SPRI supports roofing solutions

Sponsoring research studies and developing generic standards are just two of the many initiatives underwritten by SPRI to benefit the roofing industry as a whole

By working together in a national roofing trade association like SPRI, companies who make and market flexible membrane roofing membranes and related components can embark upon ambitious programs that the entire industry can utilize to better understand the performance and interaction of various roofing elements.

For example, one exciting new initiative that SPRI is underwriting is a research program with Oak Ridge National Laboratory (ORNL) to identify the thermal performance of ballasted roof assemblies.

ORNL's Andre Desjarlais, a SPRI member, explains that ballasted systems capture and hold onto heat, storing it in the mass of rock on the roof's surface and thereby preventing its transmission into a building at times of peak energy consumption during the day. Eventually, the stored heat radiates off that rooftop. "It's just a different mechanism for reducing heat flow into a building," Desjarlais explains.

What this research will attempt to do, he adds, is to quantify that behavior.

To develop a model for this type of temperature transfer, ORNL has built six small test roof sections to gather data in east Tennessee's hot, humid climate. All are assembled over a steel deck and include 1.5 inches of fiberboard insulation. Two of the test roofs - one topped with a black EPDM and one with a white TPO --have no ballast mass and will serve as controls. Three other test roofs are topped with ballast, though at different rates of loading, ranging from 10 to 23.5 lbs./sq. ft. The sixth test roof is covered with concrete pavers, also weighing 23.5 lbs./sq.ft.

Thermocouples installed just over the roof surface constantly monitor the temperatures of the deck, roof membrane and outside air and track the heat flux. Hourly averages are used to track and compare temperature changes.

Data collection began late last winter and will continue late into this autumn, giving researchers a sufficient amount of data to analyze..

This ballasted roof study builds on the recently completed three-year test program that SPRI sponsored at ORNL to examine the reflectivity of different light-colored flexible roof membranes.

In that extensive effort, researchers gauged the results of aging on 18 different types of flexible roof membranes, supplied by 10 different manufacturers. The original colors of these membranes ranged from whites to tans and grays.

Interestingly, researchers discovered that decreases in reflectivity level out after about two years and can furthermore be restored with simple cleaning measures (in accordance, of course, with the maintenance recommendations of the specific manufacturer).

The research analysts concluded that reductions in reflectivity seem to be caused by a biomass --either a fungus or a cyano-bacteria -- growing on the membrane surface in the presence of moisture, dirt and other contaminants, and influenced by temperature. Decreased reflectivity did not seem to be caused by an initial breakdown in a membrane's formulation or polymer content.

Standard development procedures

Also in the works is a performance standard for insulation. Task force members have been collecting and reviewing data on the thermal performance, dimensional stability and crush resistance of various insulation boardstock installed at a test roof site. This test roof was located in Florida to expose the insulations to high heat and humidity conditions.

In April, the first U.S. standard for retrofit roof drains, developed by SPRI, was approved as a national standard in accordance with American National Standards Institute (ANSI) protocol. This new standard is designated ANSI/SPRI RD-1, 2003, "Standard for Retrofit Roof Drains."

This standard fills an information void by detailing measures to take in order to produce leak-free connections to existing drain piping while still providing sufficient drainage.

John Hickman, chairman of the Roof Drain Standard's Task Force, explains that one of the main differences in installing retrofit drains stems from the need to place them where existing drains already are installed.

Retrofit drains, by their very nature, have a smaller drainage diameter than the original drains because they must fit inside the existing plumbing. Assuring sufficient capacity, the standard outlines, depends upon the retrofit drain diameter, the number of drain sites and the rainfall expectations for the building location.

Another SPRI initiative, a new pull-test procedure for insulation adhesives, is currently being canvassed for approval as a national standard.

SPRI members developed this uniform field test method to evaluate the suitability of insulation adhesives for attaching insulation or coverboard to a substrate. Entitled "Standard Field Test Procedure for Determining the Load Resistance of Insulation Adhesives over Various Substrates," this procedure is already available on the SPRI web site (www.spri.org) as a SPRI guide.

"The ultimate aim of all of this work," explains SPRI Technical Director Dave Roodvoets, "is to be able to provide reliable, cost-effective roofing solutions."

In all, SPRI and ANSI have worked together for nearly 10 years to promulgate the first national consensus standards for a variety of valuable test procedures and design guides.

Furthermore, to keep these standards current, they are re-canvassed every five years. Other ANSI/SPRI standards include: "ANSI/SPRI FX-1 2001, Standard Field Test Procedures for Determining the Withdrawal Resistance of Roofing Fasteners;" "ANSI/SPRI RP-4 2002, Wind Design Standard for Ballasted Single-Ply Roofing Systems;" and "ANSI/SPRI ES-1 2003, "Wind Design Guide for Edge Systems Used with Low-Slope Roofing Systems."

"ANSI/SPRI standards are all readily referenced tools that the roofing contractor can use to develop job specifications or to evaluate the performance of products," Roodvoets explains. "Having ANSI-recognized standards provides consistency among products and even more assurance that products meeting these standards will perform, therefore reducing a roofing contractor's risk."

On another front, joint efforts by SPRI's Roodvoets and the National Roofing Contractors Assn. (NRCA) saw the formal submission of two more ASTM (American Society for Testing and Materials) standards for specific flexible roofing membranes into the International Code Council (ICC) building code. These standards covered TPO (Thermoplastic Polyolefin)-based and Ketone Ethylene Ester (KEE)-based roof membranes.

The acceptance of these two standards into the ICC building code should make it easier for roofing contractors to pull building permits and get even more widespread product acceptance for a broader range of flexible membrane roofing systems.

To advance the general understanding of wind design issues, SPRI members developed a informative program on this important subject. This seminar is available for presentation to interested groups. For more details, please contact SPRI's headquarters.

Sales, membership growth

For the first five months of 2004, SPRI member shipments have recorded strong gains in a number of categories. Compared to the same period last year, sales of thermoset roofing membranes are up 14.9%. And shipments of TPO-based roofing membranes in that same time frame have increased 15.2%.

Even within the association itself, growth is the watchword. Five new members have joined SPRI this year, bringing the number of member companies to over 50.

SPRI President Mike Ennis sums up the organization's place in the roofing community: "SPRI has always been involved in providing outstanding technical solutions for the roofing industry. It provides a forum to utilize the collective expertise of its members to resolve issues facing the industry."

*Spotlight on www.spri.org

More information on a number of the topics highlighted in this article, as well as many others, can be found in SPRI's recently updated version of its comprehensive manual, "Flexible Membrane Roofing; A Professional's Guide to Specifications." This seventh edition of the "Professsional's Guide" now includes generic installation details and adhesive information. It is for sale in a handy CD-ROM format.

For further information on any of SPRI's publications, standards or ongoing activities, please visit the organization's informative web site at www.spri.org or contact its headquarters at 411 Waverley Oaks Road, Suite 331B, Waltham, MA 02452; tel. 781-647-7026. You can also e-mail the association at info@spri.org.

This article originally appeared in the August 2004 issue of RSI Magazine