D appendix III LR survey checklist

APPENDIX III SURVEY CHECKLIST FOR SHIPS CARRYING LIQUEFIED GASES IN BULK (LNG AND LPG) For Annual, Intermediate and Renewal (Periodical) surveys for ships carrying liquefied gases in bulk in accordance with the following Rules and Regulations and in addition to those items shown in the Classification Check-List (Form 2100); (a) (b) (c) (d) The Rules and Regulations for Classification of Ships Part 1, Chapter 3, Section The Rules for the Carriage of Liquefied Gases in Bulk The International Gas Carrier Code The 1978 SOLAS Protocol and the Annexes to Resolutions A.560(14) and A.746(18), Guidelines on surveys required by the 1978 SOLAS ProtocoL the International Bulk Chemical Code and the International Gas Carrier Code Surveys: (Also refer to notes on Page 11) For Annual Surveys Complete Sections: A,B & C For Intermediate Surveys Complete Sections: A,B,C & D For Annual Surveys held at Special Survey (55 & CSH) Complete Sections: A,B,C,D,E,F & Gas applicable to the age of the ship C ANNUAL SURVEYS BASIC REQUIREMENTS (CONT) - C3 Confirm that the cargo containment system temperature indicating equipment and associated alarms has been tested State date of last test by ships staff C4 Confirm that the cargo gas leakage detection systems has been examined and tested together with all alarms and found satisfactory C5 Confirm that the alarms and interlocks associated with pressurised equipment in gas dangerous locations have been tested and found in working order Note: Gas detection and systems in cargo machinery spaces to be tested State date of last test by ships staff Gas detection and systems in cargo machinery spaces to be tested State gas detection equipment makes and type for each area: Cargo area: Machinery spaces: Comments: Confirm that the pressure gauging systems for the cargo tanks, holds (if applicable) and insulation spaces have been examined and found satisfactory Confirm that there is a calibration procedure in operation for pressure gauges and if so were the calibration records reviewed and found in order C6 C7 Notes: C8 C9 C10 C11 C12 C13 C14 C15 (l) C16 Confirm that the cargo tank and inter barrier insulation space pressure and vacuum relief valves including safety systems and alarms found satisfactory Confirm the satisfactory operation of manual emergency shut down systems together with automatic shut downs of cargo pumps, filling valves and compressors Confirm that the portable and or fixed drip trays and insulation for deck protection (if fitted) for use to contain cargo leakage were examined and found in satisfactory condition Confirm that the cargo pipelines, valves (including pressure relief valves and drainage), fittings, and any liquid/vapour hoses were generally examined and expansion bellows, supports and vapour seals on insulated pipes found satisfactory Confirm that the sealing arrangements at the gas domes were examined and found satisfactory Confirm the protective screens for cargo, bunker, ballast and vent piping systems including vent masts were examined as far as practicable and found satisfactory Confirm the wheel house doors and windows, side scuttles and windows in the superstructure and deck house ends facing the cargo area in efficient condition Confirm the ventilation systems airlocks to working spaces and accommodation ventilation closing arrangements have been checked and found to be in satisfactory operation Confirm that the fixed/portable ventilation systems for spaces not normally entered are in a satisfactory condition Confirm the closing and other arrangements of any special enclosed space provided for crew protection in the event of a major cargo release examined and found satisfactory Notes: C17 ENVIRONMENTAL CONTROL Confirm that the inert gas or nitrogen supply system for environmental control of the cargo tanks and hold spaces (if applicable) has been examined and found in order (1) NITROGEN SYSTEMS BULK STORAGE NITROGEN GENERATORS State contents of bulk storage tanks: Were the N2 Generators tested and What is the normally full capacity: found in full working order? Have the nitrogen system alarms Were the N2 storage tank and been tested? associated equipment in satisfactory State last date of test by Ship's staff condition? State dates credited for survey (CSM) C ANNUAL SURVEYS BASIC REQUIREMENTS (CONT) - (2) INERT GAS SYSTEM The following examined and dealt with, where applicable; (a) External examination of the condition of all piping and components for signs of corrosion gas leakage/effluent leakage (b) Proper operation of both inert gas blowers verified (c) (d) Scrubber room ventilation system checked Checking as far as practicable the deck water seal for automatic filling and draining and checking for presence of water carry over e) Checking operation of the non return valve (f) Testing of all remotely operated or automatically controlled valves including the gas isolating valve(s) (g) Checking the interlocking features of the soot blowers (h) i) Checking that the gas pressure regulating valve automatically doses when the inert gas blowers are secured Checking as far as practicable the following alarms and safety devices of the inert gas system using simulated conditions where necessary (i) High oxygen content of gas in the inert gas main (ii) Low gas pressure in the inert main (iii) Low pressure in the supply to the deck water seal (iv) High temperature of gas in the inert gas main (v) Accuracy of portable and fixed oxygen measuring equipment by means of calibration gas (span gas) Survey carried out by the National Authority of the Country in which the ship is registered may be accepted at the discretion of the survey as meeting these requirements State Date when surveyed by the National Authorities: State other survey dates by the Society's Surveyors: (e.g surveyed as part of safety equipment survey) C18 ENVIRONMENTAL CONTROL INERT/DRYING GAS SYSTEMS Confirm arrangements for, sufficient gas to be carried to compensate for normal losses in cargo insulation spaces and were the gas control systems to these spaces together with pressure/flow gauges, found in satisfactory working order (1) Air drying systems (if applicable) to the hold spaces in efficient working order (2) Inter barrier and hold space purging inert gas system found in efficient working order C19 ELECTRICAL EQUIPMENT Confirm, as far as practicable, by visual inspection, that the electrical equipment in gas dangerous zones and spaces was in (l) good condition and properly maintained, with no evidence of any unauthorised modification to the installation in these (2) Cable runs examined as far as practicable for sheath and armouring defects and the cable supports found in good order (3) Intrinsically safe cables properly separated from other electrical cables (4) Bonding straps for the control of static electricity and earthing examined visually and found in good condition (5) Confirm the alarms and interlocks associated with pressurised lighting systems in gas dangerous spaces (compressor, motor rooms etc.) tested and found in working order State date of last test by ships staff (6)Interlocks and alarms associated with airlocks to working spaces tested and found operational, if fitted C20 CREW PROTECTION (1) suitably stored State Type and Number of Protective Suits available (mm protective suits) (2) Are there a minimum of two additional firemen's outfits in addition to those required by SOLAS 1983 Chapter 11-2, Reg 17 IGC Code to be checked (14.4.4) applied to specific cargoes as per Chapter 19 (3) Has all compressed air equipment been examined by a responsible officer each month and recorded State date of last test by ships staff C ANNUAL SURVEYS BASIC REQUIREMENTS (CONT) - (4) Decontamination arrangements and eye washes examined and found satisfactory (5) Confirm that the ship is provided with at least two sets of portable gas detection equipment suitable for the products carried together with an oxygen meter and are they in efficient working condition State Type Gas detection meters: Oxygen meters: (6) Ensure medical first-aid equipment, including oxygen resuscitation equipment and antidotes, for cargoes to be carried, are provided; (7) Confirm that respiratory and eye protection suitable for emergency escape purposes are to be provided for every person onboard and an additional sets provided on the Navigation Bridge C21 FIRE PROTECTION AND EXTINGUISHING ARRANGEMENTS (1) Water spray system for cooling, fire prevention and crew protection examined and found in order with all valves and pumps in efficient working condition State date of last test by ships staff (2) Cargo area dry powder extinguishing system examined and found in order State last service date: (3) Confirm that the fixed fire fighting installations in the gas dangerous spaces have been examined and the means of operation clearly marked C22 OTHER SURVEY ITEMS (I) Are there any special arrangements for the vessel to survive conditions of damage and are they in order (If applicable, refer to Damage Stability Manual on board) (2) Have the arrangements (if applicable) for bow or stern loading/unloading with particular reference to the electrical equipment, fire-fighting arrangements and means of communication, between the cargo control room and the shore location, been examined and found satisfactory (3) Confirm any removable pipe lengths, or other approved equipment necessary for cargo separation, available and satisfactory C23 ANNUAL SURVEYS METHANE BURNING EQUIPMENT AND OTHER EQUIPMENT COMPONENTS Confirm the following been generally examined externally together with the condition of insulation where applicable and found in order - (I) Heat exchangers and pressure vessels for use with methane burning in main boilers (2) Cargo heaters, vaporizers, masthead heaters and other miscellaneous pressure vessels (3) Cargo compressors and associated valves, instrumentation, alarms and pipework C24 (l) Confirm the fuel oil and fuel gas flame failure interlocks have been tested and fuel oil and gas valves verified to shut on operation of these shut down devices (2) Confirm that the nitrogen gas purging system for the fuel gas burning arrangements is in efficient working order (3) Inert gas purging system for the fuel gas burning arrangements in efficient working order (4) Manual and automatic gas shut off valves have been examined and found in order (5) Fuel gas non return valves and flame arresters have been examined externally and found in order (6) Fuel gas master valve to the machinery space in efficient working order (7) Confirm that there are adequate spares for each type of vent fan for the boiler gas canopies and fuel gas piping duct on board (8) All methods of testing the trips to the fuel gas master valve to the machinery space have been tested and found satisfactory (9) I Is there documented evidence (ship's check list) of all the above tests being regularly tested by ship's staff State date of last test by ships staff (10) Alarm systems are to be checked to ascertain they are in working order (11) Exhaust fans and/or pressurising system for gas trunking are to be tested (12) Safe-type equipment associated with the gas fuel supply examined visually and found to be in good order, with no evidence of any unauthorised modification C ANNUAL SURVEYS BASIC REQUIREMENTS (CONT) - C25 (l) (2) (1) (2) (3) (4) COLD SPOT EXAMINATION If the insulation arrangements are such that the insulation cannot be examined, were the surrounding structures of wing tanks, D.B tanks and cofferdams examined for cold spots prior to the survey (This examination to be held at convenient discharge port with tanks full and at minimum notation temperature) State Date and Port cold spot examination was held: A signed statement received from the master stating cold spot examinations were carried out by ship's staff State Date(s) of these examinations: C26 ANNUAL SURVEYS RE-LIQUEFACTION/REFRIGERATION SYSTEMS - If the vessel is fitted with re-liquefaction or refrigeration equipment for cargo temperature and pressure control and assigned the notation "RMC(LG)" the following examined as far as practicable; Machinery examined under working conditions Shells of all pressure vessels examined externally Cinsulation need not be removed for this examination but any deterioration of insulation or evidence of dampness which could lead to external corrosion of the vessel's or their connections is to be investigated) Primary refrigerant gas and liquid pipelines, cargo vapour and liquid condensate pipelines and condenser cooling water pipelines examined externally (Insulation need not be removed but any deterioration or evidence of dampness is to be investigated) Spare gear for the re-liquefaction/refrigeration plant found to be satisfactory Notes: D INTERMEDiATE SURVEYS (CONT) D4 ANNUAL SURVEYS CARGO CONTAINMENT SYSTEMS FIRST INTERMEDIATE SURVEY AFTER INITIAL COMMISSIONING OF THE SHIP - - Confirm that the following examinations carried out: Cargo tanks (other than independent tanks type C) (1) (2) (3) Tanks examined internally Tanks examined (where possible) externally Tower structures and other attachments within the tanks together with tank supports and securing arrangements examined and found satisfactory (4) List tanks credited for survey after above examinations: D5 Cargo tank and inter barrier space pressure and vacuum relief valves overhauled, examined and settings adjusted to the required pressures Maximum relief pressures for cargo tank relief valves are to be not more than the following percentage above the maximum vapour pressure for which the tanks have been approved The maximum vapour pressure for which the tanks have been approved is as follows; For to 1.5 bar CO to 1.5 kg/cm2) 10% For 1.5 to bar (1.5 to 3.0 kg/cm2)-6 % For pressure exceeding 3.0 bar C3.O kg/cm2) -3 % - Notes: A comprehensive list of all safety valves tested, recording their settings, is to be retained in the vessel's survey book D6 Setters for adjusting relief valves to harbour pressure examined and found satisfactory Cwhere applicable) D7 Ship's cargo hoses examined and found to be as approved and in satisfactory condition D8 Spares for cargo area mechanical ventilation fans examined and found satisfactory D INTERMEDIATE SURVEYS (CONT) D9 DIO DII E When all of the following conditions apply: Ship is 10 years of age or over; 1978 SOLAS Protocol applies; Cargoes are being carried that are not listed in Chapter 19 of the IGC Code; two spaces (being integral with the hull, and may include double bottoms), within the cargo area, should be subject to an internal examination Any internal examinations of spaces within the cargo area, which may be made for other reasons, may count towards this requirement Electrical insulation resistance test of circuits terminating in, or passing through, dangerous areas carried out, or (if the ship was not in gas-free condition) the results of previously recorded readings sighted, with satisfactory findings Integrity of safe type electrical equipment found in order, verifying that the equipment has not been impaired owing to corrosion, missing bolts, etc Confirm that there was no unauthorised modification to the installation of i-s ('zener') barriers and associated wiring; was the effectiveness of any i-s earthing arrangement verified RENEWAL SURVEY CORRESPONDING TO SS I (SHIPS FWE YEARS OLD) - GENERAL REQUIREMENTS The requirements of the annual survey and intermediate survey are to be complied with Check list items A,B,C and D - E1 All cargo tanks examined internally together with an examination of plating in way of supports of securing arrangements, tower structures, seating and pipe connections also to sealing arrangements in way of tank top/deck penetrations State cargo tanks examined and to credit for survey: Note: Provided that the structural examination is satisfactory, that the gas leakage monitoring systems have been found to be operating satisfactorily and the voyage records (cargo log book) have not shown any abnormal operation cargo tanks not require to be hydraulically tested E2 If any repairs to the cargo containment system (cargo tanks, liquid, vapour lines etc.) have been carried out full details to be reported, in survey report narrative together with any plan approval recommendations (if applicable) E3 Were independent cargo tanks of type "C" installed Non destructive testing of the plating in way of supports and also selected lengths of weld (Where such testing raises doubt as to the structural integrity a hydraulic test is to be carried out at 1.25 times the approved maximum vapour pressure Alternatively consideration will be given to pneumatic testing under special circumstances provided full details are submitted for approval.) E4 Deck mounted cargo storage tanks examined internally and externally as per the main cargo tanks E RENEWAL SURVEY CORRESPONDING TO SSI (SHIPS FIVE YEARS OLD) GENERAL REQUIREMENTS (CONT) - E5 Confirm that the cargo tank secondary barriers examined for effectiveness visually where possible or by pressure/vacuum tests on the inter barrier spaces over a 36 hour period (global tests) The results of the pressure/vacuum tests to be retained in the survey record book (Alternative means of checking the secondary barriers will be considered) Have the results of these tests been reviewed and found in accordance with the containment system manufactures/designers recommended limits) Note: (a) For Gaz Transport and Technigaz containment systems a leakage rate greater than mb/l0 hr will require to be investigated and corrective action carried out to the surveyors' satisfaction Cb) Where cargo containment systems have secondary barriers which cannot be examined or tested and have been approved on the basis of extensive prototype testing, the barriers will be considered to remain efficient provided a cold spot examination of the adjacent steel work is satisfactory and records of the steel work temperature reading are verified acceptable E6 Insulation where accessible in way of the cargo tank or hull structure examined externally together with any vapour or protective barrier E7 Were any sections of insulation removed for examination, if so report their condition and condition of structure in way Special attention should be given to insulation in way of chocks, supports and keys Portions of the insulation are to be removed, if required by the surveyor to enable the condition of the plating to be ascertained Where the insulation is not accessible refer to C-fl) E8 Cargo tank internal pipes and fittings examined and were all valves and cocks in direct communication with the interiors of the tanks opened up for inspection and the connection pipes examined internally as far as practicable Pressure relief valves and vacuum relief valves on cargo tanks and inter-barrier spaces opened up and examined E9 E10 Pressure relief valves adjusted to lift at a pressure in accordance with D5 E11 Confirm that the relief valve harbour settings checked (if applicable) E12 Relief valves on cargo liquid and gas pipelines opened up for examination and their settings correctly adjusted Note: All safety relief valves that have their pressure checked fad justed are to be listed and the list retained in the survey record Cargo pumps, cargo booster pumps and cargo vapour compressors opened up for examination State pumps and compressors examined: E13 (1) If cargo pumps, cargo booster pumps and cargo vapour compressors examined on a continuous basis, confirm that the interval between examinations does not exceed years E14 Pumping systems for the inter-barrier spaces checked and verified to be in good working order E15 Insulation to be removed from the cargo liquid and vapour pipe work, where considered necessary, to ascertain the condition of the pipe work (Areas removed to be recorded) Equipment for the production of inert gas examined and shown to be operating satisfactorily with the gas specification limits Were any repairs/modifications carried out to cargo liquid and vapour pipe work All such repairs are to be reported E16 E17 E RENEWAL SURVEY CORRESPONDING TO SSI (SHIPS FIVE YEARS OLD) GENERAL REQUIREMENTS (CONT) E18 E19 E20 E21 Pipe links, valves etc for distribution of the inert gas generally examined Pressure vessels for the storage of inert gas examined internally and externally together with the securing arrangements Pressure relief valves for the storage of inert gas demonstrated to be in good working order Liquid nitrogen storage vessels examined as far as practicable and all control equipment, alarms and safety devices verified operational See also annual survey requirements C17-(1)&(2) for inert gas and liquid nitrogen systems Gas tight bulkhead shaft seals opened up and examined and sealing arrangements confirmed satisfactory on re assembly State shaft seal alarms that were tested (If applicable) E22 E23 E24 E25 - If the ship was in dry dock were sea connections associated with confirm that the cargo handling equipment opened up and examined Arrangements for discharging the cargo overboard in an emergency checked Membrane LNG Cargo Tanks: (a) Pump mast inspected A visual inspection is required on the pump tower Special attention should be paid: to the double sleeve pipe penetrations through the inner trunk deck, from the pump tower, and by accessing the inner trunk deck space; around the 'K', 'T' and 'X' details; and to the tower's expansion/contraction guidance system at the base (b) Visual condition of punch (pneumatic or missile device) for primary barrier space been checked, if provided/installed - DO NOT TEST E26 F Tests carried out to demonstrate the effectiveness of bonding arrangements for the control of static electricity, particularly where not evident from visual examination of bonding straps and their fastenings NOTES: RI NEWAL SURVEY CORRESPONDING TO SSI (SHIPS FIVE YEARS OLD) RE-LIQUEFACTION/REFRIGERATION EQUIPMENT The following items may also be examined on a continuous basis (Refer to the Survey status/ masterlist) Fl Each reciprocating compressor opened up and examined cylinder bores, pistons, piston rods, connecting rods, valves and seats, glands, relief devices, suction fiters and lubricating arrangements are to be examined, Crankshafts are to be examined but crankcase glands and the lower half of main bearings need not be exposed if the surveyor is satisfied with the alignment and wear State compressors examined: F2 If other than reciprocating compressors were fitted were they opened up and examined State compressors examined: C) F3 Was an approved system Cby HQ) of replacement compressors in use in lieu of on board surveys F4 End covers of each condenser removed and the tubes, tube plates and covers examined State condensers examined: F RENEWAL SURVEY CORRESPONDING TO SS I (SHIPS FIVE YEARS OLD) LIQUEFACTION/REFRJGERATION EQUIPMENT F5 Refrigerant condenser cooling water pumps, including stand-by pump(s) which may be used on other services opened up and examined State pumps examined: F6 Where pressure vessels are insulated was sufficient insulation removed especially in way of connections and supports to enable the vessel's condition to be ascertained State vessel examined: Confirm that sufficient insulation removed from the insulated pipes to enable their condition to be ascertained F7 F8 An examination of all pressure relief valves and/or bursting discs throughout the system carried out to confirm they were in satisfactory working condition List all safety valves removed from the plant and tested in a workshop together with their lift pressures: NO ATTEMPT is to be made to test primary refrigerant pressure relief valves on board the ship The following items may also be examined on a continuous basis (Refer to the Survey Status/ masterlist) GI If boil off gas (methane) is used as fuel, for main propulsion purposes, were the associated compressors and heat exchangers C) opened up and examined as for re-liquefaction/refrigeration equipment (item Fl) G2 Confirm that the steam side of steam heaters hydraulically tested to 1.5 times design pressure G3 Fuel gas pipe trunks or casings generally examined and the exhaust or inerting arrangements for these spaces verified G4 All the alarms associated with fuel gas burning systems verified in working condition (See also C2 annual requirements) The requirements ofsurvey A,B,C,D,E,F and G to be complied with as applicable Hl Water cooled condensers in which the primary refrigerant is in contact with the shell pneumatically tested to a pressure equal to the designed working pressure on removal of the end covers List condensers tested together with test pressure: H2 All other pressure vessels in the re-liquefaction/refrigeration, methane burning and other cargo handling systems pneumatically tested as applicable to a pressure equal to the design working pressure List vessels tested and test pressure: H3 Liquid cargo pipe lines pneumatically tested to a pressure equal to 1.25 times the working pressure or alternatively were 10 H RENEWAL SURVEY CORRESPONDING TO SSII (SHIPS 10 YEARS OLD AND OVER) AND SPECIAL SURVEYS THEREAFTER H4 At special survey 111 (Ships 15 years old and over) and at each alternate special survey thereafter thickness gaugings to be taken of plating of independent cargo tanks and also the hull structural plating surrounding the cargo tanks where insulated on one side Report the condition of the protective coatings of the plating surrounding the cargo tanks where insulated from one side and list the areas where these examinations were held e.g ballast tank cofferdams: A survey record book is to be kept on board for the use of the Society's Surveyors, the government Representatives of the State whose flag the ship is entitled to fly, certificate Port State Authorities, staff/Owners Representatives and is to contain the following certificates and documentation and also Current of fitness forShip's the carriage of liquefied gases in bulk Current copy of the relevant requirements of the Society's Rules Society's interim certificate of class relating to all gas code, annual/intermediate classification/SOLAS surveys A blank copy of the Society's survey check list for ready information of the items to be examined at the required survey A Society's completed survey control record (Sheet of 4) detailing the surveyable items and dates of survey Ship's check lists of all testing of alarms and shut downs relating to the cargo containment and cargo handling systems All calibration records made by the manufactures representatives, ship's staff or other responsible bodies for cargo tank contents, temperature, andfor level gauges togethertesting with calibration of cargo tank high (primary and low level alarms and high level shut downs A copy of anypressure test report pressure/vacuum of the cargorecords tank inter-barrier spaces and secondary) Copies of any approved plans together with approval letters stamped and issued by the Society, covering modifications and/or repairs to by thethe cargo containment/cargo systems 10 Signed statement Master confirming thathandling a cold spot examination was carried out by ship's staff 11 Any other relevant document which testifies to the efficient management/operation of the cargo containment/cargo handling systems Note: The above information to be kept in the survey record book until the certificate of fitness that it relates to expires, thereafter this information is to be retained in accordance with the owners' document retention procedures 11 NOTES AND COMMENTS Cargo Containment: Definition of Cargo Tanks: Integral tanks Integral tanks form a structural part of the ship's hull and are influenced in the same manner and by the same loads which stress the adjacent hull structure The design vapour pressure Po as defined in 4.2.6 should not normally exceed 0.25 bar If, however, the hull scantlings are increased accordingly, Po may be increased to a higher value but less than 0.7 bar Integral tanks may be used for products provided the boiling point of the cargo is not below -100C A lower temperature may be accepted by the Administration subject to special consideration Membrane tanks Membrane tanks are non-self-supporting tanks which consist of a thin layer (membrane) supported through insulation by the adjacent hull structure The membrane is designed in such a way that thermal and other expansion or contraction is compensated for without undue stressing of the membrane The design vapour pressure Po should not normally exceed 0.25 bar If, however, the hull scantlings are increased accordingly and consideration is given, where appropriate, to the strength of the supporting insulation, Po may be increased to a higher value but less than 0.7 bar The definition of membrane tanks does not exclude designs such as those in which non-metallic membranes are used or in which membranes are included or incorporated in insulation Such designs require, however, special consideration by the Administration In any case the thickness of the membranes should normally not exceed mm Semi-membrane tanks I Semi-membrane tanks are non-sell-supporting tanks in the loaded condition and consist of a layer, parts of which are supported through insulation by the adjacent hull structure, whereas the rounded parts of this layer connecting the above-mentioned supported parts are designed also to accommodate the thermal and other expansion or contraction The design vapour pressure Po should not normally exceed 0.25 bar If, however, the hull scantlings are increased accordingly, and consideration is given, where appropriate, to the strength of the supporting insulation, Po may be increased toa higher value but less than 0.7 bar Independent tanks Independent tanks are sell-supporting; they not form part of the ship's hull and are not essential to the hull strength There are three categories of independent tanks referred to in 41.4.2 to 4.2.4.4 Type A independent tanks are tanks which are designed primarily using Recognized Standards of classical ship-structural analysis procedures Where such tanks are primarily constructed of plane surfaces (gravity tanks), the design vapour pressure Po should be less than 0.7 bar Type B independent tanks are tanks which are designed using model tests, refined analytical tools and analysis methods to determine stress levels, fatigue life and crack propagation characteristics Where such tanks are primarily constructed of plane surfaces (gravity tanks) the design vapour pressure Po should be less than 0.7 bar Type C independent tanks (also referred to as pressure vessels) are tanks meeting pressure vessel criteria and having a design vapour pressure not less than: 1.5 P0 = + AC(pr) (bar) 12 ... examined and found to be as approved and in satisfactory condition D8 Spares for cargo area mechanical ventilation fans examined and found satisfactory D INTERMEDIATE SURVEYS (CONT) D9 DIO DII E... Society's survey check list for ready information of the items to be examined at the required survey A Society's completed survey control record (Sheet of 4) detailing the surveyable items and dates... to be tested (12) Safe-type equipment associated with the gas fuel supply examined visually and found to be in good order, with no evidence of any unauthorised modification C ANNUAL SURVEYS BASIC