2. Gasunie is one of the biggest gas infrastructure companies in Europe
Gasunie is one of the biggest gas infrastructure companies in Europe. Within the company, we give safety the highest priority; it forms the basis of our license to operate. We abide by the strictest safety, health and environmental standards, both for our own employees and for our external contractors. Gasunie’s safety policy is thus characterised by a proactive approach which is designed to prevent accidents, incidents and hazardous situations.
contaminated filter candle

3. Low Specific Activity (LSA) or NORM
(Naturally Occurring Radioactive Material)
Low Specific Activity and NORM (Naturally Occurring Radioactive Material) are collective names for naturally occurring radioactive substances which can be released during the production of oil and natural gas. Originally these materials were contained in the rock from which oil and gas is mined. When HTL installations and systems are opened up, this radiation can be released. Gasunie has put in place procedures to enable workers to deal safely with this radiation. These procedures must be complied with in order to prevent radioactive contamination. The main radioactive material with which Gasunie is involved is lead 210.

4. How can LSA occur at Gasunie?
Formation of gas (radon, invisible) during pigging operations
In solid/liquid form (sludge during pigging operations, candle filters, on components in HTL system)
Solid (on various components, invisible, in the form of ‘scales’)
Radiation hazard
The radiation dose that workers can be exposed to during work is low, certainly compared with what the
average person encounters on an annual basis in terms of natural and non-natural radioactive exposure.
Radiation exposure can however constitute a danger to health if:
- it is regular and long-term
- a person is exposed to internal contact with LSA substances
contaminated components

5. Where can exposure to LSA occur?
LSA materials can be found in the HTL system during the following types of work:
In locations where there is a high level of turbulence: regulators, compressors, gas meters and corners where LSAs are not visibly attached to the surface (‘scales’)
In installations where solid and liquid components of the gas flow are separated, such as scrubbers
Release of sludge from pigging operations
How contamination can occur
Through the skin: contact with sludge (pigging), candle filters and scales (on walls of pipelines, regulators/switches, etc.)
Through inhalation: particles that are released during machining, aerosol particles (high pressure sprays), radon
Through swallowing by eating with contaminated hands (sludge splashes, contact with scales)
Through eyes: splashes in face

6. Instructions on opening the HTL system
Begin by notifying the field organisation’s radiation expert
The radiation supervisor must instruct the workers concerned beforehand on the work to be carried out
Evaluation of the work by the radiation supervisor and confirmation of any supplementary measures
When materials are being taken off-site, they must always be measured for the presence of LSA materials before they leave the location
The radiation coordinator must be consulted for work at LSA locations which is covered by a mandatory license requirement
The radiation coordinator must always be consulted about the storage and removal of contaminated materials
Personal protection measures
Standard safety provisions (no dust or aerosol formation)
- Standard PPE
- Gloves
- Disposable overalls where necessary

7. Personal hygiene High pressure cleaning of the pig - Viton overalls
- Independent breathing apparatus
Machining activities
- Standard PPE
- Gloves
- Disposable overalls
- Full-face visor with dust filter
Personal hygiene
Wash hands before eating, drinking, smoking and using the lavatory
Avoid spreading contamination by removing/disposing of PPE
The radiation supervisor must check PPE for contamination
spray clean components
Remain alert at all times when you are working. If in any doubt, always ask or suspend activities where necessary.