Alucobond® aluminum composite material (ACM) has been used for exterior cladding products in the North American building construction market for over forty years. Throughout these years, we have continued to be on the forefront of all fire and building code developments. However, the national and international building codes have recently challenged the construction market with design-oriented goals of sustainability and energy efficiency. The increasing demand for high performance, energy-efficient buildings has led to the evolution of building enclosure designs that incorporate durability, longevity, and thermal and weather protection. Architects and building owners are now required to meet stringent energy codes which has resulted in a systems approach to designing the building envelop components. As a result, fire protection and life safety issues have significantly affected the development of the fire codes and has become integral with recent International Building Code (IBC) updates. A lot is now dependent on the correct usage of materials and systems, especially when it comes to the facade of a building and ACM.
Alucobond can be provided with a choice between two types of core products: standard polyethylene (PE) and fire retardant Plus. While these product lines typically differ from one another in core composition, both are regulated by the IBC. The performance requirements for choosing one ACM product type over another primarily depend on panel height above grade or grade plane and separation distance to the property line or to other structures within the property boundaries. Moreover, these provisions have changed significantly in the 2012 version of the IBC due to the stringent energy code requirements. Choosing the correct ACM so as to mitigate the risk caused by fire has become challenging. Making the correct choice of core material can be a complex process and has become the most frequently asked question.
The 2012 IBC established criteria that determine when a standard core or a fire retardant core must be used. The major elements that dictate the type of ACM to use include: ACM height above grade or grade plane, wall construction type (rated or non-rated fire assemblies), and proximity to the property line or other structures within the property boundaries. When the construction conditions are within the limitations as outlined in the IBC, a standard core material can be used. When these installation conditions are not within the defined limitations, either the fire retardant core material must be used or the authority having jurisdiction (AHJ) must provide an approval. A number of specific performance tests are referenced to define allowable use, including several American Standard Testing Methods (ASTM) tests as well as an intermediate-scale fire test, The National Fire Protection Association (NFPA) 285 (Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Non-Load-Bearing Wall Assemblies Containing Combustible Components).
The 2003, 2006, and 2009 editions of the IBC used two critical height options, 40’ and 50’, that defined the correct choice of ACM core material. However, with the revisions included in the 2012 edition of the IBC, there are now three critical height options that impact the correct choice of ACM core material. These heights are 40’, 50’, and 75’ above grade or grade plane and the basic requirements are as follows:
Standard ACM Core Installation Less Than 40’ Above Grade Plane
The use of the PE core material on all construction types to a height of 40’ above grade plane is allowed in several sections of the IBC. Limitations include a fire separation distance of 5’-0” or greater.
Standard ACM Core Installation Greater Than 40’, but Less Than 50’ Above Grade Plane
Installations of standard core ACM up to 50’ above grade plane are defined in Section 1407.11.2 and are based on the allowable use of plastic veneer defined in Chapter 26. Limitations include section size and vertical separation of sections.
Standard Core ACM Installation Greater than 50’, but Less Than 75’ Above Grade Plane
This provision was adopted for ACM cladding assemblies in the 2012 version of the IBC. There are two options defined. The first option is based on occupancy type while the second option is based on fire separation distance. Where the building is equipped throughout with an automatic sprinkler system, the maximum height and area can be modified. The use of a flame barrier may also impact the vertical separation requirements.
Additional criteria are noted in the IBC for all conditions noted above and special care should be taken to fully understand these requirements. The stringent fire protection provisions coupled with energy codes have dramatically changed the way wall assemblies are designed. As expectations for building performance, facility life, and occupant health and safety continue to increase, Alucobond is dedicated to providing value-added capabilities regarding performance standards and code compliance. Let our technical expertise help you through the complex process of choosing the core material needed for your project.
Photography: Rush University Medical Center Hospital by Perkins + Will Chicago, Photo by Robert R. Gigliotti; MassArt Residence by ADD Boston, Photo by Kate Hensley of Suffolk Construction