BS IEC 61892-1-2015 pdf free download – Mobile and fixed offshore units — Electrical installations Part 1: General requirements and conditions.
4 General requirements and conditions
4.1 General
This clause contains conditions and requirements which are common to all equipment and installations in the IEC 61 892 series.
Electrical installations in units shall be such that:
– essential services will be maintained under various emergency conditions;
– the safety of crew, contractors, visitors and unit will be ensured;
– the requirements with respect to safety in this standard are considered;
– the requirements of the International Convention for the Safety of Life at Sea (SOLAS) are met as far as applicable;
– the requirements of the IMO MODU Code are met as far as applicable.
For floating and mobile units, all machinery and equipment shall operate satisfactorily under the static and dynamic inclination limits according to IEC 61 892-5.
The appropriate authority may have additional requirements which have to be complied with.NOTE Emergency conditions are normally defined in the safety assessment of the installation.
4.2Acceptance of substitutes or alternatives
Where in the lEC 61892 series any special type of equipment, construction, or arrangement isspecified, the use of any other equipment,construction or arrangement is admissible,providedit is not less effective and reliable.
4.3Additions and alterations
An addition or alteration, temporary or permanent, shall not be made to an existing installationuntil it has been ascertained that the ratings and the condition of existing accessories,conductors, switchgear, etc. affected, are adequate for the new situation.
Special attention is drawn to those factors affecting the existing system design such as current-carrying capacity,short-circuit level,voltage drop，harmonics，stability and proper discri-mination of the protective devices.
4.4Environmental conditions4.4.1General
Electrical equipment shall operate satisfactorily under various environmental conditions.Environmental conditions are characterised by a number of variables:
one set including mainly climatic conditions,biological conditions,conditions dependentupon chemically and mechanically active substances and mechanical conditions;
another set dependent mainly upon locations in unit,operational patterns and transientconditions.
NOTE For further information regarding environmental conditions in conjunction with some selected locations,operational patterns and transient conditions which are considered to be generally representative,see lEC 60721-3-6.
4.4.2Design parameters4.4.2.1General
Design parameters based on environmental conditions applicable to certain types of equipmentmay be determined according to location.Where no data is available,Table 1 and Table 2 giverecommended values.
In certain areas, e.g. arctic areas, lower temperatures than those given in the tables have to betaken into consideration. In certain areas,also a higher temperature than given in the tableshas to be taken into consideration.
4.4.2.2 Temperature For a specific project, the project documentation may give specific information regarding ambient temperature. In absence of such information, the following may be used: In other parts of the IEC 61 892 series, where no “high air temperature” has been specified as a design parameter for equipment, a value of 45 ºC shall apply. Where equipment is designed to operate with temperatures higher or lower than those stated in Table 1 , permissible temperature rises may be reduced or increased accordingly.
For batteries, see IEC 61 892-6.
Sea water temperature is max 32 °C.
4.4.2.3 Relative humidity
Design values for relative humidity are given in Table 2.
4.5 Materials In general, all electrical equipment shall be constructed of durable, flame-retardant, moisture- resistant materials, which are not subject to deterioration in the atmosphere and at the temperatures to which they are likely to be exposed.BS IEC 61892-1 pdf download.