Energy efficiency is a critical consideration in the design and construction of metal building systems. Adhering to energy codes not only helps reduce operational costs but also contributes to environmental sustainability. The ASHRAE 90.1 and the International Energy Conservation Code (IECC) are the governing bodies of metal buildings’ two most common energy codes. These codes outline minimum requirements for energy-efficient construction, including heating, ventilation, lighting, water heating, and power usage.
Key components of energy codes
Building envelope: The building envelope, which includes walls, roofs, windows, and doors, plays a significant role in energy efficiency. Proper insulation and high-performance materials can minimize heat loss and gain, leading to lower energy consumption. Another efficiency aspect gaining significant consideration by state governance is air infiltration1. This is the unwanted air leakage into or out of a building, which can significantly impact energy efficiency, indoor air quality, and overall building performance. In metal building systems, controlling air infiltration is crucial to meet energy codes and maintain a comfortable, efficient, and safe environment.
HVAC systems: Heating, ventilation, and air conditioning (HVAC) systems must be designed to meet energy efficiency standards. This includes using energy-efficient equipment and implementing control systems to optimize energy use.
Lighting: Energy codes often require using energy-efficient lighting solutions, such as LED lights, which consume less power and have a longer lifespan than traditional lighting options.
Water heating: Efficient water heating systems, including tankless water heaters and solar water heaters, can significantly reduce energy consumption.
Power usage: Implementing energy management systems and using energy-efficient appliances can help reduce overall power usage.
Impact of air infiltration on energy efficiency
Air infiltration can lead to substantial energy losses, forcing HVAC systems to work harder to maintain desired indoor temperatures. Uncontrolled air leakage increases heating and cooling loads, increasing energy consumption and costs. By reducing air infiltration, metal building systems can achieve greater energy efficiency, potentially lowering utility bills and reducing environmental footprints. This aligns with energy codes like ASHRAE 90.1 and the IECC, which are progressing to make whole-building testing a requirement (ASTM E779).
In 2012, the IECC incorporated an air leakage component and published three compliance options. (All are governed by an ASTM standard and at a pressure differential of 75 Pascals
(1.57 psf). The compliance options are materials with an air permeability no greater than
0.073 m3/h/m2 (0.004 cfm/sf), assemblies of materials and components not to exceed 0.073 m3/h/m2
(0.04 cfm/sf), or a whole-building air leakage test not to exceed 7.3 m3/h/m2 (0.40 cfm/sf).
With the whole building air leakage test not exceeding 7.3 m3/h/m2 (0.40 cfm/sf), the challenge for metal building systems
in the future (and present for Washington state) is meeting an air infiltration limit of 4.6 m3/h/m2 (0.25 cfm/sf). Achieving such a stringent standard requires meticulous attention to detail in both the design and construction phases.
The key challenges include:
Seal integrity: Ensuring the building envelope is tightly sealed is critical. Every joint, seam, and penetration must be meticulously sealed to prevent air leakage, often requiring high-quality materials and precise workmanship.
Material selection: Selecting appropriate materials to provide a robust air barrier is essential. The materials must be durable and compatible with each other to ensure long-term performance without degradation.
Construction techniques: Advanced construction techniques are necessary to minimize gaps and leaks. These include proper installation of insulation, vapor barriers, and other components of the building envelope.
Quality control: Rigorous quality control measures during construction are vital. Regular inspections and testing must be conducted to identify and rectify potential air leakage points.
Cost implications: Meeting air infiltration requirements is critical to complying with modern building codes and standards. Achieving such a low air infiltration rate may increase construction costs due to the need for superior materials and skilled labor. Balancing cost-effectiveness with performance is a key challenge.
These requirements ensure metal building systems are designed and constructed to minimize energy loss and improve overall performance. Non-compliance can result in penalties, increased retrofit costs, and potential legal issues. In an era where sustainability and energy efficiency are paramount, contractors and erectors must stay updated with the latest codes and employ best practices to achieve compliance, and addressing air infiltration is a critical step toward achieving these goals.
Fire safety requirements for metal building systems
Fire safety is another critical requirement in the final construction of metal building systems. Ensuring compliance with fire safety codes can help protect lives and property. The International Building Code (IBC) and Occupational Safety and Health Administration (OSHA) standards provide guidelines for fire protection and life safety systems.
Key fire safety components
Fire-rated materials: Metal buildings must use fire-rated materials for walls, roofs, and other structural components to prevent the spread of fire.
Fire protection systems: Installing fire protection systems such as sprinklers, fire extinguishers, and fire detection systems is essential for early detection and suppression of fires.
Exit routes and emergency planning: Designing clear and accessible exit routes and comprehensive emergency action plans ensures occupants can evacuate safely in case of a fire.
Maintenance and safeguards: Regular maintenance of fire protection systems and adherence to safety protocols are crucial for ensuring their effectiveness during an emergency.
Integrating energy efficiency and fire safety measures can be achieved through careful planning and design.
For example, using energy-efficient insulation materials that are also fire-rated can address both energy conservation and fire safety requirements. Additionally, incorporating smart building technologies enhances both energy management and fire safety by providing real-time monitoring and control.
Testing standards determine the required fire ratings for insulation in metal building systems. Insulation materials are typically classified into three fire ratings: Class A, B, and C. The two most common are the ASTM E84 test and the UL723 test, which evaluate insulation materials’ fire ratings. In simplest terms, they address “the Standard Test Method for Surface Burning Characteristics of Building Materials.”
Here is further information on the three fire ratings:
Class A: This is the highest level of fire resistance, with a flame spread index of 25 or less and a smoke-developed index of 50 or less.
Class B: These materials have a flame spread index of 26 to 75 and a smoke-developed index of 51 to 450.
Class C: This is the lowest level of fire resistance, with a flame spread index of 76 to 200 and a smoke-developed index of 451 to 600.
By adhering to these fire rating requirements, contractors and erectors can ensure metal building systems meet safety standards and provide a secure environment for occupants.
Conclusion
Adhering to energy codes and fire safety requirements is essential for successfully designing and constructing metal building systems. By focusing on energy efficiency and fire safety, contractors and erectors can create buildings that are not only cost-effective but also safe and sustainable.
Staying informed about the latest codes and standards and continuously improving construction practices will ensure that metal buildings meet the highest performance and safety standards.
Reference
1 Air infiltration, as defined by the IECC (International Energy Efficiency Code), is the “Unintended movement of air through gaps and cracks in the building envelope, including areas around windows, doors, and other openings.”
Sources: Mbma.com, Iccsafe.org, Energycodes.gov,
Osha.gov, Nucorbuildingsystems.com, Metalconstructionnews.com, and Smarttechonline.com
As the national accounts manager of Silvercote—a laminator in custom insulation solutions—Robert Tiffin leads foundation customer relationships in the United States and Canada. He drives interaction with the market, designer/specifiers, and end-use owners, as they are the critical connections to the industry’s future. As a fervent advocate of collaboration with industry associations, Tiffin connects his peers and network as the president of the Metal Building Contractors & Erectors Association (MBCEA) and as the chair of the architects committee of the Metal Building Manufacturers Association (MBMA).