Surface cleaning decontamination

Company, M. and Karsa, D. (2007) Vehicle cleaning. In I. Johansson and P. Somasundaran (eds), Handbook for Cleaning/Decontamination of surface, Vol 2. Elsevier, Amsterdam, The Netherlands. 

To minimize the possibility of ingestion as well as the chances of ruining experiments through accidental contamination, limiting the radioactive work to a minimum area is essential. There should be no radioactivity exc t in the immediate working area, and upon conq>letion of the particular experimrait, all activity should be removed and the area cleaned decontaminated) if necessary. For low levels, this means working in a good hood with easily cleaned nonporous surfaces. 

The corrosion protection of the HMMWV was to be provided by the military coating specification Mil-C-46164 and the CARC. The CARC paint system consists of a surface cleaning, epoxy primer, epoxy interior topcoat, and a polyurethane exterior topcoat. The purpose of this coating was to provide chemical resistance (penetration of the coating) and to aid in the decontamination of the vehicle in case of chemical attack. The coating was to provide corrosion protection as well as... 

A visual examination should be made to yield information on the general condition of the part, component or surface to be examined, including such conditions as the presence of scratches, wear, cracks, corrosion or erosion on the surface, or evidence of leaking. Optical aids such as television cameras, binoculars and mirrors may be used. Surface rephcation as a method of visual examination may be considered acceptable, provided that the resolution at the surface is at least equivalent to that obtainable by visual observation. Any visual examination that requires a clean surface or decontamination for the proper interpretation of results should be preceded by appropriate cleaning processes. 

Comparative effectiveness of selected cleaning techniques is shown in Table 5. When gauging the comparative success of these techniques on concrete, however, effectiveness alone is not a good evaluation criterion. Concrete decontamination situations typically involve surface cleaning or removal to a specified depth and are therefore not readily measured by percent removal of PCB. Proper characterization of the site is the key to the effectiveness of the removal technique, as it dictates what depth of removal is required. 

External radioactive contamination occurs when a radioactive isotope (e.g. debris from a nuclear explosion) is deposited on the skin and clothing. Such debris is usually in the form of a dust. This contamination can be removed by surface cleaning with soap and water (as for chemical contamination). Care must be taken during external decontamination to avoid accidental ingestion and subsequent internal contamination. 

Construction materials must be nonabsorbent and easily cleaned or decontaminated. Seamless flooring avoids cracks from which spilled chemicals can contribute a significant pollution burden to the laboratory air. Epoxy paint should be used for interior walls. Dropped ceilings should be made of nonabsorbent material such as enameled metal. Hoods and sinks should be fabricated of stainless steel. Wood or other porous surfaces must be avoided. 

Chemicals such as chlorine are often used to clean and decontaminate food products and food processing surfaces. The increased effectiveness of ultrasound in combination with chlorine in decontaminating broiler breast skin inoculated -with Salmonella has been investigated [46]. The mechanism suggested involved the release of Salmonella cells from the skin by sonication together with the improved penetration of chlorine into the cells through the action of ultrasound (see above). 

Because decontamination occurs after buildings have been evacuated and first responders have treated any casualties, it allows for some time lapse before decontamination begins. With some planning, damage can be minimized and the efficacy of the decontamination process can be maximized. For example, sensitive equipment, electronics, valuable artwork, and personal objects will require chemicals that are less harsh than those used to clean air ducts and walls. The lack of time sensitivity also allows the choice of a decontaminant that may have a longer reaction time, but that is more suitable for the surface or the ambient conditions suoh as humidity and temperature. Thus, it is best to obtain a suite of deoontamination methods. 

Equipment blank is a sample of water collected from the surface of a decontaminated sampling tool to verify the effectiveness of a cleaning procedure. Equipment blanks are sometimes called rinsate blanks. They are collected as samples of the final rinse water from non-disposable sampling tools after they have been cleaned between samples. The field crew pours analyte-free water over the tool s surface that has come in contact with the sampled medium. The water is diverted directly into sample containers and analyzed for the project contaminants of concern. 

Drawbacks of the RTP ports are that they cannot be hooked into the isolator clean in place (CIP) system so, they must always be considered dirty until an adequate cleaning procedure is developed. There are also size limitations to the RTP ports and their corresponding containers. Once a certain size port is selected for the isolator, this is the only diameter container that can be used, unless the isolator port is modified. The port also requires an additional penetration of the isolator wall and serves as another potential point for air leaks. In addition, the RTP containers are not amenable to the transport of flasks into and out of the isolator they require rotation and maneuvering of the RTP container to dock it into the isolator. Unless the port is mounted into the isolator floor, which will take up valuable space, the ability to transport liquids into and out of the isolator is limited to securely closed vials or bottles. The final limitation is the tendency of the seals on the mating surfaces of the RTP ports to become contaminated with potent material during transport operations. Procedures should be put in place to ensure that the mating surfaces of the RTP ports are thoroughly decontaminated as soon as the transport container is undocked from the isolator wall. 

While textured laminates offer superior resistance to scratching they are less easy to wipe clean than plane surfaces. This can be an important consideration in applications such as bench tops for microbiological and nuclear laboratories, where ease of decontamination is a primary requirement. 

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