Reconstruction of a flat in Ostrava and installation of a gas pipeline using GAS PROFI pipes

The Swedish company Heimstaden owns more than 100,000 housing units in several European countries. 43,000 rental flats are located in the Moravian-Silesian Region. Most of these flats are connected to natural gas, which is used mainly for cooking. Safety of their tenants is one of Heimstaden's top priorities. Therefore, it invests considerable funds every year in the reconstruction of gas distribution systems, regular replacements of gas cookers and hoses, including the prescribed regular revisions.

After testing a pilot installation of a gas distribution system made with stainless-steel pliable corrugated tubing in a reconstructed rental flat in Ostrava-Poruba, they unequivocally decided to change the company’s standards for the installation of gas connections. The copper piping used so far should be replaced by the modern MERABELL GAS PROFI piping system. The change also includes the using of MERABELL GAS PROFI hoses with a bayonet lock and a thermal fuse for the connection of gas cookers.

Main reasons:

  1. Standardized replacement of gas distribution systems – installation teams of Heimstaden so far used a system with pressed copper. Usually, the installer came to the site, measured system length and calculated necessary material and then left to buy it at wholesale. This step is now completely eliminated. The installation team arrives at the site already fully equipped with following items: long coil of MERABELL GAS PROFI braided pipe, nuts with seals, wall plate and appropriate adapter.
  2. Speed of installation – mostly the house gas pipelines running from the gas meter to the appliance have a complex shape, which requires many connecting elements of different angles and bridging bends. All these complicated elements are completely eliminated when a flexible stainless-steel pipe is used, because the necessary shaping of the piping is done by hand. The installation time is thus much shorter than in the case of pressed copper.
  3. Human resources – the simplification of the assembly itself means that the installation can be carried out by a less experienced worker while maintaining 100% quality of the work performed. (note: of course, after completing the prescribed training).
  4. Availability of tools – hand lever press by MERABELL is significantly cheaper and easier to operate than copper press tools. In addition, these must be calibrated regularly, which costs additional money and especially the time when tools are not available for work.
  5. Safety – because “no connection is the safest connection”. The gas pipeline can be made of MERABELL stainless-steel pipes with a minimum of joints. This eliminates the risk of potential leaks in the joints. The joints are only at the beginning and at the end of the piping and they are created by easily pressing the end of the pipe using a lever press. Moreover, stainless-steel corrugated tubing is partially flexible. Therefore, it resists vibrations and shocks very well, and so prevents possible loosening of joints.
  6. Savings in the future – the work of the inspection technician during subsequent cyclic inspections is simplified and necessary work time is shortened. The leak test is performed only at the beginning and end of the pipeline. There is no need to search for often hidden elbows on the route, as in the case of a copper gas pipeline.
  7. Warranty – the manufacturer provides an above-standard 10-year warranty on MERABELL GAS PROFI material.

The installation itself

The pilot installation was carried out by Radius-H, s. r. o., installer from Ostrava. The newly built gas pipeline made of stainless-steel corrugated tubing is located in an flat in Ostrava, which has undergone a complete reconstruction from floor to ceiling. The designed gas pipeline with total length of 5 meters runs from the gas meter in the riser in the lavatory, through the core unit up to the kitchen, where it is terminated with a gas hose for a free-standing cooker. After consulting with the strategic purchasing department, the investor selected a premium piping system consisting of MERABELL GAS PROFI stainless-steel corrugated tubing with a yellow protective jacket.

A 2 in 1 gas hose, namely MERABELL GAS PROFI with a gas lock, was chosen to connect the gas appliance. The hose is equipped with a bayonet lock which allows for repeated disconnecting of the cooker, e. g. for cleaning. The 25-year warranty period allows the use of the hose for a minimum of 5 inspection cycles.

Technical design

With using of on-line pipe calculator yellow piping was selected: MERABELL GAS PROFI with DN15 / 3/4", coil 30 m long. The gas cooker is to be connected by MERABELL GAS PROFI G1/2"–R1/2" hose with bayonet gas lock and the length of 150 cm (M0149).

The corrugated piping is to be connected to the outlet fitting of the gas meter by means of a system connection: a G3/4 "nut and a flat gasket for DN15. The 5-meter-long piping runs through the core unit and through the pantry up to the kitchen. It is installed on the surface of walls and passes through walls in protectors. Necessary shaping of the piping is made manually. In the place of the future gas appliance, the pipeline is terminated with a nut, a gasket, adapter nipple G3/4"–R1/2" (M0217) and wall plate R1/2"–G1/2", on which a gas bayonet lock of GAS PROFI hose is mounted with gas lock G1/2"–R1/2".

Main benefits of GAS PROFI pipes

The MERABELL GAS PROFI pipes are provided with an above-standard 10-year warranty and are equipped with a robust yellow protective jacket made of PE (polyethylene). For pressing purposes, this jacket can be easily removed from the ends with the help of MERABELL cutting knife (M0304). After pressing the nut, it is recommended to re-insulate the exposed pipe ends with self-vulcanizing tape (M0321).

The MERABELL GAS PROFI system is certified according to the ČSN EN 15266 standard (Stainless-steel pliable corrugated tubing kits in buildings for gas with an operating pressure of up to 0.5 bar). This EU standard allows the pipe to be routed in a wall without a protector, underground and through a building structure in a protector, when passing through a peripheral wall in a protective pipe.

Main benefits of GAS PROFI hose with gas lock and thermal fuse

The MERABELL GAS PROFI hose is certified according to the ČSN EN 15266 standard (Stainless-steel pliable corrugated tubing kits in buildings for gas with an operating pressure of up to 0.5 bar) that is already mandatory in the Europe. The hose is protected against mechanical damage on its surface by a clear PVC protective jacket and a stainless-steel braid. The swivel ending on the side of appliance (cooker) prevents the hose from twisting in the thread and possible gas leakage. The thermal fuse of the valve automatically closes the gas supply when the temperature exceeds 100 °C. The bayonet lock allows for very easy disconnection and connection of the gas appliance by the user, without the need to call a certified installer – e. g. when it is necessary for painting, cleaning.

The main benefit of this premium hose lies in a unique 25-year warranty, which allows its long-term use without the need for replacement after regular inspections or when replacing the appliance. In the long run, this abundantly compensates Heimstaden for the higher purchase price of the hose, which is only in the order of hundreds of crowns compared to the solution used so far (conventional gas hose + VAIT safety valve).

Excerpt from standards and technical regulations

Source TPG 70401:
It is necessary to use stainless-steel pipes according to EN15266 for the construction, repairs and extension of house gas pipelines.

Source EN 1775:
Article 5.2.5 prescribes that joints made of stainless steel-flexible pipes may only be made by persons with special training and reference is made to informative Annex E for instructions on how to join this type of pipes.

Recommended installation procedure

  • measure the length of the piping from the gas meter up to the appliance
  • attach the wall plate to the wall in place of the appliance
  • plan the location of holders used to fix the piping to the wall
  • prepare a protector in which the piping is to be passed through the wall
  • push the protector with piping through the wall and attach piping into respective holders
  • thread a nut on one end of the piping, press the end of the piping, fit the gasket and connect it to the gas meter
  • thread a nut on another end of the piping, press the end of the piping, fit the gasket and adapter nipple and connect to the wall plate
  • install the bayonet lock of the gas hose to the wall plate


Project assessment

The complete installation of the new gas pipeline was realized by 2 installers in 1.5 hour: The removing of the old piping took 0.25 hour and the installation of the MERABELL GAS PROFI piping system took 1.25 hour. Thus, the assumption of a significant reduction of installation time was unequivocally confirmed, and especially the risk of leakage in the joints was eliminated.

With proper training of Heimstaden in-house installers, only 1 person can manage 50% of installation tasks and this means further savings. Heimstaden Czech s. r. o. as the investor of the project, evaluated the pilot installation very positively and recommended using the MERABELL installation system with stainless-steel corrugated tubing for its further projects.

Heimstaden Czech s. r. o. is the largest provider of rental housing in the Czech Republic, we manage 43,000 rental flats in the Moravian-Silesian Region and, since April 2018, also in the Olomouc Region. Heimstaden is one of the largest players in the European rental housing market and operates altogether on five markets (Denmark, the Netherlands, Germany, Sweden, Norway). Since 1998, when it was founded, it has included 52,300 flats in its portfolio, worth of CZK 259 billion.