Clean areas services

These are areas within a clean area designed and constructed, serviced, and used with the intention to protect sterile products from microbiological and particulate contamination. 

As far as practicable, equipment, fittings and services should be designed and installed so that operations, maintenance and repairs can be carried out outside the clean area If sterilisation is required, it should be carried out after complete reassembly wherever possible. 

Aseptic Area A room, suite of rooms or special area within a Clean Area (see below) designed, constructed, serviced and used with the intention of preventing microbial contamination of the product... 

The site area is divided into two general areas. A "limited or "clean" area containing most of the nonradioactive operations and service functions is separated by a fence from an "exclusion" or "hot" area containing the reactor and its closely related radioactive auxiliaries. The exclusion area is approximately the south half of the plot< Since the subterranean and deep water flows are to the southeast, this location decreases the possibility that escaping radioactive water may flow toward the wells located in the north portion of the limited area. The most prominent wind direction at the site is from the southwest, and the direction of secondary frequency is from the northeast. Therefore the stack for the exhaust of reactor-cooling air is near the southeast corner of the site. 

Hospital incident command system—A generic crisis management plan expressly for comprehensive medical facilities that is modeled closely after the fire service incident command system. Hospital postdecontamination zone— The hospital postdecontamination zone is an area considered uncontaminated. At a hospital receiving contaminated victims, the hospital postdecontamination zone includes the emergency department (unless contaminated). This zone is sometimes called the cold zone or clean area. 

Tension leg and floating platforms can easily be released and towed away for service elsewhere, which is cheap and attractive. In the case of the fixed platforms, the topside modules are removed by lift barge and taken to shore for disposal. Gravity based structures can in theory be deballasted and floated away to be re-employed or sunk in the deep ocean, and steel jackets cut and removed at an agreed depth below sea level. In some areas jackets are cleaned and placed as artificial reefs on the seabed. The... 

Small Communities. Small communities and recent subdivision additions to larger communities, which have not yet been coimected to municipal coUection systems, must have a means of waste disposal. Septic tanks are a possibiHty, but require periodic servicing and cleaning. Furthermore, the soil is not always suitable for accepting the effluent. An alternative is the package plant. These units are commercially produced to serve small areas. They furnish primary treatment and some secondary treatment, and require only minimal operating supervision. Capacity can be varied as needs dictate. In general, pubHc health authorities prefer such installations instead of septic tanks. 

Work in connection with desahnation of seawater has shown that specially modified surfaces can have a profound effect on heat-transfer coefficients in evaporators. Figure 11-26 (Alexander and Hoffman, Oak Ridge National Laboratory TM-2203) compares overall coefficients for some of these surfaces when boiling fresh water in 0.051-m (2-in) tubes 2.44-m (8-ft) long at atmospheric pressure in both upflow and downflow. The area basis used was the nominal outside area. Tube 20 was a smooth 0.0016-m- (0.062-in-) wall aluminum brass tube that had accumulated about 6 years of fouhng in seawater service and exhibited a fouling resistance of about (2.6)(10 ) (m s K)/ J [0.00015 (fF -h-°F)/Btu]. Tube 23 was a clean aluminum tube with 20 spiral corrugations of 0.0032-m (lA-in) radius on a 0.254-m (10 -in)... 

The condition of the test metal is important. Clean metal samples with uniform finishes are preferred. The accelerating effects of surface defects lead to deceptive results in samples. The ratio of the area of a defect to the total surface area of the metal is much higlier in a sample than in any metal in service. This is an indication of the inaccuracy of tests made on metals with improper finishes. The sample metal should have the same type of heat treatment as the metal to be used in service. Different heat treatments have different effects on corrosion. Heat treatment may improve or reduce the corrosion resistance of a metal in an unpredictable manner. For the purpose of selectivity, a metal stress corrosion test may be performed. General trends of the performance of a material can be obtained from such tests however, it is difficult to reproduce the stress that actually will occur during service. 

The order used to clean these areas may be intuitive, but for clarity s sake we should keep in mind the following principle. Cleanup should be performed in the cleanest areas first. For the five-stage decontamination area mentioned, cleaning should start in the clean room. In fact, cleaning should start in the cleanest area of the clean room, and then address each area in order of cleanliness. The last area to be cleaned will be the dirty room. If workers will be performing cleanup activities, they should be properly trained and qualified. If an outside service is utilized, those workers should also be trained and qualified [4]. 

Before performing any inspection or maintenance on a flame arrester, the associated process eqnipment and piping shonld be taken ont of service or isolated. The work area mnst be proven by test to be free of any harmfnl gases or vapors. It shonld also be verified that all piping is clean and free of obstrnctions and debris. All plant, company, local, state, and federal safety and fire codes and standards shonld be followed. 

If the pumps are located indoors, a Division 1 classification is likely to apply. Motors must be Class 1, group D, explosion-proof, or they may be separately ventilated with clean outside air brought to the motor by fans. Auxiliary devices such as alarm contacts on the motor must be suitable for the area classification. The installed costs, overall efficiencies, and service factors associated with the enclosures that are available will influence the selection. 

The technical administration office needs to be quiet, clean, and central to the facilities that it administers. Hence, it should be located in the central area between the service and repair shops. This is remote from the dirty washing facility and the noisy body shop while providing good access to the gate. 

Apart from the provision of various permutations of (chemical-based) boiler water programs, it is common to find water treatment companies supplying value adding chemicals and services in other boiler plant-related areas where their expertise in applied chemical technology can deliver additional economic benefit. Such areas typically include cleaning services for boiler waterside and fireside and the provision of fuel treatments and combustion additives, dust suppressants (for coal and ash handling), acids, and cleaner products. 

Adequate washing facilities shall be provided, including hot and cold water, soap or detergent, air driers or single-service towels, and clean toilet facilities easily accesible to working areas. 

Lighting. Lighting hxtures in the manufacturing areas are dust- and airproof surfaces, flush-mounted, clean room types. They are sealed to the ceiling with pharmaceutical-grade silicone, serviced from above, outside the manufacturing area. 

This discussion assumes that the cross-sectional area of the downcomer is adequate for reasonable vapor-liquid separation. If the downcomer loading (GPM/ft2 of downcomer top area) is less than 150, this assumption is okay, at least for most clean services. 

Heat removed by condensation is easy. The heat-transfer coefficient U for condensation of pure, clean, vapors may be 400 to 1000 Btu per hour per ft2 of heat exchanger surface area, per °F of temperature-driving force. The U value for subcooling stagnant liquid may be only 10 to 30. Condensate backup is the major cause of lost heat transfer for heat exchangers, in condensing service. 

Plate-fin exchangers provide a very large heat transfer surface per unit volume and are relatively inexpensive per unit area. They are not mechanically cleanable and are ordinarily used only with very clean fluids. This combination of properties fits them very well for a wide variety of cryogenic applications, such as air separation helium separation, purification, and liquefaction liquefied natural gas production and separation of light hydrocarbons. They are also used in higher-temperature gas-to-gas services. 

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