The CT1 Chemical Storage Tank

The CT1 – A Rivet story

The story of the CT1 begins the same way as many of Rivet’s successes – with a customer asking for something unusual.

“Can you make us an IBC?”

The Intermediate Bulk Container is a sturdy square-ish tank, designed for the transportation of fluids. They’re typically stackable, featuring multiple tie-down points, integrated lifting lugs and with certified drop-test survival reports to brag about – IBC’s have proven themselves a versatile vessel. Hazardous chemical transport versions are comprised entirely of stainless steel (often grade 316) and the combination of convenient size and handling has made them commonplace as permanent storage tanks on Taranaki Oil and Gas sites.

Taranaki, we have a problem

Today, IBC’s are often used as a permanent (or semi-permanent) storage solution for highly flammable methanol. In this application an IBC must comply with AS 1692-2006 steel tanks standard for flammable and combustible liquids… and therein lies the problem. While most NZ made IBCS are robust and fit for their original purpose, many lack an important feature for use as a permanent stationary methanol storage tank; an internal liquid seal dam.

Page 8, AS1692-2006 steel tanks standard for flammable and combustible liquids

The internal liquid seal dam negates the capacity for static electricity to discharge from internal pipework to the body of the tank – a possible source for ignition when tanks are near empty. It is possible to retrofit an internal liquid seal but in the world of strict compliance inspections, dye penetrant and hydrostatic test reports etc. this represents a significant investment in an otherwise aging vessel. Some internationally produced IBC’s also don’t meet the minimum wall thickness requirement to become a stationary flammable liquids storage tank.

The CT1 was born

Steve Scott, the owner of Rivet, recalls the design process.

“Shortly after consultations began, we established that the tanks weren’t going to be getting moved around, they would be stationary, so we didn’t need to stick with that square shape which is expensive” he said.

“We developed a cylindrical tank with several engineers and technical consultants to ensure we could offer compliance out of the box, as well as some contingency for potential changes to the standards in future.”

The CT1 has an operating volume a shade under 1,000l (deliberately, to avoid breaking into the next threshold for larger tank requirements), it sits just over 1.2m tall and includes legs certified for installation almost anywhere in New Zealand (from a seismic activity perspective).

After the first unit was installed and commissioned at a Taranaki production plant, Mike O’Sullivan of Taranaki Instrument Services, remarked on the quality of fabrication and the tidiness of it’s presentation.

“It’s a smart looking little tank” he said.

A tank for one and all

Rivet is accepting orders for CT1 tanks as sites are phasing out IBC’s for flammable liquid storage. The tanks are made to order, so different material grades, additional sensor ports and specific inlet / outlet requirements can all be specified by the customer.

Mr Scott says that once a tank is certified for this level of hazard, there is no reason it couldn’t be tweaked to align with the requirements of other industries.

“I can see these tanks housing alcohol at a commercial distillery, or maybe some kind of swimming pool chemical? Acids at a glue production facility or the like,” he said.

“If someone out there is wanting to store a hazardous liquid, they should talk to Rivet about the CT1.”

Steve Scott, owner of Rivet.
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