Instructions for designers and contractors

If you are a professional or contractor, see the instructions for planning and contracting related to district heat in the area of Oulun Energia’s network.

1. Instructions for HVAC design

Heating plans are drawn up in order to determine the power and energy requirements of the building. It is sensible to connect district heating to the underfloor heating of the bathrooms, as well as the heating of the air input to air conditioners. 

Our basic and energy fees are calculated on the basis of the contracted water flow, making it very important to determine the power demand and operating temperature. 

The heating plan must contain the following information: 

• technical heating information
• dimensioning of a secondary network
• dimensioning a heating substation
• operating values of heating circuits
• connections
• functional descriptions of equipment
• schematics detailing the placement of equipment and pipes
• site plan

Please submit the heating plan as a PDF file and the layout and floor plans as a DWG file to kl-tekninenneuvonta@oulunenergia.fi.

The site plan (1:200) must detail the district heating pipeline route or at least the point at which the district heating pipe enters the building.

The floor plan (1:50) should detail the location of the district heating connecting pipe and the metering board. Submit the plans no later than two months before the start of the heat supply, to allow sufficient time for the construction of the connection. 

Dimensioning control valves

Pay particular attention to the correct dimensioning of the control valves in design work. Valves must be dimensioned on the basis of actual operating values, even when replacing an existing control valve. 

• The control valves must be dimensioned in accordance with the Finnish Energy recommendation K1
• The control valves must be dimensioned with the actual pressure difference, which shall be indicated in the plans
• The authority of the control valves shall be checked with actual pressure differences
• If the pressure difference in the district heating network varies by more than 400 kPa, we recommend the use of differential pressure regulator. Contact us to identify the pressure difference available in your area (kl-tekninenneuvonta@oulunenergia.fi)
• The pressure difference regulating devices shall be dimensioned to limit the differential pressure to 150 kPa.
• The set value of the differential pressure regulator must be indicated in the plans

2. Instructions for HVAC contractors

The customer's district heating equipment and installations must meet the technical requirements, and the connection must be ready for the metering of thermal energy before the heat supply can be commissioned. Only a representative of Oulun Energia may remove the seals in the metering board. 

The following quality assurance checks shall be carried out on the equipment: 

• leakage test
• commissioning inspection
• final inspection of district heat equipment

The contractor shall perform a leakage test for the pipes and equipment on the side of the primary network, as well as the heat exchanger, using cold district heating water. Normally the test pressure is 2.1 MPa, which is maintained for at least 15 minutes. 

The control system of the heating substation is tuned at the installation location after the heat supply has been started. The tuning record is presented as part of the documentation to be attached to the final inspection. No tuning record is required for detached houses. 

Contractors’ right of self-inspection:

The right of self-inspection refers to the contractor being permitted to carry out district heating inspections independently. Currently, Oulun Energia Oy grants right of self-inspection for replacing heating substations or individual exchangers in detached houses. 

Qualification as a district heating supervisor (KKL) is a prerequisite for being granted a self-inspection permit. The self-inspection permit is valid as long as the person has a valid KKL qualification, unless it is separately revoked. Only an authorised person is allowed to carry out the above inspections. Permits are always personal. 

The contractor must apply for the right of self-inspection from Oulun Energia Oy. The approved contractor shall be instructed in the conduct of the review and granted an inspection permit for a limited period of time. 

To apply for a right of self-inspection, please contact: lampopalvelut@oulunenergia.fi

We inspect plans and installations. You can order inspections by contacting our experts.