Safety measures

Natural gas is a colourless, tasteless and odourless gas. For safety purpose, a minute amount of an odorant is added to it for wide consumption, so it can be smelt in concentrations significantly lower from the lower flammability limit. The odorant is regularly added immediately after the exit from the Plinacro transmission system, after the main exit valve from a measuring-reduction station, at the very entry in the distribution system of a particular gas distributor.

Natural gas is not toxic, it is lighter than air (natural gas density is approx. 0.68 kg/Sm3 compared to air density which is 1.293 kg/Sm3). It is regularly measured by standard m3 (one Sm3 is equivalent to gas quantity that occupies the area of 1 m3 at the pressure 1.01325 bar and temperature 15°C).

One should differentiate between natural gas and liquefied petroleum gas (LPG or propane-butane). Liquefied petroleum gas is produced by processing of oil. It is kept in containers and gas bottles (cylinders). Unlike natural gas, liquefied petroleum gas is heavier than air, so the areas where it is used should be thoroughly ventilated.

Natural gas burns with a blue flame, without harmful products of combustion, such as soot and ash, and with minor quantities of carbon monoxide and sulphur dioxide which makes it one of environmentally cleanest energy sources.

Net calorific value of natural gas used for calculations in Croatia is 33.338 MJ/m3.

Natural gas is flammable and explosive (only when the mixture with air is within 5 to 15 percent of natural gas)

Proper use of natural gas appliances is not dangerous for people. Improper operation of natural gas appliances, chimneys or air supply system for combustion can cause suffocation, poisoning or explosion.

Suffocation occurs when oxygen concentration in air has been reduced, i.e. by increasing natural gas concentration. At concentrations below 5 percent natural gas has no harmful effect on humans. At larger concentrations it acts as an asphyxiant, reducing the oxygen concentration in the air.

Poisoning can occur indirectly, although natural gas is not poisonous. At incomplete combustion in flue gases, caused by natural gas combustion, poisonous carbon-monoxide (CO) occurs. The concentration of 0.2% of carbon-monoxide in the air is fatal within 2 hours.

Flammability limit (explosiveness) indicates the proportion of gases and air between which limits this mixture is flammable (explosive). There are lower flammability limit (LFL) and upper flammability limit (UFL), depending on gas composition, pressure and temperature.

Explosion can occur at the concentrations between 5 (LFL) and 15 (UFL) percent of natural gas in the mixture with air, with the presence of thermal energy, as ignition initiator.

Ignition temperature is the lowest temperature at which gas, in stoichiometric mixture with air (oxygen) ignites. Depending on gas composition, pressure and explosive limits (flammability), the lowest ignition temperature of natural gas ranges between 595 and 645°C. 

PROTECTION ACTIVITIES

Protection measures for people, facilities and environment in Plinacro are carried out by organisation, supervision and preventive maintenance.

All measuring-reduction stations and gas pipelines are equipped with safety devices which activate in case of extreme situations (sudden pressure increase or decrease; gas pipeline rupture, which occurs extremely rarely) to prevent (or minimise to the least possible level) adverse consequences.

Activities of fire protection and protection from technological explosions are organised and supervised at all facilities and in all spaces owned or used by Plinacro, and at all work posts and locations of activities. Preventive protection is conducted within all organisational units of Plinacro in compliance with acts, by-laws and internal acts of Plinacro