Hydrocarbon Vapours

An issue that is becoming more common is the resistance of membranes to attack by hydrocarbon vapours.

Most hydrocarbon membranes that are marketed today are just a 1mm High Density Polyethlyene and are specified wrongly for use as a hydrocarbon VAPOUR resistant membrane. These membranes are known for ther high resistance to chemicals with hydrocarbons being one of the chemicals that HDPE can offer excellent resistance against. However, the chemical resistance i.e. 100% concentration is the main factor when the membrane is used for primary or secondary containment of hydrocarbons, i.e. oil storage where there is potential for long term exposure of the membrane to the chemical at 100% concentration.

When developing land that has hydrocarbon contamination it is unlikely that the membrane will be exposed to 100% concentrations or indeed even come into contact with the chemical in liquid form. Therefore, the vapours that contact the membrane will be at very low concentrations that are unlikely to cause damage (most testing that shows damage by hydrocarbons to membranes is from long term exposure to 100% concentration liquids).

Therefore, the primary concern should be with selecting a membrane that has high vapour resistance as well as good chemical resistance properties.