Walkway

Walkways ensure the safe passage of workers from one area to another. If walkways are not clearly defined and demarcated, no defined path exists. This could be hazardous, as items could be stored in pathways, which could create trip-and-slip hazards. 

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Eor toxic materials, it usually is advisable to provide ventilated sampling hoods or breathing-air stations and masks, to assure that the sampler is adequately protected from toxic or flammable vapors and dusts. Special provision for access to and exit from sampling points also may be needed at elevated locations and to avoid tripping or bumping ha2ards and to ensure that the sampler does not transverse areas not intended as walkways, eg, tank covers or roofs. 

The center-drive mechanism and feed launder are usually supported by a walkway that extends across one-half or the whole diameter of the basin. Devices having drive mechanisms and rakes supported by a tmss across the diameter of the thickener are referred to as bridge machines. The bridge thickeners usually do not exceed 25—45 m in diameter. In thickeners with larger diameters, the drive mechanism is supported by a central column or pier and the rates are driven and supported by a drive cage. The sediment is discharged into an aimular trench around the bottom of the column. 

In even larger caisson thickeners, the central column is sufficiently large to accommodate a discharge pump at the bottom. The discharge passes through the column and along the access walkway above the basin. Caisson thickeners can be built having diameters of up to 200 m. These often have an earth bottom. 

Walkway partition each cell interior piers are optional... 

Roads and Walkways The cost of roads and walkways in chemical plants is difficult to estimate, since these vaiy with type of construction and thickness of applied cover. Some typical unit costs for roads are as follows For 305-mm (12-in) gravel base covered with 76-mm (3-in) asphalt, the cost is 17.10 per square meter ( 14.30 per square yard) for a reinforced concrete slab with a 152-mm (6-in) subbase, the cost is from 28.40 to 35.10 per square meter ( 23.80 to 29.30 per square yard), depending on the thickness of concrete (for M S = 1000). 

Usually the cost of roads and walkways amounts to 0.2 to 1.2 percent of the fixed capital cost with a typical value of 0.6 percent. Similarly, railroads cost 0.3 to 0.9 percent of the fixed capital cost, having an average value of 0.6 percent. 

Figure 13.8 A typical general arrangement of a double front panel with a walkway gallery (Courtesy ECS)...

Cast facings, walkways, etc. and as component of concrete. General construction. 

Interior wolkwoy Access walkway Tube Support cog Plenum boff le Dusi inlet port Fell tubes... 

Provide walkways, ladders, etc. to avoid pipework being clambered over. 

The diameters on these machines are over 400 ft., with operating torques to 2,400,000ft.-Lbs. The stationary center pier supports the drive and rake mechanisms. The truss extends from the center pier to the tank periphery supports walkway, power lines and feed lasunder. 

Each PR valve must be installed so that the bonnet vent does not allow released vapors to impinge on lines or equipment, or towards personnel walkways. Where necessary, a short nipple and elbow should be added to direct flow away from such areas. In these cases, the vent piping should discharge horizontally to avoid entry of rainwater and debris, and should terminate in a position which is accessible for leak testing. 

Standard shapes for composite stiffeners are not likely to occur for most aerospace applications. There, the value and function of the structure warrant optimizing the stiffener design. In contrast, for more everyday applications such as scaffolding, stairways, and walkways in chemical plants, competitive pressures lead to a situation where compromises in stiffener efficiency are readily accepted (overdesign) in order to achieve lower cost than would be associated with optimum design. 

Figure 10-5 shows a very large integral compressor. Tbi.s would he typical of compressors in the 2.000 hp to 13,000 hp size. The size of this unit can be estimated by the height of the handrails above the compressor cylinder on the walkway that provides access to the power cylinders. This particular unit has sixteen power cylinders (eight on each side) and four compressor cylinders. 

Are the doors and windows hung to avoid projecting into or blocking walkways and exits ... 

Marine dock.s/decking, broadwalks/walkways, and industrial flooring. 

Figure 10-175 illustrates the assembly of a typical forced draft unit with electric motor and gear drive. Note that walkways and access ladders are necessary to reach the exchanger connections where valves are usually installed. If... 

Pipework layout should be designed so that it does not restrict access to the plant or building. Walkways and... 

When reorganizing, keep pathways and walkways clear with no protruding containers. 

For walkways, where 3 foot-candles is an adequate amount of illumination, two 175-watt R-40 mercury vapor lamps placed every 54 ft may be specified. For these and areas that are used continuously but have adequate windows it may be assumed that the lights are on 4,500 hours per year. (This is approximately half the time.) For some interior areas they may never be turned off. At the other extreme, Sarah Lee has an automated warehouse in which the only time lights are needed is when there is an equipment failure. 

Ml unit costs arc based on niid-1 968. i hesc are not general unit costs t I or enclosed conveyors walkway multiply by 2.10 Stainless factor is 2.4... 

Floor Bare soil for planting with concrete walkway (floor area was covered with aluminum film at horizontal height of 3.5 m at winter nights) 756... 

A worker walking across a high walkway in a process plant stumbles and falls toward the edge. To prevent the fall, he grabs a nearby valve stem. Unfortunately, the valve stem shears off and flammable liquid begins to spew out. A cloud of flammable vapor rapidly forms and is ignited by a nearby truck. The explosion and fire quickly spread to nearby equipment. The resulting fire lasts for six days until all flammable materials in the plant are consumed, and the plant is completely destroyed. 

Passage from one level to another level should be by stairways, where impractical, vertical ladders are normally provided. Preferably stairways and ladders should be located on the exterior faces of structures that face away from the plant. Stairways designs that require evacuation to be through other process equipment or areas should be avoided. On fired units where the towers may be very close to the furnace, providing an additional walkway bridge link to an adjacent tower or structure may be more cost effective if the towers need to be climbed frequently. 

British Standards Institute (BSI), BS 5395 Part 3 1985. Stairs ladders and walkways. Part 3 Code of Practice for the design of industrial type stairs, permanent ladders and walkways, BSI, London, UK. 1985... 

Although it is called Central Park, New York City s great green space has no center —no formal walkway down the middle of the park, no central monument or body of water, no single orienting feature. The paths wind, the landscape constandy shifts and changes, the sections... 

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