Cable duct

Radiography provides the only means of reliably detecting voids in pre-stressed cable ducts or of detecting loss of section or fracture of eables inside the duets. The maximum thiekness of eonerete whieh ean be radiographed for confident loeation of voids inside ducts is of course dependant on a number of variables, e g. amount of reinforcing bars, size of void in duet etc... 

For several years now, cable ducts have been manufactured from plastic pipes, which are watertight and form a continuous run of piping. In laying the ducts, low points can occur in which condensed water or water penetrating from the ends can collect. In many cases this water has led to corrosion damage in lead-sheathed cables. Lead-sheathed cables must therefore only be used in such ducts with an additional PE sheath of type A-PM2Y. Cathodic protection of these cables is not possible because of their complete insulation by the plastic pipe. 

Measurement of the cable sheathing/soil potential can be used to assess the corrosion danger from stray current interference (see Section 15.5.1). Since the measured values vary widely and the stray currents cannot be switched off, IR-free potential measurements are only possible with great effort. In order to keep the IR term of the potential measurement low, the reference electrode must be placed as close as possible to the measured object. With measurements in cable ducts (e.g., underneath tramway tracks), the reference electrodes can be introduced in an open duct. 

Anodes of small impressed current protection installations can be installed close to the cable or the cable duct. They can, however, also be inserted as an... 

Cylinders within workplaces should be restricted to those gases in use. Specially designed compartments with partitions may be required to protect people in the event of explosion. Take into account emergency exits, steam or hot water systems, the proximity of other processes etc. Consider the possibility of dense gases accumulating in drains, basements, cable ducts, lift shafts etc. 

In the energy domain, new and efficient uses in gas lines, electric cable ducts and the like, will promote surface stabilization and endurance as well as complex stress capability of various extruded or cast systems. Such reactants as acetylene terminated polymers have yielded cross-linked cured, networks of exceptional density and durability. A diimide dianhydride combined with (3) ethynylaniline yields an acetylene terminated tetraimide. On further polymerization at 250°C, the cross-linked structure derived can be used continuously at about 230°C. When this is combined with polymer carbon fibers or filaments, an exceedingly refractory and tough binder is produced. 

High density PE (HDPE) is normally used for high-pressure pipes up to 20 bar for water and up to 7 bar for gas. Low density PE is used for lower pressure applications mainly in agriculture. Examples of applications are potable water up to 20 bar, gas up to 7 bar, surface water drainage systems, storm water drainage, cable ducting. 

The conductors of intrinsically safe and non-intrinsically safe circuits shall not pass the same cable. In cable ducts, an insulating layer or an earthed metallic partition (see Fig. 6.227(c)) is required. 

In the early 1980s, a multitude of patents and patent applications were registered in the field of coextrusion of multi-layer pipes. Meanwhile, a number of pipe products representing a composite of several layers are established products on the market. The technology of the coextruded foam core pipe builds on these developments. The foam core type of PVC plastic pipe today takes the largest volume share of all coextruded foam core products. This product has developed into an important and very competitive alternative for non-pressure applications such as drain pipes, sewer pipes and cable ducts. France has played the role of a pacesetter in this development. Today, over 80% of all pipes for non-pressure applications are produced in the form of foam core pipes in that country. Since the common market realised within the EU is connected with a strong market equalisation tendency, other European countries are following. 

Layout drawings for cable ducts, joint boxes, and Joint plates. 

Low modulus polyester resin mortars have also been developed. They too cure rapidly. They are principally used to fill cable slots cut across asphalt runways and also to fill over PVC cable ducts installed in concrete runways and taxiways (Shaw, 1993b). 

EN50085 Cable trunking systems and cable ducting systems for elechical installations. Part 1 General requirements ratified European text. 

The dominant material selected for cable ducting has been uPVC. In buildings and transport systems the better fire resistance characteristics of PVC are an advantage but in below ground applications, use of PE and PP materials are growing in importance. 

In summary, each of the other application areas identified irrigation, hot water, sanitation, industrial piping and cable ducting, all seem to offer favourably expanding markets throughout Europe for many years ahead. 

Fig. 13-4 Potential variation of telephone cables in a damp cable duct constructed of cable channel-shaped stone (without stray currents).

To date, the process has penetrated the application areas such as land transport, construction, infrastructure, electrical, marine and offshore, and aerospace. With the introduction of newer technologies, pultrusion can be used to produce nearly any constant cross-sectional shape (Meyer, 1985) such as channels, tubes, beams, bars and many other profiles for handrails, ladders, cable ducts, antennae, rail covers, tent poles, hockey sticks, fishing rods, pipes, slide guides, luggage racks, leaf springs, window frames, farm wagons, bridge sections, roof profiles, etc. 

Cable Duct and Buss Bar Fire Protection Systems... 

Sika Cable Duct and Buzz Bar System 30 mm Sika Firestop... 

To penetrate partitions, bulkheads, decks and ceilings, a steel cable duct tube is usually welded fully into the structure (Fig. 92), and is protected by the following three steps ... 

Switzerland has established a Swiss pipe project. The targets are sewage pipes and cable ducts. The aging behavior of recyclates was carefiilly investigated. The recyclates originated from HDPE bottles and LDPE films. Both materials were typically used for a short term application, thus only low level of processing stabilizer (phosphite) and... 

Improved fire protection measures regarding to computer based fire alarm, alarm identification and fire fighting in cable ducts ... 

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