e. BICSI, Telecommunications Distribution Methods Manual, Chapter 7 Equipments Rooms. f. OSHA concerning work spaces. A typical communications closet arrangement would be 10 ft wide allowing for 30-in deep equipment, 36-in working space on both sides, 3/4-in plywood backboard on both walls and 6 in of board-mounted equipment on both sides, with 41/2 in to spare. A closet with two open racks, one for patch panels and one for network gear would be 71/2 ft in length allowing 22 in for each rack (19-in EIA/TIA rack), two vertical-cable managers at 4 in each, a 3-ft walk, and 2 in to spare. The preferred closet is a three-rack closet which would require 10 ft in length. They are preferred because you can install two racks with a space for a future rack, or install all three and leave space in each rack based on the equipment arrangement. Keep in mind, during planning, of how difficult it is to get another 21/2 ft in the room during construction. Check and allow space for any required dedicated air-conditioning units. Locate the unit and piping so that a leak will not ruin wiring or equipment. Punch-down blocks may be arranged on the plywood. The arrangement of closets within a building is critical to the performance and cost of the wiring to the workstations. Closets must be located so that the horizontal cabling does not exceed 295 ft (90 m) in length from the patch panel to the outlet. One closet should be located on each floor. One closet should not serve more than

Clay brick High-absorption, per 4-in wythe Medium-absorption, per 4-in wythe Low-absorption, per 4-in wythe Sand-lime brick, per 4-in wythe Concrete brick 4-in, with heavy aggregate 4-in, with light aggregate Concrete block, hollow 8-in, with heavy aggregate lb/ft2 Floor Finishes lb/ft2 Asphalt block, 2-in 24 Cement, 1-in 12 Ceramic or quarry tile, 1-in 12 Hardwood flooring, 7/8-in 4 Plywood subflooring, 1/2-in 1.5 Resilient flooring, such as asphalt tile and linoleum 2 Slate, 1-in 15 Softwood subflooring, per in of thickness 3 Terrazzo, 1-in 13 Wood block, 3-in 4 8-in, with light aggregate 12-in, with heavy aggregate 12-in, with light aggregate Clay tile, loadbearing 4-in 8-in 12-in Clay tile, nonloadbearing 2-in 4-in 8-in Furring tile Wood joists, double wood floor, joist size lb/ft2 12-in spacing 9 16-in spacing 9 11/2-in 2-in Glass block, 4-in Gypsum block, hollow 2-in 4-in 6-in 8 Concrete Slabs lb/ft2 Stone aggregate, reinforced, per in of thickness 12.5 Slag, reinforced, per in of thickness 11.5 Lightweight aggregate, reinforced, per in of thickness 6 to 10 TABLE 5.1 Minimum Design Dead Loads (Continued )

Rubber Hose. Nearly all rubber hose is laminated and composed of layers of rubber combined with reinforcing materials like cotton duck, textile cords, and metal wire. Typical hose consists of an inner rubber lining, a number of intermediate layers consisting of braided cord or cotton duck impregnated with rubber, and outside that, several more layers of fabric, spirally wound cord, spirally wound metal, or in some cases, spirally wound flat steel ribbon. Outside of all this is another layer of rubber to provide resistance to abrasion. Hose for transporting oil, water, wet concrete under pressure, and for dredging purposes is made of heavyduty laminated rubber. Vibration Insulators. These usually consist of a layer of soft rubber bonded between two layers of metal. Another type of insulated consists of a rubber tube or cylinder vulcanized to two concentric metal tubes, the rubber being deflected in shear. A variant of this consists of a cylinder of soft rubber vulcanized to a tubular or solid steel core and a steel outer shell, the entire combination being placed in torsion to act as a spring. Heavy-duty mounts of this type are employed on trucks, buses, and other applications calling for rugged construction. American Concrete Institute, Polymer Modified Concrete, SP-99; Polymers in Concrete, ACI 548; and Guide for the Use of Polymers in Concrete, ACI 548.1. American Society of Civil Engineers, Structural Plastics Design Manual, and Structural Plastics Selection Manual. Modern Plastics Encyclopedia, Plastics Catalog Corp., New York. A. G. H. Dietz, Plastics for Architects and Engineers, M.I.T. Press, Cambridge,