Envex (HK) Limited

Envex (HK) Limited, founded in 1991,

has extensive knowledge and practical experience in managing risk, project consultancy, and training in Eastern Asia and Southeast Asia.

Radon Monitoring and Consultancy

What is radon?

Radon is a radioactive gas that comes from uranium which is naturally occurring in veins in granite rocks. As a gas, radon is mobile. It travels through fissures in the rock of the earth's surface and through air spaces between particles of soil. Radon enters a building by seeping through cracks in the foundation walls and in the floors. Building materials like rocks, bricks, and concrete also give off radon by emanation.

You cannot see radon, nor can you smell it. The question, therefore, is not so much whether radon is present in your building but how much of it is present?

Radon and your lungs

The radon gas in your building undergoes a process of change called "radioactive decay". This constant process produces radioactive atoms, solid particles, called "radon daughters" (also called "radon progeny").

As you breathe, some of these solid radioactive particles in the air are drawn into your lungs and are retained there. When they also change ("decay"), they emit a tiny burst of radiation that damages cells inside your lungs. This damage sometimes, but not always, leads to lung cancer. The risk of lung cancer depends on the amount of radon in your building. Simply put: the greater the amount, the greater the risk.

How do you find out?

Radon concentrations vary from building to building and place to place. It is important to know the average level of radon, because radon levels fluctuate from hour to hour and from day to day.

No reliable method has yet been found to predict the radon level of any individual building or location. The only sure way to know is to use the correct equipment and strategy to test your building or location.

How Envex can help

Radon can be monitored using specialist equipment such as Pylon WLx equipment, Lucas cells and Durridge RAD7units. They are used as part of a programme and delivering accurate results. Regular reporting will allow for example your contractors to have the required ventilation levels to meet the working circumstances. For background monitoring we use Track Etch Detectors (TEDs), a cost effective way to get regular results when used in conjunction with the equipment.

For construction sites and tunnelling we have developed and published our own strategy* for assessing radon which uses a combination of equipment and TEDs, all designed to safeguard the workplace environment for workers and allow the contractors to manage the working environment. The same strategy can be applied to ensure the public and workplace employees are not exposed to radon. For more information contact Envex.

* Development and Management of a radon assessment strategy suitable for underground railway tunnelling projects –
Purnell; Frommer; Chan; Auch: Radiation Protection Dosimetry Vol.109 No.4 Oxford University Press