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In this paper, a pyrolysis model for a PVC cable is constructed using results from thermogravimetric analysis, microscale combustion calorimeter and cone calorimeter experiments. The pyrolysis model is used to simulate fire propagation in horizontal cable trays. The simulated arrangement corresponds to a cable tray fire experiment from OECD PRISME 2 project. As laying the cables loosely along the horizontal trays is a random process, a novel stochastic method is developed for making the simplified cable tray geometries for the computational fluid dynamics model. In addition, as the simplified cable tray geometry has significantly smaller surface area than a real tray full of cables, the surface area was parametrically adjusted. In contrast to most of the earlier published numerical approaches for simulating cable tray fires, the presented approach does not use empirical correlations for predicting fire propagation and does not require any results from full-scale experiments for calibrating the model. The simulation results are compared to experimental results in terms of heat release rate, mass loss, tray ignition times and lateral flame spread rates. The maximum heat release rate was overpredicted by 8% on average.

This paper presents a mode-matching analysis of the electromagnetic coupling between open cable trays in an indoor structure when an electric-line current is generated as an electromagnetic source. We validated the mode-matching method by comparing the mode-matching results with those computed from a commercial electromagnetic simulator and then investigated the strength of the electric-field coupled in a victim cable tray while varying the distances between cable trays and architectural surfaces. The results of this study provide geometrical information on the placement of open cable trays to avoid electromagnetic interference problems.

The occurrence rate of fire events involved with cables is high and a fire hazard analysis is needed. A cable tray may be commonly placed on a wall. The fire hazards of multiple cable trays are affected by the supporting wall to give a higher maximum heat release rate. Taking the wall constraint effect on cable burning into account, a new model for the fire heat release rate of a cable tray fire against a sidewall is developed based on small scale (cone calorimeter) measurements. The newly developed model introduces a constant m to reflect the acceleration in cable burning due to the sidewall. With a properly chosen value of m, the results obtained using the newly developed model agree well with the experimental data. The error in the peak fire heat release rate value is considerably smaller than those of other models. This work improves the understanding of the fire risk of a cable tray with a sidewall.

This paper presents an analytical interpretation of electromagnetic interference between solid-bottom type open cable trays in a nuclear power plant under the assumption that an electric-line current is undesirably generated from a damaged cable in an open cable tray. Based on the superposition principle and Helmholtz's equation in conjunction with the separation of variables, we employ a mode-matching method to obtain analytical solutions to the postulated electromagnetic interference problem. Before conducting a mode-matching analysis, we investigate the radiating principle of the electric field interfering with a victim cable tray by deriving the array factor in consideration of an imaginary electric-line current. In addition, we characterize the electric fields with a propagating mode at an observation point in the victim cable tray using the derived expression of the electric field. Based on this, we validate the formulation and computation of our mode-matching method and then computationally investigate the strength and distribution of interfering electric fields in terms of the separation distances provided in regulatory guidance on the electrical independence of a nuclear power plant. Finally, we compute the strength and distribution of the interfering electric field at the observation point when the location of an electric-line current is modified. The results of the study provide us with the useful information to alleviate the electromagnetic interference between open cable trays in a nuclear power plant.

Fire hazard analysis of multiple-layer cable tray is an important part of nuclear safety analysis. Large-scale cable fire experiments with a three-layer horizontal cable tray were conducted in a closed compartment. The vertical temperature profile in the middle of the room was acquired. Distinctive stratification phenomena were found in the vertical temperature distribution. The interface between the upper and lower layer was located at approximately the height of the top cable layer. Heat transfer between the smoke and compartment walls occurred mainly above the smoke interface. A modified non-steady energy balance model in a closed compartment which included the effect of smoke interface height was used to estimate the compartment temperatures. Compared with the experimental results, the modified model for the multiple-layer cable tray fire in a closed compartment provides better estimation than the original model.

Recently, because of the global recession of the offshore plant industry and low-cost orders, there has been increasing interest in strengthening the competitiveness of domestic companies for the design and production technologies of offshore plants. However, in the offshore plant design field, the Plant Design Management System (PDMS), which is a 3D CAD program for plant layout developed by AVEVA Marine, is already commonly used as offshore plant design software and widely used in large domestic shipyards and cooperative design companies. Under this background, we have been thinking about ways to design better with the existing software. In this study, we developed a parametric design program to maximize the efficiency and reduce the working time for offshore plant electrical outfit production design based on the Programmable Macro Language (PML) of PDMS. We also examined its performance. By applying the developed program to the offshore plant module selected as an application example, it was confirmed that a 50% improvement in the work efficiency of cable tray design could be obtained compared with the existing method, with work efficiency improvements of 80% or more in other field design work.

Fire risk analysis for cables in a vertical cable tray is important for fire protection design in nuclear power plants. One important characteristic of vertical cable tray fires is the upward spreading of the cable flame along the cable tray, which should be considered as a time-varying fire source. Experiments involving vertical cable tray fires with a spacing of 0 and 8 mm between cable lines were conducted in confined compartments with dimensions of 3 m × 3 m × 3 m (length × width × height). The cable in a 0.3 m wide × 2 m long vertical cable tray was ignited using a line-source gas burner of a 20-kW premixed flame system. The experiments indicate that a room with a vertical cable tray fire could be divided into three zones with respect to thermal characteristics. Notably, a middle zone having reduced temperature was observed, even though the intensity of burning did not decrease. By considering the effect of a time-varying fire source, an expression for predicting the ceiling jet temperature was proposed. For the prediction of the maximum ceiling jet temperature, the relative errors were less than 18.8%; for the entire cable fire process, the normalized Euclidean distances were less than 20.4%. The available literature data concerning a vertical cable tray fire in a confined room were used to validate this expression. It is further confirmed that the proposed expression predicts well the literature data for vertical cable tray fires in a confined space. This new expression can be used for estimating the hazards from a vertically spreading fire in a compartment in nuclear power plants.

This paper presents a computational fluid dynamics (CFD)-based modeling strategy for the prediction of cable tray fire development. The methodology is applied to a set of five horizontal trays (each 2.4-m long and 0.45-m wide) that are positioned with a 0.3-m vertical spacing and set up against an insulated wall. Each tray contains 49 power PVC cables. Ignition is performed with an 80-kW propane burner centrally positioned at 0.2 m below the lowest tray. A collection of four groups of cables per tray (made of one homogeneous material) is considered. These groups are separated by longitudinal slots of air to "mimic" their relatively "loose arrangement." The thermal properties and surface ignition temperature are estimated from cone calorimetry (CC). When the ignition temperature is reached, the cables burn according to a prescribed heat release rate per unit area (HRRPUA) profile obtained from CC, as is or in a modified shape. A realistic flame pattern is predicted. Furthermore, using only data from CC, the peak HRR is underpredicted, and the time to reach the peak is overpredicted. The proposed "design" for the modified HRRPUA CC-profile significantly improves the results.

In order to realize the optimal design of the cable supporting system for the purpose of material saving and energy saving and green manufacturing, the strength-stiffness ratio is proposed in the paper in nondimensional form, which defines quantitatively the relation between the static load strength and stiffness of the cable tray. On the premise of ensuring service safety, the correlation between the strength and stiffness of the cable tray under static load is discussed extensively through the theoretical analysis of the mechanical model. The weakest link in the carrying capacity of the cable tray as well as the issue that needs to pay attention is proposed in the process of design and the test of the cable tray. A reasonable strength-stiffness ratio will help to make full use of the potential of material strengths. The value of the strength-stiffness ratio is obtainable by means of the finite element method or by the loading test of the cable tray. It is shown through the analysis that the value of the strength-stiffness ratio being setting in the range close to but less than 1 will make comparatively reasonable material utilization and will help the deflection test going smoothly to obtain a relatively safer allowable working load for the cable tray.

The radiated emission of the power line communication (PLC) system should be investigated to maintain electromagnetic compatibility. Recently, the development of applying the PLC system to factories and offices was started. In these environments, many cables are arranged in the cable tray. Therefore, the multi-cable effect should be investigated. In this paper, the multi-cable effect was examined by using the scale model. The 0.5 times scale model was constructed in the semi-anechoic chamber, and the maximum common-mode (CM) current was measured by changing position along with the cable. The measured result was agreed with the result using the full-size original model. The experiment by using five cables suggested that the influence by the conductive loss and the dielectric loss of cable was not large for the maximum CM current, and the CM current was dominated by the cancellation effect of the in-phase currents flowing on the cables. The investigation for dependency of the position of the signal apply was indicated that the effect can be roughly estimated from the current division factor.

U radu su prikazani modeli požara u sobi s kabelskom policom, u ormaru s električnom opremom i u sobi s pumpom i motorom unutar nuklearne elektrane. Za proračun korišten je CFD program NIST FDS (Fire Dynamic Simulator). Analiziran je utjecaj geometrije sobe, količina sastava i položaj gorivog materijala na postignutu temperaturu u sobi. Analizirana je i količina generiranog dima i mogućnost propagacije vatre unutar i van prostorije. The thesis shows the models of fire in a room with cable tray, electrical enclosure or electrical motor and pump inside the nuclear power plant. These models are made using NIST FDS CFD program (Fire Dynamic Simulator). The influence of the geometry of the room, the quantity, composition and position of the fuel material to the reached temperature in the room is analised, and also the amount of smoke generated and the possibility of propagation of fire inside and outside of the room.

nd power cable lines with various options for the mutual arrangement of conductors using a probing system based on magnetically sensitive probes. The probing system is located on the micro-tunnel-boring shield and is designed to detect power cable lines on or near the working path, directly during tunneling operations. The change in the topology of the magnetic field created by the active power cable line with different configurations of the mutual arrangement of its conductors is numerically studied. The paper also contains the exploration of the electromagnetic field weakening at a distance of advanced probing (3-3.5 meters from the cable line) due to the lay of conductors with current, as well as by placing the cable line in a reinforced concrete cable tray. The dependences for the magnetic induction values in the soil and the body of the tunnel shield on the configuration of the cable line conductors are obtained, and the possibility of detecting this induction is also determined.

To clarify the heat and smoke propagation in multi-compartments under the spread of cable fire, a large-scale multi-compartment fire test (hereinafter the CFS-2 test) was performed by the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) in France within the framework promoted by the Nuclear Energy Agency (NEA) in Organization for Economic Co-operation and Development (OECD) program PRISME2 (OECD/NEA, 2017). In the CFS-2 test, two rooms of a large-scale facility were adopted and these rooms have an identical volume (120 m3) enclosed with fire walls and were connected by a doorway (0.8 m in width and 2.17 m in height). As a fire source, five-layer cable trays (tray length of 2.4m, tray width of 0.45m and separation distance between trays of 0.3 m) with a fire-retardant PVC cable (77 kg) were used and ignited by a propane gas burner. The power level of the propane gas burner was set to around 80 kW. Moreover, all rooms were mechanically ventilated, and the renewal rate was 15 times per hour (3600 m3/h). During the fire test, the mass loss rate of fuel, gas and soot mass concentration, gas temperature, and etc. were measured. The measured peak values of the HRR, the mass loss rate and gas temperature were about 800 kW, 58 g/s and greater than 600 °C, respectively (Zavaleta, 2017). As a fire model predicting fire characteristics in a compartment, a two-zone model, which divides the fire room into the hot smoke upper layer and lower layer consisting of cool fresh air, is widely used due to the advantages of the brevity of the calculation routine and the reliability of the calculation results. Among them, the BRI2 series, developed in Japan, is now reaching the current BRI2002 software (Wakamatsu, 2004) after several upgrades to improve the calculation precision. The Central Research Institute of Electric Power Industry (CRIEPI) introduced the cable tray fire source model based on the FLASH-CAT (Flame Spread over Horizontal Cable Trays) developed by National Institute of Standards and Technology (NIST) (McGrattan, 2012) into the zone code BRI2002. By comparing the numerical results with the experimental values measured during the CFS-2 test, the methodology for ignition time delay of each tray and horizontal flame propagation speed for each tray were discussed.

Work accidents that occured in Indonesia, 32% are accidents from the construction sector. The construction sector is a sector with a work environment where there were so many hazard risks. Cable tray installation is one of the jobs in a construction project. The purpose of this research is to get an overview of the steps in the installation of cable tray and the its risk. The process of identifying work accident risk in this study uses Job Safety Analysis (JSA). Falling from height is one of the workplace accidents in the cable tray installation process. Risk control is needed to prevent work accidents that can occur due to cable tray installation.

Workplace ergonomics deals with designing or arranging work areas, products and systems so that they fit the people who use them and eliminate wastes associated with poor layout and physical environment. Elimination of ergonomic wastes in production lends itself to lean manufacturing applications. The study is not an attempt to assess a production process using the lens of lean manufacturing but aims at identifying relationships between lean elements and physical environmental factors in the context of workplace design that affects worker performance. Specifically, the setting of the study is in an electrical equipment company in which the lean elements of waste volume, workspace dimension, operating time and plant layout are analyzed together with the ergonomic aspect of work environment that include the factors of light intensity, temperature level and noise. The core idea is to find significant relationships between the two sets of factors with the end in view of improving workforce performance in terms of labor productivity, throughput, number of accidents and workers' attendance. The study is capped with the development of a model for analyzing and improving workplace design, facility layout and worker performance.

A general procedure is described to generate material parameter sets to simulate fire propagation in horizontal cable tray installations. Cone Calorimeter test data are processed in an inverse modelling approach. Here, parameter sets are generated procedurally and serve as input for simulations conducted with the Fire Dynamics Simulator (FDS). The simulation responses are compared with the experimental data and ranked based on their fitness. The best fitness was found for a test condition of 50 k W / m 2. Low flux conditions 25 k W / m 2 and less exhibited difficulties to be accurately simulated. As a validation step, the best parameter sets are then utilised to simulate fire propagation within a horizontal cable tray installation and are compared with experimental data. It is important to note, the inverse modelling process is focused on the Cone Calorimeter and not aware of the actual validation step. Despite this handicap, the general features in the fire development can be reproduced, however not exact. The fire in the tray simulation extinguishes earlier and the total energy release is slightly higher when compared to the experiment. The responses of the material parameter sets are briefly compared with a selection of state of the art procedures.

Nowadays, the Integrated Power and Energy System (IPES) is no more a marginal part of the ship and the electrical equipment arrangement is becoming increasingly difficult. Indeed, an all-electric cruise ship has 65 km of cable trays and more than 4000 km of power cables to supply all the shipboard electric loads. In this scenario, the cable layout in the cable tray is not considered during the early stage design phase. Nevertheless, different cable arrangements can have undesired effects on the power line parameters. Thus, in this paper a Python code is compared to two different Finite Element Method (FEM) software to assess its effectiveness in calculating the inductance matrix considering the power line arrangement in the cable tray. Secondly, two methods are used to determine the equivalent inductance and evaluate its dependence over the cable layout. It is shown that the effect of cable arrangement in the cable tray on the power line equivalent inductance is not negligible and it should be taken into account in the early stage design phase.

Room fire with vertical cable tray involves upward flame spread along the cable. Assessing the vertical cable tray fire hazard in confined spaces has been challenging because of the strong coupling between flame spread and heat transfer. Long computing time is required in using sophisticated field model with computational fluid dynamics. Therefore, developing an appropriate zone model in a cable room fire with experimental validation is required for engineering applications. In this study, a vertical cable tray fire in a confined compartment was simulated using a modified zone model along three new areas on having temporal variations of the fire position, upward-spreading cable flame considered as a burning source moving at a constant speed, and validated through full-scale experiments on vertical cable tray fire with two typical cable-line spacing. The modified zone model can predict accurately the upper-layer temperature in the compartment. The accuracy is at least 25% higher than the model with fixed fire position. The measured temperature at different heights started to decrease at different times, which was due to the vertical spreading of the cable flame. For interface height, the relative error and normalized Euclidean distance in the time-varying fire position model can be improved by 50%.

This paper presents the results of an examination of cracking in a phosphorous deoxidised copper fitting that had been installed in a liquid nitrogen line. The service life of the fitting was reported to be three to four years. Failure was a result of the Stress Corrosion Cracking (SCC) from the outside surface that had been placed in tension by the pipeline being chocked with a block of wood to locally raise the line above a cable tray. The active species for SCC was suspected of being Amines in the Polyurethane insulation.

Electric cable fires in nuclear power plants could be disastrous and have to be studied carefully for safety and economic considerations. Based on the results of previous work on large-scale and bench-scale cable fire testing, the Flame Spread over Horizontal Cable Trays model was modified and improved to estimate the heat release rate of large-scale cable fires using bench-scale measured data. The heat release rate per unit area measured in the cone calorimeter experiment is taken as the input, to avoid introducing any prediction uncertainties caused by inconsistent values of the heat of combustion and char yield of the cable. Cable fire experiments with vertical stacks of trays with one to three layers of cables were conducted in open space to assess the accuracy of the improved model. In comparing with the experimental results, predictions using the improved model are encouraging. The local error of prediction is less than 15% and the global error lies between 19.2% and 35.7%. In addition, three cable tray fire experiments with data available in the literature were used to validate the improved model. It is shown that the improved model had good predictions for these cable tray fires.

Electromagnetic Interference (EMI) is one of causes for medical malfunction and fire in hospital which lead to patient mortality and asset loss. Electromagnetic Interference effect can be minimized with good management of cable. This includes the use of good cable specification, good cable arrangement, good cable bonding and use of cable tray. This paper presents simulation results of various cable arrangement in hospital. Several types of high voltage (HV) cables, low voltage (LV) cables, and data or signal cable (D/S) cables have been selected. In combination with the use of ladder and tray, we simulated the output of D/S cables at various distances between D/S cables and LV or HV cables. Simulation results show that magnetic field generated from LV and HV cables without armour is coupled to D/S cable, which causes disturbed signal output at D/S cable. In order to maintain the quality of D/S cable output, it is required to have at least 10 cm distance between two core D/S cable and LV Cable, and 20 cm between two core D/S cable and HV cable, respectively. It is also found, that HV and LV cables with armour do not produce significant EMI to D/S cable. Based on simulation results, it is strongly recommended that armoured HV, LV and D/S cables on the tray shall be used for minimizing EMI effect in hospital. If no space constraint, non-armour cable can be used with considering the minimum distance between D/S cable and LV cable around 10 cm, as well as D/S cable and HV cable around 20 cm.

The cable tray system, one type of non-structural components, may suffer severe damage and even fall in case of earthquakes, causing interruptions to post-earthquake operations and even injuries or casualties. This paper introduces a toggle-brace damper (TBD) into the cable tray system to control its seismic response and damage. However, owing to the large deformation/rotation effect in the TBD equipped cable tray system, the traditional design method based on small deformation assumption is no longer applicable. The new deformation calculations of suspension frame and TBD subjected to displacement loading are established combining the optimization technique and the geometry relationship, respectively. After then, an optimization design method for connecting location of the damper brace is proposed, considering the installation errors, deformation constraints, and loading process. With the aid of numerical analysis, it is found that the large deformation effect and in-plane installation errors have considerable influence on the damping magnification function. Compared with typical seismic resistant elements such as the steel brace, diagonal- and chevron-brace damper, the proposed optimal TBD can dissipate more energy and effectively suppress the vibration of cable tray system.

A cable tray is a structure made of metal or a non-combustible material that supports cables in the electrical wiring of buildings. Cable trays should be developed to meet the various requirements of the construction site. In this study, a design system was developed to calculate the maximum support...

International audience; Cable fires are one of the main fire hazards in nuclear power plants. As part of the cable fire spreading (CFS) campaign of the OECD PRISME-2 programme, 3 real-scale cable tray fire tests were performed in open atmosphere (1 CFS support test, named CFSS-2) and in a confined and mechanically ventilated facility (2 CFS tests, named CFS-3 and CFS-4). This study aims at investigating the effects of confined and ventilated conditions on cable tray fires that used a halogen-free flame retardant cable-type. The CFS-3 and CFS-4 tests involved 2 ventilation renewal rates of 4 and 15 h−1, respectively. The confined conditions lead to decrease the fire growth rate and the peaks of mass loss rate and heat release rate, compared with open atmosphere. The reductions are larger for the lower ventilation renewal rate. Furthermore, it is shown that the CFS-4 test may be classified as a well-ventilated fire and the CFS-3 test as an under-ventilated fire. For this last one, its fire characteristics and its consequences in the fire room highlight an oscillatory behaviour, with the same low frequency, for about 30 minutes. These oscillations arise from successive combustions of unburnt gases. Copyright © 2017 John Wiley and Sons, Ltd.

The China high-speed trains use cable trays to neatly arrange the cables running through the distributed systems. On one hand, they protect cables against external electromagnetic interference and reduce external radiation from the cables. On the other hand, the cable trays create waveguide structures that affect the coupling among cables inside the cable trays. To simplify coupling analysis for cables going through a cable tray, a lumped circuit model was built using admittance blocks extracted from a mixed-potential integral equation (MPIE) formulation. In the MPIE formulation, either the half-free space or the waveguide dyadic Green's function was used depending on the region where the cables were. A test case was investigated. Results by the proposed circuit model were validated by measurement and full-wave simulation results.

Introduction The incidence of fires and explosions have led to severe damage in many industries, primarily in industries' financial losses. This study was conducted to estimate losses due to fire and explosion and the impact of control measures on the number of losses applying Dow's Fire and Explosion Index. Methods This is a case study conducted in one of the process units of an oil extraction factory. Dow's Fire and Explosion Index Hazard classification guide, 7th edition, issued by the American Institute of Chemical Engineers was applied. Data were obtained mainly through interviews and consultation with experts, as well as reported operating parameters and process documents. Results The Dow Index of the processing unit was estimated to be 243.68, and the most probable base damage was approximately $4.15 million in 2008. The actual damages were estimated to be $2,863,500, and the number of lost work days to be 64.56 days. The interruption losses were estimated to be $15,817,200 and the total losses to the system to be $18.67 million. These results demonstrated that losses resulting from production interruptions are greater than losses due to the destruction of equipment. A series of corrections was then proposed and risk analysis was performed again to examine the effects of reforms. The comparison shows that by applying reforms the FEI can change to 86.62 and the total loss can reduce to $9.03 million. Conclusion This study shows that Dow's Index is a systematic tool to examine the impact of control measures. It also enhances resource management considering an optimal insurance contract. Considering the priority of reducing damage factors, several correction actions were suggested, such as modifying the drainage system, installation of hexane detectors, an automatic sprinkler system, fire detectors on the cable tray, and finally, using the water spray washing on the tanks.