MSCCirc.1120關於Low pressure CO2 systems規則

MSCCirc.1120關於Low pressure CO2 systems規則

MSC/Circ.1120 附件

低壓 CO 2 系統 如果安裝低壓 CO2 系統以符合本規定,則適用以下規定:

1 系統控制裝置和製冷裝置應位於存放壓力容器的同一房間內。

2 額定量的液態二氧化碳應儲存在容器中,工作壓力範圍為 1。8 至 2。2 N/mm 2。 容器中的正常液體充注量應限制在提供足夠的蒸氣空間以允許液體在最高儲存溫度下膨脹,而不是對應於洩壓閥的設定,但不應超過 95%容積容量 容器。

3 應為:

- 壓力計;

- 高壓報警:不超過安全閥的設定值;

- 低壓報警:不小於1。8 N/mm2;

- 帶有用於填充容器的截止閥的支管;

- 排放管;

- 液態二氧化碳 2 個液位指示器,安裝在容器上;

- 兩個安全閥。

4 兩個安全洩壓閥的佈置應使一個閥門可以關閉而另一個閥門連線到容器上。安全閥的設定不應小於 1。1倍工作壓力。每個閥門的容量應使在火災條件下產生的蒸氣能夠在壓力升高不超過設定壓力的 20% 的情況下排出。安全閥的排放物應通向開放。

5 永久充滿二氧化碳的容器和引出管應有隔熱層,以防止安全閥在 24 小時內執行。 在環境溫度為 45 時使工廠斷電 oC 和初始壓力等於 製冷機組的啟動壓力。

6 容器應由兩個完全獨立的自動化製冷系統提供服務 僅用於此目的的裝置,每個裝置都包括一個壓縮機和相關的啟動裝置 動子、蒸發器和冷凝器。

7 各機組的製冷量和自動控制應能在海水溫度不超過 32 ℃、環境空氣溫度不超過 45 ℃的條件下 24 小時連續執行的條件下保持所需的溫度。

8 每臺電製冷機組應由主配電板母線供電 一個單獨的饋線。

9 製冷裝置的冷卻水供應(如果需要)應由至少兩個迴圈泵提供,其中一個用作備用。備用泵可以是用於其他服務的泵,只要其用於冷卻不會干擾船舶的任何其他基本服務。冷卻水應取自不少於兩個海上接頭,最好是一個左舷和一個右舷。

10 應在可能由截止閥隔離的管道的每個部分提供安全洩壓裝置,其中可能會產生超過設計的壓力 任何元件的壓力。

11 管道系統的設計應使噴嘴處的 CO2 壓力不應低於 1 N/mm 2 。

12 在以下情況下,中央控制站應發出聲音和視覺警報:

- 容器中的壓力達到 2 的低值和高值;

- 任何一臺製冷機組發生故障;

- 達到容器中液體的最低允許液位。

13 如果系統服務於一個以上的空間,則應提供控制 CO2 排放量的裝置,例如:自動計時器或位於控制位置的精確液位指示器。

14 如果設有自動調節向受保護處所排放額定量二氧化碳的裝置,也應能手動調節排放量。

MSC/Circ.1120

ANNEX

I:\CIRC\MSC\J0。DOC FFS Code

Chapter Paragraph Interpretation or reference

5 2。2

Low pressure CO 2 systems

Where a low pressure CO2 system is fitted to comply with this regulation, the following applies:

1 The system control devices and the refrigerating plants should be located within the same room where the pressure vessels are stored。

2 The rated amount of liquid carbon dioxide should be stored in vessel(s) under the working pressure in the range of 1。8 to 2。2 N/mm

2。 The normal liquid charge in the container should be limited to provide sufficient vapour space to allow for expansion of the liquid under the maximum storage temperatures than can be obtained corresponding to the setting of the pressure relief valves but should not exceed 95% of the volumetric capacity of the

container。

3 Provision should be made for:

- pressure gauge;

- high pressure alarm: not more than setting of the relief valve;

- low pressure alarm: not less than 1。8 N/mm2;

- branch pipes with stop valves for filling the vessel;

- discharge pipes;

- liquid CO

2 level indicator, fitted on the vessel(s);

- two safety valves。

4 The two safety relief valves should be arranged so that either valve can be shut off while the other is connected to the vessel。 The setting of the relief valves should not be less than

1。1 times working pressure。 The capacity of each valve should be such that the vapours generated under fire condition can be discharged with a pressure rise not more than 20% above the setting pressure。 The discharge from the safety valves should be led to the open。

5 The vessel(s) and outgoing pipes permanently filled with carbon dioxide should have thermal insulation preventing the operation of the safety valve in 24 hours after

de-energizing the plant, at ambient temperature of 45

oC and an initial pressure equal to the

starting pressure of the refrigeration unit。

6 The vessel(s) should be serviced by two automated completely independent refrigerating

units solely intended for this purpose, each comprising a compressor and the relevant prime

mover, evaporator and condenser。

7 The refrigerating capacity and the automatic control of each unit should be so as to maintain the required temperature under conditions of continuous operation during 24 hours at sea temperatures up to 32 ℃ and ambient air temperatures up to 45 ℃。

8 Each electric refrigerating unit should be supplied from the main switchboard busbars by

a separate feeder。

9 Cooling water supply to the refrigerating plant (where required) should be provided from at least two circulating pumps one of which being used as a stand-by。 The stand-by pump may be a pump used for other services so long as its use for cooling would not interfere with any other essential service of the ship。 Cooling water should be taken from not less than two sea connections, preferably one port and one starboard。

10 Safety relief devices should be provided in each section of pipe that may be isolated by block valves and in which there could be a build-up of pressure in excess of the design

pressure of any of the components。

11 The piping system should be designed in such a way that the CO2 pressure at the nozzles should not be less than 1 N/mm 2。

12 Audible and visual alarms should be given in a central control station when:

- the pressure in the vessel(s) reaches the low and high values according to 2; - any one of the refrigerating units fails to operate;

- the lowest permissible level of the liquid in the vessels is reached。

13 If the system serves more than one space, means for control of discharge quantities of CO2 should be provided, e。g。 automatic timer or accurate level indicators located at the control position(s)。

14 If a device is provided which automatically regulates the discharge of the rated quantity of carbon dioxide into the protected spaces, it should be also possible to regulate the discharge manually。

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