METAL BUILDING SYSTEMS：THE PROCESS OF BUYING A METAL BUILDING.pdf

CHAPTER 9 THE PROCESS OF BUYING A METAL BUILDING 9.1THE START 9.1.1Before It All Begins: A Note to Owners In this chapter we talk about the many things that have to happen between your decision to build and getting the keys for a newly constructed facility. Once the decision to build or expand is made, you need to establish building dimensions, shape, and clear height. No matter how well everything else goes, if these fundamentals are not properly thought through, the project will not be successful. If a critical piece of machinery does not fit by a few inches, what was the point of building? We strongly recommend that you let an experienced architect perform programming and prelim- inary design of your building:Architects are trained to analyze owners needs and to offer solutions. Many years spent with architects under one roof have convinced the writer of tremendous improve- ments these design professionals can make to the original plans conceived by their clients. An archi- tect often comes up with a completely differentand betterbuilding layout. Unless you need a small basic rectangle of a building or must suit a preestablished equipment layout, let designers, not contractors, help you make design decisions. (Of course, the architect you select should be experi- enced in specifying metal building systems or at least should have read this book.) The architect will help you identify your immediate and future space needs, prepare a preliminary cost estimate, and propose a timetable for construction. On your part, you have to determine whether adequate financing is available, a budget appropriated or planned, and the members of your in-house planning team are in agreement on what needs to be done. 9.1.2Selecting the Site After the programming phase, the project moves into schematic design. By this time a prospective location might have already been selected. If several sites are still being considered, it is best to focus on one or two choices before proceeding further, since many building parameters such as height, size, and type of construction may be affected by surrounding buildings and by local zoning codes. As usual in such transactions, prior to purchase a prospective buyer performs title and easement search, zoning check, site survey, and environmental investigation. The site should be large enough to allow for all required property setbacks, parking, access roads, and future expansion needs. If time is of the essence, it is best to stay away from protected areas such as wetlands. Ideally, the site already has or can be economically served with all the necessary utility hookups. Sewer requirements might be tightly controlled by the community and need to be specifically inves- tigated, and any site drainage problems addressed. 271 Now is the time to hire a reputable local engineer and a soil boring contractor to perform a soils investigation. Is the soil good enough to allow for economical shallow foundations? The question is not idle, because in many industrial areas the best land has long been developed, and only the less desirable parcels are leftoften those deemed uneconomical to build upon by others. Poor soils may require expensive deep foundations such as piles and caissons; the added cost could push the budget beyond the acceptable limits. Some other site preparation costs include demolition of any present structures, lot clearing, excavation, fill, and paving. 9.2THE ROLE OF THE DESIGN PROFESSIONAL 9.2.1The Basic Responsibilities After schematic design is completed, either by the owners in-house personnel or by an outside archi- tect, and the site is selected, the owner can start thinking about methods of construction delivery. With a set of schematic plans and specifications in hand, an owner can pursue any one of the three basic construction methods: conventional (design and bid or negotiate), design-build, or contracting directly with a preselected manufacturer of metal building systems. In both conventional and pre-engineered construction, the owner can be represented by an inde- pendent architect; in a design-build mode, the architect is a part of the builders team. Since we are specifically interested in metal building systems, and since the manufacturers staff rarely includes architects, the best course for the owner to follow is to hire an independent design team. One of the first priorities of the design team is to develop a site-plan package for review and approval by a local planning and zoning board. The package will demonstrate how the owner intends to comply with federal, state, and local regulations. It may address such issues as wetland protection, increased traffic, pollution, sewage flow, parking, and appearance. While some localities are devel- opment-friendly, others might not be; occasionally, obtaining all the permits may take longer than the design and construction time combined. In order to prepare the site package, the design team undertakes a comprehensive code review. (It goes without saying that the intimate knowledge of complex code provisions is a good enough rea- son to retain an architect in the first place!) By submitting a set of documents in compliance with the local code and all the local regulations, the owner can save a lot of valuable time and lower con- struction loan interest charges. Design development and final design can proceed while the site package is being reviewed. The goal is to produce a set of contract documents that adequately communicate design intent without being overly specific and prescriptive. In broad terms, the design professional is responsible for selecting the design criteria, for any items not normally carried by the metal building manufacturer, and for overall coordination. The items not commonly available from the manufacturers are listed in the MBMAs Common Industry Practices, and include foundations, insulation, fireproofing, finishes, cranes, electrical and mechanical equip- ment, overhead doors, and miscellaneous iron. The Practices specifically state that ventilation, condensation, and energy conservation issues are beyond the manufacturers responsibility and therefore are to be included in the design profession- als scope of services. The design team should examine the effects of the proposed building on adjacent structures, such as a possibility of snow drifting onto a lower existing roof. The manufacturer should not be expected to perform this purely engineering task, because some smaller manufacturers might not even have a full-time engineer on staffonly a technician who punches the numbers into a computer program. (Most owners are not aware of this fact, because the term pre-engineered building implies the pres- ence of an engineer.) The owners, on their part, should help the design professionals establish the appropriate project design criteria by supplying them with adequate data describing the details of the current and prob- 272CHAPTER NINE able future operations. These data might include, for example, the dimensions and weight of the equipment that will be housed in a metal building system and any crane requirements. Major indus- trial and government clients should also make available copies of their in-house design and con- struction standards and any other pertinent design material. 9.2.2What to Specify Some people still think that the architects role in specifying metal building systems is selecting sid- ing colors. It isnt quite so. While construction documents prepared for a pre-engineered building might not be as extensive or detailed as for conventional construction, they still need to communicate a great deal of information. Some of the items sought by manufacturers for proposal preparation are:1 Information on the governing building code including, significantly, the edition. Avoid listing too many codes that may contain conflicting design criteria. While reputable manufacturers will use the most conservative criteria in cases of such conflict, some hungry upstarts might choose to do otherwise. Design loads to be used, such as collateral, snow, live, wind, and seismic. Some recurring prob- lems with specifying snow vs. roof live loads are addressed in Chap. 10. Collateral (superimposed) dead load allowance should be carefully considered and its nature preferably identified. Rooftop HVAC equipment needs to be located on the roof plan, its weight and required roof openings spec- ified. Any other concentrated loads, such as from a suspended walkway, warrant a separate men- tion. It is important to research the local code, which might contain higher design load requirements than model codes. For example, the design wind speed might be specified by a local code as 110 mi/h, while a national code calls for only 70 mi/h. (Of course, the opposite could be true, too: The local code could be based on an obsolete edition of a model code.) Load combinations. In addition to the combinations listed in the governing code, the designers may wish to include some others, as discussed in Chap. 3. The structural scheme assumed in the design (e.g., multispan rigid frame with pinned supports). Building dimensions, including length, width (do not forget that, to a manufacturer, building width is the distance between outside flanges of wall girts, not between column centerlines), eave height, and clear height. Exterior wall materials, finishes, and insulation. Some specifiers choose to leave doors and win- dows out of a metal building package: By purchasing these items locally, it is often possible to buy sturdier products with better hardware, and to avoid transit damage. However, in this case the design wind pressures to be used for these important components of the building envelope must be conveyed to their suppliers. Locations where wall bracing is to be avoided, for aesthetic or functional reasons and, perhaps, where bracing is desired. Also, any open-wall locations. Corrosion protection requirements. The specifiers are well advised to mention a presence of any existing facilities within 1?2-mile radius which emit corrosive chemicals, a proximity to saltwa- ter areas, and any other possible sources of corrosion. They should also evaluate a corrosive or moisture-producing potential of the operations within the building itself. In metal buildings, cor- rosion from the inside is difficult to protect against. While the exterior panel finishes might be quite good in fighting corrosion, interior steel framing is often protected only by a primer coat (Fig. 9.1). Many manufacturers lack the facilities for high-quality surface preparation and for application of premium coatings; they send the steel to specialty shops if those coatings are specified, driving up the cost. For main framing, it is preferable to use a high-quality field- applied paint than to specify a galvanized finish: Hot-dip galvanizing tends to promote warpage and distortion of framing members made of thin built-up plates. A few manufacturers offer mill- galvanized C or Z girts and purlins. THE PROCESS OF BUYING A METAL BUILDING273 Any restrictions on framing sizes. The drawings should indicate the largest column depth that the foundations can accept. The rate of column taper should also be controlled if any equipment or interior walls are to be located near the columns. Lateral drift and vertical deflection criteria for both the main and the secondary framing. (This issue is critical enough to deserve its own chapter; see Chap. 11.) Crane requirements, if any are needed, including service levels, as is further explained in Chap. 15. The authors practice for most projects, including those using metal building systems, is to provide a drawing with general structural notes. The notes summarize the design loads, material specifica- tions, concrete strength, etc. A sample section dealing with pre-engineered buildings is reproduced in Fig. 9.2. The design loading, including collateral load, would be shown in a separate note section (usually Section I). A set of typical details that show the areas where specific performance is required (instead of the standard manufacturers details) could also be included. Among those could be the details of purlin bracing, anchor bolt construction, backup plates at hillside washers, framing around overhead doors, and any other features deemed necessary. 9.3THE MANUFACTURERS RESPONSIBILITIES The manufacturer is responsible for design and fabrication of the metal building, exclusive of the items mentioned above, down to the bottom of the column base plates. Using the owner-supplied 274CHAPTER NINE FIGURE 9.1Shop primer is applied to a segment of primary frame. THE PROCESS OF BUYING A METAL BUILDING275 FIGURE 9.2Sample set of notes for specifying metal building systems. design criteria, the manufacturer either selects a “pre-engineered” frame from a catalog of standard products or custom designs it. While the industry started out with the former approach (hence the buildings were called “pre-engineered”), presently the latter is the norm. Computers have revolu- tionized design of metal building systems by erasing the line between “standard” and “custom” choices; today, a vast majority of metal building systems are custom designed for a specific project. Many larger manufacturers have developed extensive CAD libraries of details and connections which can help quickly assemble a computerized framing design. While each company tends to develop its own software with slightly different features, all the programs perform similar functions. Typically, computers help generate anchor bolt plans and details, frame elevations, structural compu- tations for each member, and cost data. The newest graphic software can generate impressive-looking documents useful for presentations to owners and permitting agencies. Large metal building manu- facturers view their advanced software capabilities as both technical and marketing tools differentiat- ing them from less equipped competitors whose staff might not even include registered engineers. 9.4THE BUILDERS ROLE Usually, the manufacturer does not contract with the owner directly. The entity that does is a local franchised builder. Builders can act either as general contractors for the project with complete responsibility for it, or only as suppliers of the pre-engineered building. In either case, they may sub- contract building erection to another firm. Major manufacturers are quite selective in the kind of people they allow to become their builders, seeking contractors who are financially stable, experienced, and dedicated to quality workmanship. A prospective builder is often required to complete a course sponsored by the manufacturer and receive a renewable certificate. The builder does not simply take a set of the owners contract documents and send it to the man- ufacturer; many manufacturers would not want to struggle through a thick set of plans and specifi- cations to make