REQUIREMENTS OF EQUIPMENTS DESIGN AND CONSTRUCTION

Oil industry equipment tends to be more robust than normal industrial equipment due to the often harsh and hostile environments in which it is expected to function without trouble for long periods of time. The indirect cost of equipment failures and outages is high and reliability is of paramount importance.

An essential requirement is the definition of the degree of protection of the enclosure for the environment, which may be either outdoor or indoor, and hazardous or non-hazardous. The international standards most often used are IEC60529 and NEMA-ICS1-110 for the degree of protection against liquids and particles. These references are applied for the hazardous area protection.

Wound components such as motor and transformer windings need to have their insulation specified to withstand the surface temperature of the copper conductors. IEC60085 and ANSI/NEMA describe the different classes of insulation that are normally available. Where IEC60085 or ANSI/NEMA is the reference, the two most common are Class B and Class F. These state the maximum temperature rise in degrees Celsius above the conductor temperature when the temperature of the cooling medium for the equipment is no greater than 40◦C.

For most equipment ratings used in the oil industry the temperature rise limits are 80◦C for Class B and 100◦C for Class F (Class H allows 125◦C). It is common practice to specify Class F insulating materials but to restrict the actual temperature rise to that of Class B. These stem from the recommendation in IEC60085 that for ratings equal and above 5000 kVA or if the iron core length is equal and above one metre, that this combination of classes should be used.

The owner may have particular requirements for the materials to be used for insulation and their impregnation. This may be due to their experience with marine and highly humid environments.

Other aspects that should be included are protective devices, measurement detectors, terminal blocks, segregation of circuits and terminals, voltage surge suppression, skid construction, floor frames, lifting eyes, jacking points, earthing bosses, indicating devices, control switches, automatic voltage regulators, exciters, detachable panels and doors, forced cooling, shaft bearings and seals, lubrication systems, anti-condensation heaters, noise levels, labelling and nameplates, painting etc. Some of these may be efficiently included in the data sheet.