive area in in Metro Vancouver offering a mix of residential high-rises, shops and office buildings. The Brewery District provides quick access to the area and is connected via a SkyTrain to public
plazas, greenways, view decks, cycling paths, and a central community green gathering place. This master-planned community includes groceries, pharmacies, restaurants and other mixed-use retail outlets.

Roof Report

The project included roof areas of varying heights totaling approximately 21,320 square feet. Owner Wesgroup Properties wanted an aesthetically pleasing pattern for their roof design as well as the option to expand and add additional stories. IKO was able to meet their expectations with an SBS system using IKO TP 180 Granular Cap in a pattern of multiple colors. The IKO SBS Roofing System was recommended by GRC Columbia Roofing Inc., based on the specific client requirements to create a colorful rooftop pattern.

Team

Client/Owner:Wesgroup Properties
Architect/Designer:
Henrizquez & Partners Architects
Roofing Contractor:GRC Columbia Roofing Inc.
The Roof System:
IKO MVP Vapour Barrier
IKO MF 95 SF (Poly/Sand) Vapour
Barrier
IKO Therm III Insulation
IKO 3/16-inch Protectoboard
IKO TP 180 FF Base Sheet
IKO TP 180 SF Base Sheet
IKO TP 180 Granular Cap Sheet

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Published at Mon, 31 Jul 2017 21:00:27 +0000