Hazardous materials are substances or objects that are a threat to health, safety, property or the environment. They also include all types of explosives, poisonous, inflammable, radioactive, gases, corrosive, organic peroxides, oxidising and infectious materials. They can exist in gaseous, liquid and solid states. They are listed in the list of dangerous goods, in the transport regulations or, if not listed, are classified according to international regulations. We distinguish between 9 classes of hazardous materials:
- Explosive - ammunition, fuses, fireworks;
- Gases - flammable (butane, propane, acetylene); non-flammable, non-poisonous (carbon dioxide, neon, helium, liquid nitrogen); toxic;
- Flammable liquids - adhesives, paints, fuel, acetone;
- Solids - flammable (sulphur, matches); susceptible to self-ignition (magnesium, yellow or white phosphorus); flammable on contact with water (carbide, sodium);
- Oxidising substances - oxidisers (lime, fertilisers), organic peroxides;
- Poisonous and infectious substances - poisonous (arsenic, cyanide), infectious (bacteria, viruses, medical waste);
- Radioactive materials
- Corrosive materials - battery acid, sulphuric acid;
- Miscellaneous - fragrances, anaesthetics, asbestos.
Construction, supervision and marking
Each UNO device must be designed and manufactured to take into account the hazards associated with the device, the potential risks to human life and health and to property and the environment. They must be manufactured, equipped and installed so as to be safe for use, taking into account the relevant factors, ensuring safety during operation. The equipment should be equipped with systems to ensure hermetic filling and emptying of tanks, overfill protection systems and stop work in case of failure. UNO equipment should also have earthing and emergency disconnection connections. Where this equipment has a dry shut-off connector it should have an interlocking system to prevent self-opening and a manual release.
Overview of transport tanks
Equipment for filling and emptying transport tanks is subject to the Transport Technical Supervision. No equipment may be put into service without being approved by a TDT inspector and issued with a register. The technical conditions for technical supervision are enshrined in the Regulation of the Minister of Transport of 20 September 2006 on technical supervision conditions to be met by equipment for filling and emptying transport tanks. The legal basis for technical supervision is the following legal acts: the Act of 1 December 2000 on technical supervision, the Regulation of the Council of Ministers of 7 December 2012 on the types of technical devices subject to technical supervision, the Regulation of the Minister of Entrepreneurship and Technology of 21 May 2019 on the manner and mode of verification of qualifications required for operation and maintenance of technical devices and the manner and mode of extension of the validity period of qualification certificates, and the Regulation of the Minister of Economy of 26 November 2010 on the amount of fees for activities of technical supervision units.
All equipment for filling and emptying tanks should have a factory plate which contains the following data: Factory number, name of the manufacturer, year of manufacture, purpose of the equipment, type designation, quality control mark, date of the last pressure test and stamp of the TDT inspector, parameters of the equipment (flow rate, nominal diameter, permissible temperature range and working pressure). NO equipment should also have a registration number, which has been assigned by the Transport Technical Supervision. Markings for the transport of hazardous materials are orange signs with a black border, which are placed on the front and rear of the vehicle.
Filling and emptying of tanks
Filling and emptying tanks are the most responsible operations, requiring great care in execution and the observance of certain rules. In order to avoid dangerous stresses in the tank structure, measures must be taken to protect the tanks from hydraulic and mechanical shocks that may be transmitted by the pumps if they are incorrectly installed or operated. Pipework connected to the tank should not be allowed to vibrate during tank operation. Each tank must be filled to a predetermined level, ensuring that the product does not overflow when it expands under heating. Before filling, check that the vent valve is operational. If, due to a malfunction or other reasons, this valve is closed, the tank must not be filled until the valve is removed. Then open the manhole, the aeration port and start the pump. The pumping rate of flammable or gaseous liquids through the pipelines should be limited to the limits allowed by the standards. The level of the product should be constantly monitored. Connecting and disconnecting the earth cable during filling and emptying operations is prohibited. At the end of each operation, the manhole, aeration spigot, knob wheel, cap and side drain valves must be sealed. The procedures for emptying the tanks are similar to those for filling. The tanks are emptied through the main valve and one of the side drain valves using a pump or gravity. When emptying, connect the discharge line to the side drain valve, open the valve and the aeration port. Be sure to take steps to remove all product.
Working with filling and emptying tanks is a highly responsible job that is extremely dangerous. Only authorised persons are allowed to carry out these activities. Courses and training of all kinds are ideal for acquiring them. These provide professional and comprehensive training for filling and emptying tanks. Such courses cover the most important topics in hazardous materials, technical supervision, tank marking and tank design. It is also extremely important to know and comply with general health and safety and fire protection regulations when working on tanks.