Wall Penetrations

In fig, 4 local corrosion by erosion is shown in a pipe with a bore of 100 mm behind a welding. In this case only the nominal wall thickness of the pipe is known (6.3 mm). To calibrate the obtained density changes into wall thickness changes a step wedge exposure with a nominal wall thickness of 13 mm (double wall penetration in the pipe exposure) and the same source / film system combination was used. From this a pcff = 1-30 1/cm can be expected which is used for the wall thickness estimation of the pipe image according to equation (4). 

Fig. 4 Corrosion inside a pipe (bore 100 mm, wall thickness 6.3 mm), projection technique at 160 kV (double wall penetration), profile plot with calibrated wall thickness loss...

An other worst case for the projection technique used is the ease if corrosion is on both sides of the wall in the double wall penetration. Then by the nature of the double wall penetration it is only possible to determine the integral material loss in the penetrating direction without any possibility to distinguish the side on which the erosion can be found. 

Fig. 22-3 (1) Total number of wall penetrations by corrosion per kilometer of a DN 500 pipeline as a function of service life. (2) Total number of wall penetrations per kilometer of a pipeline with severe stray current exit.

Fig. 22-4 Total repair costs (1) and (2) for wall penetrations (1) and (2) in Fig. 22-3 and comparison with total annual cost of cathodic protection at 400 DM km (3), at 3000 DM km (4), and with subsequent installation (400 DM km ) after...

Fig. 22-5 Total number of wall penetrations in well casings in an oil field.

For facilities susceptible to the contamination of nitroglycerin liquids and vapors, basic construction materials of wood framing, reinforced concrete, fiberglass reinforced plastic, and sandwich panels were chosen for development of architectural details incorporating lead conductive floor lining, equipment doors, personnel escape chutes and doors, ceiling and wall interfaces, interior finishes, joint sealing, door and wall louvers, wall vents, wall penetrations, and fixed windows. 

A very important factor in ensuring that full cell wall penetration has occurred is to allow sufficient time for the impregnant molecules to diffuse into the intracellular spaces. Many workers allow several days (weeks in some cases) for this to occur. It is important to emphasize that pressure treatment will aid penetration of larger wood samples, but will not in any way result in cell wall penetration, which is a purely diffusion-controlled process. 

Rozman etal. (1997a) treated rubberwood by impregnation with a methanolic solution of TMPS for 24 hours, followed by curing at 110°C for 5 hours. No solvent extraction was employed after treatment. Volume increases due to treatment were considerably lower than predicted theoretically, showing that little cell wall penetration had occurred. ASE measurements were made over two cycles, and it was found that ASE increased in the second cycle. This odd behaviour was not explained and the experimental details for ASE determination were not given. 

A solution of styrene in methanol to impregnate wood samples, followed by polymerization, was used by Furuno and Goto (1979). Penetration of the monomer into the cell wall was determined by solvent extraction of samples after polymerization. This removed lumen located polymer, whilst leaving the cell wall bound polymer in place. This showed that the concentration of cell wall bound polymer increased in proportion to the monomer content in methanol, up to a maximum of 80% of the monomer in the solvent. No cell wall penetration was observed for treatment with neat monomer. This was also found for bulking of the wood, as determined from external dimensions of the samples. Improvements in ASE were obtained as a result of the presence of cell wall bound polymer. To achieve similar ASE values with lumen located polymer required very high polymer loadings. 

Where large cable trays feed into the control building or I/O room, these openings or wall penetrations should be sealed against fire and smoke. Penetration seals should be provided that are or should meet the appropriate test requirements of ASTM E 814, Standard Method of Fire Tests of Through-Penetration Fire Stops or other test methods, such as IEEE 634, Testing of Fire Rated Penetration Seals. 

Wall penetrations for cables and conduits should be sealed with an approved fire retardant sealant. If conduit is used that subsequently passes through flammable areas, appropriate conduit seals must be used at the MCC terminus. 

Radiation-based level detection continues to be very appealing for cryogenic, hard-to-handle, toxic, and corrosive processes, because it does not require vessel wall penetrations. Costs and licensing requirements do limit the number of applications but are not serious impediments to the implementation of carefully designed systems. 

Seal around all through-the-wall penetration and weather hoods for ... 

Figure 34 The steps involved in determining the depth of container wall penetration under Canadian nuclear waste disposal conditions using data obtained in an electrochemical galvanic coupling experiment. (A) Crevice propagation rate (R cc Ic) as a function of temperature (T) (B) RCc as a function of 02 concentration [02] (C) calculated evolution of container surface temperatures and vault 02 concentrations with time in the vault (D) flux of 02 (Jo2) to the container surface as a function of time (E) predicted evolution of Rcc up to the time of repassivation (i.e., at [02]p) (F) total extent of crevice corrosion damage expressed as the total amount of 02 consumed (Q) up to the time of repassivation (G) experimentally determined maximum depth of wall penetration (Pw) as a function of 02 consumed (Q) (H) predicted maximum value of Pw up to the time of repassivation (fP)-...

G), the extent of wall penetration as a function of exposure time can be calculated... 

What is clear from these analyses is that the avoidance of crevice corrosion will delay eventual container failure significantly, irrespective of whether it occurs by wall penetration or by HIC. With this is mind, the galvanic coupling technique (along with the associated analytical methods outlined above) can be used to compare qualitatively the crevice corrosion performance of a series of titanium alloys. Figs. 36A and B compare the parameter (/c, Ec, Ep) values ob-... 

Figure 5.6 Through wall penetrators in ERW weld3 Figure 5.7 Stitch weld (intermittent fusion) in ERW weld4...

Chemical modification will be defined for this chapter as any chemical reaction between some reactive part of a wood cell wall component and a simple single chemical reagent, with or without catalyst, that forms a covalent bond between the two components. This excludes in situ polymerizations of monomers in the lumen structure of the wood and those reactions that result in cell wall-penetrating polymer systems that do not result in any cell wall attachment. It is well known that lumen-filling polymer treatment results in large improvements in mechanical properties, but these are mainly a result of the properties of the new polymer introduced [ 1 ]. 

The DC breakdown strength was determined under conditions applied in the rapid rise AC breakdown test, but with direct current. In the absence of trees, both PE and XLPE exhibited DC breakdown strengths in excess of 50 kV, and flashovers at this stress prevented the determination of exact values. About wall penetration lowered this value to 15 kV for XLPE and it remained approximately constant at higher penetration. 

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