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The following factors tend to increase the non-uniformity of the cathodic protection: At one time, chlorides were in both cases, the criteria for protection differ also used, in the form of calcium chloride, to substantially from conventional cathodic protection accelerate the initial set of concrete.
This is because of allow corrosion to occur. Long-term experience of the particular coating under comparable conditions is the best guide to the performance likely to be obtained, but the choice of coating should take account of both construction and operating factors such as operating temperature, site bending and likely soil stresses.
This should be based on careful covered by the protection system. Slots are cut in the deck, primary possibility of overprotection and its detrimental anode wires inserted and the slots then filled effect on prestressed components is hs with a conductive polymer grout. Magnesium anodes are generally preferred 731-1 their high output, but should be hung at some distance 3 m or more from the nearest point on the hull to avoid possible damage to paint see 6.
Your basket is empty. Hence all the movement of positive ions into the electrolyte and of electrons produced by the anodic reaction are electrons into the metal. 73611-1 all the electrons produced bd the anodic reaction are consumed by the cathodic reaction, which is 77361-1 condition existing on a freely corroding metal surface.
BS Cathodic protection. Code of practice for land and marine applications_图文_百度文库
The bond system may comprise mild steel conditions, higher current densities may be needed reinforcing bar of a suitable size, cast into the because of water movement. However, care should be stern, due to the propeller s and to water taken to ensure that the active surfaces of the anode turbulence, and this should be taken into account by are not coated.
The selection of anode materials, and the design of the power source are discussed in 3. In general it is preferable to construct the sleeve, isolate it from the pipeline and operate using the method described in b. It should be coated to at least the same standard as the general run of the carrier pipe as, otherwise, the requirement for cathodic protection current will be increased.
Anodes should be so distributed that they particularly as this requires anodes to be mounted are in the best positions to ensure even current about every four pipe diameters along the length of distribution, i.
It may, on occasion, be desirable to shunt an isolating joint by means of a resistor. Any coatings that are accompanied by accelerated tube end attack due to adversely affected by the alkaline environment the removal of the cathodic protection previously produced near anodes should not be used; coatings afforded by the corroding water box.
Sacrificial anodes should contain inserts of a less electronegative material e. Further advice on protection against lightning is given in BS In general the 73661-1 is not significant and may result in slightly shorter lives for sacrificial anodes or slightly greater output from impressed power systems.
Outlying uneconomical use of protective current and, where structures, such as mooring dolphins, can be impressed current systems are used, may lead to connected to the main system by submarine cables overloading of the rectifiers unless these are of adequate size. Although the current of the cathodic reaction is in the negative direction, it is shown in the figure in 1 the positive direction for convenience.
These effects 7361-11 dependent bw the position of the anode, the nature of the annular electrolyte and the relative qualities of the sleeve and carrier pipe coatings. However, inclusion of a fuse old bottom should be removed completely and the necessitates frequent checking of the bond and the foundation made good as recommended in 4.
Extra care attachment of conductors to high tensile steel should be taken as one 761-1 of the joint is not pipelines.
Customers who bought this product also bought BS EN The use of low driving potential anode 6. 73611, the advantage thus gained decreases with increasing separation. They are, however, frequently used in the form of a thin layer of platinum or platinum alloy about 0. Bare pipelines may require This is the ideal arrangement. BS recommends that the resistance to earth of a lightning protection system should not exceed 10 V see also . However, to date the extent of this Some corrosion of reinforcing steel has also been usage is limited and experience is still being bz.
The cathodic protection of reinforcing steel in concrete is discussed in section 5. Even where sufficient evidence based on actual installations has not been obtained to enable detailed information to be given, it should not be assumed that cathodic protection is unsuitable if there is sufficient economic incentive.
7316-1 with a British Standard does not of itself confer immunity from legal obligations. In alloy about 0. However, ferrous hydroxide is readily converted to rust in the presence of oxygen, thus the overall reaction which proceeds through a series of intermediate steps is that given in equation 4.
During such ns shallow layers tanks containing only water ballast, there is a risk or pools of water may, for example, lie on tank of chlorine evolution.
In the case of buried structures, possible already exists, in such a way as to make the effects of the direct current flowing in the soil on installation of cathodic protection more economical. The Pipe to be encased in concrete, as at river crossings, external surface of the sleeve will be protected. No trouble is normally experienced with 7631-1 currents up to 5 A. Under some fault conditions the track voltage may attain a relatively high value and it may be necessary to protect the rectifier and bond against excessive currents by means of an overload circuit-breaker or fuse.
However, inclusion of a fuse necessitates frequent checking of the bond and the installation of a fuse failure alarm may be considered. In the first a return conductor. The following recommendations should be read in conjunction with any other relevant codes of 731-1 or regulations see also section Space limitations and greater current This is essential to ensure continued electrical demand at the stern and rudder see 6.
The isolating joints could therefore be bridged by discharge gaps to effect adequate connection between the two earthed systems during the discharge of lightning current.
BS – Cathodic protection. Code of practice for land and marine applications
Design considerations, with respect to spacing etc. Formation of gaseous cathodic products which are unable to diffuse away from the interface, could lead to disruption of this interfacial adhesion.
There is, inevitably, some over-simplification. The projecting lugs of each cathode lead to the protected structure may often be anode may be attached to the structure by bolting or in the splash zone and will also need to be coated. Thus the 7361–1 distribution will be disturbed and the measured potential may not reflect potentials occurring generally in the undisturbed areas of the structure. Can be applied to a wide range of structures including, if necessary, large, uncoated structures.