The analysis of the requirements resulted in working normative documents on a safety of oil product loading and unloading in the tank trucks.

The basic normative documents used at the development of the equipment for realization of technological operations of tank truck loading are:
Rules of industrial safety of tank farms and warehouses of oil products ПБ 09-560-03. GOST 1510-84 "Oil and oil products ". GOST 50913-96 " Automobile vehicles for transportation and refueling of oil products". GOSTs 51330.0-51330.20-99" Electric equipment explosion-proof ". GOST of 12.4.124-83" Means of protection against static electricity ". Rules of protection against the static electricity, acting across Ukraine. As well we are guided by rules of protection against static electricity acting in Germany.

Technological system of oil product loading in which combustible liquids and gaseous products consist of:

1. Installations of loading, including: pump blocks, filters, gas-separator, flowmeters, cut off valves, ball pipelines, loading tips, electronic devices, which:
   • Control condition of integrity sensors of grounding circuit;
   • Control condition of sensors of overfilling prevention;
   • Control condition of sensors of position of auxiliary devices;
   • Control condition of sensors of flowmeters;
   • Accept tasks from the operator on a set doze and broadcast to it the data on the current delivered amount, and condition of controllable sensors;
   • Operate the cut off valves of pump units, barriers and breakers of vacuum.
2. Families of automobile tanks for transportation of oil product which Automobile vehicles for transportation and refueling of oil product "should correspond to GOST 50913-96".
3. Hard-software complexes with which help processing of documents is carried out, distribution of loading posts and tank trucks, and also the control over realization and fiscal events (operation of all components of system) which should be carried out during procedure of tank truck loading from the moment of its start on the loading post till the moment of the termination of coming from the post.

Tank trucks

The standard of GOST 50913-96, for tank trucks has been developed without taking into account the international requirements, in particular the European norms and rules, and also norms and the rules developed by American standard API. The standard rigidly does not regulate measures on protection against static electricity, in particular there are no instructions what should be partitions and breakwaters either what or other internal acting parts which can be the reasons of occurrence of categories at loading of non-conductive liquids which mirror can be on distance from the basic walls. Between the metal cores even located in parallel to the mirror, and a liquid there is electrostatic category.

There is no instructions how to prepare the boiler of a tank truck at change of a transported product, in particular as it is necessary to prepare the boiler after transportation of gasoline before the loading of diesel fuel in order to prevent occurrence inside the boiler of explosive concentration of gasoline vapours due to the absorption of vapours of high (not explosive) concentration.

As last researches in the field of catching gasoline vapours have shown, such products as diesel fuel, kerosene, separate marks of oils are a good absorbent and at contact with light hydrocarbons, butanes, pentanes, hexanes, benzene sharply reduce their concentration in capacity from 15-55 up to 2-7 volumetric interests, the last is explosive. Therefore creation of conditions for occurrence of explosive concentration of vapours in the tank truck at loading of diesel fuel after gasoline is necessary for preventing by its preparation (blowing, washing or another way).

In general Requirements of the European norms do not allow to change the kind of a product, and each compartment is intended only for one kind of product. In joint connections "tank truck - installation" loading the blocking is stipulated, not allowing to connect, for example, a compartment in which diesel fuel delivered to a hose which is giving out gasoline and vice versa.

The standard does not stipulate application of devices and technologies of bottom hermetically sealed loading, by the European rules in particular at realization bottom loading of tank truck two independent systems of restriction from overfilling should be applied. One of which, on the basis of pneumomanagement, is established on each compartment, blocks submission of a product irrespective of installation of loading, the second system of prevention of overfilling by means of electronic sensors, is directly connected to installation of loading and closes the cut off valve of installation at achievement by a level of a liquid of limiting value.

However till now the most various tank trucks with the various sizes of filling necks through which their loading is made are issued by factories- manufacturers, and the sizes of filling neck do not allow to develop convenient and safe joint unit with a cover of manhole for top loading. In operation different departments have tank trucks of manufacture since 80th years of the last century which application for a long time it is time to forbid since they concern to dangerous objects and that at them inside is welded to nobody dependently. To carry out and guarantee safe technology of loading such tanks it is impossible.

Installation of loading

Section 2.4 Automobile loading/unloading stations PB 09-560-03 items 2.4.1:
Automobile loading/unloading stations should meet the requirements of industrial safety, norms of designing of the automated installations of clock loading of light oil products in rail tank cars and automobile tank trucks, building norms and rules, standards and the present rules.

The point covers all and nothing concrete. Automobile unloading/loading stations in the nature do not exist. Tank trucks are loaded on the loading installations at the tank farms, and unloaded into the tanks at the gas station at loading and unloading the different technologies are applied, and technical requirements should be divided into them.

Loading of rail tank car can be dot or it is called clock or gallery at the loading trestles. Loading gallery trestles can be unloading if they are equipped with installations of bottom unloading of oil products.

Technological processes at clock and gallery are various and requirements to them should be different.

The basic requirements to railway loading/unloading trestles (it is obviously gallery type) are given in section 2.3

Item 2.4.2 The refueling station or loading post should include:
premises of management point, platform for tank truck loading at which the loading posts and devices are equipped. Pumps can separately settle down from loading devices.

In sections 1 and 2 of rules ПБ 09-560-03 the speech is about dangerous industrial objects, tank farms and warehouses of oil products, decoding of the term " the refueling station " is not given. Actually "the refueling station " includes:

• A platform of expectation of a tank truck;
• Operational;
• A platform of loading.

Platform of expectation - a place where there is a tank truck at arrival for loading
Operational - premise where the driver of a tank truck under a corresponding post of loading at the platform of loading is identified.
The platform of loading includes posts of loading, system of fire-fighting, devices of control НКПР, devices for illumination.

The post of loading includes installation for tank truck loading through the top manhole (top loading) or installation for bottom loading (bottom loading) and a platform for positioning tank trucks. The post of top loading can have modification for tank truck loading on the one hand or from two sides similarly to fuel dispenser at the gas station.

Installation top loading depending on types of served tanks can include from one up to 4 loading arms with loading tips and deliver through each loading arm from one up to 4 kinds of products without mixing.

Installation of bottom loading can include from one up to 4 loading arms with the connecting head in the size 4 " according to standard API and deliver only one product through a separate arm.

Each kind of a product poured through any loading arm should move through: the separate pipeline, the electropump, the hydraulic module ( filter -gas-separator, return valve, a measuring instrument of volume or weights) and cut off controlled valve which serves as border of the unit of delivered product and after which pipes of the loading arm at tank truck loading always are completely released from a product into the tank truck, and before it all hydraulic system ( feeding pipeline, pump, the filter - gas-separator, measuring instrument and connecting pipes up to controlled cut off valve) should be always filled.

Item 2.4.3 without comments.

Item 2.4.4 At the stations and points of tank truck loading should be applied loading posts (loading struts) and installations of automated loading with local and remote control from operational.

Here there is a new term "point of loading" its value is entered is not deciphered, what means under local control? Whether it is necessity of presence of emergency button " STOP ", whether the device similarly foreign which there name " the dead operator " i.e. when the operator constantly holds the button pressed and process of loading is implementing, at release of button the process of loading automatically stops?

Item 2.4.5 Drives of loading/unloading devices, used for loading of LVZH and GZH, at realization of operations manually, hydraulics or a pneumatic, should exclude spontaneous movement of mechanisms of devices.

The item contradicts safety requirements in the following:

• The horizontal mobile loading pipe with loading tip, by change of its corner of an inclination, positions a loading tip which is fixed on the neck in process of loading. When the boiler of a tank truck under action of a poured product compresses springs and goes down, the loading pipe together with a tip should move spontaneously behind the boiler of the tank, differently there will be a undocking and a passage of a product.
• Cut off valve at emergency switching-off of voltage or pressure drop in a pneumonetwork should be closed spontaneously under action of springs.

Item 2.4.6 For LVZH loading with elasticity of vapours from 500mm m.c unloading/loading devices should be supplied with devices of vapour removal.

In spite of the fact that there is section 2.10" of System of catching of vapours "in the rules and as section 2.6" tank parks ", the requirements in devices of vapour removal and gas catching pipelines. With the help of what valves or fire-protective devices should they be incorporated, what speeds of PVS are allowable? What working pressure of PVS should be supported in gas catching lines, taking into account the pressure of operation of respiratory valves, tanks with products? What products can be connected by gas catching pipelines?

Item 2.4.7 At loading of LVZH and GZH telescopic or joint pipes should be used. The distance from the end of the loading pipe up to the bottom forming tank should not exceed 200 mm.

Item 2.4.8 The Tip of loading pipe should be made of a material excluding the sparkle-forming at impacts with the boiler of the tank. The design of a tip should exclude vertical falling and spray of product flow at the beginning of loading operation.

Actually, delivered loading posts consist of the joint pipes with loading telescopic tip and a basic cone for positioning a tip in the neck of tank truck with various diameter and hermetic sealing of internal space of a tank truck concerning the atmosphere. The basic cone for loading of diesel fuel does not seal the internal space of a tank truck as it has an open hole for the connection with the atmosphere. Besides the basic cone with the help of the mechanism equipped with a cable and a hook, is attached to the neck with the purpose of exception of an opportunity of its spontaneous rise during the time of loading, and also there is a sensor of positioning of a loading tip in the neck which condition traces electronic device TSBU, and in case of occurrence of a supernumerary situation (the driver has not fixed a tip or there was a spontaneous displacement of a tip upwards) CBU disconnects process of loading (closes the cut off valve and disconnects the pump). All details of a loading tip adjoining with the boiler of the tank are made of aluminium alloys and brass which do not concern to sparkle- forming at impact with steel.

The sizes (depth from the top forming loaded neck to the bottom) at different tanks are in a range (1200-2700 mm) and thus to observe a condition that the end of a loading pipe of a tip was at height no more than 200 mm, it is necessary to make a loading pipe compound (telescopic). Similarly act and conducting foreign firms which make such equipment, for example:

• American firm OPW;
• German firm EMCO;
• Italian firm OMC.

The difference between firms and "Prompribor" is in various ways of lowering and rise of a final pipe.
OPW - the Final pipe has the handle on all length with which help the operator omits and lifts it.
OMC - Uses for this purpose winch with two cables with which help the pipe falls and rises.
EMCO - also applies a telescopic pipe with the device of rise and lowering both manually, and automatically.

Mobile loading pipes of tips of all firms are not condensed in relation to motionless since they should fall freely under a body weight. Mobile loading pipes with automatic rise is more preferable, since there is no necessity to supervise the operator (if he omitted the pipe or not).

In delivered bulk struts bulk tips with the automatic device of lowering and rise of a telescopic pipe of a bulk tip are applied.

The mobile pipe is located inside motionless and represents a glass with the valve on the end.

The pipe is constantly supported in the top position with the help spring equalizing and under action of a stream at start of loading on the small consumption falls down to a meeting of the valve pivot with a bottom of the tank. Since in a loading pipe there is the constant pressure caused by a high-speed pressure and weight of a column of a liquid which presses a pipe to the bottom of the tank the valve opens lateral windows at the end of a pipe and flow of a product are directed in parallel the bottom. Presence of the pressure caused by a high-speed stream, constantly presses a pipe to a bottom of the tank, in case of its{her} rise final windows are covered, and value of pressure increases. Thus, at presence of a stream the pipe is always kept at a bottom of the tank, having poured a product is carried out under a layer. On the termination of loading at seal failure of loading post with the help of the breaker of vacuum, i.e. Connection of an internal cavity of loading pipe with an atmosphere, occurs discharge of loading pipes of a due to gravitation, and the loading pipe rises in the top position due to force created spring equalizing.

The loading pipe also carries out additional function of removal of static electricity since it together with pipes of loading post is made from electroconductive materials and earthed. Therefore the mobile pipe of loading tip is not condensed in relation to a motionless pipe, and between them there is a backlash of 0,5 mm through which also passes a part of a poured liquid. And as mobile and motionless pipes have constant connection this backlash is good neutralizer of static electricity. At movement of a liquid in a pipe, layers of a liquid which do not contact to walls of the pipe, electrize, and layers which contact to walls relax the charges of static electricity. This process passes constantly and depends on speed and conductivity of liquids. In the tank there always comes a liquid with a residual electrostatic charge. In the beginning of loading when there is not enough liquid,i.e the height of loading has not reached 200 mm, at an earthed tank truck when there is an opportunity due to rough hashing an acting liquid to contact to metal walls, there is more effective relaxation (running off of charges) on the ground. However when the level of a liquid rises, and the volume of it becomes big, intensity of hashing decreases and the relative area of contact of layers of a liquid with walls of the tank decreases, speed of a relaxation of charges is reduced and in case of intensive receipt (the big speed of loading), charges have not time to relax, there is their accumulation in the volumes which are taking place on distance from walls of the tank. At presence what or the metal designs connected to the tank and located in parallel or with an inclination to a mirror of a surface of a liquid there is a category which capacity happens, it is sufficient to provoke explosion of vapours, at presence of the last in explosive ratio with air.

Therefore at realization of technology of loading it is necessary to exclude events at which in the boiler of the tank explosive concentration ratio of gasoline vapour in air starts to arise within the limits of 2? 6 volumetric interests). Actual concentration of gasoline vapour at loading, unloading and even in completely merged tank due to the rests on walls depending on temperature of air is always in limits от15 up to 55 volumetric interests.

Explosive concentration arises always when it is made having poured diesel fuel in the tank in which before there was a gasoline.

Item 2.4.9 With a view of exception of product overfilling through the neck of the boiler of the tank, it is necessary to apply automatic limiting terminators of loading level, allowing automatically to stop having poured at achievement of a preset value.

Actually, in delivered loading posts the sensors of the top limit level which can be adjusted for each type of the tank and which condition traces the electronic block of management which at change of a condition of the sensor of a level gives out a command on deenergizing of the pump and closing of the cut off valve are applied, and also gives out the message on the top level of management for fiscal events.

Item 2.4.10 should be stipulated the measures providing full clearing of loading pipe from a product and excluding an opportunity of its passage on the tank at the termination of loading.

Actually, there is an electrocontrolled valve which connects internal cavities of pipes to an atmosphere after each termination of loading and copes from the electronic block.

Border of the unit of delivered product is cut off valve after which pipes of loading post at tank truck loading always are completely released from a product into the tank truck, and up to it all hydraulic system (pump, filter, measuring device and connecting pipes) is always filled.

For gathering the rests of the product which is flowing down from loading pipe at its extraction from the tank, it is necessary to apply item 2.4.11 drip pan.

Actually, the put installations are completed drip pan.

Item 2.4.12 Taking into account a design of drain devices which elements are connected by hinges with oil seals, made of nonmetallic materials, it is necessary to check each change grounding, not supposing infringement of a uniform contour.

Actually in the engineering specifications the instruction on size of resistance between a pipe of loading tip and a point of grounding which is 10 Ohm , this parameter is supervised at release, commissioning, should be supervised at operation.

Item 2.4.13 for bottom loading of products into the tank trucks of aviation enterprises should be applied connecting joint pipes from the aluminium, excluding sparkle-forming at joining with a flange of tank truck. The application of flexible metal hose.

Actually connecting head of installations of bottom loading which are made by JSC "Prompribor" and connecting valves of tank truck are made of aluminium alloys.

Item 2.4.14 on the post of loading with computer-controlled the emergency (manual) remote switching-off of the pump should be provided. The button of emergency switching-off should be readily available. The system of loading of avia GSM in ТЗ should provide them having poured from below, i.e. the bottom filling. Having poured ТЗ from above it is not supposed.

Actually on all installations of loading the emergency button " STOP " is stipulated, N.Z contacts of which are included in a circuit of management of the coil of the actuator of the pump of installation.

As to bottom loading of tank trucks it is necessary to process rules ПБ 09-560-03 GOST 50913-96 regarding a safety of process from break of the boiler of the tank, removal of static electricity, preparation of the boiler of the tank at change of a product, a design and the sizes of joint sockets on a product and joint sockets, on system of protection against overflow.

Item 2.4.15 at stations and posts of oil product loading into the tank truck the signal devices of safe concentration should be mounted.

Installation of the signal devices of safe concentration is defined by the general designer.

At the customer's request the manufacturer of installations АSN can include these units in the complete set of delivery and include them in a contour of management of the loading terminal ASU tank farm.

Item 2.4.16 Excess of concentration oil product vapour at stations and loading posts more than 20 % NKPR the termination of operations of loading and an interdiction of start of engines of automobiles should be provided.

Actually this requirement should be carried out by the operator of loading from operational manually through the managing device and by submission by a voice of a command on an interdiction of start of the automobile.

In case of inclusion of sensors NKPR in a contour of management of operation on loading will automatically stop.

Item 2.4.17 Is forbidden to start the engines of the tank truck which are located on the operative platform, in case of oil product overfill before full cleaning of overfilled oil product.

Actually given command should be carried out by the operator of loading by submission by a voice and instructing by the driver.

Item 2.4.18 filling stations should be equipped with special devices (traffic lights, barriers, etc.) for prevention of departure of the tank truck filled with oil product with the loading devices omitted in their necks.

Actually put installations are completed with barriers on departure posts налива which cope from electronic device TSBU and open, when the operator has executed all necessary manipulations with a strut and a gangway.

Items 2.4.19 of the tank truck which are under unloading/loading at the filling stations should be earthed with presence of the blocking excluding an opportunity of start of pumps for swapping of oil product at absence of such grounding.

Actually electronic blocks TSBU carry out the control of a circuit of grounding between the automobile and grounded circuit which provides safe contact of grounded tongs with a tanker and supervises its integrity, simultaneously attaches it to the plug of grounding with the help of the electronic relay and in case of infringement of contact or increase in its resistance disconnects the pump and closes the cut off valve.

Section 3 "Lightning protection and protection against the static electricity "
Item 3.3.11 For the prevention of dangerous static electricity, elimination of an opportunity of accumulation of charges of static electricity on the equipment and oil product is necessary by grounding of the metal equipment and pipelines, decrease of speed of movement of oil product in the pipeline and prevention spray of oil product or decrease of concentration of oil product vapour up to safe limits.

At operations of loading and unloading of gasoline concentration of vapour is always higher than limits of explosion hazard. As have shown results of researches on absorption (to absorption of gasoline vapour) diesel fuel, kerosene or oils, just decrease of high not explosive concentration of gasoline vapour up to a level of their explosion hazard is inadmissible. This process in practice turns out at loading of diesel fuel into the tank truck in which before there was a gasoline. This action is necessary for excluding legislatively by inclusion in rules ПБ-09-560-03.

As to sources of occurrence of spark categories, all oil products have very low conductivity and at friction of layers very strongly electrized. However at movement on pipes layers which adjoin to walls, relax the charges and at moving inside of a pipe are again charged owing to friction.

Thus, oil products moving on a pipe carries in itself any cumulative electrostatic charge characterized in volumetric density C/m3. The charged product gets into the tank truck. The distributed part of a product, adjoining with walls of an earthed tank truck, and a part of a product which does not adjoin to walls, any time has an electrostatic charge. At receipt of the following quantity into the tank truck the quantity of a product increases and accordingly the size of a charge of that part which accumulates on distance from walls increases. Therefore there is a category on any acting metal subject, and at presence of explosive concentration of vapour and sufficient volume for development of process of fast burning (explosion) there is a clap and sharp increase of pressure up to 10-12 kg / sm2 that results in destruction of the boiler of the tank.

The characteristic of explosion is equal a trotyl equivalent to weight of the reacted substances. For example, at presence of free volume into the tank truck of 5 m3 at concentration of vapour 5 % in it is 250 dm3 sated vapours of gasoline in density of 2-4 g/dm3, in recalculation on weight is 500-1000.
The quantity of air of 4750 dm3 in density of 1,2 g/dm3 is 5700.

The state standard of GOST 1510-84 "Oil and oil product" section 3 item 3.5 the appendix 2 precisely defines the order of preparation of rail tank cars, tank trucks and cars for oilbitumen to loading of oil and oil product.
In particular before in bulk diesel fuel in the tank where before were automobile этилированные, and неэтилированные the rest is required to remove gasoline, to wash out hot water, and to dry the bottom. The same is required to be made before in bulk gasoline in the tank where before there was a diesel fuel.

Conclusions

Realization of safe process of technology of delivery of a product into the tank truck, by virtue of that the different equipment is involved in it a lot of, including a plenty of various tank trucks which can be uncontrolled to the basic responsible for safety of process, is problematic for the following reasons:

• The requirements of normative documents leaves much to be desired.
• Normative documents reflect requirements to objects which they serve in particular not enough:
  • Rules ПБ 09-560-03 section 2.4 Automobile unloading/loading stations:
    - It is not determined, what tank truck should be served at these stations to that they should correspond;
    - Preparation of tank truck is not registered at change of a transported product;
    - Recommended values of speed of loading as it is made in the European rules are not given
    - Presence of protecting designs and transitive bridges is not stipulated since the operator should move elements of loading post from garage position up to hatches of the tank and back at height from 2,5 up to 3,8 m.
  • GOST Р 50913-96 " Automobile vehicles for transportation and refueling of oil product":
    - It is not registered, to what tank truck it is distributed its actions regarding terms of release. In operation there is tank truck of release of 70-80 years of the last century. By what rules and requirements of them it is required to use in dangerous productions on loading of oil product.
    - The requirements to operations on loading and unloading of products are not registered;
    - Section 5, the general technical requirements of item 5.1.1.3, it is registered, all operations on filling tank trucks are carried out by the closed way through the tight device in accordance with GOST 20772. If to follow this item top loading it is not lawful, it should not be.
    - The standard does not stipulate unification of designs and parameters of filling manholes, and also connecting devices for bottom hermetically sealed налива for performance to requirements of item 5.1.1.3 given STATE THAT.
    - There are no requirements to internal cavities of compartments, regarding breakwaters and acting parts with the purpose of a safety from categories of static electricity at loading and unloading.

In one document it is not registered that installation of loading and the family of tanks which it serves, is uniform technological system which carries out dangerous production, and in this system each tank should be surveyed, fixed and adapted to service on concrete type of installations of loading.

The industrial personnel also should pass training and has the right for work on dangerous objects. Absence and disparity of normative documents does not allow neither to the chief engineer of a tank farm, nor the manufacturer of installations of loading, neither to the manufacturer of tank truck, nor the chief engineer of the transport organization to develop local normative documents and instructions, and also to appoint and prepare responsible persons for safe realization of technology of product transfer with the help of tank truck.

Consequences of specified disparity in normative documents, absence of results of in-depth studies of the mentioned dangerous processes, and also incomplete revealing of the true reasons of some failures, finally results in new failures.

On the basis of stated and with the purpose of the further exception of emergencies, at performance of dangerous productions on oil product transfer, I think necessary urgently to develop the technical rules in which all necessary requirements to performance of technology and the equipment participating at performance of dangerous productions would be registered.

• Tanks;
• Product pipelines;
• Gas-equalizing lines;
• Pumps;
• Installations of loading;
• Tank trucks;
• Installations of vapour recycling;
• THE GAS STATION;
• Systems of automation.

The specified equipment should be included in uniform system of safety at unloading/ loading, transportation and storage of oil product. Accordingly this uniform system will allow to reduce losses of oil product at operations of transportation.

Very much frequently it is possible to see on separate objects as the expensive import equipment is applied complete with the equipment of poor quality of the doubtful manufacturer since there is no the precise regulation, corresponding requirements and accordingly knowledge.

Yours faithfully, The general director JSC "Prompribor"

N.I.Kobylkin