Document QgV4Qzjag2y6710jrEjOJJ8R4

FLAMMABLE AND COMBUSTIBLE LIQUIDS first sample may be so diluted in its passage down the sampling tube that the first part of the vapor will bum enough to give a reading, but on further sampling the point er will drop back to zero The dial should be watched closely dunng the sampling The sampling hose should be kept from an area where flammable liquid or water might be drawn into the instrument Either flammable liquid or water would put it out of service Hot vapors also may affect the Indicator if they condense inside A tank, tested before being cleaned, may be found vapor-free However, if it con tains sludge or scale, flammable liquid and vapor may be released as soon as the sludge or scale is disturbed. A safe rule to follow is that no tank should be considered free from the possibility of dangerous vapors as long as it contains sludge or scale. If workmen leave a tank for a period of time, such as overnight, gas tests should be made the next morning before they are per mitted to continue work Many companies use a written permit form when it is neces sary for men to enter vessels which have contained flammable liquids or to do "hot work" repairs in them Devices are available for testing for car bon monoxide, benzene, hydrogen sulfide, and tetraethyl lead hazards (This last in strument is available from the Ethyl Cor poration.) Loading and Unloading Tank Cars Only trained employees should load or unload tank cars containing flammable liq uids These men should understand the dan ger of possible fire and explosion and of asphyxiation from breathing flammable va pors As an added precaution, unloading and pumping operations should be discon tinued dunng electrical storms. Invoices and shipping papers on incoming tank cars should be checked closely for cor respondence with actual tank cor numbers, and in doubtful cases contents should be tested in order to prevent accidental mix ture of flammable liquids in plant tanks See Fig 32-6 for typical tank car construc tion details. Spotting cars A car mover should be used if it is neces sary to hand spot a car The worker should stand with the handle of the bar to one side of the track rail and face the car with his feet well apart so that he cannot be over balanced easily. After the car is spotted, with the dome outlet opposite die loading or unloading line, the brakes should be set and the car wheels blocked The "blue flag" stop sign (at least 12 by 15 in, with words such as STOP - TANK CAR CONNECTED or STOP-MEN AT WORK) should be set before loading lrnes are connected or work Flp- 32-6. Typical tank cor with ports identified A Car broke B Wheel block C Identification number D Car seal E Safety valve F Dome cover G Outlet leg valve H Outlet leg cop J Drain pan K Outlet nozzle l "Flammable" card 32-11