Safety at gas delivery station

You must be able to show that the installation has been designed, manufactured and inspected according to the legislation and regulations applicable to this installation. You must be able to show that the installation has been maintained and inspected according to the applicable legislation and regulations throughout its use.

See "Standards applicable to industrial installations" and "Overview of European standards and developments in standards" for a full summary of the relevant guidelines and standards.

New gas pipelinesGas pipelines designed for a pressure of >500mbar must be constructed according to the Pressure Equipment Directive. According to this directive, the design of a gas pipeline must be checked by an organisation designated for this purpose by the Ministry of Social Affairs and Employment (Notified Body, NoBo for short). The manufacturer or assembler should draw up an EU Declaration of Conformity for the product or combination of products supplied, as specified in the Pressure Equipment Directive.

Existing gas pipelinesThe requirements applicable to using gas pipelines in a safe and environmentally-friendly manner are based on the Dutch Environmental Management Act. The act applies to organisations obliged to hold a permit and subject to disclosure obligations, however residential buildings are also covered. This is regulated in the Dutch Activities Decree Environmental Management (Decree providing general regulations for environmental management facilities (BARIM)).

The Dutch Activities Decree Environmental Management specifies that gas pipeline installations should be inspected periodically (once every 4 years). Depending on the pressure and diameter of the pipelines concerned, this may be performed by a company certified by the Foundation for Certification, Inspection and Maintenance of Combustion Plants (SCIOS), scope 7B or must be performed by a NoBo (www.scios.nl). Providing details of the exact boundaries between both working areas is beyond the scope of these FAQ, you should therefore consult your installer or inspection body for precise information.

New standard gas appliancesUnder the Gas Appliance Directive (GAD), new standard gas appliances, such as central heating boilers and hot air heating, are required to have a CE mark.For standard appliances, which have a CE mark, the installer must produce a report stating that the appliance has been set according to the manufacturer's settings.For standard appliances, or assemblies (cascade connections) being one combustion plant with a nominal capacity of >100 kw, which have a CE mark, a certified body must produce a report stating that the appliance has been set according to the manufacturer's settings. For more information, please go to: www.scios.nl.

New special gas appliancesA complete manufacturing file must be prepared by the manufacturer and assessed by a certified body for these appliances. The manufacturer or assembler of these appliances should also prepare an EU Declaration of Conformity. In the declaration of conformity, the manufacturer states which standards have been applied to the appliance.

Maintenance of existing appliancesExisting appliances should be maintained and inspected at the intervals specified by the manufacturer. Appliances or assemblies (cascade arrangements) with a capacity of  >100kW should be inspected every four years by a SCIOS-certified company. More information and a list of SCIOS-certified inspection and maintenance companies can be found on its website.

If, at the request of the connected party, the gas installation connection is temporarily decommissioned for alterations, adaptations or repairs to the gas installation located behind the transfer point, such alterations or repairs must comply with the relevant legislation and regulations. This will usually involve an adaptation to the piping system or pipeline. See also "which standards can I apply?"

This adaptation or repair should be performed in a manner that demonstrates integrity. Integrity is demonstrated via an organisation accredited under the Commodities Act Decree on pressure equipment (Notified Body) or a certified inspection department (IVG). See also "What actions are taken when a gas delivery station (GOS) is brought into or taken out of operation?" 

After the transfer point, cathodic protection is the responsibility of your organisation/company.

• Control measurements should be taken in accordance with EN 12954;
• The frequency of the measurements depends on a number of different factors but annual measurements generally suffice;
• A limited power supply from the Gasunie network will remain available;
• Any Gasunie-related identifying features on the cathodic protection posts behind the transfer point are removed.

A summary of the relevant legislation relating to the integrity of the gas installation connection is given in "Relevant legislation for industrial installations".

The Dutch Activities Decree Environmental Management specifies that not only appliances but also fuel supply lines must be inspected. The inspection of fuel supply lines consists of two parts:

• SCIOS scope 7A for fuel lines with a working pressure of < 500mbar
• SCIOS scope 7B or NoBo inspection for fuel lines with a working pressure of > 500mbar (SCIOS or NoBo inspection depends on the pressure and diameter of the pipeline)

The prescribed frequency of these inspections is once every four years. An extended test is also carried out once every eight years. The appliance inspection is performed at least once every four years. This period may be shorter if this is indicated on the most recent inspection report.

The environmental permit may contain varying or additional conditions.Safety requirements for gas delivery stations are summarised in "the regulations based on ATEX".

Further sites about legislation are:

• overheidsloket.overheid.nl
• www.infomil.nl
• www.europa.eu

An overview of the applicable standards is given in "Standards applicable to industrial installations" and "Overview of European standards and developments in standards" which have been harmonised with the Pressure Equipment Directive (PED). All Dutch standards can be found and ordered from the Netherlands Standardisation Institute (NEN) website, www.nen.nl. The website www.euronorm.net provides a great deal of information about legislation and standardization.

You can find the organisations that are accredited for the work area concerned on the website of the national accreditation body, the Dutch Accreditation Council (www.rva.nl).

Search on scopes:Country settings = Netherlands

Search in the content of the scopes = pressure equipment

Please note that not all organisations shown here perform inspections for third parties.

The design pressure must always be higher than the pressure of the gas supplied by Gas Transport Services to the connected party. This is necessary because the regulated pressure is protected in the GOS by a safety relief valve and one or two cut-out safety features. A margin is necessary to ensure that this is set up to operate safely.

The relationship between the supply pressure (MOP: maximum operating pressure) and the maximum outlet pressure (MIP: maximum incidental pressure) of the GOS is shown in the table below.

The minimum design pressure of the connected party's gas system depends on the highest setting (MIP) of the safety features in the gas delivery station and on the chosen design code/standard for the connected party's system. Based on this information, a Notified Body (NoBo) should determine the design pressure of the connected party's gas system.

We will agree the level of the normal supply pressure with you. The maximum pressure in the event of an incident is derived from the normal pressure.  See the question "What should be the design pressure of the gas installation connection and the gas installation after the gas receiving station?" for an overview of the normal (agreed) pressure for delivery and the maximum pressure in the event of an incident. You should ensure that the design pressure of your piping system or pipeline is suitable for the maximum incidental pressure outlet side (MIP) mentioned above. If appliances are connected to this system which do not operate normally if the gas pressure approaches MIP (see 2^nd column), then these appliances must be protected against this. This can be done by using protective electrical or mechanical devices against overpressure.

The gas pressure regulator in the gas receiving station usually comprises one supply gas pressure regulator equipped with safety devices to reduce the gas pressure to the set value of the gas outlet pressure and a second, identical reserve gas pressure regulator. For higher capacities there are three gas pressure regulators (two supplying gas plus a reserve). In the event of a fault in the supply gas pressure regulator or when maintenance work is being done, the reserve takes over the gas supply at a lower pressure. To give an indication, the pressure can drop 0,3 bar in such circumstances in a gas receiving station with two gas pressure regulators. Where there are three gas pressure regulators, the pressure can drop by about 0,6 bar in the worst-case scenario. This can affect the settings of the low-pressure monitoring system in your gas consumption installation. You are therefore recommended to set the low-pressure monitoring system in your own installation to a minimum of 0, 4 to 0,7 bar (depending on the number of runs in the gas receiving station) lower than the settings of the gas receiving station, taking account of the loss of pressure across the connecting pipelines.

New emission requirements came into force in 2017 for existing medium-sized combustion plants that are being used by industries, companies and utility buildings.

Section 3.2.1 of the Dutch Activities Decree Environmental Management gives the emission limits for small and medium-sized combustion plants:

• boiler plant, nominal capacity of 1 MW or more: article 3.10
• boiler plant, nominal capacity of 400-1000 kW or more: article 3.10a
• boiler plant, nominal capacity of 400 kW or less: article 3.10b
• gas turbine: article 3.10d
• diesel engine: article 3.10e
• gas engine: article 3.10f

The emission limits are based on the best available techniques for combating emissions of sulphur dioxide (SO2), nitrogen oxide (NOx), hydrocarbons (CxHy) and total dust (TSP).

Possible ways of achieving this are:

• Optimising the burner
• Adapting the burner construction or installing new burner(s) and possibly boiler
• Using flue gas recirculation

The requirements apply not only to new combustion plants but to all boilers, engines and gas turbines, i.e. also those constructed prior to 1 April 2010.