Design and Performance Benefits of Insulated Metal Panels

In a prior post on insulated metal panels (IMPs) we reviewed some of the basic things everyone should know about this versatile and lightweight metal building component. In this posting, we will drill down a bit more on the benefits of incorporating IMPs into a new or retrofit construction project. Here are some of the top reasons they are so popularly used in both walls and roofs:

Insulated metal panels (IMPs) are a popular choice for walls and roofs for their energy conservation, durability, longevity and cost-savings.
Insulated metal panels (IMPs) are a popular choice for walls and roofs for their energy conservation, durability, longevity and cost-savings.

Energy Conserving, Space Saving Insulation

Foam plastic insulation is used between the metal skins of IMPs. Such insulation has been accepted for use by building codes for quite awhile provided it meets certain conditions. IMPs have been tested and shown to meet or exceed all code requirements for construction and for energy conservation too. Part of their appeal over other ways to insulate is that they can achieve high performance in a thinner wall or roof assembly than would be required with other types of insulation, such as fiberglass. IMPs are available in thicknesses that range from 2 to 6 inches and have corresponding R-values from R-14 to R-46 allowing design professionals to select the thickness that matches the energy performance level sought in a particular building. Other insulation types would require thicknesses of at least twice as much to approach the same R-values as IMPs. Further, the metal interior and exterior skins are the only finish material needed so the total panel thickness is very space efficient. Thinner IMPs in the walls and roofs can save space in the building or on the site all while achieving high energy performance.

Durability, Longevity, and Low Maintenance

The manufactured panels are rigid and quite strong. They have been tested for compression, tensile, and shear strength with impressive numbers that come about because of the combination of the rigid foam and steel properties. The surfaces are made from the same long-lasting galvanized and factory finished steel used in other metal wall and roof panels so their resistance to weather, abuse, and even harsh conditions has been proven, making them very easy to maintain. In locations where severe weather and storms are a concern, they can also be specified to meet requirements for heavy winds, hail, and similar concerns. Plus, since the skins of the IMPs are made of noncombustible steel, they provide an ignition barrier as part of an overall fire protection scheme for the building.

Cost Saving Construction

IMPs are an “all-in-one” product that takes the place of many other products and components used in traditional construction. Instead of requiring multiple trades and materials to be installed individually over some number of weeks, IMPs are installed by a metal building contractor and allow the walls and roof to be completely closed in with a single trade. The use of concealed fasteners in the side joint of the panels makes installation quick and easy. Unlike other construction systems, the inherent strength and resiliency of IMPs means that work doesn’t need to stop over weather concerns. All of this saves a considerable amount of labor costs and can also save a lot of time meaning buildings can be completed quicker and more economically. It could also mean that an owner is able to occupy and use the building sooner, thus reducing construction financing costs and allowing operations to begin more quickly.

Versatility for Use in Many Building Types

IMPs can be used in virtually any type of new construction and for many retrofit applications too. There is a range of modular panel sizes that can work successfully with different structural elements of the rest of the building. The finished profiles and colors can all be selected to match the design needs of the building with edges, corners, and trim details all based on simple, appealing aesthetics. There are even IMPs specially designed for cold storage or refrigerated space applications. These panels may be part of the building exterior or create an isolated space within a larger building. Either way, they are designed for the rigors of a high use installation.

With such a broad range of benefits and capabilities, you owe it to yourself to check them out for a building project that you may be involved in. The best place to start is by contacting your local MBCI representative, and by signing up for our newsletter to subscribe to our blog.

Urban Heat Island, Part 2: How Cool Metal Roofs Benefit Building Owners

In our prior blog post, Urban Heat Islands, Part 1: How Cool Metal Roofs Benefit the Community, we identified the existence of urban heat islands and their contribution to higher air temperatures that are found in urban areas compared to surrounding locations. We also identified a high Solar Reflectance Index (SRI), on a scale of 0-100, as the means to specify materials that can help reduce urban heat islands and benefit entire communities. In this post, let’s focus on the specific benefits to the building owner when cool metal roofs are used.

Cool Metal Roof
The Boundy Residence features a cool metal roof

Energy Savings for Cool Metal Roofs

In many commercial and industrial buildings, energy use is one of the largest ongoing operating expenses, meaning that building owners and operators are usually quite interested in lowering or controlling that expense. Cool metal roofs with a high SRI rating can help with that quest. For instance, since air conditioning is commonly a larger cost that heating for many such buildings, it is a natural place to target. Lowering the temperatures at the roof means there is less heat surrounding the building, reducing air conditioning load and directly impacting energy costs.

Comfort in Outdoor Areas

Some building types, such as restaurants, retail, and entertainment facilities, rely on outdoor seating or gathering areas to support their business. If urban heat islands make these spaces uncomfortable to spend time in, the business usually suffers too. Providing these buildings with high-SRI metal roofing can improve the situation.

Long-Term Durability

Building materials can degrade prematurely if they routinely exposed to high heat. The heat can cause them to dry out, become brittle, or simply decompose faster than expected. Using high-SRI roofing is not only good for the longevity of the roofing, it can be good for the durability of the materials directly under the roof as well. Roof sheathing and other substrate materials directly in contact with the roofing receive the same intense solar radiation that the roofing surface does.

Attic spaces below the roofing plane also receive the heat, making attic temperatures in excess of 130 degrees common, causing degradation of materials in those spaces, including mechanical and electrical equipment. That could mean more expansion and contraction of connections and joints or it could mean that air conditioning duct work is being heated, contrary to the efficient operation of the system. In any of these cases, a cool metal roof will help alleviate the negative impacts of solar heat and allow materials to achieve full life expectancy.

Supports LEED Certification

In the Sustainable Sites category of the LEED rating system, Heat Island Reduction can be selected as a credit to receive either one or two points toward certification. This credit relies on both roof and non-roof strategies and looks for calculations of solar reflectance (SR) and demonstrated Solar Reflectance Index (SRI) levels on specified products.

Cool Metal Roofs

Favorable Payback

All of these benefits above can translate to financial benefits to the building owner or operator. Any cost premium incurred for selecting a high-SRI cool metal roof can likely be realized very quickly in energy cost savings, increased business, or maintenance and durability savings. In addition, the benefits of human comfort and achievement of LEED or other sustainability goals can be realized for the life of the building.

Using Wind Clamps to Improve Wind Uplift on Standing Seam Metal Roofs

Among the most important factors to account for when specifying a standing seam metal roof are wind control and wind uplift. It is imperative to take the necessary measures to ensure the safety and efficacy of the metal roof. The wind clamp—an extruded piece of aluminum that is placed on the panel seams at clip locations—is one accessory that can be used to improve wind uplift characteristics on metal roofs, delivering substantial time and cost savings as these devices help mitigate risk of wind uplift and improve overall wind design.

Panel Deflection
Standing Seam Panel Deflection as a Result of Wind Uplift

Why Use a Wind Clamp

A typical failure mode of a standing seam metal roof panel is the clip top pulling out of the panel seam when the panels are subjected to high winds.  With a standard install of a standing seam panel, the seams just fold into each other. With enough pressure, wind will force seams to come apart—be it a vertical failure, horizontal movement of the seam or from clip disengagement. The clip top can then pull out of the panel seam.

The wind clamp resists the panel seam being opened, allowing for higher uplift loads. The purpose of wind clamps, in fact, is to prevent Windclamprszdfailures at the seam openings due to any deflection of the panel. The wind clamps provide more strength, thereby dramatically improving wind uplift performance.

The clamp is installed over the panel seam at clip locations, in the edge and corner zones of the roof.  This allows the roof to resist the higher wind pressures in these zones, usually eliminating the need for additional purlins or joists. On large roofs, the savings can be substantial.

Another benefit is shorter installation time. Since additional purlins or joists are typically not required at the edge or corner zones of the roof, the building can be erected faster.

Choosing Wind Clamps

When choosing the type of wind clamp, it is important to consider the type of panel and the special features of the clamps. MBCI, for example, uses S-5!’s patented wind clamps, which work for two panel types—Ultra-Dek® and Double-Lok®. The S-5! wind clamps do not penetrate the steel, thereby eliminating the risks of corrosion and water leakage that can be introduced by a hole in the steel. Since the screws are hidden from the weather elements, it helps to maintain waterproofing.

Quantitative Difference with Wind Clamps

One of the biggest benefits of using wind clamps in the edge and corner zones is that usage minimizes the quantity of purlins needed, resulting in substantial cost savings. For example, let’s look at a comparison using MBCI’s Double-Lok 24” – 24 ga. panels with and without wind clamps.Chart for blog image

In this example:

  1. The use of wind clamps in the edge and corner zones eliminated 3,800 linear feet of purlins.
  2. Assuming 8” x 2-1/2” Zee 14 ga. purlins were used, there would be a cost savings of $10,400.

Conclusion

Utilizing wind clamps to protect the investment of a standing seam metal roof can increase strength, make installation faster and lower overall cost.

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