What is Integrity Testing for Interceptors?

Interceptors are large underground tanks on the drainage network that are designed to separate oil from water discharges (for more information, read our fact sheet here).  Interceptors should be regularly serviced and maintained to ensure they remain effective, but in addition, they should also be checked for integrity, which this blog will focus on.

What is involved in integrity testing?

Integrity testing for interceptors provides a more detailed analysis on the condition of the interceptors you have on site to ensure they are in good repair and continue to provide you with the best pollution prevention.  In order to carry out an integrity test, the whole interceptor will need to be emptied of any contaminants (oil and silt) and all of the water.  Confined spaces entry to inspect the condition of the tank is the usual method but can be carried out with specialist equipment and experience to avoid the requirement for confined spaces.  After the test, the interceptor should be filled with clean water up to the static water level to ensure it continues to provide pollution protection and remove contaminants.

Why should I test the integrity of my interceptors?

Interceptors are essential pollution control devices, particularly in areas where oil contamination is possible, such as refuelling areas or car parks.  During regular use, oil floats to the top of the tank while silt sinks to the bottom, allowing clean water to leave site.  If the tank is damaged, or has worn, it may affect the effectiveness and contaminants could leave your site.  Some trade effluent licences (for a reminder on what they are, click here) require effluent to be passed through an interceptor prior to discharge so you should ensure that the interceptor is working correctly and removing contaminants effectively to maintain compliance.

How often should interceptor integrity be tested?

As best practice, interceptors should be integrity tested every 5 years.  This should be in addition to your interceptor servicing and maintenance visits, at least every 6 months.

What should I expect from integrity testing?

When you have your integrity test carried out, you should receive information on the specification of your interceptor, for example, its size, type and any associated equipment.  You should also have a full report on the condition of the interceptor, including any areas of wear or anything that needs repairing or replacing.  You should have recommendations, including frequency of integrity tests and you must review all of your recommendations and ensure that you action those necessary to maintain the effectiveness of your interceptors.

If you have interceptors on your site, it is essential that you maintain and service them, so they remain effective.  As well as regular servicing and maintenance, you should fully empty your interceptor and have them thoroughly checked by an experienced engineer to ensure they are not damaged or worn.  You should ensure that you address any issues or damage and take all possible actions to ensure your interceptors provide continued protection.