maximum shearing strength, psi Side hardness, load perpendicular to grain, lb Locust, black 0.66 13.8 1850 6,800 1160 1760 1570 Larch, western 0.48 4.9 960 3,760 400 870 510 Maple, sugar 0.56 9.4 1550 4,020 640 1460 970 Oak, northern red 0.56 8.3 1350 3,440 610 1210 1000 Oak, white 0.60 8.3 1250 3,560 670 1250 1060 Pine shortleaf 0.47 7.4 1390 3,530 350 910 440 Pine, longleaf 0.54 8.5 1590 4,320 480 1040 590 Pine, sugar 0.34 4.9 1030 2,460 210 720 270 Pine, western white 0.35 4.7 1190 2,430 190 680 260 Yellow poplar 0.40 6.0 1220 2,660 270 790 440 Redwood, old growth 0.38 7.5 1180 4,200 420 800 410 Spruce, white 0.37 5.6 1070 2,570 240 690 320 Tupelo, black 0.46 7.0 1030 3,040 480 1100 640 *From U.S. Forest Products Laboratory. Values in first line are for green material. Values in second line are adjusted to 12% moisture content. as longitudinal, or parallel to grain, differ from those in the other (radial or circumferential) directions, or across the grain. Because of its structure, wood has different strength properties parallel and perpendicular to the grain. Tensile, bending, and compressive strengths are greatest parallel to the grain and least across the grain, whereas shear strength is least parallel to the grain and greatest across the grain. Except in plywood, the shearing strength of wood is usually governed by the parallel-to-grain direction. The compressive strength of wood at an angle other than parallel or perpendicular to the grain is given by the following formula: C C C  2 2 (4.2)  C sin2   C cos2  1 2 in which C is the strength at the desired angle  with the grain, C1 is the compressive strength parallel to grain, and C2 is the compressive strength perpendicular

Additional devices are needed for power-operated doors to reopen the car and hoistway doors when they start to close on a passenger or other object. The National Elevator Industry standard, Suggested Minimum Passenger Elevator Requirements for the Handicapped, recommends that the devices be capable of sensing a person or object in the path of a closing door, without requiring contact for activation, at a nominal 5 and 29 in above the floor. Also, the doors should be kept open for at least 20 s after reopening. Still other devices should be installed for other safety reasons, for example, to prevent car and hoistway doors from closing and the car from moving when it is overloaded. 16.8.2 Car Equipment The interior of the car should be ventilated and illuminated with at least two electric lamps. Lighting provided at the landing edge of the car platform should be at least 5 fc for passenger elevators and 2.5 fc for freight elevators. In addition, an emergency electric-lighting power source should be installed, to operate immediately after failure of the normal power source. For a period of at least 4 h, this system should maintain at least 0.2 fc at a level 4 ft above the car floor and about 1 ft in front of a car station. The car must also house an approved communication device consistent with rules outlined in the Americans with Disabilities Act. The communication device provides a means for two-way communication with persons outside the hoistway. To be available for use by persons in wheelchairs, an alarm button should be installed in the car. When pressed, this button should sound an alarm outside the hoistway, and an emergency stop switch should be installed about 35 in above the platform. The height of the highest push button or of a telephone should not exceed 48 in. A handrail should be provided about 32 in above the floor along the rear car

TABLE 5.19 Architectural Components Coefficients Architectural component or element p a Rp Interior nonstructural walls and partitions Plain (unreinforced) masonry walls 1.0 1.25 Other walls and partitions 1.0 2.5 Cantilever elements (unbraced or braced to structural frame below its center of mass) Parapets and cantilever interior nonstructural walls 2.5 2.5 Chimneys and stacks when laterally braced or supported by the structural frame Cantilever elements (braced to structural frame above its center of mass) Parapets 1.0 2.5 Chimneys and Stacks 1.0 2.5 Exterior Nonstructural Walls 1.0 2.5 Exterior nonstructural wall elements and connections Wall element 1.0 2.5 Body of wall panel connections 1.0 2.5 Fasteners of the connecting system 1.25 1.0 Veneer Limited deformity elements and attachments 1.0 2.5 Low deformity elements or attachments 1.0 1.25 Penthouse (except when framed by an extension of the building frame) 2.5 3.5 Ceilings 1.0 2.5 Cabinets Storage cabinets and laboratory equipment 1.0 2.5