To work on liquefied gas, not only the re-equipment of consumption devices and stoves with replacement of nozzles is required, but also the correct arrangement of the gas pipeline and the storage area for cylinders.
This manual is useful for those who use propane as a fuel source in a private home.
Work on liquefied gas
- Safety rules and restrictions
- Materials, products and fittings
- Pipe laying rules
- Ramp and strapping
Safety rules and restrictions
You can’t just connect a gas burner and a cylinder with a hose, for stable and safe operation you need:
- bring gas parameters to a certain standard;
- ensure the optimal flow rate;
- eliminate any possibility of leakage;
- in case of leakage, exclude the possibility of gas accumulation in a closed volume;
- install an alarm;
- to provide stable all-season work.
The fulfillment of these requirements in practice is implemented by a number of technical solutions, the use of special materials and products for installation. For example, it is not obvious when operating plants on liquefied gas that it is cooled by evaporation. In winter, this can lead to freezing of the cylinders, due to which only one component of the mixture will evaporate. This leads to the accumulation of residual butane, which itself burns rather poorly.
Unlike mains gas, liquefied gas is heavier than air and can accumulate in lowlands. Because of this, it is prohibited:
- stationary placement of cylinders below ground level or in buildings with more than three storeys;
- storage of liquefied gas in rooms with an entrance to the basement;
- installation of more than two cylinders within the house.
Cylinders installed in rooms must be located no closer than 1 m to heaters without a screen and no closer than 0.5 m to sources of open flame or screens of heating devices. For outdoor installation, a distance of 3 m from openings, doors and windows of underground buildings should be observed. The main requirements are set out in section 8 of SNiP 42-01-2002.
The optimal and safest way of placing cylinders is inside a lockable metal cabinet attached to the outer wall. From it to the place of entry into the house, a steel pipe should be laid on welded joints, and immediately after leaving the wall, a transition to semi-rigid bellows inlets made of stainless steel is made.
There are certain technical requirements for the equipment of the liquefied gas supply system from the street. At the same time, there is no difference in what the consumer will be: stove, oven, boiler or generator. The scheme is universal and can be re-equipped by replacing a small part of the shut-off and control devices.
Materials, products and fittings
Before starting installation, it is recommended to purchase all the necessary materials and locking and control devices. For strapping cylinders in a closet, you can buy a ready-made kit called a comb. It includes all the equipment necessary for the safe operation of the installation, but the price tag for such assemblies is impressive: about $ 400-500 for two cylinders.
In an attempt to save money, you can purchase all the necessary items at random. In this case, most of the problems with the arrangement of equipment inside the cabinet are eliminated, because most of the combs are assembled on rigid pipelines and it is not always possible to place the entire piping in the inner space of the cabinet.
According to safety requirements, the gas pipeline must be protected by safety-relief (PSK) and safety-shut-off (PSK) valves. It is better if all safety devices are part of the pressure regulator. The highest quality and most reliable products of this kind are produced by GOK, Pietro Fiorentini, Rego, SRG, as a budget option for a battery from two cylinders, you can use the domestic RD-32M.
There are several types of pressure regulators, the best option is a reverse-acting device with a two-stage reduction. The exceptions are those cases when several devices with different requirements for gas pressure are connected to one battery. In such cases, a first stage reducer is installed on the comb, while the final pressure correction is performed by compact second stage reducers installed at each gas consumer.
Pipe laying rules
According to safety standards, the total capacity of one battery of cylinders should not exceed 600 liters when installed against the walls of buildings and 1000 liters for free-standing ones. The minimum distance from the house may be 8-10 m, depending on the fire resistance of the structures.
But even such a small distance must be overcome somehow, making the gas supply to the house reliable and safe. Materials for this can be used the following:
- Steel pipes will be the most reliable option, but only if the services of a good gas welder are available. After commissioning, the gas pipeline must be protected with an anti-corrosion coating.
- Special metal-polymer and multilayer pipes for gas supply systems are flexible, which often facilitates installation, but the presence of detachable joints reduces overall reliability.
- Polymer rubber and bellows hoses for hydrocarbons are suitable when cylinders are located near the wall of a building near the point of entry or indoors. The inlet length should not exceed 150 cm. For greater distances, a rigid or semi-rigid pipeline should be laid.
A characteristic feature of liquefied gas lines is the need to lay them underground in order to avoid the formation of a liquid fuel phase. If condensate forms in the pipeline at subzero temperatures, it will drain into the lower part, where it will heat up and evaporate again. That is why all above-ground areas are made predominantly vertical, while horizontal ones should have an appropriate slope.
Methods for introducing bottled gas into the house: 1 – gas cabinet; 2 – gas cylinder; 3 – flexible hose; 4 – reducer; 5 – metal pipe; 6 – shut-off valve; 7 – bellows hose; 8 – gas stove; 9 – steel sleeve
It is possible to avoid underground laying only at relatively small distances (3-5 m) or when organizing heating with a self-regulating cable, the use of which RMNT.RU has already written about. When operating in cold climates, it is highly recommended to use insulating shells for pipes and to equip a thermal protection of a gas cabinet. All heating systems must operate at a voltage not exceeding 50 V.
Ramp and strapping
It is necessary to install a gas valve on each cylinder with the type of connection that the connecting pipes and the regulator are equipped with. It is allowed to use steel or copper pipes as connections, or reinforced hoses for hydrocarbon gases with fittings installed at the ends for crimping the clamps.
Most regulators have two inlets, so it is easiest to connect two cylinders with only two connections. If there are more cylinders, you will need to purchase tees to connect them. It is also recommended to install a pressure gauge in the high pressure line to monitor the amount of gas remaining. The pressure gauge can also be installed after the regulator, although this is not required provided that high-quality imported fittings are used. If there are burners in the gas industry without a regulator and safety devices, there must be a fire valve at the point where the comb is connected to the gas pipeline.
At the points of connection of gas appliances, it is necessary to install shut-off valves for emergency shutdown of the gas supply. If there are several gas consumers in the system and each has a second stage reducer, a rigid insert must be installed between it and the valve, securely fixed to a stationary object.
The assembly of the entire system is carried out without connecting to the ramp connecting the cylinders, this connection is performed last. During commissioning, the gas pipeline must be subjected to an increased pressure test, setting the maximum value on the reducer. Regardless of the type of connections, all of them must be checked for leaks using a soap solution. published by econet.ru
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