GB/T 17436-1998 Selection of explosion-proof electrical equipment in hazardous areas of ships
Some standard content:
1CS 47.020.60
National Standard of the People's Republic of China
GB/T17436--1998
Selection of explosion proof electrical equipment in ship hazardous areas1998-07-24 Issued
Implementation on 1999-05-01
Issued by the State Administration of Quality and Technical Supervision
W.GB/T174361998
Technical content and writing rules of chapters 3, 5 to 1998 and the IEC publication IFC92-502 Ship electrical equipment - Tankers Part 3 (1991 edition) are equivalent. Other parts also refer to relevant international standards and rules. The various provisions of this standard involve the selection and special technical requirements of ship hazardous areas and their electrical equipment, and try to be consistent with international standards as much as possible.
This standard has not been formulated yet, and it may be supplemented and amended during the implementation of the standard. Appendix A and Appendix B of this standard are appendices to the standard; Appendix C of this standard is a suggested appendix, which is proposed by the National Technical Committee for the Promotion of Ocean Shipping Standards. Standard tThe Seventh Research Institute and the Seventh Eighth Research Institute of China Shipbuilding Industry Corporation The drafting unit of this standard: The Seventh Research Institute and the Seventh Eighth Research Institute of China Shipbuilding Industry Corporation The main drafters of this standard: Qu Guanglu, Huang Jianzhang. W1 Scope
National Standard of the People's Republic of China
Selection of explosion proof electrical equipment in hazardous areas of ships Selcction of explosion proof electrical equipment in hazardous areas of ships CB/T174361998
This standard specifies the special technical requirements and selection of hazardous areas and electrical equipment in the cabins of ocean-going ships. This standard is applicable to AB, CI) class cargo ships, ships carrying motor vehicles and coal ships. It can also be used as a reference for inland ships. 2 Reference standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised. All parties using this standard should explore the possibility of using the latest versions of the following standards. GL3836.1-83 General requirements for explosion-proof electrical equipment for explosive atmospheres G33836.2-83 Explosion-proof electrical equipment for explosive atmospheres Flameproof electrical equipment \d GB3836.3-83 Explosion-proof electrical equipment for explosive atmospheres Increased safety electrical equipment \e” GB3836.4-83 Explosion-proof electrical equipment for explosive atmospheres Intrinsically safe circuits and electrical equipment \” GB3836.5—87 Dry-proof electrical equipment for explosive atmospheres Industrial pressure electrical equipment \p” GB3836.8—87 Explosion-proof electrical equipment for explosive atmospheres Non-incineration electrical equipment \n” G4208-93: External protection level (IP code) GE/T7358-1998 General design of marine electrical equipment systems TEC:797:1990 Electrical equipment for explosive atmospheres IEC 79 10:1986
Electrical equipment for explosive gas atmospheres
Electrical equipment for explosive gas atmospheres
IEC 79-15:1987
TEC 92-101:1994
Electrical equipment in ships
3 Definitions
This standard adopts the following definitions.
3.1 Tanker
Section 7: Increased safety electrical equipment\c\
Section 10: Classification of hazardous areasWww.bzxZ.net
-Section 15: Electrical equipment with protective type\n\ Section 101: Definitions and general requirements
Ships built or suitable for the carriage of bulk liquid cargoes are divided into the following types according to the type of cargo: Class A - Bulk Class B - Tankers transporting crude oil and petroleum products with a flash point (closed cup test) not higher than 60°C. Class C - Tankers transporting liquefied gas or other flammable products in bulk. This type of liquid cargo is listed in the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code), Chapter 19, Part 2 of the 1983 Amendment to the International Convention for the Safety of Life at Sea, 1974. Class T - Tankers transporting in bulk flammable, chemically unstable, or easily regurgitated, or other flammable products, or a combination of two or more of these characteristics. This type of liquid cargo is listed in Chapter 17 of the International Code for the Construction and Equipment of Tankers Carrying Dangerous Chemicals in Bulk (IBC Code), approved by the State Administration of Quality Supervision, Inspection and Quarantine on July 24, 1999, and implemented on May 1, 1999. W.B.Z.S.O.C.M. (1986 Edition) and revised in 1992, GB/T17436-1998. 3.2 Hazardous areas 3.2.1 Areas where flammable or explosive gases or vapors may accumulate. The following four types of liquid cargoes, A, B, C, D, are applicable. The specific areas are listed in 6.1 to 6.2. It should be noted that the applicable areas are described in two ways: a) during all normal working conditions; b) during the loading, ballast or degassing operations, the hazardous area may be expanded beyond the specified range. 3.2.2 Enclosed and semi-enclosed spaces that do not contain any hazard source and are assigned to a danger zone by means of ventilation shall be considered dangerous. Category C allows for some exceptions, see 8.2. Semi-enclosed spaces are spaces that have decks and/or decks as interfaces and have significantly different ventilation conditions from spaces on deck.
3.3 Qualified a-type equipment Electrical equipment that can operate safely in the relevant flammable atmosphere and provide relevant personnel with a safety assurance that this assurance is provided in the form of an inspection certificate issued by the competent authority and its basis is at least equivalent to IEC 79.3.4 Qualified a-type equipment Electrical equipment with type f explosion proof "n" Electrical equipment with protection against oxygen during normal operation that does not contain ignitable gas/vapour mixtures and does not cause ignition faults.
Such equipment should be prevented in accordance with IEC 79-15.4 General
4.1 Explosion-proof electrical equipment
4.1. 1. Classification, classification and severity group of electrical equipment 4.1.1.1 Explosion-proof electrical equipment for explosive atmospheres shall be designed according to specified requirements and shall not cause explosion in explosive atmospheres. Intrinsically safe electrical equipment is divided into Class I and Class II. Class I electrical equipment is divided into three groups: A, B and C according to the minimum test safety pulse or minimum current in the explosive gas atmosphere to which it is applicable, and is divided into six groups from T1 to T6 according to its maximum current. The requirements are in accordance with GB3836.1. 4.1.1.2 Intrinsically safe electrical equipment shall have a system energy storage capacity not greater than the minimum ignition energy of the corresponding class of explosive gas. The requirements are in accordance with GB 3836. 4.1.2 Maximum allowable surface temperature of electrical equipment 4.1.2.1 Maximum allowable surface temperature of various types of electrical equipment, the requirements are in accordance with GB3336.1. 4.1.2.2 The grouping of humidity agents and gases of electrical equipment should be adapted to the grouping of humidity agents of electrical equipment, corresponding to the grouping of humidity agents of electrical equipment, and combustible gases and hot gases can also be divided into six groups according to the ignition degree. The requirements are in accordance with the provisions of Appendix A of GB3836.1. 4.1.3 Explosion-proof type and mark
To prevent the ignition of explosive mixtures, electrical equipment shall adopt a special anti-phosphorus type anti-ignition type and mark of electrical equipment, the requirements are in accordance with the provisions of GB3836.1~GB38365.5 and GB3R836.8, 4.2 Dangerous areas of contact
4.2.1 Dangerous areas of ships carrying dangerous goods are classified according to the type of ship and the physical properties, chemical properties and possibility of explosion hazards of the transported goods: Dangerous cargo ventilation area
- Delayed or closed areas and places of dangerous cargo areas, ventilation ducts of dangerous cargo areas and special areas and places; battery room:
- Paint room:
- Lighting room:
- W. room
- Rapid-release room,
Other places with explosion hazards.
GB/T 17436—1998
4.2.2 Dangerous places of ships carrying containers and liquid cargo Special places for passenger vehicles, loading places and closed ro-ro loading places of cargo ships, loading places and their ventilation ducts. 4.2.3 Examples of dangerous areas of ships
Examples of dangerous areas of various types of ships are shown in Appendix C (Supplementary Appendix). 4.3 Electrical equipment in dangerous areas of ships
4.3.1 Explosion-proof type of electrical equipment
Class qualified explosion-proof electrical equipment should be used in dangerous areas of ships. The following explosion-proof equipment is usually used! a) Qualified explosion-proof electrical equipment:
One-way type
~Increased safety\e\,
"Intrinsically safe\i\
Positive pressure type\p\.
b) Electrical equipment with protective type\n\, 4.3.2 Electrical equipment type, grade and temperature maintenance The type, general type and degree of qualified explosion-proof electrical equipment allowed to be installed in dangerous areas of ships are distinguished, and their general minimum requirements are studied in detail. The types and levels of electrical equipment in chemical tankers are as follows: Class, level and temperature group of the lowest temperature group B (standard attachment). Table 1 Class, level and temperature group of electrical equipment in hazardous areas of ships Hazardous areas, battery rooms, oil lamps and related areas, places and centers, and the following types and levels of hazardous goods selection: Class and level of electrical equipment listed in the table 1A. IB. 1C are only applicable to flame retardant electrical equipment and safety-oriented electrical equipment. If other types of equipment are included, Class I equipment shall be recorded. 4.3.3 Electrical equipment in hazardous areas or on ships shall have permanent anti-drying marks or nameplates on the obvious places of their shells. 4.3.4 Protection enclosure
The protection type of the enclosure of explosion-proof electrical equipment in hazardous areas of ships should be suitable for the installation location. The requirements shall be in accordance with B4208 standard,
4.4 Selection of electrical equipment in hazardous areas of ships 4.4.1 Selection of qualified explosion-proof electrical equipment
Different types of qualified explosion-proof electrical equipment shall be selected for different conditions. Considering the special conditions on board, the equipment can be used without bottle maintenance
Appendix A (Annex of the standard) gives the requirements for qualified explosion-proof electrical equipment. Note: For the same above-mentioned tasks and the requirements of this system, qualified explosion-proof equipment may not be composed of different protection types, and different types of protective equipment shall be used.
W.GB/T 17436—1998
This type of qualified explosion-proof electrical equipment: can be considered as follows: a) Lighting equipment
Positive safety type\\
Isolated type\d"
Increased safety"".
b) Junction box
Increased safety type\;
Explosion-proof type""
c) Control, verification, monitoring and communication equipment or circuits, including portable radio transmitters/receivers" (divided into and two levels). When the application of intrinsically safe enterprise equipment is technically impractical, such as solenoid valves, gas detection sensors, with the approval of the competent authority, the following protection types of equipment can be used instead of "i\ level equipment: positive pressure type\p"
Explosion-proof type"
Increased safety type\e".
d) Motors
-- Flameproof type \\ Increased safety type \\; Pressure-proof type \\"
Flameproof agent \\" :
Increased safety type \\e\\
Note: According to the requirements of the installation location, when necessary, the motor should adopt the outer shell with protection level of 1P56 of GH/T7358 standard. e) Portable lights
-- Intrinsically safe type \\i\\ or \\d\\ or increased safety type \\s\\", and each type has its own replacement battery t-- It is a positive pressure type outer shell when driven by air. 4.4.2 Selection of protective type n gas equipment During positive working, ensure that there is no spark, arc and \hot spot\. Electrical equipment with protective type "n\, if it complies with IEC715 provisions and is approved by the competent authority, can be installed in the explosive environment of 5 General requirements for liquid cargo ships
5. 1 Distribution system
The distribution system shall comply with the provisions of GB/T7358. Except as specified in 5.8, it is not allowed to use the connection system or the system with compensation as the return step. 5-2 Power supply and distribution equipment
The power distribution station, distribution board and storage tank group shall be separated from the liquid cargo tank by means of a separate compartment or equivalent facilities, and separated from the cargo pump room by an oil-tight or gas-tight bulkhead.
53 Cables and their laying
The structure, test and laying requirements of cables shall comply with the relevant series of IEC 92. Except for those that are essential for operation, they shall comply with the provisions of Chapters 6, 8 and 11. Cables shall be avoided as much as possible in dangerous areas. In this case, all electrical display and H-excitation facilities shall comply with 5.3.1~5.3.6 of this standard. 5.3.1 All cables installed in dangerous areas shall have at least one of the following sheaths: a) Metal braided sheath or other armored sheath for grounding detection and mechanical protection, such as non-metallic chip impermeable sheath: 1) Steel or stainless steel sheath (insulated relay for instrumentation) Aluminum sheathed mining insulated cable for special purposes, such as valves, used in liquid cargo tanks of liquefied gas carriers, 5.3.2 All metal sheaths of power and lighting cables passing through dangerous areas or connected to equipment in other dangerous areas shall be grounded at least at both ends, 4
W.(R/T174 36-1998
The metal sheath of other cables in the hazardous area should be grounded at least at one end. Special consideration should be given to single-core cables for AC power, DC semiconductor control, etc. It is best to connect them at a single point in the hazardous area. 5.3-3 All cables in small corrosive places should be covered with non-metallic impermeable sheaths outside their braided sheaths or armor. 5.3.4 Cables installed on the load bridge on the exposed board should be protected to prevent mechanical damage. The installation of cables and protective brackets should avoid negative stress deformation and should take into account the expansion or replacement of the structure. Leave appropriate margins. When a retractor is provided, it should be easily accessible for maintenance. When cables are placed in metal pipes or metal wire ducts, the cable ducts shall be provided with extension devices: cable boxes shall be provided at their branches. The metal ducts and wire arms shall be grounded, and mechanical and electrical continuity shall be maintained at all joints. 5.3.5 Cables placed in the accumulator shall be properly protected to prevent mechanical injury. 5.3.6 Cables for intrinsically safe circuits shall be dedicated and separated from cables for non-intrinsically safe circuits (for example, they shall not be placed in the same cable bundle or cable duct, nor shall they be fixed together with the same line). In hazardous areas where only "grade" intrinsically safe systems are allowed, the related cables of "grade" intrinsically safe systems should not contain related circuits of "grade" intrinsically safe systems: when selecting and modifying cables, necessary measures should be taken to prevent the safety of this law from being damaged by induction phenomena. 5.4 During normal operation: ensure that there are no sparks, arcs and "hot spots" in the equipment during normal operation. The temperature of any part of the equipment when working should not be able to ignite the gas or gas of the transported goods. With the approval of the management authority, it can be installed in the specified hazardous area. 5.5 Portable equipment
5.5.1 Only explosion-proof portable equipment can be used in hazardous areas. Portable equipment powered by cables should not be used in hazardous areas. 5.5.2 Except for cables of portable equipment containing only intrinsically safe circuits, soft cables used for portable equipment should not pass through hazardous areas. 5.6 Mechanical ventilation of closed or semi-closed spaces containing hazardous sources 5.6.1 The driving motor of the fan of the exhaust system of the closed or enclosed space containing hazardous sources shall be installed outside the ventilation duct. 5.6.2 The motor of the qualified explosion-proof plastic ventilator approved by the relevant competent authorities may be installed in a ventilation duct. The motor shall have a protection level of at least IP44 to prevent the duct airflow from invading the motor housing. 5.7 Ground detection
A device shall be provided to continuously monitor the insulation resistance of all distribution systems. The device shall also monitor all circuits connected to the phases in the hazardous area or passing through the hazardous area, except for intrinsically safe circuits. When the leakage is below the normal level, an audible and visual alarm shall be issued. 5.8 Hull current
Hull currents arising from the following locations are not subject to the restrictions specified in 5.1: protective systems attached to the "hold" or hull; - impressed current protection systems for the hull - limited local grounding systems, such as internal combustion engine starting and ignition systems; - local control circuits in non-hazardous areas (see 11.4.2 of GB/T7358--1998); - monitoring devices with a current not exceeding 30 mA in the worst case; - distribution systems with a midpoint grounding voltage (line effective value) of 3 kV and above, if it can be ensured that any current in the grounding conductor does not flow directly through the hazardous area specified in this standard. Special provisions for Class 6A tankers
Method; note the 1984 SOLAS Convention and include 1283 of 1987 Part 12: lead fire retardant. 6.1 Danger Zone City
6.1.Dangerous areas of Category 1A liquid cargo ships under all normal working conditions include: a) liquid cargo tanks and liquid cargo piping systems, b) cofferdams of Batch X liquid cargo tanks, ice-permanent (partial) positive load tanks; c) cargo holds: WGB/T 17436-1998 d) enclosed or semi-enclosed spaces directly above the liquid cargo tanks (such as deck rooms) or above the liquid cargo tanks whose bulkheads are in line with the liquid cargo tank height. 1) Any enclosed or semi-enclosed space directly above or in front of the vertical upper airflow of cargo tanks, except those separated by gastight decks and provided with appropriate mechanical ventilation;
1) Spaces adjacent to liquid cargo tanks and to the left of the general ceiling of liquid cargo tanks (for example, passageways, corridors and cargo vents in the figure), except bulkheads; 2) Any space on the required deck or semi-enclosed space on the required deck within 3 m from any liquid cargo tank outlet, gas or vent outlet, liquid cargo main, cargo pipe flange, cargo system inspection port or cargo tank vent; Note: for example, liquid cargo intake, observation port, liquid cargo tank selection port, liquid cargo volume measurement port, bulkheads, all areas below 3 m from the cargo tank outlet.
h) Areas of open deck within the baffle of liquid cargo hold overflow, and within 3 m of such baffle or other baffles which protect living or service spaces, and within 2.4 m of the deck height; 1) The open deck above all liquid cargo hold (including all cargo hold in the cargo hold), with a vertical extension of 3 m in all directions, and within 2.4 m of the deck height. Areas in front of these areas, below the main deck and with openings directly facing the main deck, are considered to be extremely dangerous, provided that: the entrance to this area does not face the cargo hold, and all other openings, including the air inlets and exhaust outlets of the ventilation system, are located at least 5 m horizontally above the foremost cargo hold or at least 10 m horizontally above any cargo outlet, air intake or air outlet, whichever is farther!
Organically ventilated
i) Energy rooms containing effective cargo handling
k) Closed or semi-enclosed spaces with openings to any hazardous area (excluding hazardous sources) 6.1.2 During defueling, ballast or degassing operations, hazardous areas also include ta) Openings (including ventilation system openings)> Closed or semi-enclosed spaces within 3 m and 10 m horizontally from liquid cargo outlets, gas or vent outlets (not hazardous sources) b) Closed or semi-enclosed spaces within 3 m and 10 m horizontally from liquid cargo outlets, gas or vent outlets, and in areas connected to hazardous areas other than those specified in 6.1.1 g), 6.1.1 h) and 6.1.1 i3. 6.2 Electrical equipment in hazardous areas
Except those that are essential for operation, electrical equipment and electrical environment shall not be installed in hazardous areas. If it complies with 6.2.1~6.2.10, it is possible to consider installing electrical equipment and electrical environment in the hazardous area. 6-2.1 Liquid cargo tanks and ballast tank systems are only allowed to install "i,\ and other safety equipment of this institute and their related lines. 6.2.2 Two empty tanks adjacent to liquid cargo, water-permanent (such as separated) ballast tanks 6.2-2. 1 Install intrinsically safe equipment and electric lungs of grade i,i. 6.2.2.2 Install hull mountings equipped with electric depth sounding and speed log transducer groups, or terminal blocks for anodes or reference electrodes of the external current cathodic protection system or hull mountings through the ship. These mountings are to be of gas-tight structure or installed in gas-tight enclosures, and the installation position is not adjacent to the cargo tanks. All relevant electrical environments passing through these places are to be installed in thick strong copper pipes with gas-tight joints and lead to the main deck. In the entire room that may be filled with seawater, corrosion-resistant piping that can provide adequate mechanical protection is to be used. 6.2.3 Cargo system temporary
6.2.31 Install intrinsically safe equipment,
6.2-3-2 Install the equipment described in 6.2.2.2 and set it according to its requirements. 6.2-33 Cyclic or Positive pressure type membrane lighting fixtures shall be arranged at least in two independent sections. All switches and protective devices shall be isolated from all remote phases and shall be installed in non-hazardous areas. Lighting fixtures, switches and protective devices shall be properly and permanently marked for identification. The lights on two sections shall be staggered so that one section can be used to maintain lighting while the other section is used for maintenance. W.CB/T17436—1998
6.2.3.4 Except for cables for intrinsically safe circuits and cables for lighting fixtures as described in 6.2-3.3, if it is necessary to pass through the cargo pump room entrance walkway, these barriers shall be installed in steel pipes with gas joints. 6.2.3.5 General fire extinguishing agents shall be used to prevent the alarm sound. As an exception, explosion-proof type is allowed. 6. 2.4 Closed or semi-enclosed spaces directly above the cargo tank (e.g. between decks) or in the cargo tanks in a straight line with the cargo tank wall
Closed or semi-enclosed spaces directly above the cargo pump room or above the extended space adjacent to the cargo tank (except those separated by air-through decks and with appropriate mechanical ventilation)
Compartments where cargo hoses are stored
62.4.1 Install intrinsically safe equipment.
6.2.4.2 Install qualified explosion-proof lighting equipment as described in 4.4.1, which should be arranged in at least two independent most dangerous circuits. All switches and protective devices should be able to disconnect all poles or phases and should be installed in non-hazardous areas. Lighting fixtures, switches and protective devices should be appropriately marked for easier identification.
6-2. 4. 3 Install passing cables
6.2.5 Except for the empty tank. In the places below the cargo hold top plate (such as wall passages, corridors and cargo holds) 6.2.5.1 Install intrinsically safe equipment. 6.2.5.2 Install the equipment described in 6.2.2.2 and design it according to its requirements. 6.2.5.3 Flameproof or positive pressure sudden lighting lamps should be arranged on at least two independent final branches. The switches and protective devices available shall be capable of disconnecting all general or phase hazards and shall be installed in non-hazardous areas. The switches and protective devices shall be appropriately marked for easy identification. 6.2.5.4 General purpose slow-acting and fire extinguishing agent environment alarm sound equipment, as an alternative, may be used as isolation type, 6.2.5.5 Sensitive equipment passing through cables, in addition to the use of water-quality Anlun type. The laying of such cables shall be specially considered - for example, through airtight steel pipes.
6 2.6. 6.2.6.1 Equipment of qualified type as described in 4.4.1. These equipments shall be suitable for use in exposed areas. In these areas, no blocking devices shall be installed. 6.2.7 The deck above all cargo tanks (including all ballast tanks in the cargo tank area) shall have a width equal to the ship's beam and extend 3m in each direction. The area within 2.4m above the deck shall be installed with qualified anti-drying equipment as described in 4.1.1. These equipment shall be suitable for the deck contact. 6.2.7.2 The installation of passing cables, closed or semi-closed spaces with no direct access to any dangerous area (not a dangerous source) 6.2.8.1 The installed electrical equipment shall meet the requirements of the openings in these areas. The equipment in the semi-closed spaces shall be considered to meet the requirements of the open air area.
6.2.9 Opening (including ventilation system openings) The horizontal distance from liquid cargo outlets, gas or vapor outlets is more than 3 m and less than 10 m. To closed or semi-enclosed spaces (excluding hazardous sources) The horizontal distance from filtered cargo outlets, gas or vapor outlets is more than 3 m and less than 10 m. 1i. In connection with 6.].1*), 6. The exposed single-plate area outside the danger zone specified in 6.1.1h) and 6.1.1j) shall be installed with equipment that ensures that there is no spark, arc and "hot spot" during normal operation (see 4.2 and 5.11 or intermediate explosion-proof equipment, 6.2.10 understands the area on the deck
transmitting antenna, the installation position of which (such as stabilizing cable) is relative to the body, and the position of the gas outlet is appropriately changed. 7
WGB/T174361998
During the loading of liquid cargo and ballast layer, and during the degassing by mechanical shaking, the danger zone may be expanded. The straightening plate and superstructure areas outside the danger zone specified in 6.1 may be exposed to gas or vapor. The equipment in these areas that may be used during this period is not available. For example, lighting equipment, equipment on the bridge and bridge wings, etc.Its protection level shall be at least I1\56, or fully ejected, or sparks, arcs and hot spots shall be guaranteed during normal operation. It shall be either \\ type or explosion-proof type. It shall be protected against sparks, arcs and hot spots during normal operation. Its working risk limit shall also be IPe. The use of winding change monitoring sensors in limited operation, positive pressure or increased safety motors is not prohibited, but the cables of these sensors shall be installed through 65.2 6.3 Electric drive equipment in cargo tanks
The electric motors driving various equipment (such as cargo pumps, cargo pumps, ventilators) in cargo pump rooms are separated from cargo tanks by gas-tight bulkheads or decks. Flexible couplings or other measures to ensure alignment should be installed on the shafts between the pumps and the motors. In addition, suitable stuffing boxes should be installed where the shafts pass through the gas-tight bulkhead. The ventilation arrangement should be such that the tank or space with the motors and the cargo pump room space can be positively pressurized. 6.4 Cabin design for motors of cargo pumps or stripping pumps located directly above the pump room If the motors of the electric drive system are installed in a dedicated compartment above the cargo pump room, the compartment constitutes a combined 6. 5. When the location and arrangement of the tank indicate that gas or vapour may accumulate, effective mechanical ventilation shall be provided and interlocking of electrical equipment with the ventilation system shall be provided to prevent electrical equipment other than the approved dry-proof type from being energised and the motor of the cargo pump from being started before the tank is adequately ventilated. 6.5 Spaces between decks
Except for the time-lighting lamps as described in 6.2, any other electrical equipment may also be installed in spaces directly above the cargo tanks, provided that they are in tanks equipped with appropriate mechanical ventilation and that the tanks have access only on the upper deck, and their floors are separated from the cargo tanks by cofferdams, and the boundaries between the cofferdams and the spaces between the cofferdams and the decks are oil-tight and "smooth". 7 Special provisions for Class B tankers
7.1 General provisions
The main types of Class B tankers are:
Parts carrying full or containing products;
Oil tankers carrying fuel oil or diesel.
7.2 Types of electrical equipment
Generally speaking, as far as electrical equipment is concerned, Class B cargo ships do not have any danger caused by flammable or explosive gases or vapors. In this case, the requirements of Chapter 1 do not apply! For this type of cargo ship, there is no need to consider the danger zone, but it is hoped to reduce the potential for explosions and pay attention to the following requirements:
A remote control circuit in direct contact with the liquid cargo is of intrinsically safe type: The drive motor of the system in the cargo tank should be able to provide no sparks, arcs and "hot spots" during normal operation (see 4.4.2 and 5.4) or a qualified anti-drying type:
Portable electrical equipment used in liquid cargo tanks is of qualified explosion-proof type. 7.3 Limit
For transporting flash point (closed test) higher than 6\℃ Vessels built for the carriage of bulk liquid cargoes shall not be used to carry other types of fuel liquid cargoes under any circumstances, nor shall they be used to transport liquid cargoes heated to a temperature below their flash point (closed cup test) and with a difference of less than 15°C from their flash point.
Vessels intended to transport asphalt or tar products heated to a temperature below their flash point (closed loop test) and with a difference of less than 15°C from their flash point: The gas equipment installed shall comply with the provisions of 9.1.2.2. 8 Special provisions for Class C liquid cargo ships
8.1 Hazardous areas
WGB/T 17436- 1998
8.1.1 The hazardous areas of Category C liquid cargo ships in working condition include: 1) Liquid cargo containment system and cargo piping system
2) Cargo hold spaces where cargo is contained in a cargo containment system requiring secondary barriers; 3) Cargo hold spaces where cargo is contained in a cargo containment system not requiring secondary barriers; 4) Spaces separated from the cargo spaces described in 3.1.1b> by a steel gas-tight interface; 5) Cargo pump room and liquid cargo compressor room; |f) Areas on open deck or enclosed spaces on sky deck within 3m from any cargo tank outlet, gas or vapour inlet, cargo main, cargo valve, cargo pipe flange, cargo pump room and cargo pressure tank inlet and ventilation opening; g) Areas on sky deck above all cargo areas and areas between open deck areas and channels extending 3m each and within 2.4m from the height of open deck; h) Areas on open deck within 2.4m from the exterior of cargo containment system 1) Closed or sealed spaces with pipelines containing goods, except those approved by the relevant competent authorities*
) Compartments for storing liquid cargo hoses:
&) Sealed or semi-closed spaces adjacent to liquid cargo pump rooms or cargo compressor rooms, except those separated by gas-tight panels or gas-tight bulkheads and with appropriate mechanical ventilation:
m) Closed spaces with ports leading to any hazardous area but not containing any hazardous source 8.1.2 During the loading and unloading of liquid cargoes, the dangerous areas include: a) closed or semi-enclosed spaces (including ventilation system openings) where the horizontal distance of any gas or vapor outlet of the liquid cargo enclosure or liquid cargo loading and unloading system is more than 3m and less than 10m (not a dangerous source); b) open deck areas outside the dangerous areas specified in 8.1.1 1), 8.1.1 g), and 8.1.1 h) where the horizontal distance of any gas or vapor outlet of the liquid cargo enclosure or liquid cargo loading and unloading system is more than 3m and less than 10m. ) The liquid cargo area includes the liquid cargo containment system, cargo hold, liquid cargo medical tank, and the general area A above this warning position along the entire length and width of the ship: if there is a chemical energy cargo space at the end or the front end of the cargo space, these areas are not included in the liquid cargo area.
2 For the transport of liquefied petroleum gas (LPG) or other gases other than air under normal atmospheric flow. According to the area mentioned in 8.1.1g), the space connected to and concave in front of the main plate of the room can be considered as non-hazardous space, provided that the personnel of these spaces do not face the liquid cargo area, and all other openings of the space (including exhaust and non-gas valves of the ventilation system): the horizontal height of the foremost cargo oil tank is at least ) m or the horizontal distance from any cargo hold outlet, gas or hydrogen inlet is at least , ℃ m + extension; these spaces are located near the machinery.
3. For spaces transporting liquefied natural gas (LNG) and other gases which are lighter than air at atmospheric pressure, the requirements of above 2 still apply, except that mechanical ventilation is not required for the space.
4 US F8.1.: i) If the gas sampling pipe has a sensitive device or similar device to prevent direct discharge into the atmosphere outside the hazardous area specified by the company at a distance of at least 3 m2 from the ignition source, the installation of gas detection equipment will not make the installation space a hazardous space.
) As long as appropriate preventive measures are taken, such as double-pipe ventilation, gas detection equipment, etc., the space with a vapor gas fuel combustion system is not considered to be a hazardous space. 8.2 Enclosed spaces located within the dangerous area of open decks and with openings to the dangerous area of the ceiling, which do not contain any hazardous source, shall not be considered as dangerous spaces if all of the following conditions are met: a) The air room has two self-closing steel doors with buckles: WW.bzsoso.cOm Free download of US standard industry data CB/T 17436--1998 c) The air lock space and its enclosed space are mechanically ventilated from the normal safe area: d) The ventilation is carried out according to 5, B Provisions:
c) The air lock space maintains positive pressure relative to the external danger zone, and the enclosed space also maintains positive pressure relative to the air lock space; ") The relative positive pressure between the enclosed space and the air lock space or the air flow into the enclosed space and the air lock shall be continuously monitored and arranged. When a ventilation failure occurs, an audible and visual alarm will be issued, and the power supply of all non-qualified explosion-proof equipment will be automatically cut off. If necessary, it can be delayed appropriately, but if the emergency stop of the equipment system will cause more danger, it should not be cut off. +g) When a ventilation failure occurs, the electrical equipment that still needs to be operated are all qualified explosion-proof equipment. h) Electrical equipment other than qualified explosion-proof equipment, measures Ensure that the power cannot be turned on before the air in the space is safe, for example, by ventilation, the ventilation volume is at least 10 times the volume of the space. i) There are sound and light indicators on each side of the air lock. If the doors are opened at the same time, the indicator sends a signal: 1) It can monitor the liquid vapor entering the air smelling space. 8.3 Electrical equipment in hazardous areas
Except for those that are essential for operation, electrical equipment and cables should not be installed in hazardous areas. If it meets 8.3.1~8.3.9, it can be considered to install electrical equipment and cables in hazardous areas. 8.3.1 Liquid cargo containment system and quarantine cargo piping system
8.3.1.1 Installation\i.\Grade intrinsically safe equipment and related circuits. 8.3.1.2 Install the motor of the immersed liquid cargo pump and its feeder cable. The type of cable and its installation should be specially considered. The motor should be able to stop automatically when the level is low and report to the model cargo control station. During the degassing operation, the motor and the power supply cable should be isolated from their power supply. Note that automatic stopping can be achieved by controlling the low exhaust pressure of the measuring system. The motor has a low current or low vibration level. B.3.2 Liquid cargo in cargo holds in cargo protection systems requiring grey screens B.3.2.1 Installation of intrinsically safe equipment such as “i” and related circuits. 8.3.2.2 Installation of power supply for the diffused cargo motor. 8.3.3 Cargo holds in cargo protection systems not requiring secondary screens are separated from cargo holds by gas-tight interfaces of carbon steel and specified in 8.1-16). B.3.3.1 Installation of intrinsically safe equipment. 8.3.3.2 Installation of hull mountings with electric depth sounders or odometer transducers, or hull mountings with wiring for anodes or reference electrodes of impressed current cathodic protection systems on or through the hull. These mountings shall be of gas-tight structure and installed in gas-tight outer casings. Any installation not in accordance with 8.1.1 shall be d) The airtight material interface involved, Note: In compartments that may be filled with water, such as pressurized teaching cabins, the installation of relevant electric exhaust gas should be resistant to corrosion. And it should be able to provide sufficient mechanical protection. 8.3.3.3 Explosion-proof or positive pressure lighting fixtures should be arranged at least on two independent final branches. All switches and protective devices should be able to disconnect all panels or phases and should be installed in non-hazardous areas. Lighting fixtures, switches and protective devices should be properly permanently marked for easy identification.
8.3.3.4 The value of the digital equipment passing through the cable should not be equipped with a telescopic assembly. 8.3.3.5 Positive pressure or isolation type motors for valves of liquid cargo and ballast systems can be installed in the places described in 8.1.11). 8.3.3.6 Sound control device for general alarm and fire extinguishing agent release - As an exception, flameproof type is allowed. Note: According to the room noted in 6.1.1d>, in order to prevent the damage of the net point, the room is not allowed to install the lighting fixtures, passing cables and reporting indicators.
8.3.4 Cargo hold and cargo compressor room
8.3.4.1 Install intrinsically safe equipment,
8-3.4.2 Install qualified anti-freeze type lighting equipment according to 6+2.3.3. 3.3.4.3 Install qualified explosion-proof plastic motors for liquid cargo and cargo compressors and their related auxiliary systems as specified in 8.1. The related starting and protection devices should be installed in non-hazardous areas. Any indirect wiring connection with these motor filters should not be installed in a cabin or compressor room:
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