Mini-control units: the UNI-7131 standard
What does the UNI-7131 standard say regarding the mini control units, an essential connection for gas?
The UNI-7131 regulation, the last revision of which dates back to May 2014, serves to regulate the design and installation of LPG gas systems not connected to the distribution network. In addition to this, it also establishes the basic rules for replacing the cylinders connected to the mini-control units.
The positioning of the cylinder
There are areas, domestic and non-domestic, in which the cylinder, in connection with the mini-control unit, cannot be placed:
- Lower ground level;
- Near electrical systems, fuels, air intakes, compartments or ducts connected to lower floors;
- Bedrooms and bathrooms;
- Rooms with fire risk (for example garages);
- Rooms with a volume less than 10 m3.
It is instead possible to place in certain areas, such as:
- Open space: it must not be put in contact with inclement weather, sunlight, sources of heat, accidental impacts and areas of possible tampering.
- Suitable compartments: the housing must have a volume equal to 1.5 times the volume of the cylinder and the walls must be sealed.
- Special rooms: each cylinder must have a free surface area of 100 cm2 and openings must be provided for ventilation, even at floor level.
The connection of the cylinder with the mini-control unit
The mini-control units are the compact solution for connecting multiple gas tanks to the same plant and constitute a characterizing product for Gnali Bocia, which produces different configurations suitable for the connection of one, two or three cylinders. This component is also connected to a pressure gauge necessary to control the pressure of the gas in circulation and, for the most sensitive applications, there are dual-stage gearboxes, as too high a pressure can damage the system devices.
The cylinder, through the mini-control unit, can be connected to the user device in two different ways:
- Directly: mini-control unit connected to the cylinder and flexible hose which from the latter connects directly with the hose fitting of the user appliance.
- Through fixed installation: the mini-control unit plays the same role but the tube connects to the hose connector placed at the beginning of the fixed installation.
- Directly: mini-control unit connected to the cylinder and flexible hose which from the latter connects directly with the hose fitting of the user appliance.
- Through fixed installation: the mini-control unit plays the same role but the tube connects to the hose connector placed at the beginning of the fixed installation.
What does the legislation say about mini-control units?
The UNI-7131 standard indicates the mini-control units as fundamental elements for the connection because they allow the replacement of the tank without dispersion of gas in the environment. Usually, these devices are fixed to the external walls and protected in masonry or with a metal net.
The fundamental point is that, since the mini-control units can be connected to several tanks, you must never leave any attack without a connection to a tank to avoid working in the absence of safety.
The connected tube must be made in a single piece to avoid, even in this case, losses of generalized gas or concentrated in its length.
The importance of compliance with the UNI 7131 standard
The use of gas cylinders in domestic systems is as widespread as it causes more or less serious problems and accidents for buildings and persons.
Some indications, also provided within the UNI 7131 standard, are essential to reduce risks:
1. Gas cylinders cannot be exposed to the sun, because as the temperature rises, the gas tends to expand and can cause explosions;
2. They cannot even be placed in basements or rooms below the houses because the gas tends to have a greater density than the air, settling on the bottom, and creating a flammable "bed";
3. The dimensions of the compartments are also important: it is essential to understand how many cylinders can be placed at the same time in the same room;
4. Finally, the cylinders cannot be filled up to 100% of their capacity with gas but up to a maximum of 80%, with a residual 20% of water vapor to prevent sudden increases in pressure due to various causes (including, as said the temperature);
5. The position of the cylinders must always be vertical, that is, never overturned or inclined;
6. The replacement can and must always be done with the tap closed, even if they are empty.
These measures, dictated by both the UNI 7131 standard (which also has more technical aspects within it) and the common sense of the installer and maintenance technician, allow to minimize the risks associated with a gas system.
Some indications, also provided within the UNI 7131 standard, are essential to reduce risks:
1. Gas cylinders cannot be exposed to the sun, because as the temperature rises, the gas tends to expand and can cause explosions;
2. They cannot even be placed in basements or rooms below the houses because the gas tends to have a greater density than the air, settling on the bottom, and creating a flammable "bed";
3. The dimensions of the compartments are also important: it is essential to understand how many cylinders can be placed at the same time in the same room;
4. Finally, the cylinders cannot be filled up to 100% of their capacity with gas but up to a maximum of 80%, with a residual 20% of water vapor to prevent sudden increases in pressure due to various causes (including, as said the temperature);
5. The position of the cylinders must always be vertical, that is, never overturned or inclined;
6. The replacement can and must always be done with the tap closed, even if they are empty.
These measures, dictated by both the UNI 7131 standard (which also has more technical aspects within it) and the common sense of the installer and maintenance technician, allow to minimize the risks associated with a gas system.
20/07/2021
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