Air foam (mechanical foam) is made by mechanical mixing of water and a protein-based chemical concentrate. There are several methods of combining the components, but essentially the foam concentrate is induced into a flowing stream of water through a metering orifice and a suitable device, such as a venturi. The volume of foam generated is from 16 to 33 times the volume of water used. Several kinds of mixing apparatus are available, choice depending on volume required, availability of water, type of hazard, and characteristics of the protected area or equipment. Air foam can be conducted through pipes and discharged through a fixed chamber mounted in a bulk fuel storage tank, or it can be conducted through hoses and discharged manually through special nozzles. This foam can also be distributed through a sprinkler system of special design to cover small equipment, such as process vessels, or in multisystem applications, over an entire airplane hangar. The standard for use and installation of air foam is NFPA 11, and for foam-water sprinkler

Percentage of the construction cost of the project Cost plus fee Multiple of direct personnel expense Multiple of technical personnel hourly rates Stipulated or lump sum Billing rates for personnel classification For a project requiring what could be described as standard services, the percentage-of-construction-cost fee is a safe standard. Years of experience with the relationship between the scope of architectural services required for various sizes of standard construction contracts provide a basis for such rule-of-thumb fee agreements. For projects where atypical services are required, other arrangements are more suitable. For example, for projects where the scope of service is indefinite, a costplus fee is often best. It permits services to proceed on an as-authorized basis, without undue gambling for either party to the agreement. Under such an arrangement, the architect is reimbursed for costs and also receives an agreed-on fee for each unit of effort the architect expended on the project. Special studies, consultations, investigations, and unusual design services are often performed under such

When stiffeners having a combined cross-sectional area Ast, in2, are required on the column whenever Ast computed from Eq. (7.48) is positive P  F t(t  5k) yc b A  (7.48) st Fys where t  thickness of column web, in tb  thickness, in, of beam flange delivering concentrated load Fyc  column steel yield stress, ksi Fys  stiffener steel yield stress, ksi P  computed force delivered by beam flange or connection plate multiplied by 5/3 when force is a result of dead and live loads, or by 4/3 when it is a result of wind or earthquake forces, kips k  distance from face of column to edge of fillet on rolled sections (use equivalent for welded sections) Regardless of the preceding requirement, a single or double stiffener is needed opposite the compression force delivered to the column at point a when 4100 t3
Fyc d  (7.49) c P where dc  clear distance, in, between column flanges (clear of fillets). Also, a pair of stiffeners is needed opposite the tension force at point b when