The Basics

SEMESTER

MODULE

Lighting Systems

Summary of Regulations

1) A main electric lighting system which provides illumination throughout those parts of the ship normally accessible to and used by passengers or crew shall be supplied from the main source of electrical power.

2) The arrangement of the main electric lighting system shall be such that a fire or other casualty in spaces containing the emergency source of electrical power, associated, transforming equipment, if any, the emergency switchboard and the emergency lighting switchboard will not render the main electric lighting system inoperative.

3) Lighting fittings shall be so arranged as to prevent temperature rises which could damage the cables and wiring, and to prevent surrounding material from becoming excessively hot.

4) All lighting and power circuits terminating in a bunker or cargo space shall be provided with a multiple-pole switch outside the space for disconnecting such circuits.

The Basics

Lighting of the ship's deck areas, engine room and accommodation to meet specified levels of illumination is provided by various light fittings designed to work safely in their particular locations. They also meet the safety and comfort levels of illumination required throughout a ship. Historically, the original application of electricity in ships was for lighting. Oil lanterns were a definite fire risk and the ship's lamp trimmer had great difficulty in maintaining his navigation lights in stormy weather.

The power ratings of the lamps used will vary from a few watts for alarm indicator lamps to a few kW for deck floodlights and searchlights (e.g. a Suez Canal Projector Light).

The amount of light falling on a particular area can be measured with an 'illuminance meter' or more commonly known as a 'lux meter'. This light meter is calibrated in units called lux (lx), where one lux is the illumination of one lumen per square metre (lm/m²) and a lumen is the unit of luminous flux. The minimum illumination standards required in a ship are given in Table 22.1.

Dirt on the lamp reflector and the lamp itself will also reduce its luminous efficiency. Group replacement of lamps is often considered by shipping companies to be more economical and convenient than individual replacement following a lamp's failure. Cleaning of the fittings can also be carried out during the replacement of lamps hence maintaining a high luminous efficiency.

Table 22.1 - Typical Illumination Levels Onboard a Ship