SPRI Updates and Improves Roof Edge Standards

Low-slope metal perimeter edge details, including fascia, coping and gutters, are critical systems that can strongly impact the long-term performance of single-ply roofs. Photo: Johns Manville

The effect of high winds on roofs is a complex phenomenon, and inadequate wind uplift design is a common factor in roofing failures. Damage from wind events has historically been dramatic, and wind-induced roof failure is one of the major contributors to insurance claims.

Roofing professionals have long recognized the importance of proper low-slope roof edge and gutter designs, particularly in high-wind conditions. For this reason, SPRI, the association representing sheet membrane and component suppliers to the commercial roofing industry, has spent more than a decade enhancing testing and design standards for these roofing details.

SPRI introduced the first version of its landmark standard, ANSI/SPRI/ES-1 “Wind Design Standard for Edge Systems Used with Low Slope Roofing Systems” in 1998. Since then, the association has continually revised, re-designated and re-approved the document as an ANSI (American National Standards Institute) standard.

Testing of edge securement per ANSI/SPRI ES-1 is required per the International Building Code (IBC), which has been adopted by every state in the country.

This standard provides the basic requirements for wind-load resistance design and testing for roof-edge securement, perimeter edge systems, and nailers. It also provides minimum edge system material thicknesses that lead to satisfactory flatness, and designs to minimize corrosion.

Construction professionals have been successfully using the standard, along with the specifications and requirements of roofing membrane and edge system manufacturers to strengthen their wind designs.

Until recently, the biggest news on the wind design front was the approval of ANSI/SPRI/FM 4435/ES-1, “Wind Design Standard for Edge Systems Used with Low-slope Roofing Systems.” Let’s call it “4435/ES-1” for short. SPRI knew recent post-hurricane investigations by the Roofing Industry Committee on Weather Issues (RICOWI) and investigations of losses by FM Global consistently showed that, in many cases, damage to a low-slope roof system during high-wind events begins when the edge of the assembly becomes disengaged from the building. Once this occurs, the components of the roof system (membrane, insulation, etc.) are exposed. Damage then propagates across the entire roof system by peeling of the roof membrane, insulation, or a combination of the two.

Recognizing that edge metal is a leading cause of roof failures, SPRI has redoubled its efforts to create a series of new and revised documents for ANSI approval. As has always been the case, ANSI endorsement is a critical step toward the ultimate goal of getting these design criteria included in the IBC.

A Systems Approach to Enhancing Roof Edge Design

Roofing professionals understand that successful roof design requires the proper integration of a wide variety of roofing materials and components. For years, leading roofing manufacturers have taken a “systems” approach to their product lines. Recently, SPRI has zeroed in on the roof edge. Low-slope, metal perimeter edge details include fascia, coping and gutters, are critical systems that can strongly impact the long-term performance of single-ply roofs.

As part of the ES-1 testing protocol, RE-3 tests upward and outward simultaneous pull of a horizontal and vertical flanges of a parapet coping cap. Photo: OMG Edge Systems

SPRI first addressed roof gutters in 2010 with the development of ANSI/SPRI GD-1. The testing component of this document was recently separated out to create a test standard and a design standard. The test standard, GT-1, “Test Standard for Gutter Systems,” which was approved as an American National Standard on May 25, 2016.

Similarly, SPRI has revised 4435/ES-1 to only be a test standard.

Making both edge standards (4435/ES-1 and GT-1) into standalone testing documents makes it easier for designers, contractors and building code officials to reference the testing requirements needed for metal roof edge systems.

IBC requires that perimeter edge metal fascia and coping (excluding gutters), be tested per the three test methods, referred to as RE-1, RE-2 and RE-3 in the ES-1 standard. The design elements of ES-1 were never referenced in code, which caused some confusion as to how ES-1 was to be applied. The latest version of 4435/ES-1 (2017) only includes the tests referenced in code to eliminate that confusion.

Test methods in 4435/ES-1 2017 have the same names (RE-1, RE-2, and RE-3), and use the same test method as 4435/ES-1 2011. Because there are no changes to the test methods, any edge system tested to the 2011 version would not need to be retested using the 2017 version.

FM Global’s input was instrumental in the changes in 2011 when ANSI/SPRI ES-1 incorporated components of FM 4435 to become 4435/ES-1. However, there are no additional FM related changes in the latest 4435/ES-1 standard.

This gravel stop is being tested according to the ANSI/SPRI ES-1 standard using the RE-2 test for fascia systems. Photo: OMG Edge Systems

Per ANSI requirements, 4435/ES-1 2011 needed to be re-balloted, which is required by ANSI every five years. SPRI took this opportunity to have it approved as a test standard only to eliminate the confusion referenced above. FM Global was consulted and indicated it wanted to keep “FM” in the title. (FM was on the canvas list for the test standard and actually uses it as its own test standard.)

With 4435/ES-1 becoming a test standard for coping and fascia only, and GT-1 being a test standard for gutters, SPRI determined that a separate edge design standard was needed. Meet ED-1, a design standard for metal perimeter edge systems.

The design portions of the ES-1 edge and the GD-1 gutter standards have been combined and are now referenced by SPRI as ED-1. It has been developed and is currently being canvassed as an ANSI standard that will provide guidance for designing all perimeter edge metal including fascia, coping, and gutters.

ED-1 will be canvassed per the ANSI process later this year. However, SPRI is not planning to submit ED-1 for code approval.

SPRI ED-1 will include:

Material Design

  • Nailer attachment
  • Proper coverage
  • Recommended material thicknesses
  • Galvanic compatibility
  • Thermal movement
  • Testing requirements
  • “Appliance” attachment to edge systems

Limited Wind Design

  • Load to be required by the Authorities Having Jurisdiction (AHJ).
  • Tables similar to those included in 4435/ES-1 will be included for reference.

If this sounds a tad complex, imagine the design work required by the dedicated members of SPRI’s various subcommittees.

The Test Methods in Detail

The GT-1 standard is the newest, so let’s tackle this one first. As noted above, the ANSI/SPRI GT-1 test standard was developed by SPRI and received ANSI Approval in May of 2016. Testing of roof gutters is not currently required by IBC; however, field observations of numerous gutter failures in moderate to high winds, along with investigations by RICOWI following hurricanes have shown that improperly designed or installed gutters frequently fail in high wind events. GT-1 provides a test method that can be used by manufacturers of gutters, including contractors that brake or roll-form gutters, to determine if the gutter will resist wind design loads. Installing gutters tested to resist anticipated wind forces can give contractors peace of mind, and may provide a competitive advantage when presented to the building owner.

This gutter is being tested using the test method specified in ANSI/SPRI GD-1, “Design Standard for Gutter Systems Used with Low-Slope Roofs.” Photo: OMG Edge Systems

GT-1 tests full size and length samples (maximum 12 feet 0 inches) of gutter with brackets, straps, and fasteners installed per the gutter design. It is critical that the gutter be installed with the same brackets, straps, and fasteners, at the same spacing and locations as per the tested design to assure the gutter will perform in the field as tested. The fabricator should also label the gutter and/or provide documentation that the gutter system has been tested per GT-1 to resist the design loads required.

GT-1 consists primarily of three test methods (G-1, G-2, and G-3). Test method G-1 tests the resistance to wind loads acting outwardly on the face of the gutter, and G-2 tests the resistance to wind loads acting upwardly on the bottom of the gutter. G-3 tests resistance to the loads of ice and water acting downwardly on the bottom of the gutter.

Tests G-1 and G-2 are cycled (load, relax, increase load) tests to failure in both the original GD-1 standard and the new GT-1. The only change being that in GD-1 the loads are increased in increments of 10 lbf/ft2 (pound force per square foot) from 0 to failure, and in GT-1 they are increased in increments of 15 lbs/lf (pounds per linear foot) from 0 to 60 lbs/lf, then in 5 lbs/lf increments from above 60 lbs/lf to failure.

Note also that the units changed from lbf/ft2 (pound force per square foot) to lbs/lf (pounds per linear foot), which was done so that the tests could be run using the test apparatus loads without having to convert to pressures.

The GT-1 standard specifies a laboratory method for static testing external gutters. However, testing of gutters with a circular cross-section is not addressed in the standard, nor does the standard address water removal or the water-carrying capability of the gutter. In addition, downspouts and leaders are not included in the scope of the standard.

SPRI intends to submit ANSI/SPRI GT-1 for adoption in the next IBC code cycle.

As referenced above, IBC requires that perimeter edge metal (fascia and coping), excluding gutters, be tested per three test methods, referred to as RE-1, RE-2 and RE-3 in the ES-1 standard.

RE-1 tests the ability of the edge to secure a billowing membrane, and is only required for mechanically attached or ballasted membrane roof systems when there is no peel stop (seam plate or fasteners within 12 inches of the roof edge). RE-2 tests the outward pull for the horizontal face of an edge device. RE-3 tests upward and outward simultaneous pull on the horizontal and vertical sides of a parapet coping cap.

Calculating Roof Edge Design Pressures

All versions of ANSI/SPRI ES-1 and ANSI/SPRI GD-1, the 2011 version of ANSI/SPRI 4435/ES-1, and the new ED-1 standard all provide design information for calculating roof edge design pressures. These design calculations are based on ASCE7 (2005 and earlier), and consider the wind speed, building height, building exposure (terrain), and building use.

A gravel stop failure observed during roof inspections after Hurricane Ike in Sept. 2008. Photo: OMG Edge Systems

However, as stated above, IBC requires that the load calculation be per Chapter 16 of code, so the SPRI design standards are intended only as a reference for designers, fabricators, and installers of metal roof edge systems.

ES-1-tested edge metal is currently available from pre-manufactured suppliers, membrane manufacturers and metal fabricators that have tested their products at an approved laboratory.

The roofing contractor can also shop-fabricate edge metal, as long as the final product is tested by an approved testing service. The National Roofing Contractors Association (NRCA) has performed lab testing and maintains a certification listing for specific edge metal flashings using Intertek Testing Services, N.A. Visit www. nrca.net/rp/technical/details/files/its details.pdf for further details.

A list of shop fabricators that have obtained a sub-listing from NRCA to fabricate the tested edge metal products are also available at www. nrca.net/rp/technical/details/files/its details/authfab.aspx.

SPRI Continues to Take Lead Role in Wind Testing

As far back as 1998, SPRI broke ground with its ANSI/SPRI/ES-1 document addressing design and testing of low-slope perimeter edge metal. Today, the trade association has a variety of design documents at the roofing professional’s disposal, and is working to get ED-1 approved as an Edge Design Standard to be used for low-slope metal perimeter edge components that include fascia, coping and gutters.

All current and previously approved ANSI/SPRI standards can be accessed directly by visiting https://www.spri.org/publications/policy.htm.

For more information about SPRI and its activities, visit www.spri.org or contact the association at info@spri.org.

An EPA Proposal to Reduce Ground-level Ozone Will Affect the Roofing Industry

On Nov. 26, 2014, the Washington, D.C.-based U.S. Environmental Protection Agency announced a proposal to reduce the National Ambient Air Quality Standard (NAAQS) for ground-level ozone. The existing National Ozone Standard, last strengthened in 2008, sets the acceptable level of ozone at 75 parts per billion (ppb); the proposal calls for lowering that level to 65-70ppb, or even as low as 60ppb. The National Association of Manufacturers, Washington, has called the new proposed standard the “the most expensive regulation in history,” and its passage could result in widespread effects felt across the nation and a wide array of industries, including roofing.

Ozone NAAQS and Nonattainment

Tropospheric (ground-level) ozone is one of six “criteria” pollutants regulated by the EPA, pursuant to the 1990 Clean Air Act, because it has negative human-health impacts and can be damaging to vegetative growth. Ozone is formed when volatile organic compounds (VOCs) and nitrogen oxides (NOx) combine with sunlight. Significant anthropogenic (manmade) sources of VOC and NOx emissions include industrial and manufacturing facilities, vehicle exhaust, gasoline vapors, and solvents used in consumer and commercial coatings and paints.

The ozone NAAQS sets permissible ozone levels; those states and regions that do not meet those thresholds are designated as “nonattainment” areas. A nonattainment designation requires that the state develop and submit a State Implementation Plan (SIP) to the EPA, which outlines the steps that will be taken to reach and maintain compliance, or “attainment”. The steps that a state may take to work toward ozone attainment are varied but often include control measures over manufacturing and industrial processes; regulations aimed to reduce VOC emissions from paints, coatings, and manufacturing processes; or voluntary measures, such as programs that encourage the use of mass transit to reduce vehicle usage.

Additionally, the nonattainment designation comes with specific mandates from the EPA. These include tougher permitting requirements for new or expanding facilities, potential loss of federal highway and transit funding, EPA oversight in permitting, and requirements to “offset” any new emissions sources by reducing emissions in existing operations or by purchasing emissions credits from others.

Many states and regions, including California and the majority of the Northeast’s I-95 corridor, are still working to comply with the 2008 ozone standard’s 75ppb level. The proposal to lower the existing ozone standard to within the range of 65-70ppb will result in a significant increase in nonattainment areas across the country, which will in turn result in growth of stationary source restrictions and state-level regulations as states develop SIPs for achieving lower ozone levels.

The effects of a stricter ozone standard will be felt across the nation and in a wide variety of industries. “Background ozone”, or the ozone levels that would exist regardless of the presence of industry, is 30ppb or higher in most areas. For such regions, lowering the standard from 75ppb to 65ppb would represent a mandate to reduce anthropogenic ozone by more than 20 percent. Additional reductions may prove difficult to achieve and costly, especially for those areas of the country that have already implemented control measures to achieve attainment with the 2008 Standard.

Effects on the Roofing Industry

One area of particular significance to the roofing industry will be VOC regulations for architectural and industrial maintenance (AIM) coatings, as well as for industrial adhesives and sealants, which are used in the application of certain roof systems and for continued maintenance and protection of many roofs. The VOC content for a variety of AIM coatings is regulated on the national level by the EPA. Additionally, there are more stringent VOC regulations in place today across the majority of the Northeast, in several Great Lakes states, and in California’s 35 air districts for AIM coatings and adhesives and sealants as part of those states’ and regions’ SIPs for reaching attainment on existing ozone standards.

While there are regulatory bodies, such as the California Air Resources Board, Ozone Transport Commission and the Lake Michigan Air Directors Consortium that provide guidance on ozone attainment, it is ultimately left up to the states (and in the case of California, individual air districts) to develop and implement VOC regulations. As such, VOC regulations vary from state to state and region to region with rules that contain disparate VOC content limits, compliance dates, and record-keeping and reporting requirements, which can make compliance highly challenging.

Purpose of VOCs in Roof Coatings

VOCs are included in a wide array of coatings for several reasons. Solvent-based coatings can be used as an alternative to waterborne technologies, especially where freeze/thaw resistance and product application and storage in cooler climates or in winter months is required. VOCs are used to dissolve solids to keep coatings in a liquid phase, allowing for them to be applied prior to the solvent flashing out and the product curing to form a solid layer. Furthermore, coatings may be formulated with VOCs because of the solvents’ ability to soften the substrate that the coating is being applied to, improving the application and ultimate performance of the coating.

As new, stricter VOC regulations are introduced and VOC content limits are lowered in different roof coating, adhesive and sealant product categories, several negative consequences may occur. First, it may become more difficult to apply the product or to apply the product at an appropriately thin layer. Additionally, the performance of the product may be negatively impacted, which could result in the need for additional product application throughout the lifetime of the roof or, in extreme cases, a reduced life-span of the roof. Although there are many excellent waterborne technologies available, the use of water-based coatings may not be an acceptable alternative in all situations or in all roof systems.

The Path Forward

The ozone NAAQS’s publication in the Federal Register begins a 90-day comment period, which will be supplemented by several public hearings in the early months of 2015. Should the rulemaking continue forward and a lower ozone standard be approved, the EPA will begin designating attainment and nonattainment areas, which will start the process for the development of SIPs containing a host of new regulations across the country.

For manufacturers, specifiers and contractors alike, an influx of VOC regulations will prove challenging. Formulators will be forced to create high-performing products using lower-solvent content or through the use of exempt solvents; applicators will need to be aware of the rules in place to ensure they are applying compliant products; end-users will need to learn that products they have had in the past may no longer be available. Even under today’s ozone standard, keeping apace of the multitudinous and constantly changing VOC regulations is a large task. EPA’s final determination of a new ozone standard could prove to have significant and long-term ramifications that will be felt for many decades to come.

New VOC Regulations Threatened the Quality of Roofing Assemblies until the Roofing Industry Became Involved

Ellen Thorp, associate executive director of the EPDM Roofing Association, makes it a point to be responsive to the many inquiries she gets. Most deal with routine requests for information about EPDM, but one phone call Thorp fielded six years ago from one of ERA’s member companies stood out from the rest. Ultimately, it changed the way ERA and the roofing industry do business.

A manufacturer’s rep had heard from a customer in Connecticut that the state was about to implement VOC regulations. The problem: The new regulations would ban some of the adhesives, sealants, and primers essential to installing EPDM and other roofing products, and there were no substitute products available to meet the new standards. If the new regulations went into effect as scheduled, they threatened to negatively impact the safety and quality of roofing assemblies in the affected area and the roofing industry as a whole.

The proposed regulations were part of an effort by the Ozone Transport Commission, or OTC, to achieve federally mandated air-quality standards in the Northeast and Mid-Atlantic. The OTC was created under the Clean Air Act to develop solutions for the New England states, as well as Delaware; Maryland; New Jersey; New York; Pennsylvania; Virginia; and Washington, D.C. At the time of OTC’s creation, most of these states had not attained federally mandated ozone standards, and the region lagged behind other parts of the U.S. in achieving compliance.

As part of its initial work, OTC developed a Model Rule for Adhesives and Sealants, based on regulations used in California, incorporating provisions effective in the climactic and market conditions of that state. At the time of the phone call to Thorp, the OTC had released the model rule, and states were beginning to draft their own regulations that included implementation dates within the next year. “The VOC limits the OTC was proposing would have required products that did not exist in the Northeast and Mid-Atlantic,” Thorp explains. “It was also concerning that they were basing the limits on California regulations. The climate in the Northeast is very different than in California, so we didn’t feel it was good science to be creating a model rule based on a place that had a completely different climate.”

Thorp and the ERA member companies were very interested in working with state regulators. “It certainly is our priority to reduce VOC emissions wherever possible, but it also is important to us to have regulations that our industry could work with and are based on the best available science,” she says. In fact, products that would meet the new regulations were in development but were not yet available. In addition, the new adhesives and sealants would require new or modified application techniques. That meant the roofing industry needed time to train thousands of roofing contractors.

ERA’s first step was to support its assertion that the climate of the Northeast differed dramatically from that of California. ERA hired Jim Hoff of Tegnos Research Inc. to review weather data and the effects the weather has on low-VOC products. “At ERA’s expense, we assembled relevant scientific data and provided it to the state regulators,” Thorp adds.

ERA worked with regulators in each state, sharing the results of its research. ERA provided the state environmental protection and air quality bureaus with detailed information about what sealants were available and explained the time needed to train roofing contractors. Working together, the regulatory bodies and ERA were able to agree on a phased-in or seasonal approach. For instance, in a majority of the states, the new low-VOC products were required initially only in the summer for three months. The year after, they were required for five months. Then, the following year, they were required year-round. Once these states had found success with this approach, others followed suit. “We explained to the regulators the importance of being consistent since many roofing companies do work across multiple states, especially in the Northeast where the states are small and roofing companies are likely to work across state lines,” Thorp notes.

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Roofs Are a Potential Solution for Urban Stormwater-management Issues

Can stormwater management using rooftops in urban areas be the financial solution to our growing urban stormwater problem? Will public-private partnerships with building owners help to provide a government service—stormwater drainage—in a more cost-effective manner? As cities struggle with the high administrative and procurement costs and time delays to manage stormwater, should we be looking up to roofs as part of the solution? Can we avoid more regulations and instead look to market-based solutions? These questions are beginning to be discussed and tested as new, innovative approaches to solving difficult and expensive urban stormwater-management issues.

Consulting and engineering firm Geosyntec Consultants is monitoring and controlling runoff from an existing New York City Parks and Recreation facility green roof.

Consulting and engineering firm Geosyntec
Consultants is monitoring and controlling runoff from an existing New York City Parks and Recreation facility green roof.


Many cities and counties are dealing with more stringent stormwater permits issued from the Washington, D.C.-based U.S. Environmental Protection Agency (EPA) and state environmental agencies that implement the federal Clean Water Act. Many communities are operating under federal court orders and administrative consent orders from EPA to reduce stormwater runoff into rivers, lakes and streams. In addition, there are 177 communities in the U.S. where stormwater and wastewater-collection systems are combined, known as combined sewer overflows (CSOs). These CSOs result in billions of gallons per year of combined untreated stormwater and wastewater discharged into waterways during large rainfall events. Funding crises have developed in many municipalities as they create programs, hire new staff, and design and construct new infrastructure to meet these regulatory requirements.

Many cities have spent billions of dollars separating stormwater drainage from wastewater-collection systems by installing new, costly drainage systems. In addition, large underground storage tunnels and vaults have been installed by many cities at the costs of billions of dollars per installation. These tunnels and vaults are designed to collect, hold and slowly release the stormwater into the treatment network. Increasing stormwater pipe sizes and creating tunnels and vaults is extremely costly. For example, Washington, D.C., just broke ground on the construction of two stormwater tunnels that are currently projected to cost $2.6 billion dollars to construct. Just one of the tunnels will be 13-miles long and hold 157 million gallons of combined stormwater and wastewater in 23-foot-diameter tunnels, 100-feet below the surface.

Green-infrastructure approaches to stormwater issues are included in most municipal stormwater permits and orders. For example, New York City is spending $187 million on green infrastructure for stormwater control in CSO areas to control the equivalent of 1 1/2 inches of runoff from impervious surfaces by December 2015. Public and private areas are under consideration for green-infrastructure solutions, and the city expects to spend $2.4 billion in green infrastructure during the next 20 years.

As cities address urban stormwater management, stormwater fees are being assessed on private-property owners to help fund the programs to solve urban stormwater issues. Close to 1,500 stormwater utilities are now in operation in the U.S., and the number is rapidly growing. These stormwater utilities typically are assessing stormwater fees based on the amount of impervious surfaces by property owner. The fees can range from a few hundred dollars per year to tens of thousands.

Roofs are considered an impervious surface because they are designed to shed stormwater through drainage networks into the collection system beneath city streets. For example, in New York City alone roofs make up 11.5 percent of the total area, or roughly 944.3 billion square feet, according to the city’s Department of Design and Construction’s Cool & Green Roofing Manual. Rather than looking at roofs as part of the stormwater problem in cities, they should be viewed as a possible solution.


Baltimore enacted a stormwater fee
in 2013. Currently a building with a
200,000-square-foot roof would be
assessed $11,400 per year.

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