PVC Roofing An Active Asset For Your Building — Facility Management Roofing Information

PVC Roofing An Active Asset For Your Building - Facility Management Roofing Information

Drew Ballensky ,

General Manager,

Duro-Last Roofing

Roofing has become more than just a lid on a building. What do you mean when you say that a commercial roofing system is an “active asset?” It has become an active asset – even generating payback. The rooftop is now a place that provides “value-added” benefits like energy savings, energy generation, and environmental enhancement. For a roof system to be considered truly high performance, it should offer superior sustainability. Sustainability in roofing involves avoiding or minimizing the impacts of a building on its occupants and the environment, both local and global, from design to construction, through maintenance, rehabilitation and eventual demolition with an emphasis throughout its life cycle on using natural resources efficiently.

Give us a few specific examples of how a PVC roofing system is sustainable. There are ten key reasons why a cool, high-performance PVC roofing system is sustainable:

1) High reflectivity and emittance provide energy savings. Saving energy is an obvious sustainability benefit that helps reduce a roof system’s total life-cycle cost and conserve limited resources.

2) PVC membranes have a low carbon footprint compared to products like TPO or EPDM. A typical PVC may have only 44% carbon versus almost 100% for EPDM or TPO.

3) Custom pre-fabrication reduces jobsite waste. With its flexibility and ease of welding, some PVC membranes are custom prefabricated specifically for each job, meaning less scrap is generated at the jobsite.

4) Is is true that PVC systems are better prospects for recycling than other types of commercial roofing systems? PVC is completely recyclable, meaning virtually no fabrication scrap goes to landfills, and post-consumer membranes can be re-utilized.

5) By following strict quality-control procedures during manufacturing, PVC roofing system performance is enhanced and maintenance issues are minimized or eliminated.

6) Can you talk specifically about how PVC roofing systems can protect building assets during a fire? PVC membranes contain a chlorine component that makes them inherently fire resistant, making it much easier to achieve Class A fire ratings with PVCs than with some other systems.

7) PVC roofing works well as the waterproofing component of rooftop photovoltaic systems that provide renewable energy and reduce dependence on non-renewable sources.

8) PVC also supports vegetative systems through its durability and waterproof characteristics – vegetative roofing reduces a building’s energy consumption and water runoff.

9) PVC roofing is long-lasting with some systems boasting over 30 years of proven service. A longer life reduces total life-cycle costs.

10) A solid warranty also helps reduce life-cycle costs and gives the building owner peace of mind.

“Cool” performance is a big part of what makes PVC roofing systems so sustainable. High reflectivity is a key characteristic that helps keep buildings cooler and reduce energy usage. Reflectivity, or albedo, is the ability to reflect energy from the sun. Stated in percentage terms, the higher the percentage, the more energy is reflected. As much as 40% less cooling energy may be needed for buildings that have highly-reflective roofs.

Drew, tell us about some of the other benefits besides dollars saved due to reductions in energy consumption. Cool roofing delivers other benefits that are not as tangible as dollars saved, but are valuable nonetheless:

Insulation can be 25%-50% more effective

Extremely high temperatures reduce the effective R-value of the most widely used types of insulation (Leonard & Leonard, 2005). Cooler surfaces help preserve and keep rooftop insulation materials cooler.

HVAC equipment can operate more efficiently

Inlet air temperature can be 5–15 degrees cooler 30 inches above a cool roofing surface compared to a black surface. Most HVAC units are designed with efficiency ratings evaluated at 95 degrees F (York International, 2005); rooftop temperatures on a black surface can reach 160 degrees F or higher.

Substrate deterioration may be slowed by as much as 75%

Ultraviolet and infrared radiation and moisture penetration accelerate substrate deterioration. A cool roofing system will reflect this radiation and help protect the substrate (Kirn et. al. 1994).

Ambient interior temperatures can be up to 20 degrees F cooler than outside

Studies of worker performance with machine operation and high physical activity reveal that productivity drops 10% at 84 degrees F and 38% at 95 degrees F (Schweisheimer, W. 1962).

Sustainability attributes of all components for the entire system should be considered, including film production, reinforcement scrim, fabrication scrap, flashing parts and accessories, shipping materials and methods, installation components, fasteners, and so on. This is more than just a consideration of direct product attributes. It involves a deeper look into the facilities and activities that are utilized in the production and delivery of the system. Modern, highly-efficient closed-loop manufacturing equipment and processes make the most of valuable resources. Here are examples of actions taken by some companies to glean the most out of their processes:

• Reinforcement scrim and film production: polyester yarn tailings can be saved and recycled; vinyl film edge trim can be routed back into the film production; laminator trim and scrap can be reground and used in other products

PVC Roofing An Active Asset For Your Building - Facility Management Roofing Information

• Fabrication plant scrap: materials can be collected and reground for use in products like roofing walkpads, flooring, and concrete expansion joint products

• Component fabrication: roof flashing components can be fabricated from portions of material scrap; roof system fastening plates are made from post-consumer recycled components

• Shipping: cardboard cores used for rolled membrane products are made from recycled material and can themselves be recycled; undamaged pallets used for receiving and shipping goods can be returned for re-use; foam cradles used for holding rolls of material can be re-used and/or re-cycled;

• Post-use reclamation: post-consumer roof materials can be reground and recycled

• Screws and fasteners: the wire coil used to make these items typically has recycled content

• Metal edge details: steel coil used for fabricating metal edge details typically has recycled content

Architects and specifiers who are interested in designing high performance buildings can get help from green design programs. LEED® and Green Globes are two well-established programs that aid specifiers in the high-performance design process and recognize the installation of high performance PVC roofing systems by offering opportunities to attain credits toward certification.

LEED, a program of the United States Green Building Council, stands for Leadership in Energy and Environmental Design and was one of the first green design programs to become widely accepted. While some streamlining is being pursued through standardized documentation and auditing, a typical LEED application currently requires a large time commitment. Of more than 25,000 projects registered since 2000, only about 2300 have achieved certification to date.

A new version of LEED is due out in early 2009; however the current version, 2.2, offers several areas to consider where high performance PVC roofing systems may help contribute to LEED certification.

Another green design program that is gaining wide acceptance comes from the Green Building Initiative (GBI) and is known as Green Globes. This program, Internet based and very user-friendly, was developed from BREEAM, a program originating in Europe and Canada. Green Globes has actually been in existence longer than LEED and has similar goals for promoting green design but is less costly for registration and auditing. The program has relevant weighting of credits and looks at the entire chain of the product’s life. Green Globes doesn’t require an energy engineer to calculate energy performance. GBI is pursuing an ANSI Standard for Green Globes with approval anticipated in 2009.

Why is a PVC roofing system a good choice for photovoltaic and vegetative roofing applications? A high performance roof also offers possibilities as an active asset through photovoltaics and rooftop gardens. Emerging new technologies with photovoltaic (PV) systems are increasing efficiencies, improving paybacks, and making PVs a more viable electricity generating source. PV systems offer a clean source for energy and, with net metering arrangements, building owners have the opportunity to sell excess electricity to the power grid, further enhancing system payback.

Rooftop gardens can go by many names with many different techniques, but generally they involve planting various forms of vegetation on a rooftop. Besides aesthetic enhancements, the vegetation offers other benefits. In urban areas that experience significant water runoff during rainstorms, vegetative roof systems help reduce runoff that stresses the capacities of storm sewer systems. Vegetation also acts to insulate and keep the roof surface cool, reducing building cooling requirements and mitigating urban heat island effects. Drawbacks of rooftop gardens include the added weight, increased maintenance requirements, and a much higher initial cost for the roof system.

Drew – any closing remarks?

Sustainable building design can take many forms and utilize many different approaches to obtain similar performance results. But regardless of what design actions are taken or what products are used, profit is a key criteria for sustainability – if an act is not profitable it is not sustainable. As roofing systems take on the role of active assets, they will contribute more toward helping typical facilities become high performance buildings.


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