Principles
Clause 5, Schedule 9 of Hazardous Substances (Dangerous Goods and Scheduled Toxic Substances) Transfer Notice 2004 (as amended) stipulates that the Authority must approve or decline a compliance plan setting out a programme for bringing the secondary containment system into compliance with the HSNO requirements or variations to the requirements which are deemed to be compliance, or both.
Background
To assist owners of existing stationary container systems larger than 250,000 litres the Authority has approved criteria for compliance plans for secondary containment systems.
Existing stationary container systems are stationary container systems which were being used to contain a hazardous liquid and which the controls for stationary container systems as set out in Schedule 8 of the Hazardous Substances (Dangerous Goods and Schedule Toxic Substances) Transfer Notice apply and:
- were in use immediately before the commencement date of the relevant transfer notice, or
- construction of the stationary container system to that design had commenced before the commencement date of the relevant transfer notice.
For hazardous liquids that were transferred in the Hazardous Substances (Dangerous Goods and Scheduled Toxic Substances) Transfer Notice 2004, the commencement date is the 1st April 2004.
It is recognised that secondary containment systems associated with these stationary container systems will have been constructed to varying standards. The criteria approved by the Authority was developed to set the standard expected of existing systems, and to allow compliance plans to be submitted that met these requirements. However, it is possible for alternatives to be acceptable and these can still be proposed in a compliance plan. However, it must be realised that alternatives may not be acceptable and compliance plans not based on the approved criteria may not be approved.
The approved criteria are:
| Criteria | Yes/No/Not Applicable |
|---|---|
| 1 Do the substances stored in the compound have a viscosity or gelling/solidification property that inhibits them from soaking into the compound floor?1 | |
| 2 Does the compliance plan have a base line determination or a commitment to undertake a baseline determination within 5 years? | |
3 Does the compound meet the following criteria:
|
|
| Does the site have an emergency response plan?3 | |
| If the maximum loss rate is greater than 5mm per hour does the compliance plan demonstrate how the loss rate will be reduced to below 5mm per hour, and provide a timetable to achieve this? | |
| Are penetrations of the compound floor and bunds appropriately sealed?4 | |
| Does the compliance plan agree to review, and if practicable, to upgrade the impermeable layer under the tank if any major works are undertaken? (e.g. new floor of the tank). | |
| Does the compliance plan include periodic inspection e.g. a 5 yearly technical inspection? | |
| 4 Have any other matters which the Authority should have regard to been addressed? (e.g. total containment capacity of the secondary containment system, surface area of the secondary containment system, fire fighting requirements). |
Notes to the table:
- In the criteria the loss rate is a single measurement. Consideration must be given to specific sections of the compound which may be porous e.g. if there is a noticeable wet area in the ground alongside the compound during the flood test, this is likely to indicate a deficiency in the compound lining.
- These criteria have been developed to expedite the process for the approval of compliance plans for the secondary containment of stationary containers in excess of 250,000 litres capacity and to enable applicants to develop compliance plans with certainty. It some situations, secondary containment systems as required by these criteria may be impracticable. The compliance process does not preclude other solutions which offer equivalent standards. Furthermore, there may be some circumstances whereby the above criteria in themselves may be insufficient and other matters may need to be taken into account.
Footnotes
- A loss rate of the substance through the compound floor less than 5mm per hour is to be used as a guide.
- The loss rate of 5mm per hour is the drop in water level at full hydrostatic head and is applicable only to secondary containment systems for existing tanks.
- In circumstances where there is gravel; or other porous material over the impervious layer, this porous material is not to be taken into consideration.
- Penetrations of the compound floor for existing compounds may include drains, earth rods, pipe supports or even interceptors.