Compressors shelter

It is generally agreed that a shelter with a roof having ridge ventilation and with curtain walls not extending lower than 8 feet above the operating platform would be freely ventilated. Because a gas compressor would not be a source of hazard, except under abnormal conditions such as an equipment failure, this type of compressor shelter is usually classified as a Division 2 area. 

Compressor installations and most other equipment may be located either in open areas of the plant or in struaures that have a roof only or a curtain wall or are completely enclosed. For the plant layout designer, client preference and climate conditions are the two primary considerations that determine the inclusion of compressor shelters. The faa that machines may be either elevated or grade mounted creates a variety of maintenance problems for the plant layout designer. 

The compressor or blower installation in a typical refinery or chemical process unit is not out-of-doors completely. Some form of shelter often is provided, ranging from only a roof to a completely closed building. When process equipment such as a centrifugal gas compressor, which is not hazardous in normal operation, is present in the shelter, the hazard classification depends on the extent to that which the shelter restricts ventilation. The extent of the shelter provided determines the area classification and the type of motor enclosure that should be applied. 

Motor enclosure types for compressor service under shelters are applied as follows ... 

Plant layout studies are made by template and model methods, as explained in Chap. 5. Ample space is provided for access by crane or fork truck to heavy equipment requiring repair or replacement and for snow- and ice-removal equipment. Shelters of some kind must be provided for equipment requiring protection from rainfall and snow and/or frequent maintenance and operating attention. Examples of equipment of this nature are centrifuges, compressors, and pumps. A relatively cheap shelter of structural steel, designed for overhead crane and monorail support, with corrugated sheet-metal roof and partially open sides suffices. An example of an indoor-outdoor plant with equipment shelters is shown in Fig. 5-6. 

Apart from building that house equipment (e.g., compressor houses), it is often necessary to position control houses, substations, analyzer houses, and operator shelters within the process unit battery limits. Administration buildings and warehouses are generally located away from process unit areas. Control houses and substations are usually located at the edge of the unit adjacent to a plant road, 50 ft (15,000 mm) from the operating equipment. As seen in Exhibit 3-24, analyzer houses and operator shelters should be located next to the equipment that they service. 

Exhibit 4-28 illustrates how compressor maintenance affects the size of the shelter or structure. Although operational access often determines floor space requirements, the height of a compressor house is strialy a function of maintenance. Consequently, the size of the maintenance area must permit the largest single item to pass unobstructed from one end of the building to the other and should be set as close to the operating level as possible. The centerline elevation of the hook that allows all items to pass through the maintenance area must be set. The hook elevation. 

EXHIBIT 4-29 Grade-Mounted Centrifugal Compressor No Shelter... 

The compressor arrangement in Exhibit 4-31 is a cumin wall structure with four sides, open from the operating level to a height of 8 ft (2,400 mm). This arrangement is often found in temperate climates. Maintenance is accomplished with a traveling crane. The drop zone for the equipment may be within or outside the shelter if the chop zone is outside the shelter, removable panels must be furnished and iden-... 

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