3.D) possible hazards associated with the filling and transfer operation.
During filling operations, whether tanker, the discharging liquid should not endurable to fall through the vapour space from the time when this causes the liquid to take on a stagnant charge relative to the tank shell (even though the tank is grounded).At filling time, if not special earthing connections are made, the resistance to earth of a lorry with pneumatic tyres on dry concrete could well exceed 106 O. stipulation must be made to reduce this resistance to 10 O. All hoses should be electrically conductive. 
This process should be at equilibrium conditions otherwise non-equilibrium conditions may increases the fire hazards associated with the product. First step at beginning of filling should see whether the tanker approved or not. when the product is flowing through the pipes a static electrical charge can be accumulated, nozzles or filters and when it is agitated. Particularly during dry weather conditions a static spark discharge can ignite collect vapours. Always bond receiving containers to the fill pipe before and during the loading. Always confirm that receiving container is properly grounded. Bonding and grounding alone may be insufficient to eliminate fire and explosion hazards associated with the electrostatic charges. review operations carefully that may increase the risks associated with static electricity such as tank filling. throughout the loading process always keep nozzle in contact with the container. During filling process do not use compressed air, product container is not designed for elevated pressure. Before filling empty tanker should be cleaned properly otherwise material residues which can ignite with explosive force. After filling product tanker should be tightly closed why because the vapours of the n-heptane flammable, vapour may be ignited by static discharge. 
n-heptane filling a tank should be avoided by employing bottom entry or by using a fill pipe terminating close to the bottom of the tank. At the start of filling the pumping rate should be given pumping rate(maximum 100 liters/sec). the inlet pipe is covered to twice its diameter, the pumping rate can be increased but should always be kept below pumping rate. The recommended pumping rate can be observed regularly , better we have put some valve for regulation which is under manual control. 
The first step in a transfer operation involving a tank truck should be to attach a temporary earth connection to the truck. The final step should be the removal of the connection n-.heptane filling into a tank should be avoided by the use of main inlet line at low level, or a fill pipe to the tank bottom. When transferring n-heptane in to the tank the linear velocity should be kept below, the inlet pipe is covered to twice its diameter. After this the pumping rate could increase, but it is advisable to keep as low as reasonably practicable. 
Once transfer operation finished it may be necessary to dip or sample. During the stage of transfer or agitation, static charge will have accumulated with in the tank, sufficient time must be allowed for this charge to dissipate. This is called as relaxation time. for dipping the equipment should be of metal or natural fiber and be earthed. Sampling cords should also be of natural fibers with resistivities which are unlikely to give rise to the accumulation of static charge. Dipping and sampling of flammable liquids should not be carried out in extreme adverse weather conditions.