{"id":4028,"date":"2014-05-30T14:27:42","date_gmt":"2014-05-30T18:27:42","guid":{"rendered":"http:\/\/www.constructionspecifier.com\/?p=4028"},"modified":"2017-01-13T15:36:05","modified_gmt":"2017-01-13T20:36:05","slug":"a-paradigm-shift-in-specifying-temporary-structures","status":"publish","type":"post","link":"https:\/\/www.constructionspecifier.com\/a-paradigm-shift-in-specifying-temporary-structures\/","title":{"rendered":"A paradigm shift in specifying temporary structures"},"content":{"rendered":"
\"All<\/a>
All images courtesy Mahaffey Fabric Structures<\/em><\/figcaption><\/figure>\n

by Beth Wilson
\n<\/strong>Clear-span aluminum structures and temporary steel buildings have advanced over the years. Knowing when to use them is a skill worth mastering for construction specifiers, procurement professionals, and facility managers. Familiarity with specific spaces, and knowing the assemblies\u2019 framework of costs and benefits, may also help designers and specifiers incorporate them into their own sites and make optimal recommendations.<\/p>\n

For those who have been in the trade for a while, there may be a natural aversion to temporary structures. Historically, these options have been expensive, constrictive, and almost universally required functional concessions on some level. Up until about a decade ago, if space was needed immediately or in the near-term for occupancy of less than five years, there were not a lot of reasonable options (Figure 1).<\/p>\n

\"Traditional<\/a>
Traditional options for occupancies of less than five years.<\/span><\/figcaption><\/figure>\n

New options<\/strong>
\nSince the turn of the century, there have been exponential improvements in the strength, quality, versatility, cost-effectiveness, and energy efficiency of clear-span aluminum and temporary steel structures. The result has been a paradigm shift in the consideration of temporary space.<\/p>\n

Although modular trailers have come a long way in form, function, and versatility, they are generally designed for office and classroom use and are not typically scalable without creating a village. When larger, contiguous, weather-tight warehouse or workspace is needed, the two best options are industrial clear-span tents and temporary steel buildings.<\/p>\n

Clear-span structures<\/em>
\nThere are several classes of clear-span structures that can be installed onsite in less than one week, outfitted with utilities and a full range of access, safety, and security features. Also called \u2018industrial tents,\u2019 these aluminum systems include stretched fabric.<\/p>\n

These are lightweight aluminum structures offering both durability and versatility. Typically, they are deployed for up to six months at a time in temperate climates where sun protection is more of a priority than severe weather, such as petrochemical facilities and oil fields in Texas and Louisiana. A structure rated for a wind speed of 144 kph (90 mph) is more than sufficient to protect contents and occupants from summer thunderstorms. Further, these structures can be relocated fairly easily, making them a good choice if site flexibility is an issue.<\/p>\n

\"Interior<\/a>
Interior view of final strucutre deployment around existing nuclear facilities at Grand Gulf Nuclear Power Station in Port Gibson, Mississippi.<\/span><\/figcaption><\/figure>\n

If a more substantial structure is needed in harsher climates for at least three months, an aluminum box beam system is a better option. These can withstand winds up to 209 kph (130 mph) and snow loads of up to 146 kg\/m2<\/sup> (30 lb\/sf).<\/p>\n

For hangar-type applications or environmental remediation sites in snow country, a peaked arch structure is the best option, as it is engineered with a slope for snow shedding. This is a light-weight structure, which can also be moved with ease.<\/p>\n

Temporary steel buildings<\/em>
\nSimilar to clear-span aluminum systems, temporary steel buildings offer the key benefits of a permanent structure without the long \u2018planning\/building\u2019 wait and long-term commitment to real estate. They are designed with the aggregate of state and local building codes in mind. Most, if not all, are compliant with American Society of Civil Engineers (ASCE) guidelines, International Building Code<\/em> (IBC<\/em>), and California Fire Marshall Code<\/em> (equal to or exceeding the standard issued by the National Fire Protection Association [NFPA]). Given these considerations, obtaining permits and approvals is usually expedient. Also, because clear-span structures have no interior uprights to impede usable space, flexibility is maximized.<\/p>\n

Perhaps most compelling in the consideration of temporary steel buildings is their low upfront and monthly cost over a three-year term when compared to plan\/build and lease options. Particularly when one considers lease and plan\/build expenses start well before the space is ready, it is worth noting the cost per square meter for time-in-use during the first year (Figure 2).<\/p>\n

Time-framing the decision<\/strong>
\nThere are two primary questions that frame the ideal spot for using clear-span aluminum structures and temporary steel buildings: How soon is it needed, and for how long?<\/p>\n

A clear-span aluminum structure can easily meet an immediate need and is typically durable enough to remain installed onsite for up to two years. Temporary steel buildings can also be onsite quickly\u201421 to 30 days in most cases\u2014and serve a three- to five-year term. The structures can certainly last longer, but it becomes a less economical choice.<\/p>\n

If the need is not immediate, and the term is more than five years, then leasing, purchasing, or building offsite space become better options (Figure 3).<\/p>\n

While some larger organizations have entire departments dedicated to property planning, investment, and management, others choose to stay focused on core businesses and avoid the complexities of long-term real estate entanglements. The latter is an ideal scenario for temporary structures. Also, because temporary buildings are considered an operating expense as opposed to a capital expense, many organizations see tax benefits in their use. Additionally, the overall cost for space needed for five years or less can be as much as 81 percent less per square meter.<\/p>\n

Finally, both aluminum and steel clear-span structures can generally be installed without a poured or pieced foundation. A dry, level lot, or a paved parking lot, are all that is needed for installation. This is a big factor on the shortened installation timeline, and also exempts temporary buildings from property taxes in most jurisdictions.<\/p>\n

\"Various<\/a>
Various costs associated with temporary steel buildings compared with other routes.<\/span><\/figcaption><\/figure>\n

Energy efficiency, sustainability, and LEED<\/strong>
\nPreviously, the term \u2018temporary\u2019 was used to infer flimsy and disposable. With advances in materials and engineering, temporary structures can be designed to be energy-efficient, and their elements are generally reusable and recyclable. A temporary building may not be certified under Leadership in Energy and Environmental Design (LEED) on its own, but employing one may help qualify a larger project for points. Suitable vendors should obtain materials from recycled sources, repurpose its structures (or elements thereof), and recycle materials at the end of their useful life. For example, a manufacturer targeting LEED accreditation could use a temporary structure to expand a production facility, as opposed to building a larger permanent facility.<\/p>\n

Specifically, potential LEED credits include:<\/p>\n