Transport Guidance for Steel Cargoes
Comparison of temperatures
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6.5 Comparison of temperatures 6.5.1 In many instances, it is impracticable to measure hold dew point temperatures accurately, or at all. Therefore, it is recommended that the “3º Celsius Rule” should be applied as described in Sections 6.5.3, 6.6.2 and 6.8.6. 6.5.2 The temperature of the bulk of a stowed cargo will remain the same, or will change little throughout the voyage. Conversely, the temperature of the ambient air at the vessel’s position will change during each day, and progressively over the course of the voyage. Experience has shown that ventilation can be effective in removing moisture from a cargo hold if the outside air is at least 3º Celsius (C) below the temperature of the cargo stowage. 6.5.3 In order to use the 3º Celsius Rule, the temperature of the cargo should be obtained accurately during loading. This process might involve taking a number of temperature readings within cargo loaded into each hold in order to establish an accurate temperature for the cargo in each hold. During the voyage, a reading from the dry-bulb thermometer in the box on the bridge should be taken by the crew during each watch and then compared with the cargo temperatures for each hold established during loading. Therefore: (1) if the temperature of the outside air is 3º C below the cargo temperature for any hold, that hold should be ventilated; conversely; and (2) if the outside air is not 3º C below the cargo temperature in the particular hold, that hold should not be ventilated. 6.6 When to ventilate—Rules 6.6.1 Dew Point Rule. Ventilate when the dew-point of the outside air is lower than the dew point of the air in the hold. 6.6.2 3º Celsius Rule. Ventilate when the dew-point of the outside air is at least 3º C below the temperature of the cargo taken during loading. tải về 1.97 Mb. Chia sẻ với bạn bè của bạn:
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