ZODIAC MARITIME AGENCIES LTD GAS OPERATIONS MANUAL 13 Form Issue Date Approved : : : : GOM 002 05-05-02 M.J.R MEASURINGINSTRUMENTS As of now the gas ships will be supplied with measuringinstruments for use during cargo handling according to list below For measuring: Quantity Instrument Oxygen Drager Oxopac II Oxygen Servomex Model 262A Oxygen in low concentration Teledyne Model 311 Gas concentration ( ppm ) Drager Multi Gas Detector Gas concentration (% LEL ) MSA Combustible Gas Indicator Model LV Gas concentration ( % ) Riken Interferometer HC17 Organic vapours and chlorinated compounds ToxiRAE pocket PID Explosive limit ( LEL ) Explosimeter Model 2E /storage1/vhost/convert.123doc.vn/data_temp/document/nsb1554800578-1959494-15548005781218/nsb1554800578.doc Page of ZODIAC MARITIME AGENCIES LTD GAS OPERATIONS MANUAL 13.1 Form Issue Date Approved : : : : GOM 002 05-05-02 M.J.R Span Gases The following standard stock of span gases to be kept on board of the ships: Gas 99.9 % of Nitrogen Quantity btls x 10 ltrs 2% of Merthane in air btl 50% of Methane in air btl 100 ppm Isobutylene 0,75 % of Propane in N2 btl btl 13.2 For which instrument Drager Oxopac II Servomex 262A Teledyne 311 Oxygen Analyser of IGS Moss Gas Deterctor MSA Comb Gas Indicator LV (for LEL calibration ) Explosimeter Model 2E MSA Comb Gas Indicator LV ( for volume range calibration ) ToxiRAE pocket PID Moss gas detector Description of instruments Drager Oxopac is an instrument which has proven very reliable and easy to operate in addition to requiring almost no maintenance This instrument should be on board as units with integrated sensor in addition to I unit with sensor on a 10 metre long cable Inclusion of Oxopac (and Teledyne) into the standard stock makes it possible to reduce the number of Servomex instruments to one The Servomex oxygen analyser is primarily used when good accuracy is required This instrument is advantageous to use when measuring oxygen concentration in void spaces during transport of e.g propylene oxide, and during nitrogen purging cargo tanks before reaching the lowest concentration of typically 0.1% oxygen at which point the accuracy of the instrument is not good enough Additionally, Servomex can be used as a replacement for Teledyne, should that instrument be inoperative The Teledyne which can only be used for measurements of concentrations up to 1% oxygen has been specially purchased for use when conditioning cargo tanks before gas-up This instrument is very accurate and with high sensitivity, thus also making it vulnerable It should in particular be remembered that the cell sensor is destroyed by oxygen making it necessary to purge with pure nitrogen after use The Drager Multi Gas Detector is mainly used during tank cleaning to check tank atmosphere before opening the tanks to ensure that the threshold limit value is not exceeded while working in the tanks Combustible Gas Indicator model LV can be used for measurements of explosive gases in the range up to LEL and measurements of concentrations by volume up to 100% The instrument is /storage1/vhost/convert.123doc.vn/data_temp/document/nsb1554800578-1959494-15548005781218/nsb1554800578.doc Page of ZODIAC MARITIME AGENCIES LTD GAS OPERATIONS MANUAL Form Issue Date Approved : : : : GOM 002 05-05-02 M.J.R delivered calibrated for propane When measuring other gases, the proper response curves must be used to convert value read off from the display to the correct value Purchase of this instrument has made it possible to reduce the number of explosimeters to one Riken Interferometer has for a number of years been absent from the gas carriers but has again been implemented There are a number of advantages to using this instrument as it is easy and quick to operate, requires very little maintenance, and is the only one which is not actually damaged when used for measuring VCM vapours The supplied version can measure in two ranges, 0-6% and 0-30% by volume It is not possible to purchase an interferometer with a range up to 100% by volume for gases other than methane ToxiRAE is a programmable pocked Photo –Ionization Detector (PID) designed to provide continuous exposure monitoring of toxic gases Explosiometer is generally used for checking the atmosphere in enclosed spaces and tanks before entering them for carrying out repairs or cleaning All gas carriers have been equipped with MSA explosimeter model 2E in order to enable fast and easy determination of presence of flammable gases The scale on the explosimeter goes from 0-100% of lower explosion limit (LEL) MSA Calibration Test Kit is supplied for checking the explosimeter The test kit consists of a pressure vessel with test gas composed of approximately 40% LEL methane in air Spangas for the gas indicator cannot be used directly as this gas has been mixed with nitrogen in the pressure vessel and the explosimeter does not work in an inerted atmosphere The pressure vessel contains sufficient gas for about 20 testings The calibrating procedure can be read from the instructions delivered with the calibrating equipment Additionally, graphs are delivered with the instructions showing acceptable instrument readings while introducing test gas to the explosimeter Control and use of explosimeter The explosimeter must be checked regularly using the above mentioned test Checks must also be carried out prior to using the instrument for a series of measurements before tank inspection or repair work in cargo and ballast tanks and void spaces The chief officer and other deck officers must be fully confident with using and maintaining the explosimeter and the calibrating equipment In order to achieve reliable measurements and calibrations it is necessary that the instruction material delivered with the equipment is closely followed Records of calibration, testing and servicing of the explosimeter shall be maintained on board /storage1/vhost/convert.123doc.vn/data_temp/document/nsb1554800578-1959494-15548005781218/nsb1554800578.doc Page of ZODIAC MARITIME AGENCIES LTD GAS OPERATIONS MANUAL Form Issue Date Approved : : : : GOM 002 05-05-02 M.J.R Guidelines for using Explosimeter Rubber suction bellows and sample tube is attached to the explosimeter The explosimeter and tube are flushed with fresh air Use pump strokes plus I stroke per metre sample tube Lift the locking pin and turn the "On"-switch 1/4 turn clockwise The instrument pointer deflects and settles around zero The scale is illuminated Suck fresh air through the instrument using the number of strokes as described above Turn the switch to make the pointer indicate zero The open end of the tube is placed where a sample is to be drawn from The sample is sucked into the instrument using the rubber bellows and with the number of strokes as above If sucking water into the instrument is at risk, the liquid trap delivered with the explosimeter must be used When drawing samples from tanks with overpressure it must be ensured that the flow is limited in order to prevent damage to the instrument It may be possible to collect a sample in a balloon from the test kit and then suck the sample from the balloon into the instrument Combustible gas indicator Model LV This instrument is designed for measuring concentrations of flammable gases The model currently in use having a digital display is reliable and readout of the measured concentration is less ambiguous than was often the case using the previous model with analogue display Concentration read off from the display is only valid for the gas for which the instrument has been calibrated normally propane It is possible to calibrate the instrument to other gases but the procedure is not suitable for performing on board Instead, response curves for measuring volume-percent for other gases have been issued; concentration read off is referenced to the vertical axis and the concentration in volume-percent appropriate for the measured gas is read off from the horizontal axis Response curves to be used when measuring the following gases: Ammonia Butadiene Ethylene Butane Butenes Methane Hydrogen Propane Propylene /storage1/vhost/convert.123doc.vn/data_temp/document/nsb1554800578-1959494-15548005781218/nsb1554800578.doc Page of ZODIAC MARITIME AGENCIES LTD GAS OPERATIONS MANUAL Form Issue Date Approved : : : : GOM 002 05-05-02 M.J.R Note: that even though the instrument is calibrated for propane a response curve must still be used as at concentrations above about 60% it will gradually show less than the actual concentration VCM It is not possible to use this instrument for measuring VCM as it does not react to VCM vapours Additionally, the measuring filament will be destroyed by VCM Records of testing, calibration and servicing of the instruments shall be maintained on board 13.3 Maintenance of instruments The explosimeter and calibrating equipment should be stored in the deck office or cargo control room together with other portable instruments The chief officer is responsible for the care of the instrument being in accordance with the instructions To prevent malfunction it is important that the instrument and ancillary equipment is c cleaned after use, and that batteries are removed if the instrument is not going to be used for some time 13.4 Reasons for malfunctions The most frequent reasons for malfunctions are: The instrument is damaged by leaking batteries Dirty and clogged cotton filters Clogged lead filters Water in the measuring filament 13.5 Changes in the standard stock Most of the ships will have for a period of time a stock which differs from the above standard Instruments in the standard stock not presently on board should be ordered It is, however, not the intention that surplus instruments are sent home as they of course can still be used on board 13.6 Cell sensors Oxygen meters by Drager and Teledyne use special cell sensors but this is not the case with Servomex which employs another measuring principle These cell sensors deteriorate gradually, mainly when used but also when stored Consequently, it will not serve any purpose to carry any /storage1/vhost/convert.123doc.vn/data_temp/document/nsb1554800578-1959494-15548005781218/nsb1554800578.doc Page of ZODIAC MARITIME AGENCIES LTD GAS OPERATIONS MANUAL Form Issue Date Approved : : : : GOM 002 05-05-02 M.J.R spares in stock on board Instead, new sensors for replacing worn out ones should be ordered as late as possible but naturally early enough to ensure that the instruments are not rendered unusable As delivery times can often be difficult to predict there will possibly be instances when sensors are received before those in instruments have to be replaced, but only applying this procedure prevents the purchase of sensors which by reason of obsolescence are never going to be used 13.7 Drager test tubes Test tubes which are used with the Drager Multi Gas Detector have a limited lifetime It has, however, been established that these tubes generally function flawlessly after their lifetime has expired, especially if they have been stored in a refrigerator Consequently, it is not necessary to discard tubes past their expiry date; they can be used during the initial inerting and gas freeing, preserving the new tubes for the final measurements Before cargo tanks are entered after tank cleaning it is necessary to ensure that the atmosphere in the cargo tanks is safe for entering Further some shippers require that the remaining con-tent of the previous cargo loaded is known prior to loading the next cargo Ordering The standard stock should as far as possible be maintained and supplements should be ordered in as good time as possible in order to avoid expensive air-freight Lifetime of Test Tubes The manufacturer normally guarantees a tube lifetime of years The tubes may however be used beyond their guaranteed lifetime, provided they are stored in a refrigerator Tubes beyond their expiry date may be used for initial measurements while tubes inside valid lifetime shall be used for final and conclusive measurements /storage1/vhost/convert.123doc.vn/data_temp/document/nsb1554800578-1959494-15548005781218/nsb1554800578.doc Page of ... instrument for measuring VCM as it does not react to VCM vapours Additionally, the measuring filament will be destroyed by VCM Records of testing, calibration and servicing of the instruments shall... reduce the number of Servomex instruments to one The Servomex oxygen analyser is primarily used when good accuracy is required This instrument is advantageous to use when measuring oxygen concentration... board 13.3 Maintenance of instruments The explosimeter and calibrating equipment should be stored in the deck office or cargo control room together with other portable instruments The chief officer