Installation critical

Any of the above reasons tnay result in noise and an increase in temperature and must be corrected. Critical installations such as a refinery, a petrochemical plant, a chemical plant or a petroleum pipeline may require special precautions and control to avert any excessive heating of the bearings, which may become fire hazards. For these installations, bearing temperature detectors with a relay and alarm facility may also be installed in the control circuit of the switching device to give warning or trip the motor if the temperature of the bearing exceeds the preset safe value. 

To have a modular construction with a wide choice of module sizes for optimum utilization of the usable area in each vertical panel, which is normally 1800 mm as illustrated in Figure 13,32, The general practice is to have the module sizes in the ratio of 1/6 (300 mm), 1/4 (450 mm), 1/3 (600 mm) and 1/2 (900 mm), etc. Some manufacturers, however, supply 1/8 (225 mm) and 1/9 (200 mm) size of modules when the sizes and number of components for a module are less and can be accommodated in such a small module size. For critical installations, however, such as for a refinery or a petrochemical plant or for the essential services of a powergenerating station or installations that are in humid conditions or are contaminated, it is advisable to have a module size no smaller than 1/6 (300 mm)... 

As a result of tlie generally high rating of protective fuses they provide no adequate protection against an inter-turn fault. For critical installations, and for HT VTs particularly, a separate protection may be provided for inter-turn faults. 

Fault level is normally not mentioned, nor is it requested by the CT manufacturer. Generally, it should be sufficient to meet the likely fault level of the system and its duration in most cases, particularly on an LT system. For critical installations, large feeders and all FIT systems, however, it is recommended to check the suitability of the CTs for the system fault level and its duration. 

From the above it is essential lo predetermine the nature, magnitude and steepness of such transients to decide the most appropriate protection or preventive measures for an FIT motor, particularly, for critical installations, such... 

The severity of the transient conditions can be established on the basis of past experience or data collected from similar installations. However, for large and more critical installations, such as a generating station or a large switchyard, it is advisable to carry out transient network analysis (TNA) or electromagnetic transient programme analysis (EMTP) with the aid of computers. For more details refer Gibbs et al. (1989) in Chapter 17. Where this is not necessary, the system may be analysed... 

When equipment is exposed to direct lightning strikes Equipment connected directly to an overhead line, or even through a transformer, will fall into this category. Select the highest value of BIL and even then a surge protection will become necessary for critical installations. 

For critical installations, 1 is considered as 250°C for annealed copper conductors. At higher temperatures, the annealing may erode. 

When selecting a machine for more critical installations. 

Seismic effects and earthquake engineering is covered in this part to study the behaviour of an object under seismic conditions and its suitability for critical installations. The formation of the earth and movements of tectonic plates that cause earthquakes and volcanic eruptions are described,... 

A critical installation should have the metal temperature sensors in the thrust pad. Axial proximity probes may be used as a backup system. If metal temperatures are high and the rate of change of those temperatures begins to alter rapidly, thrust-bearing failure should be anticipated. 

Corrosion by essentially pure steam arises principally in connection with power generating plant. Temperatures up to about 600°C in association with pressures up to about 15 MN/m are involved, although in the most advanced super-critical installations being planned for the future, temperatures of 650°C and pressures of 40MN/m are under consideration. The highest temperatures occur in the superheater tubes, but it is probable that the severest corrosion conditions on these components will arise from the presence of fuel ashes on the outside of the tubes rather than from the steam on the inside. Perhaps the most critical components in such installations will... 

Utilities such as steam, electricity, fire water should be separated protected by the effects of an incident so that they may be continuously maintained. Where large facilities or critical installations are present the supply of these services from two or more remote locations should be evaluated. 

Specification references, including purchase orders and contract numbers Verification of calibration of critical installed components Verification of procedures (e.g., operation, maintenance, cleaning, change control)... 

Closed or contained equipments should be used whenever appropriate. Where open equipment is used, or equipment is opened, appropriate precautions should be taken to minimize the risk of contamination. A set of current drawings should be maintained for equipment and critical installations (e.g., instrumentation and utility systems). 

Where trips are critical, install a hi -reliability trip system. Test it regularly. Carefully examine the behavior of the control system when determining trip and relief requirements. 

Another development that facilitated preparations for chemical warfare under the Munitions Program was the receipt of pertinent information from the British. The assistant military attache in London in the emergency period, a CWS officer, obtained access to data on development and production methods for chemical warfare items, on British smoke operations for screening critical installations, on the effects of incendiary bombing, and on the types of German incendiaries dropped on London. 

Steam trap stoppage is, arguably, the single most prevalent cause of freeze-up in vaporizers. For critical installations, duplicate traps may be installed in parallel. 

---